Display Devices

Abstract

A display device is provided. The display device includes: a substrate; a light-emitting layer configured to emit light, the light-emitting layer including a first semiconductor layer disposed on the substrate, an active layer disposed on the first semiconductor layer, and a second semiconductor layer disposed on the active layer; and a plurality of color conversion layers disposed on the light-emitting layer and configured to emit light of a specific color according to the light emitted from the light-emitting layer.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority benefit of Korean Patent Application No. 10-2017-0148717 filed on November 9, 2017 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Example embodiments of the present disclosure relate to a display device, and more particularly, to a high-resolution display device with improved light efficiency and color quality. Background Art

[0004] Liquid crystal displays (LCDs) and organic light emitting diode (OLED) displays have been widely used as display devices. Recently, technology for manufacturing high-resolution display devices using micro light emitting diodes (micro LEDs) has attracted attention. However, in order to manufacture high-resolution display devices using micro LEDs, it is necessary to manufacture high-efficiency small LED chips, and highly complex transfer technology is required to arrange the small LED chips at appropriate locations. Summary of the invention

[0005] One or more example embodiments provide a high-resolution display device with improved light efficiency and color quality.

[0006] According to an aspect of an example embodiment, there is provided a display device including: a substrate; a light emitting layer configured to emit light, the light emitting layer including a first semiconductor layer disposed on the substrate, an active layer disposed on the first semiconductor layer, and a second semiconductor layer disposed on the active layer, and configured to emit light; and a plurality of color conversion layers disposed on the light emitting layer and configured to emit light of a predetermined color according to light emitted from the light emitting layer, wherein the light emitting layer is disposed to correspond to the plurality of color conversion layers.

[0007] The display device may further include at least one first electrode electrically connected to the first semiconductor layer and a plurality of second electrodes electrically connected to the second semiconductor layer.

[0008] A region of the second semiconductor layer adjacent to a contact region between the second semiconductor layer and the second electrode may be etched to a predetermined depth or less.

[0009] The at least one first electrode may be disposed to correspond to at least one of the plurality of color conversion layers to form a common electrode, and the plurality of second electrodes may be disposed to correspond one-to-one to the plurality of color conversion layers.

[0010] The plurality of second electrodes may be connected to the thin film transistors, respectively.

[0011] The display device may further include: a current injection limiting layer disposed on the second semiconductor layer and configured to limit current injected from the plurality of second electrodes into the second semiconductor layer.

[0012] The display device, wherein a region of the second semiconductor layer adjacent to a contact region between the second semiconductor layer and the second electrode may be etched to a predetermined depth or less via an opening portion of the current injection restricting layer.

[0013] The current injection limiting layer may include an insulating film.

[0014] The current injection limiting layer may include a plurality of insulating films.

[0015] The multilayer insulating film may include a plurality of layers respectively having different refractive indexes.

[0016] The current injection limiting layer may include an insulating film and a metal reflective layer disposed on the insulating film.

[0017] The metal reflective layer may include a first metal layer and a second metal layer disposed on the first metal layer, the second metal layer having a reflectivity higher than that of the first metal layer.

[0018] The current injection limiting layer may include a metal reflective layer disposed on the second semiconductor layer and an insulating film disposed on the metal reflective layer.

[0019] The display device may further include: a selectively transparent insulating layer disposed between the plurality of second electrodes and the plurality of color conversion layers and configured to transmit light emitted from the light emitting layer and reflect light emitted from the plurality of color conversion layers.

[0020] The display device may further include: a selective shielding layer disposed on the plurality of color conversion layers and configured to shield light of a predetermined color.

[0021] The display device may further include: a light absorbing layer disposed between the substrate and the first semiconductor layer or disposed on the first semiconductor layer.

[0022] The display device may further include: a refractive index matching layer disposed between the substrate and the first semiconductor layer and configured to reduce reflection of light.

[0023] The refractive index matching layer may include aluminum nitride (AlN).

[0024] The display device may further include: a light absorbing member disposed on a surface of the substrate opposite to the light emitting layer.

[0025] The first semiconductor layer may include n-GaN, the second semiconductor layer may include p-GaN, and the active layer may include a multi-quantum well (MQW) structure.

[0026] The light emitting layer may be configured to generate blue light.

[0027] The plurality of color conversion layers may include a red conversion layer configured to emit red light by being excited by the blue light, a green conversion layer configured to emit green light by being excited by the blue light, and a blue transmission layer configured to transmit the blue light.

[0028] The light emitting layer may be configured to generate ultraviolet light.

[0029] The plurality of color conversion layers may include a red conversion layer configured to emit red light by being excited by the ultraviolet light, a green conversion layer configured to emit green light by being excited by the ultraviolet light, and a blue conversion layer configured to emit blue light by being excited by the ultraviolet light.

[0030] The light emitting layer may be formed by sequentially growing the first semiconductor layer, the active layer, and the second semiconductor layer on the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and / or other aspects will become apparent and more readily understood from the following description of example embodiments in conjunction with the accompanying drawings, in which:

[0032] Figure 1 is a cross-sectional view of a display device according to an example embodiment;

[0033] Figure 2 yes Figure 1 an enlarged cross-sectional view of a portion D of FIG.

[0034] Figure 3 is a cross-sectional view of a display device according to an example embodiment;

[0035] Figure 4 is a cross-sectional view of a display device according to an example embodiment;

[0036] Figure 5 yes Figure 4 an enlarged cross-sectional view of a portion E of FIG.

[0037] Figure 6 is a cross-sectional view of a display device according to an example embodiment;

[0038] Figure 7 is a cross-sectional view of a display device according to an example embodiment;

[0039] Figure 8 is a cross-sectional view of a display device according to an example embodiment;

[0040] Fig. 9 is a cross-sectional view of a display device according to an example embodiment;

[0041] Fig.10 is a cross-sectional view of a display device according to an example embodiment;

[0042] Fig.11 is a graph showing reflectivity of a material of a confinement layer according to current injection;

[0043] Fig.12 is a cross-sectional view of a display device according to an example embodiment;

[0044] Fig.13 is a cross-sectional view of a display device according to an example embodiment;

[0045] Fig.14 is a cross-sectional view of a display device according to an example embodiment;

[0046] Fig.15 is a cross-sectional view of a display device according to an example embodiment;

[0047] Fig.16 is a cross-sectional view of a display device according to an example embodiment;

[0048] Fig.17 is a perspective view of a display device according to an example embodiment;

[0049] Fig.18 yes Fig.17 A perspective view of a modified example of a display device of ; and

[0050] Fig.19 yes Fig.17 A plan view of an example circuit configuration of a display device. DETAILED DESCRIPTION

[0051] Reference is now made in detail to the embodiments, examples of which are shown in the accompanying drawings, wherein similar reference numerals throughout the drawings represent similar elements. In addition, the size of each layer shown in the drawings may be exaggerated for ease of explanation and clarity. Example embodiments may have different forms and should not be construed as being limited to the description set forth herein.

[0052] In the following description, when a constituent element is arranged “on” or “over” another constituent element, the constituent element may be directly located on and in contact with the other constituent element, or located on the other constituent element in a non-contact manner with one or more elements located therebetween.

[0053] Unless otherwise clearly specified in the context, singular expressions in this specification include plural expressions. In addition, terms such as "include" and / or "comprising" may be interpreted as indicating constituent elements, but may not be interpreted as excluding the possibility of the presence or addition of one or more other constituent elements.

[0054] The use of the terms "a," "an," and "the," and similar referents should be interpreted to cover both the singular and the plural. Expressions such as "at least one of..." when following a list of elements modify the entire list of elements rather than modifying the individual elements of the list. For example, the expression "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0055] In addition, the steps of all methods described herein may be performed in any appropriate order, unless otherwise noted herein or the context otherwise clearly indicates otherwise. The present disclosure is not limited to the described order of steps. The use of any and all examples or exemplary language (e.g., "such as (for example)") provided herein is intended only to better illustrate the inventive concept and does not impose limitations on the scope of the present disclosure, unless otherwise stated.

[0056] Figure 1 is a cross-sectional view of a display apparatus 100 according to an example embodiment. Figure 2 yes Figure 1 An enlarged cross-sectional view of portion D of FIG.

[0057] refer to Figure 1 and Figure 2 , the display device 100 includes a plurality of pixels. Figure 1 In the figure, only two pixels are shown for ease of explanation, and it will be understood that the display device may include more than two pixels. Each pixel may include a plurality of sub-pixels of different colors. In detail, each pixel may include a red sub-pixel SR, a green sub-pixel SG, and a blue sub-pixel SB.

[0058] The display device 100 may include a substrate 110 , a light emitting layer 120 disposed on the substrate 110 , and a plurality of color conversion layers 160R, 160G, and 160B disposed on the light emitting layer 120 .

[0059] The substrate 110 may be a growth substrate for growing the light emitting layer 120 thereon. The substrate 110 may include a substrate formed of various materials used in a general semiconductor process. For example, a silicon substrate or a sapphire substrate may be used as the substrate 110. However, example embodiments are not limited thereto, and various other materials may be used for the substrate 110.

[0060] The light emitting layer 120 emitting blue light B is disposed on the upper surface of the substrate 110. The light emitting layer 120 may be an inorganic-based light emitting diode (LED) layer. The light emitting layer 120 may be formed by sequentially growing a first semiconductor layer 121, an active layer 123, and a second semiconductor layer 122 on the upper surface of the substrate 110.

[0061] The first semiconductor layer 121 may be disposed on the upper surface of the substrate 110. The first semiconductor layer 121 may include, for example, an n-type semiconductor. However, example embodiments are not limited thereto, and in some cases, the first semiconductor layer 121 may include a p-type semiconductor. The first semiconductor layer 121 may include an n-type semiconductor based on group III-V, for example, n-type gallium nitride (n-GaN). The first semiconductor layer 121 may have a single layer or a multilayer structure.

[0062] The active layer 123 may be disposed on an upper surface of the first semiconductor layer 121. When electrons and holes are combined with each other, the active layer 123 may emit blue light B. The active layer 123 may have a multi-quantum well (MQW) structure. However, example embodiments are not limited thereto, and in some cases, the active layer 123 may have a single quantum well (SQW) structure. The active layer 123 may include a III-V group-based semiconductor, such as gallium nitride (GaN). According to the example Figure 2 In the example embodiment shown, the active layer 123 may be formed in a two-dimensional (2D) thin film shape. However, example embodiments are not limited thereto, and the active layer 123 may be formed in a three-dimensional (3D) shape of a rod or pyramid structure by growth using a mask.

[0063] The second semiconductor layer 122 may be disposed on the upper surface of the active layer 123. The second semiconductor layer 122 may include, for example, a p-type semiconductor. However, example embodiments are not limited thereto, and in some cases, the second semiconductor layer 122 may include an n-type semiconductor. The second semiconductor layer 122 may include a p-type semiconductor based on a III-V group, such as p-GaN. The second semiconductor layer 122 may have a single layer or a multi-layer structure.

[0064] Color conversion layers 160R, 160G, and 160B that may emit light of a specific color by converting or transmitting blue light B emitted from the active layer 123 of the light emitting layer 120 are disposed above the light emitting layer 120. The color conversion layers 160R, 160G, and 160B may be disposed corresponding to the light emitting layer 120 grown on the substrate 110. In detail, the color conversion layers 160R, 160G, and 160B may include a red conversion layer 160R, a green conversion layer 160G, and a blue transmission layer 160B. The red conversion layer 160R, the green conversion layer 160G, and the blue transmission layer 160B may correspond to a red sub-pixel SR, a green sub-pixel SG, and a blue sub-pixel SB, respectively.

[0065] The red conversion layer 160R may convert the blue light B emitted from the active layer 123 into red light R and emit the red light R. The red conversion layer 160R may include a quantum dot (QD) having a specific size, which is excited by the blue light B to emit the red light R. The QD may have a core-shell structure including a core part and a shell part, and may have a microparticle structure not including a shell. The core-shell structure may have a single shell or multiple shells. The multiple shells may be, for example, double shells.

[0066] The QD may include at least one of the following items: for example, a semiconductor based on a II-VI group, a semiconductor based on a III-V group, a semiconductor based on a IV-VI group, a semiconductor based on a IV group, and a graphene QD. For example, the QD may include at least one of cadmium (Cd), selenium (Se), zinc (Zn), sulfur (S), and indium phosphide (InP), but example embodiments are not limited thereto. Each QD may have a diameter of tens of nanometers or less, for example, about 10 nm or less. In addition, the red conversion layer 160R may include a phosphor that is excited by the blue light B emitted from the active layer 123 and emits red light R. The red conversion layer 160R may also include a photoresist or a light scatterer having a higher transmittance characteristic to emit the red light R more uniformly.

[0067] The green conversion layer 160G may convert the blue light B emitted from the active layer 123 into green light G and emit the green light G. The green conversion layer 160G may include QDs having a specific size, be excited by the blue light B, and emit the green light G. In addition, the green conversion layer 160G may include a phosphor excited by the blue light B emitted from the active layer 123 and emit the green light G. The green conversion layer 160G may further include a photoresist or a light scattering agent.

[0068] The blue transmission layer 160B may transmit the blue light B emitted from the active layer 123 to be emitted to the outside. The blue light transmission layer 160B may further include a photoresist or a light scattering agent. A black matrix 170 for absorbing light may be provided between the red conversion layer 160R, the green conversion layer 160G, and the blue transmission layer 160B. The black matrix 170 may prevent crosstalk between the red conversion layer 160R, the green conversion layer 160G, and the blue transmission layer 160B, respectively, to improve contrast.

[0069] The light emitting layer 120 may include a first electrode 131 electrically connected to the first semiconductor layer 121 and a plurality of second electrodes 132 electrically connected to the second semiconductor layer 122. When the first semiconductor layer 121 and the second semiconductor layer 122 include an n-type semiconductor and a p-type semiconductor, respectively, the first electrode 131 and the second electrode 132 may be an n-type electrode and a p-type electrode, respectively.

[0070] The first electrode 131 may be used as a common electrode of the sub-pixels SR, SG, and SB. For example, by sequentially etching the second semiconductor layer 122, the active layer 123, and the first semiconductor layer 121, a groove 120a for exposing the first semiconductor layer 121 may be formed to a certain depth in the light emitting layer 120. The first electrode 131 may be disposed to contact the first semiconductor layer 121 exposed via the groove 120a. An insulating material for insulating the first electrode 131 from the first semiconductor layer 121 and the active layer 123 may be disposed in an inner wall of the groove 120a.

[0071] Figure 1 An example embodiment is shown in which the first electrode 131 is disposed to correspond to six sub-pixels SR, SG, and SB collectively. However, example embodiments are not limited thereto, and the number of sub-pixels SR, SG, and SB corresponding to a single first electrode 131 may vary. The first electrode 131 may include a metal having a relatively high conductivity.

[0072] The second electrode 132 may be disposed on the second semiconductor layer 122. The second electrode 132 may be disposed in one-to-one correspondence with the sub-pixels SR, SG, and SB (i.e., the color conversion layers 160R, 160G, and 160B). The second electrode 132 may be disposed below each of the red conversion layer 160R, the green conversion layer 160G, and the blue transmission layer 160B. The second electrode 132 may include a transparent conductive material. For example, the second electrode 132 may include indium tin oxide (ITO), zinc oxide (ZnO), indium zinc oxide (IZO), silver (Ag), gold (Au), graphene, or nanowires. However, example embodiments are not limited thereto.

[0073] A plurality of thin film transistors (TFTs) 140 electrically connected to the second electrode 132 may be disposed on the second semiconductor layer 122. The TFTs 140 selectively drive at least one of the sub-pixels SR, SG, and SB. The TFTs 140 may be disposed under the black matrix 170.

[0074] The etched region 125 for preventing the current injected from the second electrode 132 into the second semiconductor layer 122 from flowing laterally may be formed in the second semiconductor layer 122 to a certain depth. The etched region 125 may be formed by etching the area around the contact area between the second semiconductor layer 122 and the second electrode 132 to a certain depth or less. An insulating material may be provided in the etched region 125. The etched region 125 may be formed to a depth of, for example, 1 / 2 or 2 / 3 of the thickness of the second semiconductor layer 122, but example embodiments are not limited thereto. An insulating layer 150 may be provided to cover the second electrode 132 and the TFT 140.

[0075] according to Figure 1In the illustrated exemplary embodiment, for example, when one of the TFTs 140 corresponding to the red sub-pixel SR is driven and a specific voltage is applied between the first electrode 131 as a common electrode and one of the second electrodes 132 corresponding to the red sub-pixel SR, blue light B is emitted from the active layer 123 located below the red conversion layer 160R. When the blue light B emitted as above is incident on the red conversion layer 160R, the red conversion layer 160R emits the red light R to the outside. In addition, for example, when one of the TFTs 140 corresponding to the green sub-pixel SG is driven and a specific voltage is applied between the first electrode 131 as a common electrode and one of the second electrodes 132 corresponding to the green sub-pixel SG, blue light B is emitted from the active layer 123 located below the green conversion layer 160G. When the blue light B emitted as above is incident on the green conversion layer 160G, the green conversion layer 160G emits the green light G to the outside.

[0076] For example, when one of the TFTs 140 corresponding to the blue sub-pixel SB is driven and a specific voltage is applied between the first electrode 131 as a common electrode and one of the second electrodes 132 corresponding to the blue sub-pixel SB, blue light B is emitted from the active layer 123 located below the blue transmission layer 160B. The blue light B emitted from the active layer 123 is transmitted through the blue transmission layer 160B to be emitted to the outside. Figure 2 An exemplary embodiment is shown in which red light R, green light G, and blue light B are emitted to the outside from the red conversion layer 160R, the green conversion layer 160G, and the blue transmission layer 160B, respectively.

[0077] In order to realize a high-resolution display device, it may be necessary to manufacture smaller LED chips corresponding to the sub-pixels separately, and it is necessary to transfer the smaller LED chips to an appropriate position. In this case, since the active layers as the emission areas are separated from each other for each sub-pixel, the exposure area of ​​the active layer increases, and thus the light efficiency may deteriorate. In addition, the process of transferring the small LED chip to a precise position may require a more complex transfer technology. In the display device according to the example embodiment, since a plurality of sub-pixels are provided corresponding to one light-emitting layer (in detail, the active layer), the active layers as the light-emitting areas may not be separated from each other for each sub-pixel, which can improve the light efficiency. In addition, since the portion around the contact area between the second semiconductor layer and the second electrode can be etched to a certain depth or less, the lateral flow of the current injected from the second electrode can be prevented or reduced. In addition, since the light-emitting layer is directly formed on the substrate by growth, the transfer process may not be too difficult.

[0078] Figure 3 is a cross-sectional view of a display apparatus 200 according to an example embodiment.

[0079] refer to Figure 3 , the display device 200 may include a substrate 210, a light emitting layer 220 disposed on the substrate 210, and color conversion layers 260R, 260G, and 260B disposed on the light emitting layer 220. For example, a silicon substrate or a sapphire substrate may be used as the substrate 210, but example embodiments are not limited thereto.

[0080] The light emitting layer 220 emitting ultraviolet (UV) light may be disposed on the substrate 210. The light emitting layer 220 may be an LED layer based on an inorganic material. The light emitting layer 220 may be formed on the upper surface of the substrate 210 by sequentially growing a first semiconductor layer 221, an active layer 223, and a second semiconductor layer 222.

[0081] The first semiconductor layer 221 disposed on the upper surface of the substrate 210 may include, for example, an n-type semiconductor. For example, the first semiconductor layer 221 may include an n-type semiconductor based on the III-V group, such as n-GaN. When electrons and holes are combined with each other, the active layer 223 disposed on the upper surface of the first semiconductor layer 221 may generate ultraviolet rays. The active layer 223 may have, for example, an MQW structure. The active layer 223 may include a semiconductor based on the III-V group, such as GaN. The second semiconductor layer 222 disposed on the upper surface of the active layer 223 may include, for example, a p-type semiconductor. The second semiconductor layer 222 may include a p-type semiconductor based on the III-V group, such as p-GaN.

[0082] Color conversion layers 260R, 260G, and 260B that emit light of a specific color by converting ultraviolet rays emitted from the active layer 223 are disposed above the light emitting layer 220. The color conversion layers 260R, 260G, and 260B may be disposed corresponding to a single light emitting layer 220. The color conversion layers 260R, 260G, and 260B may include a red conversion layer 260R, a green conversion layer 260G, and a blue conversion layer 260B. The red conversion layer 260R, the green conversion layer 260G, and the blue conversion layer 260B may correspond to a red sub-pixel SR, a green sub-pixel SG, and a blue sub-pixel SB, respectively.

[0083] The red conversion layer 260R may convert ultraviolet light emitted from the active layer 223 into red light R and emit red light R. The red conversion layer 260R may include QDs having a specific size and the QDs emit red light R by being excited by ultraviolet light. For example, the QDs may have a core-shell structure. The QDs may include, for example, at least one of a semiconductor based on II-VI groups, a semiconductor based on III-V groups, a semiconductor based on IV-VI groups, a semiconductor based on IV groups, and a graphene QD. For example, the QDs may include at least one of Cd, Se, Zn, S, and InP, but example embodiments are not limited thereto. The green conversion layer 260G may convert ultraviolet light emitted from the active layer 223 into green light G and emit green light G. The green conversion layer 260G may include QDs having a specific size and the QDs emit green light G by being excited by ultraviolet light. The blue conversion layer 260B may convert ultraviolet light emitted from the active layer 223 into blue light B and emit blue light B. The blue conversion layer 260B may include QDs having a specific size and the QDs emit blue light B by being excited by ultraviolet light. Black matrices 270 for absorbing light may be disposed between the red conversion layer 260R, the green conversion layer 260G, and the blue conversion layer 260B, respectively.

[0084] The light emitting layer 220 may include a first electrode electrically connected to the first semiconductor layer 221 and a plurality of second electrodes 232 electrically connected to the second semiconductor layer 222. When the first semiconductor layer 221 and the second semiconductor layer 222 include an n-type semiconductor and a p-type semiconductor, respectively, the first electrode and the second electrode 232 may be an n-type electrode and a p-type electrode, respectively.

[0085] As described above, the first electrode may be used as a common electrode with respect to the sub-pixels SR, SG, and SB. For example, a groove for exposing the first semiconductor layer 221 may be formed to a certain depth in the light emitting layer 220. The first electrode may be disposed to contact the first semiconductor layer 221 exposed by the groove. The number of sub-pixels SR, SG, and SB that collectively correspond to the first electrode may vary.

[0086] The second electrode 232 may be disposed in the second semiconductor layer 222 to correspond to the sub-pixels SR, SG, and SB (ie, the color conversion layers 260R, 260G, and 260B) one by one. The second electrode 232 may include a transparent conductive material. In addition, a plurality of TFTs 240 electrically connected to the second electrode 232 may be disposed on the second semiconductor layer 222.

[0087] An etched region 225 for preventing a current injected from the second electrode 232 into the second semiconductor layer 222 from flowing laterally may be formed to a certain depth in the second semiconductor layer 222. The etched region 225 may be formed by etching a region around a contact region between the second semiconductor layer 222 and the second electrode 232 to a certain depth or less. An insulating layer may be provided to cover the second electrode 232 and the TFT 240.

[0088] According to Figure 3 In the illustrated exemplary embodiment, for example, when one of the TFTs 240 corresponding to the red sub-pixel SR is driven and a specific voltage is applied between the first electrode as a common electrode and one of the second electrodes 232 corresponding to the red sub-pixel SR, ultraviolet light is emitted from the active layer 223 located below the red conversion layer 260R. When the ultraviolet light emitted from the active layer 223 is incident on the red conversion layer 260R as described above, the red conversion layer 260R emits red light R to the outside. In addition, for example, when the TFT 240 corresponding to the green sub-pixel SG is driven and a specific voltage is applied between the first electrode as a common electrode and the second electrode 232 corresponding to the green sub-pixel SG, ultraviolet light is emitted from the active layer 223 located below the green conversion layer 260G. When the ultraviolet light emitted from the active layer 223 is incident on the green conversion layer 260G as described above, the green conversion layer 260G emits green light G to the outside.

[0089] For example, when the TFT 240 corresponding to the blue sub-pixel SB is driven and a specific voltage is applied between the first electrode as the common electrode and the second electrode 232 corresponding to the blue sub-pixel SB, ultraviolet rays are emitted from the active layer 223 located below the blue conversion layer 260B. When the ultraviolet rays emitted as above are incident on the blue conversion layer 260B, the blue conversion layer 260B emits blue light B to the outside. Figure 3 An exemplary embodiment is shown in which red light R, green light G, and blue light B are emitted to the outside from the red conversion layer 260R, the green conversion layer 260G, and the blue conversion layer 260B, respectively.

[0090] In the display device 200 according to the example embodiment, as Figure 3 As shown, since the sub-pixels SR, SG, and SB are disposed to correspond to the single light emitting layer 220, the active layer 223 as a light emitting region is not divided into the sub-pixels SR, SG, and SB, so that light efficiency can be improved.

[0091] Figure 4 is a cross-sectional view of a display apparatus 300 according to an example embodiment. Figure 5 yes Figure 4 An enlarged cross-sectional view of portion E of FIG.

[0092] refer to Figure 4 and Figure 5 The display device 300 may include a plurality of pixels, and each of the plurality of pixels may include a red sub-pixel SR, a green sub-pixel SG, and a blue sub-pixel SB. The light emitting layer 320 is disposed on the substrate 310, and a plurality of color conversion layers 360R, 360G, and 360B are disposed on the light emitting layer 320.

[0093] A substrate for growth (e.g., a silicon substrate or a sapphire substrate) may be used as the substrate 310. A light emitting layer 320 for emitting blue light B is provided on an upper surface of the substrate 310. The light emitting layer 320 may be formed by sequentially growing a first semiconductor layer 321, an active layer 323, and a second semiconductor layer 322 on an upper surface of the substrate 310.

[0094] The first semiconductor layer 321 disposed on the upper surface of the substrate 310 may include, for example, an n-type semiconductor. The first semiconductor layer 321 may include an n-type semiconductor based on the III-V group, such as n-GaN. When electrons and holes are combined with each other, the active layer 323 disposed on the upper surface of the first semiconductor layer 321 may generate blue light B. The active layer 323 may have, for example, an MQW structure. The active layer 323 may be formed in a 2D film shape or a 3D shape. The second semiconductor layer 322 may be disposed on the upper surface of the active layer 323. The second semiconductor layer 322 may include, for example, a p-type semiconductor. The second semiconductor layer 322 may include a p-type semiconductor based on the III-V group, such as p-GaN.

[0095] Color conversion layers 360R, 360G, and 360B that emit light of a specific color by blue light B emitted from the active layer 323 of the light emitting layer 320 are disposed above the light emitting layer 320. The color conversion layers 360R, 360G, and 360B may be disposed corresponding to a single light emitting layer 320 and grown from the substrate 310. For example, the color conversion layers 360R, 360G, and 360B may include a red conversion layer 360R, a green conversion layer 360G, and a blue transmission layer 360B. The red conversion layer 360R, the green conversion layer 360G, and the blue transmission layer 360B may correspond to a red sub-pixel SR, a green sub-pixel SG, and a blue sub-pixel SB, respectively.

[0096] The red conversion layer 360R may convert the blue light B emitted from the active layer 323 into red light R and emit the red light R. The red conversion layer 360R may include a QD or a phosphor having a specific size. The green conversion layer 360G may convert the blue light B emitted from the active layer 323 into green light G and emit the green light G. The green conversion layer 360G may include a QD or a phosphor having a specific size. The blue transmission layer 360B may transmit the blue light B emitted from the active layer 323 to emit to the outside. A black matrix 370 for absorbing light may be provided between the red conversion layer 360R, the green conversion layer 360G, and the blue transmission layer 360B, respectively.

[0097] The light emitting layer 320 may include a first electrode 331 electrically connected to the first semiconductor layer 321 and a plurality of second electrodes 332 electrically connected to the second semiconductor layer 322. When the first semiconductor layer 321 and the second semiconductor layer 322 include an n-type semiconductor and a p-type semiconductor, respectively, the first electrode 331 and the second electrode 332 may be an n-type electrode and a p-type electrode, respectively.

[0098] The first electrode 331 may be used as a common electrode for sub-pixels SR, SG, and SB. For example, by sequentially etching the second semiconductor layer 322, the active layer 323, and the first semiconductor layer 321, a groove 320a for exposing the first semiconductor layer 321 may be formed to a certain depth in the light emitting layer 320. The first electrode 331 may be disposed to contact the first semiconductor layer 321 exposed via the groove 320a. An insulating material for insulating the first electrode 331 from the first semiconductor layer 321 and the active layer 323 may be disposed in an inner wall of the groove 320a.

[0099] Figure 4 An example embodiment is shown in which the first electrode 331 is disposed to commonly correspond to all six sub-pixels SR, SG, and SB. However, example embodiments are not limited thereto, and the number of sub-pixels SR, SG, and SB commonly corresponding to a single first electrode 331 may vary.

[0100] The second electrode 332 may be disposed on the second semiconductor layer 322. The second electrode 332 may be disposed in one-to-one correspondence with the sub-pixels SR, SG, and SB (i.e., the color conversion layers 360R, 360G, and 360B). Each second electrode 332 may be disposed below the red conversion layer 360R, the green conversion layer 360G, and the blue transmission layer 360B, respectively. The second electrode 332 may include a transparent conductive material. For example, the second electrode 332 may include ITO, ZnO, IZO, Ag, Au, graphene, or nanowires. A plurality of TFTs 340 electrically connected to the second electrode 332 are disposed on the second semiconductor layer 322. The TFT 340 may be disposed below the black matrix 370.

[0101] A current injection limiting layer 337 for limiting current injected from the second electrode 332 into the second semiconductor layer 322 may be provided on the second semiconductor layer 322. Blue light B emitted from the active layer 323 located below at least one of the color conversion layers 360R, 360G, and 360B may travel laterally. In this case, since light of an undesirable color may be emitted to the outside from the adjacent color conversion layers 360R, 360G, and 360B, color quality may be deteriorated.

[0102] In order to prevent or reduce the emission of undesired colors, in example embodiments, a current injection limiting layer 337 may be provided on the second semiconductor layer 322. The current injection limiting layer 337 may reduce the contact area between the second semiconductor layer 322 and the second electrode 332. In this case, due to the current injection limiting layer 337, the contact area between the second semiconductor layer 322 and the second electrode 332 may have a smaller area than each of the color conversion layers 360R, 360G, and 360B, and correspond to the central portion of each of the color conversion layers 360R, 360G, and 360B. Due to the current injection limiting layer 337, the current injected from the second electrode 332 into the second semiconductor layer 322 may be limited. Therefore, the emission area of ​​the blue light B emitted from the active layer 323 located below at least one of the color conversion layers 360R, 360G, and 360B may be reduced. Therefore, it is possible to reduce or prevent color quality degradation that occurs when blue light B emitted from active layer 323 located under at least one of color conversion layers 360R, 360G, and 360B travels to an adjacent one of color conversion layers 360R, 360G, and 360B, thereby emitting light of an undesired color.

[0103] The current injection limiting layer 337 may include an insulating film having a certain thickness. The insulating film may include, for example, silicon dioxide (SiO 2 ), silicon nitride (SiN), aluminum oxide (Al 2 O 3 ) or titanium oxide (TiO 2 ), but example embodiments are not limited thereto.

[0104] The etched region 325 for preventing the current injected from the second electrode 332 into the second semiconductor layer 322 from flowing laterally may be formed to a certain depth in the second semiconductor layer 322. The etched region 325 may be formed by etching the area around the contact area between the second semiconductor layer 322 and the second electrode 332 to a certain depth or less through the opening portion of the current injection limiting layer 337. The etched region 325 may be provided with an insulating material. An insulating layer 350 may be provided to cover the second electrode 332, the TFT 340, and the current injection limiting layer 337.

[0105] The light absorbing member 380 may be further disposed on the lower surface of the substrate 310. The light absorbing member 380 may absorb the blue light B emitted from the active layer 323 and transmitted through the substrate 310, thereby reducing or preventing the blue light B from being reflected from the lower surface of the substrate 310 and traveling toward the upper portion of the substrate 310. The light absorbing member 380 may include a material having a refractive index similar to that of the substrate 310. For example, the light absorbing member 380 may include a polymer-based material.

[0106] Figure 5 An example embodiment in which red light R is emitted from the red conversion layer 360R is shown. Figure 5 , when one of the TFTs 340 corresponding to the red sub-pixel SR is driven and a specific voltage is applied between the first electrode 331 as a common electrode and one of the second electrodes 332 corresponding to the red sub-pixel SR, blue light B is emitted from the active layer 323 located below the red conversion layer 360R. When the blue light B emitted from the active layer 323 is incident on the red conversion layer 360R as described above, the red conversion layer 360R emits the red light R to the outside. In this case, since the contact area between the second semiconductor layer 322 and the second electrode 332 is reduced by the current injection restriction layer 337, the emission area of ​​the blue light B emitted from the active layer 323 located below the red conversion layer 360R is reduced. Therefore, the emission of light of an undesired color that occurs when the blue light B emitted from the active layer 323 located below the red conversion layer 360R travels to the green conversion layer 360G or the blue conversion layer 360B can be reduced or prevented. In addition, since the blue light B emitted from the active layer 323 and transmitted through the substrate 310 can be absorbed by the light absorption member 380 provided on the lower surface of the substrate 310, it is possible to reduce or prevent the blue light B from being reflected from the lower surface of the substrate 310 and traveling toward the upper portion of the substrate 310. Since the portion around the contact area between the second semiconductor layer 322 and the second electrode 332 is etched to a certain depth or less, the current injected from the second electrode 332 into the second semiconductor layer 322 can be reduced or prevented from flowing laterally.

[0107] Figure 6 is a cross-sectional view of a display apparatus 300 ′ according to example embodiments. Figure 6 The display device 300′ and Figure 5 The display device 300 is substantially the same as the display device 300, except that no Figure 5 outside the etched area 325.

[0108] Figure 7 is a cross-sectional view of a display apparatus 400 according to example embodiments. Figure 7 The display device 400 and Figure 5 The display device 300 is substantially the same except that Figure 7The display device 400 includes a selectively transparent insulating layer 410 and a selective shielding layer 420 .

[0109] refer to Figure 7 , the selectively transparent insulating layer 410 may be disposed between the second electrode 332 and the color conversion layers 360R, 360G, and 360B. The selectively transparent insulating layer 410 may transmit the blue light B emitted from the active layer 323 of the light emitting layer 320 and reflect the light emitted from the color conversion layers 360R, 360G, and 360B. The selectively transparent insulating layer 410 may have a multi-layer structure having different refractive indices.

[0110] A selective shielding layer 420 for shielding light of a specific color may be further provided on the color conversion layers 360R and 360G. For example, the selective shielding layer 420 may be provided on the red conversion layer 360R and the green conversion layer 360G, and may include a blue cutoff filter for preventing the blue light B emitted from the active layer 323 from being emitted to the outside. The selective shielding layer 420 may include, for example, a resin or a multi-layer insulating film.

[0111] Figure 7 An example embodiment in which red light R and green light G are emitted from the red conversion layer 360R and the green conversion layer 360G, respectively, is shown. Figure 7 , blue light B may be emitted from the active layer 323 located below the red conversion layer 360R and the green conversion layer 360G, and then the blue light B emitted from the active layer 323 as described above may be transmitted through the selective transparent insulating layer 410 and incident on the red conversion layer 360R and the green conversion layer 360G. Therefore, red light R and green light G may be emitted from the red conversion layer 360R and the green conversion layer 360G, respectively. The red light R and the green light G may be emitted to the outside through the selective shielding layer 420.

[0112] Figure 8 is a cross-sectional view of a display apparatus 500 according to example embodiments. Figure 8 The display device 500 and Figure 5 The display device 300 is substantially the same except that Figure 8 The display device 500 further includes a light absorbing layer 510 .

[0113] refer to Figure 8 , the light absorbing layer 510 may be disposed between the substrate 310 and the first semiconductor layer 321. The light absorbing layer 510 may absorb the blue light B emitted from the active layer 323. The light absorbing layer 510 may include, for example, carbon nanotubes (CNTs), graphene, aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), InGaN / GaN superlattice, AlGaN / GaN superlattice, titanium nitride (TiN), tungsten nitride (WN), or boron nitride (BN), but the present disclosure is not limited thereto.

[0114] Figure 8 An example embodiment in which red light R is emitted from the red conversion layer 360R is shown. Figure 8 , blue light B is emitted from the active layer 323 located below the red conversion layer 360R, and the blue light B emitted from the active layer 323 is incident on the red conversion layer 360R as described above to generate and emit red light R. The blue light B emitted from the active layer 323 and traveling toward the substrate 310 may be absorbed by the light absorption layer 510 disposed between the substrate 310 and the first semiconductor layer 321. Figure 7 As shown, a selective transparent insulating layer may be further disposed between second electrode 322 and color conversion layers 360R, 360G, and 360B, and a selective shielding layer may be further disposed on color conversion layers 360R, 360G, and 360B. Figure 8 An example embodiment in which the light absorbing layer 510 is disposed between the substrate 310 and the first semiconductor layer 321 is illustrated, but the light absorbing layer 510 may be disposed in the first semiconductor layer 321 .

[0115] According to Figure 7 In the example embodiment shown, a refractive index matching layer 390 may be provided between the substrate 310 and the first semiconductor layer 321. The refractive index matching layer may reduce the amount of blue light B reflected between the substrate 310 and the first semiconductor layer 321 by using the difference in refractive index between the substrate 310 and the first semiconductor layer 321. The refractive index matching layer 390 may include, for example, AlN. In this case, the refractive index matching layer 390 may be formed by depositing AlN on the substrate 310 to a certain thickness (e.g., about 10 nm to about 150 nm). However, example embodiments are not limited thereto.

[0116] Fig. 9 is a cross-sectional view of a display apparatus 600 according to an example embodiment. Fig. 9 The display device 600 and Figure 5 The display device 300 is substantially the same except that ultraviolet rays are emitted from the active layer 623 .

[0117] refer to Fig. 9 , the light emitting layer 620 is disposed on the substrate 610, and a plurality of color conversion layers 660R, 660G, and 660B are disposed above the light emitting layer 620. The light emitting layer 620 may be formed by sequentially growing a first semiconductor layer 621, an active layer 623, and a second semiconductor layer 622 on an upper surface of the substrate 610.

[0118] The first semiconductor layer 621 may include, for example, an n-type semiconductor. For example, the first semiconductor layer 621 may include an n-type semiconductor based on the III-V group, such as n-GaN. When electrons and holes are combined with each other, the active layer 623 may generate ultraviolet rays. The active layer 623 may have, for example, an MQW structure. The second semiconductor layer 622 may include, for example, a p-type semiconductor. In detail, the second semiconductor layer 622 may include a p-type semiconductor based on the III-V group, such as p-GaN.

[0119] Color conversion layers 660R, 660G, and 660B (i.e., a red conversion layer 660R, a green conversion layer 660G, and a blue conversion layer 660B) for emitting light of a specific color by ultraviolet rays emitted from the active layer 623 are disposed above the light emitting layer 620. The red conversion layer 660R may convert ultraviolet rays emitted from the active layer 623 into red light R and may emit the red light R. The green conversion layer 660G may convert ultraviolet rays emitted from the active layer 623 into green light G and may emit the green light G. The blue conversion layer 660B may convert ultraviolet rays emitted from the active layer 623 into blue light B and may emit the blue light B. Black matrices 670 for absorbing light may be disposed between the red conversion layer 660R, the green conversion layer 660G, and the blue conversion layer 660B, respectively.

[0120] The light emitting layer 620 may include a first electrode electrically connected to the first semiconductor layer 621 and a plurality of second electrodes 632 electrically connected to the second semiconductor layer 622. As described above, the first electrode may be used as a common electrode relative to the sub-pixels SR, SG, and SB. The number of sub-pixels SR, SG, and SB corresponding to the first electrode may vary. The second electrode 632 may be disposed on the second semiconductor layer 622 to correspond to the sub-pixels SR, SG, and SB (i.e., the color conversion layers 660R, 660G, and 660B) one by one. A plurality of TFTs 640 electrically connected to the second electrode 632 may be disposed on the second semiconductor layer 622.

[0121] A current injection limiting layer 637 for limiting the current injected from the second electrode 632 into the second semiconductor layer 622 may be provided on the second semiconductor layer 622. The current injection limiting layer 637 may reduce or prevent the emission of light of an undesirable color by reducing the contact area between the second semiconductor layer 622 and the second electrode 632. The current injection limiting layer 637 may include an insulating film having a specific thickness. The insulating film may include, for example, SiO 2 、SiN、Al 2 O 3 or TiO 2 An insulating layer 650 may be provided to cover the second electrode 632 , the TFT 640 , and the current injection limiting layer 637 .

[0122] The light absorbing member 680 may be further disposed on the lower surface of the substrate 610. When the light absorbing member 680 absorbs ultraviolet rays emitted from the active layer 623 and transmitted through the substrate 610, ultraviolet rays may be reduced or prevented from being reflected from the lower surface of the substrate 610 and traveling to the upper portion of the substrate 610.

[0123] The etched region 625 for reducing or preventing lateral flow of current injected from the second electrode 632 into the second semiconductor layer 622 may be formed to a certain depth in the second semiconductor layer 622. The etched region 625 may be formed by etching a region around a contact region between the second semiconductor layer 622 and the second electrode 632. Fig. 9 An exemplary embodiment is shown in which ultraviolet rays are emitted from the active layer 623 and thus red light R, green light G, and blue light B are emitted to the outside from the red conversion layer 660R, the green conversion layer 660G, and the blue conversion layer 660B, respectively.

[0124] Fig. 9 The display device 600 may further include a selectively transparent insulating layer between the second electrode 632 and the color conversion layers 660R, 660G, and 660B, and a selective shielding layer for shielding light of a specific color may be further disposed on the color conversion layers 660R, 660G, and 660B. The selectively transparent insulating layer and the selective shielding layer may be similar to Figure 7 The selective transparent insulating layer and the selective shielding layer shown in . The selective shielding layer may include, for example, a red filter, a green filter, and a blue filter. In addition, a light absorbing layer may be provided between the substrate 610 and the first semiconductor layer 621 or in the first semiconductor layer 621, and a refractive index matching layer 690 may be provided between the substrate 610 and the first semiconductor layer 621.

[0125] Fig.10 is a cross-sectional view of a display apparatus 700 according to example embodiments. Fig.10 The display device 700 and Figure 5 The display device 300 is substantially the same as that of FIG. 7 , except that the current injection restricting layer 738 is formed of a multi-layer insulating film.

[0126] refer to Fig.10 , a light emitting layer 720 is disposed on a substrate 710, and a plurality of color conversion layers 760R, 760G, and 760B are disposed above the light emitting layer 720. The light emitting layer 720 may be formed by sequentially growing a first semiconductor layer 721, an active layer 723, and a second semiconductor layer 722 on an upper surface of the substrate 710.

[0127] The first semiconductor layer 721 may include, for example, an n-type semiconductor. For example, the first semiconductor layer 721 may include an n-type semiconductor based on the III-V group, such as n-GaN. When electrons and holes are combined with each other, the active layer 723 may generate blue light B. The active layer 723 may have, for example, an MQW structure. The second semiconductor layer 722 may include, for example, a p-type semiconductor. For example, the second semiconductor layer 722 may include a p-type semiconductor based on the III-V group, such as p-GaN.

[0128] Color conversion layers 760R, 760G, and 760B (i.e., a red conversion layer 760R, a green conversion layer 760G, and a blue transmission layer 760B) for emitting light of a specific color by converting or transmitting the blue light B emitted from the active layer 723 are disposed above the light emitting layer 720. The red conversion layer 760R may convert the blue light B emitted from the active layer 723 into red light R and emit the red light R. The green conversion layer 760G may convert the blue light B emitted from the active layer 723 into green light G and emit the green light G. The blue transmission layer 760B may transmit the blue light B emitted from the active layer 723 and emit the blue light B. A black matrix 770 for absorbing light may be disposed between the red conversion layer 760R, the green conversion layer 760G, and the blue transmission layer 760B.

[0129] The light emitting layer 720 may include a first electrode electrically connected to the first semiconductor layer 721 and a plurality of second electrodes 732 electrically connected to the second semiconductor layer 722. The first electrode may be used as a common electrode for sub-pixels SR, SG, and SB. The number of sub-pixels SR, SG, and SB corresponding to the first electrode may vary. The second electrode 732 may be disposed on the second semiconductor layer 722 to correspond to the sub-pixels SR, SG, and SB (i.e., the color conversion layers 760R, 760G, and 760B) one by one. A plurality of TFTs 740 electrically connected to the second electrode 732 may be disposed on the second semiconductor layer 722.

[0130] A current injection limiting layer 738 for limiting current injected from the second electrode 732 into the second semiconductor layer 722 may be disposed on the second semiconductor layer 722. The current injection limiting layer 738 may reduce or prevent emission of undesired color light by reducing a contact area between the second semiconductor layer 722 and the second electrode 732.

[0131] The current injection limiting layer 738 may include a multilayer insulating film having a multilayer structure having different refractive indices. The insulating film may include, for example, SiO 2 、SiN、Al 2 O 3 or TiO 2 .like Fig.10As shown, the current injection confinement layer 738 formed of a multi-layered insulating film may reflect the blue light B emitted from the active layer 723 and traveling laterally.

[0132] Fig.11 is a graph showing the reflectivity of the material of the current injection confinement layer according to the current injection confinement layer. Fig.11 In FIG. 1 , “C1” represents the wavelength of blue light emitted from the active layer. “C2” represents SiO having a thickness of about 200 nm. 2 The reflectivity of a single layer with respect to blue light emitted from the active layer. "C3" represents the reflectivity of a multilayer insulating film with respect to blue light emitted from the active layer. Fig.11 , it can be seen that when the current injection limiting layer 738 is formed of a multi-layer insulating film, the current injection limiting layer 738 can have a higher reflectivity with respect to the blue light B emitted from the active layer 723 .

[0133] An insulating layer 750 may be provided to cover the second electrode 732, the TFT 740, and the current injection limiting layer 738. A light absorbing member 780 may be further provided on the lower surface of the substrate 710. The light absorbing member 780 may prevent the blue light B from being reflected from the lower surface of the substrate 710 and traveling toward the upper portion of the substrate 710 by absorbing the blue light B emitted from the active layer 723 and transmitted through the substrate 710. An etched region 725 for reducing or preventing a current injected from the second electrode 732 into the second semiconductor layer 722 from flowing laterally may be formed in the second semiconductor layer 722 to a certain depth. The etched region 725 may be formed to surround a contact region between the second semiconductor layer 722 and the second electrode 732.

[0134] Fig.10 An exemplary embodiment is shown in which blue light B is emitted from the active layer 723 disposed under the red conversion layer 760R and red light R is emitted from the red conversion layer 760R. Fig.10 , when one of the TFTs 740 corresponding to the red sub-pixel SR is driven and a specific voltage is applied between the first electrode as a common electrode and one of the second electrodes 732 corresponding to the red sub-pixel SR, blue light B is emitted from the active layer 723 located under the red conversion layer 760R. When the blue light B emitted from the active layer 723 is incident on the red conversion layer 760R, the red conversion layer 760R emits red light R to the outside.

[0135] According to Fig.10In the example embodiment shown, since the contact area between the second semiconductor layer 722 and the second electrode 732 is reduced by the current injection limiting layer 738, the emission area of ​​the blue light B emitted from the active layer 723 located below the red conversion layer 760R is reduced. Therefore, the emission of light of an undesired color that occurs when the blue light B emitted from the active layer 723 located below the red conversion layer 760R travels to the green conversion layer 760G or the blue conversion layer 760B can be reduced or prevented. In addition, the current injection limiting layer 738 formed of a multi-layer insulating film can effectively reduce or prevent the blue light B emitted from the active layer 723 disposed below the red conversion layer 760R from traveling to the green conversion layer 760G or the blue conversion layer 760B.

[0136] Since the blue light B emitted from the active layer 723 and transmitted through the substrate 710 may be absorbed by the light absorption member 780 disposed on the lower surface of the substrate 710, it is possible to reduce or prevent the blue light B from being reflected from the lower surface of the substrate 710 and traveling toward the upper portion of the substrate 710. Since the etched region 725 is formed to a certain depth around the contact region between the second semiconductor layer 722 and the second electrode 732, the current injected from the second electrode 732 into the second semiconductor layer 722 may be reduced or prevented from flowing laterally.

[0137] Fig.12 is a cross-sectional view of a display apparatus 800 according to example embodiments. Fig.12 The display device 800 and Fig.10 The display device 700 is substantially the same except that Fig.12 The display device 800 includes a selectively transparent insulating layer 810 and a selective shielding layer 820 .

[0138] refer to Fig.12 , the selectively transparent insulating layer 810 may be disposed between the second electrode 732 and the color conversion layers 760R, 760G, and 760B. The selectively transparent insulating layer 810 may transmit the blue light B emitted from the active layer 723 of the light emitting layer 720 and reflect the light emitted from the color conversion layers 760R, 760G, and 760B. The selectively transparent insulating layer 810 may have a multi-layer structure having different refractive indices.

[0139] A selective shielding layer 820 for shielding light of a specific color may be further provided on the color conversion layers 760R and 760G. For example, the selective shielding layer 820 is provided on the red conversion layer 760R and the green conversion layer 760G, and may include a blue cutoff filter for preventing the blue light B emitted from the active layer 723 from being emitted to the outside. The selective shielding layer 820 may include, for example, a resin or a multi-layer insulating film.

[0140] Fig.13is a cross-sectional view of a display apparatus 900 according to example embodiments. Fig.13 The display device 900 and Fig.10 The display device 700 is substantially the same except that Fig.13 The display device 900 further includes a light absorbing layer 910 .

[0141] refer to Fig.13 , the light absorbing layer 910 may be disposed between the substrate 710 and the first semiconductor layer 721. The light absorbing layer 910 may absorb the blue light B emitted from the active layer 723. A selective transparent insulating layer may be further disposed between the second electrode 732 and the color conversion layers 760R, 760G, and 760B, and a selective shielding layer may be further disposed on the color conversion layers 760R, 760G, and 760B. Fig.12 An example embodiment in which the light absorbing layer 910 is disposed between the substrate 710 and the first semiconductor layer 721 is shown, but the light absorbing layer 910 may be disposed in the first semiconductor layer 721. The refractive index matching layer 790 may be disposed between the substrate 710 and the first semiconductor layer 721. The refractive index matching layer 790 may reduce the amount of blue light B reflected between the substrate 710 and the first semiconductor layer 721 by using the difference in refractive index between the substrate 710 and the first semiconductor layer 721.

[0142] exist Fig.10 , Fig.12 and Fig.13 In the display devices 700 , 800 , and 900 , blue light B is emitted from the active layer 723 . However, ultraviolet rays may be emitted from the active layer 723 .

[0143] Fig.14 is a cross-sectional view of a display apparatus 1000 according to example embodiments. Fig.14 The display device 1000 and Figure 5 The display device 300 is substantially the same as that of FIG. 1 , except that the current injection limiting layer 1036 includes an insulating film 1037 and a metal reflective layer 1038 .

[0144] refer to Fig.14 , the light emitting layer 1020 is disposed on the substrate 1010, and a plurality of color conversion layers 1060R, 1060G, and 1060B are disposed above the light emitting layer 1020. The light emitting layer 1020 may be formed by sequentially growing a first semiconductor layer 1021, an active layer 1023, and a second semiconductor layer 1022 on an upper surface of the substrate 1010.

[0145] The first semiconductor layer 1021 may include, for example, an n-type semiconductor. For example, the first semiconductor layer 1021 may include an n-type semiconductor based on the III-V group, such as n-GaN. When electrons and holes are combined with each other, the active layer 1023 may generate blue light B. The active layer 1023 may have, for example, an MQW structure. The second semiconductor layer 1022 may include, for example, a p-type semiconductor. For example, the second semiconductor layer 1022 may include a p-type semiconductor based on the III-V group, such as p-GaN.

[0146] A plurality of color conversion layers 1060R, 1060G, and 1060B (i.e., a red conversion layer 1060R, a green conversion layer 1060G, and a blue transmission layer 1060B) for emitting light of a specific color by blue light B emitted from the active layer 1023 are disposed on the light emitting layer 1020. The red conversion layer 1060R may convert the blue light B emitted from the active layer 1023 into red light R and emit the red light R. The green conversion layer 1060G may convert the blue light B emitted from the active layer 1023 into green light G and emit the green light G. The blue transmission layer 1060B may transmit and emit the blue light B emitted from the active layer 1023. A black matrix 1070 for absorbing light may be disposed between the red conversion layer 1060R, the green conversion layer 1060G, and the blue transmission layer 1060B.

[0147] The light emitting layer 1020 may include a first electrode electrically connected to the first semiconductor layer 1021 and a plurality of second electrodes 1032 electrically connected to the second semiconductor layer 1022. The first electrode may be used as a common electrode for sub-pixels SR, SG, and SB. The number of sub-pixels SR, SG, and SB corresponding to the first electrode may vary differently. The second electrode 1032 may be disposed on the second semiconductor layer 1022 to correspond to the sub-pixels SR, SG, and SB (i.e., the color conversion layers 1060R, 1060G, and 1060B) one by one. A plurality of TFTs 1040 electrically connected to the second electrode 1032 are disposed on the second semiconductor layer 1022.

[0148] A current injection limiting layer 1036 for limiting current injected from the second electrode 1032 into the second semiconductor layer 1022 may be disposed on the second semiconductor layer 1022. The current injection limiting layer 1036 may reduce or prevent emission of undesired color light by reducing a contact area between the second semiconductor layer 1022 and the second electrode 1032.

[0149] The current injection limiting layer 1036 may include an insulating film 1037 and a metal reflective layer 1038 disposed on the insulating film 1037. The insulating film 1037 may include, for example, SiO 2 、SiN、Al 2 O 3 or TiO2 The metal reflective layer 1038 may reflect the blue light B emitted from the active layer 1023 and the light emitted from the color conversion layers 1060R, 1060G, and 1060B. The metal reflective layer 1038 may include, for example, Ag, Al, chromium (Cr), or nickel (Ni).

[0150] The metal reflective layer 1038 may include a multilayer structure formed of different materials. For example, the metal reflective layer 1038 may include a first metal layer and a second metal layer disposed on the first metal layer and having a reflectivity greater than that of the first metal layer. For example, the first metal layer may include a metal material with a relatively low reflectivity, such as Cr, Ni, or Ti, and the second metal layer may include a metal material with a relatively high reflectivity, such as Ag or Al. In this way, when the metal reflective layer 1038 is formed by a first metal layer with a low reflectivity and a second metal layer with a high reflectivity on the first metal layer, the reflection of light emitted from the active layer 1023 may be reduced by the first metal layer, thereby increasing light loss, and the reflection of light emitted from the color conversion layers 1060R, 1060G, and 1060B may be increased by the second metal layer, thereby improving light efficiency.

[0151] The insulating layer 1050 may be provided to cover the second electrode 1032, the TFT 1040, and the current injection limiting layer 1036. The light absorbing member 1080 may be further provided on the lower surface of the substrate 1010. The light absorbing member 1080 absorbs the blue light B emitted from the active layer 1023 and transmitted through the substrate 1010, and thus, the blue light B may be reduced or prevented from being reflected from the substrate 1010 and traveling to the upper portion of the substrate 1010. The etched region 1025 for reducing or preventing the lateral flow of the current injected from the second electrode 1032 into the second semiconductor layer 1022 may be formed to a certain depth in the second semiconductor layer 1022. The etched region 1025 may be formed by etching the region around the contact region between the second semiconductor layer 1022 and the second electrode 1032 to a certain depth or less.

[0152] Fig.14 An exemplary embodiment is shown in which blue light B is emitted from the active layer 1023 disposed under the red conversion layer 1060R and red light R is emitted from the red conversion layer 1060R. Fig.14 , when one of the TFTs 1040 corresponding to the red sub-pixel SR is driven and a specific voltage is applied between the first electrode as a common electrode and one of the second electrodes 1032 corresponding to the red sub-pixel SR, blue light B is emitted from the active layer 1023 located under the red conversion layer 1060R. When the blue light B emitted from the active layer 1023 is incident on the red conversion layer 1060R, the red conversion layer 1060R may emit red light R to the outside.

[0153] According to Fig.14 In the example embodiment shown, since the contact area between the second semiconductor layer 1022 and the second electrode 1032 is reduced by the current injection limiting layer 1036, the emission area of ​​the blue light B emitted from the active layer 1023 located below the red conversion layer 1060R is reduced. Therefore, the emission of undesired color light that occurs when the blue light B emitted from the active layer 1023 located below the red conversion layer 1060R travels to the green conversion layer 1060G or the blue conversion layer 1060B can be reduced or prevented. In addition, the current injection limiting layer 1036 formed by the insulating film 1037 and the metal reflective layer 1038 disposed on the insulating film 1037 can more effectively reduce or prevent the blue light B emitted from the active layer 1023 disposed below the red conversion layer 1060R from traveling to the green conversion layer 1060G or the blue conversion layer 1060B. Therefore, the light emitted from the color conversion layers 1060R, 1060G, and 1060B is reflected upward, so that the light efficiency can be improved.

[0154] The blue light B emitted from the active layer 1023 and transmitted through the substrate 1010 may be absorbed by the light absorption member 1080 disposed on the lower surface of the substrate 1010. Since the etched region 1025 is formed to a certain depth around the contact region between the second semiconductor layer 1022 and the second electrode 1032, the lateral flow of current injected from the second electrode 1032 into the second semiconductor layer 1022 may be reduced or prevented. In the above description, in the current injection limiting layer 1036, the metal reflective layer 1038 is disposed in the insulating film 1037. However, the metal reflective layer 1038 may be disposed on the upper surface of the second semiconductor layer 1022, and the insulating film 1037 may be disposed to cover the metal reflective layer 1038.

[0155] Fig.15 is a cross-sectional view of a display apparatus 1100 according to example embodiments. Fig.15 The display device 1100 and Fig.14 The display device 1000 is substantially the same except that Fig.15 The display device 1100 includes a selectively transparent insulating layer 1110 and a selective shielding layer 1120 .

[0156] refer to Fig.15 , the selectively transparent insulating layer 1110 may be disposed between the second electrode 1032 and the color conversion layers 1060R, 1060G, and 1060B. The selectively transparent insulating layer 1110 may transmit the blue light B emitted from the active layer 1023 and reflect the light emitted from the color conversion layers 1060R, 1060G, and 1060B. The selectively transparent insulating layer 1110 may have a multi-layer structure having different refractive indices.

[0157] A selective shielding layer 1120 for shielding light of a specific color may be further provided on the color conversion layers 1060R and 1060G. For example, the selective shielding layer 1120 may be provided on the red conversion layer 1060R and the green conversion layer 1060G, and may include a blue cutoff filter for preventing the blue light B emitted from the active layer 1023 from being emitted to the outside. The selective shielding layer 1120 may include, for example, a resin or a multi-layer insulating film.

[0158] Fig.16 is a cross-sectional view of a display apparatus 1200 according to example embodiments. Fig.16 The display device 1200 and Fig.14 The display device 1000 is substantially the same except that Fig.16 The display device 1200 further includes a light absorbing layer 1210 .

[0159] refer to Fig.16 , the light absorbing layer 1210 may be disposed between the substrate 1010 and the first semiconductor layer 1021. The light absorbing layer 1210 may absorb the blue light B emitted from the active layer 1023. A selective transparent insulating layer may be further disposed between the second electrode 1032 and the color conversion layers 1060R, 1060G, and 1060B, and a selective shielding layer may be further disposed on the color conversion layers 1060R, 1060G, and 1060B. Although Fig.15 It is shown that the light absorbing layer 1210 is disposed between the substrate 1010 and the first semiconductor layer 1021, but the light absorbing layer 1210 may be disposed in the first semiconductor layer 1021. The refractive index matching layer 1090 may be disposed between the substrate 1010 and the first semiconductor layer 1021. The refractive index matching layer 1090 may reduce the amount of blue light B reflected between the substrate 1010 and the first semiconductor layer 1021 by using the difference in refractive index between the substrate 1010 and the first semiconductor layer 1021.

[0160] Fig.17 is a perspective view of a display apparatus 1300 according to an example embodiment. Fig.17 is a perspective view of the exterior of a display device 1300 to which the structure of the above-described exemplary embodiments may be applied.

[0161] refer to Fig.17 , the display device 1300 may include blue sub-pixels SB, red sub-pixels SR, and green sub-pixels SG arranged in an array on a substrate 1310. At least one common electrode 1331 corresponding to the blue sub-pixel SB, the red sub-pixel SR, and the green sub-pixel SG may be provided on the substrate 1310. The common electrode 1331 corresponds to the first electrode ( Figure 1 131 or Figure 4331). Compared with the blue sub-pixel SB, the red sub-pixel SR and the green sub-pixel SG, the common electrode 1331 may be arranged to occupy a relatively very small area. The common electrode 1331 may be, for example, an n-type electrode. Fig.17 It is shown that a single common electrode 1331 is provided to correspond to one of the blue sub-pixel SB, the red sub-pixel SR, and the green sub-pixel SG, but the single common electrode 1331 may be provided to correspond to a plurality of blue sub-pixels SB, red sub-pixels SR, and green sub-pixels SG. Fig.18 As shown in the display device 1300' of FIG. 1 , a single common electrode 1331 may be arranged to correspond to three sub-pixels, for example, a blue sub-pixel SB, a red sub-pixel SR, and a green sub-pixel SG. In addition, the number of sub-pixels corresponding to one common electrode may vary.

[0162] Fig.19 yes Fig.17 A plan view showing the circuit configuration of the device. Fig.19 The circuit configuration of a pixel (i.e., a blue sub-pixel SB, a red sub-pixel SR, and a green sub-pixel SG) is shown, and reference numerals 1360B, 1360R, and 1360G respectively represent a blue conversion layer (or a blue transmission layer), a red conversion layer, and a green conversion layer, which are described as color conversion layers in the above-mentioned example embodiments.

[0163] refer to Fig.19 , can be on the substrate ( Fig.17 A scan line SL extending in a first direction and a data line DL and a power line VL extending in a second direction intersecting the scan line SL are provided on the color conversion layer 1310 of FIG. 1360B. Two transistors TR1 and TR2 and a capacitor CP may be provided to each sub-pixel SB, SR, and SG. In detail, the first transistor TR1 may be provided between the power line VL and the color conversion layer 1360B, 1360G, and 1360G, and the second transistor TR2 may be provided at or around the intersection of the scan line SL and the data line DL. In addition, the capacitor CP may be provided between the power line VL and the first transistor TR1 and the second transistor TR2. The first transistor TR1 as the TFT described in the above exemplary embodiment may be a driving transistor, and the second transistor TR2 may be a switching transistor.

[0164] In the above structure, when one of the sub-pixels SB, SR, and SG is driven, blue light B (or ultraviolet light) is emitted from the light-emitting layer in the sub-pixels SB, SR, and SG. When the blue light B (or ultraviolet light) emitted from the light-emitting layer is incident on the color conversion layers 1360B, 1360G, and 1360G in one of the sub-pixels SB, SR, and SG, light of a specific color is emitted, so that an image can be formed.

[0165] According to the above-described exemplary embodiments, since one active layer is formed to correspond to a plurality of color conversion layers, the area for exposing the active layer can be reduced, and thus the light efficiency can be improved. In addition, since the contact area between the semiconductor layer and the electrode can be reduced by using a current injection limiting layer to reduce the emission area of ​​the active layer, the emission of light of an undesirable color can be reduced or prevented, and thus the color quality can be improved. Since the current injection limiting layer can be formed in a multilayer insulating film or can include an insulating film and a metal reflective layer disposed in the insulating film, the color quality can be further improved. In addition, since the portion around the contact area between the semiconductor layer and the electrode can be etched to a certain depth or less, the lateral flow of current injected into the semiconductor layer through the electrode can be reduced or prevented. In addition, since the light-emitting layer can be directly formed on the substrate by growth, the conventional LED chip transfer process may not be necessary.

[0166] It should be understood that the embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects in each embodiment should generally be considered as available for other similar features or aspects in other embodiments.

[0167] Although one or more embodiments have been described with reference to the drawings, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the invention as defined by the following claims.

Claims

1. A display device, comprising: substrate; a light emitting layer configured to emit light, the light emitting layer comprising a first semiconductor layer disposed on the substrate, an active layer disposed on the first semiconductor layer, and a second semiconductor layer disposed on the active layer; a plurality of color conversion layers disposed on the light emitting layer and configured to emit light of a predetermined color according to the light emitted from the light emitting layer; at least one first electrode electrically connected to the first semiconductor layer; a plurality of second electrodes electrically connected to the second semiconductor layer; as well as A current injection limiting layer is disposed on the second semiconductor layer and is configured to limit current injected from the plurality of second electrodes into the second semiconductor layer by reducing a contact area between the second semiconductor layer and the plurality of second electrodes.

2. The display device according to claim 1, wherein: A region of the second semiconductor layer adjacent to a contact region between the second semiconductor layer and one of the plurality of second electrodes is etched to a predetermined depth or less.

3. The display device according to claim 1, wherein: The at least one first electrode is disposed to correspond to at least one of the plurality of color conversion layers to form a common electrode, and The plurality of second electrodes are disposed in one-to-one correspondence with the plurality of color conversion layers.

4. The display device according to claim 3, wherein: Each of the plurality of second electrodes is connected to a thin film transistor.

5. The display device according to claim 1, wherein: A region of the second semiconductor layer adjacent to a contact region between the second semiconductor layer and one of the plurality of second electrodes is etched to a certain depth or less via the opening portion of the current injection restricting layer.

6. The display device according to claim 1, wherein: The current injection limiting layer includes an insulating film.

7. The display device according to claim 1, wherein: The current injection limiting layer includes a plurality of insulating films.

8. The display device according to claim 7, wherein: The multilayer insulating film includes a plurality of layers respectively having different refractive indices.

9. The display device according to claim 1, wherein: The current injection limiting layer includes an insulating film and a metal reflective layer disposed on the insulating film.

10. The display device according to claim 9, wherein: The metal reflective layer includes a first metal layer and a second metal layer disposed on the first metal layer, the second metal layer having a reflectivity higher than that of the first metal layer.

11. The display device according to claim 1, wherein: The current injection limiting layer includes a metal reflective layer disposed on the second semiconductor layer and an insulating film disposed on the metal reflective layer.

12. The display device according to claim 1, further comprising: A selectively transparent insulating layer is disposed between the plurality of second electrodes and the plurality of color conversion layers and is configured to transmit light emitted from the light emitting layer and reflect light emitted from the plurality of color conversion layers.

13. The display device according to claim 1, further comprising: A selective shielding layer is disposed on the plurality of color conversion layers and is configured to shield light of a predetermined color.

14. The display device according to claim 1, further comprising: The light absorbing layer is arranged between the substrate and the first semiconductor layer or on the first semiconductor layer.

15. The display device according to claim 1, further comprising: The refractive index matching layer is disposed between the substrate and the first semiconductor layer and is configured to reduce reflection of light.

16. The display device according to claim 15, wherein: The refractive index matching layer includes aluminum nitride AlN.

17. The display device according to claim 1, further comprising: A light absorbing member is provided on a surface of the substrate opposite to the light emitting layer.

18. The display device according to claim 1, wherein: The first semiconductor layer includes n-GaN, The second semiconductor layer includes p-GaN, and The active layer includes a multi-quantum well "MQW" structure.

19. The display device according to claim 1, wherein: The light emitting layer is configured to generate blue light.

20. The display device according to claim 19, wherein The plurality of color conversion layers include a red conversion layer configured to emit red light by being excited by the blue light, a green conversion layer configured to emit green light by being excited by the blue light, and a blue transmission layer configured to transmit the blue light.

21. The display device according to claim 1, wherein: The light emitting layer is configured to generate ultraviolet light.

22. The display device according to claim 21, wherein: The plurality of color conversion layers include a red conversion layer configured to emit red light by being excited by the ultraviolet light, a green conversion layer configured to emit green light by being excited by the ultraviolet light, and a blue conversion layer configured to emit blue light by being excited by the ultraviolet light.

23. The display device according to claim 1, wherein: The light emitting layer is formed by sequentially growing the first semiconductor layer, the active layer, and the second semiconductor layer on the substrate.

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