Light-emitting element and display device

Abstract

A light emitting element and a display device including the same are provided. The light-emitting element includes: a first semiconductor layer; a first light emitting layer disposed on the first semiconductor layer; a tunnel layer disposed on the first light emitting layer; a second light emitting layer disposed on the tunnel layer, and configured to emit light having a wavelength different from a wavelength of light emitted from the first light emitting layer; and a second semiconductor layer disposed on the second light emitting layer, in which the first light emitting layer includes a plurality of first sub-light emitting layers configured to emit light having different wavelengths, and in which the second light emitting layer includes a plurality of second sub-light emitting layers configured to emit light having different wavelengths.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10 - 2023 - 0195579, filed with the Korean Intellectual Property Office on December 28, 2023, the disclosure of which is incorporated herein by reference. Technical field

[0003] The present disclosure relates to a light - emitting element and a display device, and more particularly to a light - emitting diode (LED). Background art

[0004] As display devices for displays of computers, televisions, cellular phones, etc., there are organic light - emitting display (OLED) devices as self - emissive devices, liquid - crystal display (LCD) devices that require a separate light source, etc.

[0005] The applicable range of display devices has been diversified to personal digital assistants and displays of computers and televisions, and display devices having a large display area and reduced volume and weight are being studied.

[0006] In addition, recently, display devices including light - emitting diodes (LEDs) have been attracting attention as next - generation display devices. Since LEDs are formed of inorganic materials rather than organic materials, they have excellent reliability, so that their lifespan is longer than that of liquid - crystal display devices or organic light - emitting display devices. In addition, LEDs have a fast light - emitting speed, excellent light - emitting efficiency, and strong impact resistance, so that their stability is excellent, and images with high brightness can be displayed. Summary of the invention

[0007] An object to be achieved by an embodiment of the present specification is to provide a light - emitting element having improved light - emitting efficiency.

[0008] Another object to be achieved by an embodiment of the present specification is to provide a light - emitting element having high brightness.

[0009] Still another object to be achieved by an embodiment of the present specification is to provide a light - emitting element having an improved color - reproduction range.

[0010] The objects of the present disclosure are not limited to the above - mentioned objects, and other objects not mentioned above can be clearly understood by those skilled in the art from the following description.

[0011] According to one aspect of the present disclosure, a light-emitting diode is provided. The light-emitting element includes: a first semiconductor layer; a first light-emitting layer disposed on the first semiconductor layer; a tunnel layer disposed on the first light-emitting layer; a second light-emitting layer disposed on the tunnel layer, and the second light-emitting layer is configured to emit light having a wavelength different from that of the light emitted from the first light-emitting layer; and a second semiconductor layer disposed on the second light-emitting layer, wherein the first light-emitting layer includes a plurality of first sub-light-emitting layers configured to emit light having different wavelengths, and wherein the second light-emitting layer includes a plurality of second sub-light-emitting layers configured to emit light having different wavelengths.

[0012] According to another aspect of the present disclosure, a display device is provided, including: a display panel including a plurality of sub-pixels, the display panel being configured to display an image, wherein each of the plurality of sub-pixels includes a light-emitting element provided according to one aspect of the present disclosure; and a gate driving unit and a data driving unit, the gate driving unit and the data driving unit being configured to drive the display panel.

[0013] Other details of the exemplary embodiments are included in the detailed description and the drawings.

[0014] According to the present specification, the light-emitting element includes a light-emitting layer that emits light having various wavelengths, which can improve the color reproduction range of the light-emitting element.

[0015] According to the present specification, the light-emitting element includes a plurality of light-emitting layers, which can improve the brightness of the light-emitting element.

[0016] According to the present specification, the film quality of the plurality of light-emitting layers can be improved.

[0017] The effects according to the present disclosure are not limited to those illustrated above, and more various effects are included in the present specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above aspects, other aspects, features, and other advantages of the present disclosure will be more clearly understood from the following detailed description in conjunction with the accompanying drawings, in which:

[0019] Figure 1 is a schematic cross-sectional view of a light-emitting element according to an embodiment of the present specification;

[0020] Figure 2 is a schematic cross-sectional view of a light-emitting element according to another embodiment of the present specification;

[0021] Figure 3A and Figure 3B are views for explaining the effects of the light-emitting element according to various embodiments of the present specification;

[0022] Figure 4 is a schematic configuration diagram of a display device according to an embodiment of the present specification; and

[0023] Figure 5 is a cross-sectional view of a pixel region of a display device according to an embodiment of the present specification. Detailed Embodiments

[0024] Advantages and features of the present disclosure and methods for achieving these advantages and features will be clear by referring to the exemplary embodiments described in detail below in conjunction with the accompanying drawings. However, the present disclosure is not limited to the exemplary embodiments disclosed herein, but will be implemented in various forms. The exemplary embodiments are provided only by way of example so that those skilled in the art can fully understand the disclosure content and the scope of the present disclosure.

[0025] The shapes, sizes, ratios, angles, numbers, etc. shown in the drawings for describing the exemplary embodiments of the present disclosure are merely examples, and the present disclosure is not limited thereto. Throughout the specification, like reference numerals generally denote like elements. In addition, in the following description of the present disclosure, detailed descriptions of known related technologies may be omitted to avoid unnecessarily obscuring the subject matter of the present disclosure. Terms such as "including", "having", and "consisting of" used herein are generally intended to allow the addition of other components, unless these terms are used together with the term "only". Any reference to the singular may include the plural unless otherwise explicitly stated.

[0026] Even if not explicitly stated, components are interpreted to include a normal error range.

[0027] When using terms such as "on", "above", "below", and "adjacent to" to describe the positional relationship between two parts, one or more parts may be located between the two parts, unless these terms are used together with the terms "immediately" or "directly".

[0028] When an element or layer is disposed "on" another element or layer, the element or the layer may be directly disposed on the other element or layer, or other layers or other elements may be interposed therebetween.

[0029] Although terms such as "first", "second", etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from other components. Therefore, the first component mentioned below may be the second component in the technical concept of the present disclosure.

[0030] Throughout the specification, like reference numerals generally denote like elements.

[0031] For ease of description, the dimensions and thicknesses of each component shown in the drawings are illustrated, and the present disclosure is not limited to the dimensions and thicknesses of the components shown.

[0032] The features of the various embodiments of the present disclosure may be partially or completely dependent on or combined with each other, and may be interlocked and operated in various ways technically, and the embodiments may be performed independently of each other or in association with each other.

[0033] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the drawings.

[0034] Figure 1 is a schematic cross-sectional view of a light-emitting element according to an embodiment of the present specification.

[0035] Referring to Figure 1 , the light-emitting element ED1 may include a first electrode 134, a first contact layer CTL1, a first-first type cladding layer CLa1, a first barrier layer B1, a first light-emitting layer 132a, a second barrier layer B2, a second-first type cladding layer CLb1, a tunnel layer TL, a first-second type cladding layer CLa2, a third barrier layer B3, a second light-emitting layer 132b, a fourth barrier layer B4, a second-second type cladding layer CLb2, a window layer WL, a second contact layer CTL2, and a second electrode 135.

[0036] The light-emitting element ED1 may have various structures, such as a lateral, vertical, and flip-chip structure. The lateral light-emitting element includes a first electrode and a second electrode horizontally disposed on two opposite sides of the light-emitting layer. The vertical light-emitting element includes a first electrode and a second electrode disposed on the upper side and the lower side of the light-emitting layer. The flip-chip light-emitting element is substantially the same as the lateral light-emitting element in structure. The lateral light-emitting element has a first electrode and a second electrode horizontally disposed on the upper side of the light-emitting layer, while the flip-chip light-emitting element has a first electrode and a second electrode horizontally disposed on the lower side of the light-emitting layer. Hereinafter, it is assumed that the light-emitting element ED1 has a vertical structure for description. However, the type of the light-emitting element ED1 is not limited thereto.

[0037] The light-emitting element ED1 may emit light beams of various colors according to the emission wavelength of the light-emitting layer. For example, the light-emitting element ED1 may emit light beams of various colors such as red, green, blue, etc. Hereinafter, it is assumed that the light-emitting element ED1 is a red light-emitting element, and the first light-emitting layer 132a and the second light-emitting layer 132b emit light beams having wavelengths in the red region for description. However, the light-emitting element ED1 may be a light-emitting element configured to emit light having various wavelengths. The light-emitting element ED1 may be a light-emitting element configured to emit green or blue light.

[0038] The first electrode 134 may be disposed on the lower side of the light-emitting element ED1.

[0039] The first electrode 134 may be made of a conductive material, such as a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO), or an opaque conductive material such as titanium (Ti), gold (Au), silver (Ag), copper (Cu), or an alloy thereof. However, the present specification is not limited thereto.

[0040] The first electrode 134 may be disposed adjacent to the first-first type cladding layer CLa1 of the light-emitting element ED1. Therefore, in the case where the first-first type cladding layer CLa1 is a semiconductor layer doped with an n-type impurity, the first electrode 134 may be referred to as an n electrode. However, the present specification is not limited thereto.

[0041] The first contact layer CTL1 may be disposed above the first electrode 134.

[0042] The first contact layer CTL1 may be disposed between the first electrode 134 and the first-first type cladding layer CLa1, and improve the ohmic characteristics between the first electrode 134 and the first-first type cladding layer CLa1.

[0043] The first-first type cladding layer CLa1 may be disposed above the first contact layer CTL1.

[0044] The first-first type cladding layer CLa1 may be a semiconductor layer configured to inject electrons into the first light-emitting layer 132a. For example, the first-first type cladding layer CLa1 may be a layer doped with a material such as aluminum indium phosphide (AlInP), which has n-type and p-type impurities. In this case, the p-type impurity may be magnesium (Mg), zinc (Zn), beryllium (Be), etc. The n-type impurity may be silicon (Si), germanium, tin (Sn), etc. However, the present specification is not limited thereto. In the present specification, the first-first type cladding layer CLa1 may be a layer doped with an n-type impurity and is referred to as the first semiconductor layer. However, the present specification is not limited thereto.

[0045] The first barrier layer B1 may be disposed on the first-first type cladding layer CLa1.

[0046] The first barrier layer B1 may inhibit holes from moving from the first light-emitting layer 132a onto the first barrier layer B1, and promote the coupling between electrons and holes. Therefore, among the plurality of barrier layers provided in the light-emitting element ED1, the first barrier layer B1 disposed adjacent to the first-first type cladding layer CLa1, i.e., the n-type semiconductor layer, may have a larger bandgap than the fourth barrier layer B4 disposed adjacent to the second-second type cladding layer CLb2, i.e., the p-type semiconductor layer.

[0047] The first barrier layer B1 can be made of a material such as aluminum gallium indium phosphide (AlGaInP). However, this specification is not limited thereto.

[0048] The first light-emitting layer 132a can be disposed above the first barrier layer B1.

[0049] The first light-emitting layer 132a can emit light by receiving holes and electrons from the first-first type cladding layer CLa1 and the second-second type cladding layer CLb2. For example, in the case where the first-first type cladding layer CLa1 is a semiconductor layer doped with an n-type impurity and the second-second type cladding layer CLb2 is a semiconductor layer doped with a p-type impurity, the first light-emitting layer 132a can receive electrons moving upward from the first-first type cladding layer CLa1 and holes moving downward from the second-second type cladding layer CLb2, and emit light when the electrons and holes are coupled. The first light-emitting layer 132a can be configured as a single layer or a multi-quantum well (MQW) structure. However, this specification is not limited thereto.

[0050] The first light-emitting layer 132a can include a plurality of first sub-light-emitting layers configured to emit light beams having different wavelengths. For example, the plurality of first sub-light-emitting layers can include a first-first sub-light-emitting layer 132a1, a first-second sub-light-emitting layer 132a2 disposed on the first-first sub-light-emitting layer 132a1, and a first-third sub-light-emitting layer 132a3 disposed on the first-second sub-light-emitting layer 132a2.

[0051] The plurality of first sub-light-emitting layers can be made of a material such as aluminum gallium indium phosphide (AlGaInP).

[0052] Meanwhile, the plurality of first sub-light-emitting layers can have different aluminum contents. The aluminum contents of the plurality of first sub-light-emitting layers can increase in one direction. For example, the aluminum contents of the plurality of first sub-light-emitting layers can increase in the downward direction. For example, in the case where an n-type semiconductor layer is disposed on the lower side of the light-emitting element ED1 and a p-type semiconductor layer is disposed on the upper side of the light-emitting element ED1, the aluminum contents of the plurality of first sub-light-emitting layers can increase as the plurality of first sub-light-emitting layers get closer to the n-type semiconductor layer. The aluminum content of the first-first sub-light-emitting layer 132a1 can be 0.18% to 0.19% by weight, the aluminum content of the first-second sub-light-emitting layer 132a2 can be 0.17% to 0.18% by weight, and the aluminum content of the first-third sub-light-emitting layer 132a3 can be 0.16% to 0.17% by weight.

[0053] Therefore, the emission wavelengths of the plurality of first sub-light-emitting layers can increase in one direction. Specifically, the emission wavelengths of the plurality of first sub-light-emitting layers can increase in the upward direction. For example, in the case where the n-type semiconductor layer is disposed on the lower side of the light-emitting element ED1 and the p-type semiconductor layer is disposed on the upper side of the light-emitting element ED1, the emission wavelengths of the plurality of first sub-light-emitting layers can increase as the plurality of first sub-light-emitting layers become closer to the p-type semiconductor layer. The first-first sub-light-emitting layer 132a1 can emit light having a wavelength of about 616 nm, the first-second sub-light-emitting layer 132a2 can emit light having a wavelength of about 618 nm, and the first-third sub-light-emitting layer 132a3 can emit light having a wavelength of about 620 nm.

[0054] Meanwhile, the materials constituting the plurality of first sub-light-emitting layers and the emission bands of the plurality of first sub-light-emitting layers are not limited thereto.

[0055] The second barrier layer B2 can be disposed on the first light-emitting layer 132a.

[0056] The second barrier layer B2 can be configured to promote the coupling between electrons and holes and is made of a material such as aluminum gallium indium phosphide (AlGaInP). However, the present specification is not limited thereto.

[0057] The second-first type cladding layer CLb1 can be disposed on the second barrier layer B2.

[0058] The second-first type cladding layer CLb1 can be a semiconductor layer configured to inject holes into the first light-emitting layer 132a. For example, the second-first type cladding layer CLb1 can be a layer doped with a material such as aluminum indium phosphide (AlInP) having n-type and p-type impurities. In this case, the p-type impurity can be magnesium (Mg), zinc (Zn), beryllium (Be), etc. The n-type impurity can be silicon (Si), germanium, tin (Sn), etc. However, the present specification is not limited thereto. In the present specification, the second-first type cladding layer CLb1 is defined as a p-type semiconductor layer, that is, a layer doped with p-type impurities. However, the present specification is not limited thereto.

[0059] Meanwhile, the light-emitting element ED1 may not include the second-first type cladding layer CLb1 to reduce the manufacturing cost and the number of processes of the light-emitting element ED1. However, the present specification is not limited thereto.

[0060] The tunnel layer TL can be disposed on the second-first type cladding layer CLb1.

[0061] The tunnel layer TL can be disposed between the first light-emitting layer 132a and the second light-emitting layer 132b and improve the light-emitting efficiency and color reproduction range of the light-emitting element ED1.

[0062] The first-second type cladding layer CLa2 may be disposed on the tunnel layer TL.

[0063] The first-second type cladding layer CLa2 may be a semiconductor layer configured to inject electrons into the second light-emitting layer 132b. For example, the first-second type cladding layer CLa2 may be a layer doped with a material such as aluminum indium phosphide (AlInP) having n-type and p-type impurities. In this case, the p-type impurity may be magnesium (Mg), zinc (Zn), beryllium (Be), etc. The n-type impurity may be silicon (Si), germanium, tin (Sn), etc. However, the present specification is not limited thereto. In the present specification, the first-second type cladding layer CLa2 is defined as an n-type semiconductor layer, i.e., a layer doped with n-type impurities. However, the present specification is not limited thereto.

[0064] Meanwhile, the light-emitting element ED1 may not include the first-second type cladding layer CLa2 to reduce the cost and number of processes for manufacturing the light-emitting element ED1. However, the present specification is not limited thereto.

[0065] The third barrier layer B3 may be disposed on the first-second type cladding layer CLa2. The third barrier layer B3 may promote the coupling between electrons and holes. The third barrier layer B3 may be made of a material such as aluminum gallium indium phosphide (AlGaInP). However, the present specification is not limited thereto.

[0066] The second light-emitting layer 132b may be disposed on the third barrier layer B3. The second light-emitting layer 132b may emit light by receiving holes and electrons from the first-first type cladding layer CLa1 and the second-second type cladding layer CLb2. For example, in the case where the first-first type cladding layer CLa1 is a semiconductor layer doped with n-type impurities and the second-second type cladding layer CLb2 is a semiconductor layer doped with p-type impurities, the second light-emitting layer 132b may receive electrons moving upward from the first-first type cladding layer CLa1 and holes moving downward from the second-second type cladding layer CLb2, and emit light when the electrons and holes are coupled. The second light-emitting layer 132b may be configured as a single layer or a multi-quantum well (MQW) structure. However, the present specification is not limited thereto.

[0067] The second light-emitting layer 132b may emit light having a wavelength different from the wavelength of the light emitted from the first light-emitting layer 132a. For example, the second light-emitting layer 132b and the first light-emitting layer 132a may be made of different materials.

[0068] The second light-emitting layer 132b may include a plurality of second sub-light-emitting layers configured to emit light beams having different wavelengths. For example, the plurality of second sub-light-emitting layers may include a second-first sub-light-emitting layer 132b1, a second-second sub-light-emitting layer 132b2 disposed on the second-first sub-light-emitting layer 132b1, and a second-third sub-light-emitting layer 132b3 disposed on the second-second sub-light-emitting layer 132b2.

[0069] The plurality of second sub-light-emitting layers may be made of aluminum gallium indium phosphide (AlGaInP). At the same time, the plurality of second sub-light-emitting layers may have different aluminum contents. In this case, the aluminum content of the plurality of second sub-light-emitting layers may increase in one direction. For example, the aluminum content of the plurality of second sub-light-emitting layers may increase in the downward direction. For example, in the case where the n-type semiconductor layer is disposed on the lower side of the light-emitting element ED1 and the p-type semiconductor layer is disposed on the upper side of the light-emitting element ED1, the aluminum content of the plurality of second sub-light-emitting layers may increase as the plurality of second sub-light-emitting layers become closer to the n-type semiconductor layer. The aluminum content of the second-first sub-light-emitting layer 132b1 may be 0.13% to 0.14% by weight, the aluminum content of the second-second sub-light-emitting layer 132b2 may be 0.12% to 0.13% by weight, and the aluminum content of the second-third sub-light-emitting layer 132b3 may be 0.11% to 0.12% by weight.

[0070] Therefore, the emission wavelengths of the plurality of second sub-light-emitting layers may increase in one direction. Specifically, the emission wavelengths of the plurality of second sub-light-emitting layers may increase in the upward direction. For example, in the case where the n-type semiconductor layer is disposed on the lower side of the light-emitting element ED1 and the p-type semiconductor layer is disposed on the upper side of the light-emitting element ED1, the emission wavelengths of the plurality of second sub-light-emitting layers may increase as the plurality of second sub-light-emitting layers become closer to the p-type semiconductor layer. The second-first sub-light-emitting layer 132b1 may emit light having a wavelength of about 626 nm, the second-second sub-light-emitting layer 132b2 may emit light having a wavelength of about 628 nm, and the second-third sub-light-emitting layer 132b3 may emit light having a wavelength of about 630 nm. However, this specification is not limited thereto.

[0071] At the same time, the materials constituting the plurality of second sub-light-emitting layers and the emission bands of the plurality of second sub-light-emitting layers are not limited thereto.

[0072] The fourth barrier layer B4 may be disposed on the second light-emitting layer 132b.

[0073] The fourth barrier layer B4 may inhibit electrons from moving from the second light-emitting layer 132b in the direction in which the fourth barrier layer B4 is disposed. The fourth barrier layer B4 may promote the coupling between electrons and holes.

[0074] The fourth barrier layer B4 can be made of a material such as aluminum gallium indium phosphide (AlGaInP). However, this specification is not limited thereto.

[0075] The second - second type cladding layer CLb2 can be provided on the fourth barrier layer B4.

[0076] The second - second type cladding layer CLb2 can be a semiconductor layer configured to inject holes into the second light - emitting layer 132b. For example, the second - second type cladding layer CLb2 can be a layer doped with a material such as aluminum indium phosphide (AlInP) having n - type and p - type impurities. In this case, the p - type impurity can be magnesium (Mg), zinc (Zn), beryllium (Be), etc. The n - type impurity can be silicon (Si), germanium, tin (Sn), etc. However, this specification is not limited thereto. In this specification, the second - second type cladding layer CLb2 can be a layer doped with p - type impurities and is referred to as the second semiconductor layer. However, this specification is not limited thereto.

[0077] The window layer WL can be provided on the second - second type cladding layer CLb2. To improve the light extraction efficiency, the window layer WL can be provided on the second - second type cladding layer CLb2 which is disposed on the upper side of the light - emitting element ED1 among the first - first type cladding layer CLa1 and the second - second type cladding layer CLb2.

[0078] The second contact layer CTL2 can be provided above the window layer WL. The second contact layer CTL2 can be provided between the second electrode 135 and the second - second type cladding layer CLb2 and improves the ohmic characteristics between the second electrode 135 and the second - second type cladding layer CLb2. For example, the second contact layer CTL2 can be a semiconductor layer doped with a gallium phosphide (GaP) material having carbon (C). However, this specification is not limited thereto.

[0079] The second electrode 135 can be provided on the second contact layer CTL2. The second electrode 135 can be made of a conductive material such as a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) or an opaque conductive material such as titanium (Ti), gold (Au), silver (Ag), copper (Cu), or an alloy thereof. However, this specification is not limited thereto.

[0080] The second electrode 135 can be disposed adjacent to the second - second type cladding layer CLb2 of the light - emitting element ED1. Thus, in the case where the second - second type cladding layer CLb2 is a layer doped with p - type impurities, the second electrode 135 can be referred to as a p - electrode. However, this specification is not limited thereto.

[0081] The light-emitting element ED1 according to an embodiment of the present specification includes a first light-emitting layer 132a including a plurality of first sub-light-emitting layers and a second light-emitting layer 132b including a plurality of second sub-light-emitting layers. Accordingly, the luminance of the light-emitting element ED1 can be increased, and the luminous efficiency of the light-emitting element ED1 can be increased.

[0082] In addition, the plurality of first sub-light-emitting layers and the plurality of second sub-light-emitting layers of the light-emitting element ED1 according to an embodiment of the present specification emit light beams having different wavelengths. Accordingly, the light-emitting element ED1 can emit light beams of various wavelength bands, so that the color reproduction range of the light-emitting element ED1 can be improved.

[0083] Meanwhile, a display device includes a light-emitting element configured to emit light beams having various wavelengths to realize various colors. Meanwhile, the luminance and the luminous efficiency of the light-emitting element can vary according to the emission wavelength of the light-emitting element. For example, the luminous efficiency of a light-emitting element configured to emit red light is lower than that of a blue light-emitting element and a green light-emitting element. Accordingly, when all the light-emitting elements of the display device operate to exhibit maximum luminance, the luminance of the red light may be relatively lower than the luminance of the blue light and the luminance of the green light. Accordingly, there is a problem in that a luminance deviation occurs according to the color in the display device.

[0084] Accordingly, in the light-emitting element ED1 according to an embodiment of the present specification, the plurality of first sub-light-emitting layers and the plurality of second sub-light-emitting layers emit red light having different wavelengths. Accordingly, compared with a red light-emitting element in which a light-emitting layer configured to emit light having a single wavelength is provided, the light-emitting element ED1 according to an embodiment of the present specification can increase the luminance and the luminous efficiency. For example, the luminance of the light-emitting element ED1 that emits red light can be increased to a level corresponding to the maximum luminance of a green light-emitting element and the maximum luminance of a blue light-emitting element. Accordingly, the light-emitting element ED1 according to an embodiment of the present specification can solve the problem of luminance deviation occurring according to the color.

[0085] In addition, the light-emitting layer of the red light-emitting element may have a smaller bandgap than the light-emitting layer of a light-emitting element configured to emit light having another color. Accordingly, the bandgap of the light-emitting layer can be easily adjusted, and the emission wavelength can be easily adjusted. Accordingly, in the light-emitting element ED1 according to an embodiment of the present specification, the emission wavelengths of the plurality of first sub-light-emitting layers and the plurality of second sub-light-emitting layers of the red light-emitting element can be easily adjusted.

[0086] In addition, in the light-emitting element ED1 according to the embodiment of the present specification, the aluminum content of the plurality of first sub-light-emitting layers and the plurality of second sub-light-emitting layers can increase from one surface in contact with the first-first type cladding layer CLa1 toward the other surface in contact with the second-second type cladding layer CLb2. Therefore, the lattice parameter difference that appears at the interface between the plurality of first sub-light-emitting layers and the plurality of second sub-light-emitting layers can be reduced. Therefore, the film quality of the light-emitting element ED1 can be improved.

[0087] Figure 2 is a schematic cross-sectional view of a light-emitting element according to another embodiment of the present specification. In addition to the first light-emitting layer 232a and the second light-emitting layer 232b, Figure 2 the light-emitting element ED2 in Figure 1 is basically the same as the light-emitting element ED1 in

[0088] Referring to Figure 2 , the first light-emitting layer 232a may include a plurality of first sub-light-emitting layers configured to emit light beams having different wavelengths. For example, the plurality of first sub-light-emitting layers may include a first-first sub-light-emitting layer 232a1, a first-second sub-light-emitting layer 232a2 provided on the first-first sub-light-emitting layer 232a1, and a first-third sub-light-emitting layer 232a3 provided on the first-second sub-light-emitting layer 232a2.

[0089] The plurality of first sub-light-emitting layers may be made of a material such as aluminum gallium indium phosphide (AlGaInP).

[0090] Meanwhile, the plurality of first sub-light-emitting layers may have different aluminum contents. The aluminum content of the plurality of first sub-light-emitting layers can increase in one direction. For example, the aluminum content of the plurality of first sub-light-emitting layers can increase in the upward direction. For example, in the case where the n-type semiconductor layer is provided on the lower side of the light-emitting element ED2 and the p-type semiconductor layer is provided on the upper side of the light-emitting element ED2, the aluminum content of the plurality of first sub-light-emitting layers can increase as the plurality of first sub-light-emitting layers get closer to the p-type semiconductor layer. The aluminum content of the first-first sub-light-emitting layer 232a1 may be 0.11% to 0.12% by weight, the aluminum content of the first-second sub-light-emitting layer 232a2 may be 0.12% to 0.13% by weight, and the aluminum content of the first-third sub-light-emitting layer 232a3 may be 0.13% to 0.14% by weight.

[0091] Therefore, the emission wavelengths of the multiple first sub-light-emitting layers can increase in one direction. Specifically, the emission wavelengths of the multiple first sub-light-emitting layers can increase in the downward direction. For example, in the case where the n-type semiconductor layer is disposed on the lower side of the light-emitting element ED2 and the p-type semiconductor layer is disposed on the upper side of the light-emitting element ED2, the emission wavelengths of the multiple first sub-light-emitting layers can increase as the multiple first sub-light-emitting layers get closer to the n-type semiconductor layer. The first-first sub-light-emitting layer 232a1 can emit light with a wavelength of approximately 630 nm, the first-second sub-light-emitting layer 232a2 can emit light with a wavelength of approximately 628 nm, and the first-third sub-light-emitting layer 232a3 can emit light with a wavelength of approximately 626 nm.

[0092] Meanwhile, the materials constituting the multiple first sub-light-emitting layers and the emission bands of the multiple first sub-light-emitting layers are not limited thereto.

[0093] Referring to Figure 2 , the second light-emitting layer 232b can be disposed on the third barrier layer B3.

[0094] The second light-emitting layer 232b can emit light with a wavelength different from the wavelength of the light emitted from the first light-emitting layer 232a. For example, the second light-emitting layer 232b and the first light-emitting layer 232a can be made of different materials.

[0095] The second light-emitting layer 232b can include multiple second sub-light-emitting layers configured to emit light beams with different wavelengths. For example, the multiple second sub-light-emitting layers can include a second-first sub-light-emitting layer 232b1, a second-second sub-light-emitting layer 232b2 disposed on the second-first sub-light-emitting layer 232b1, and a second-third sub-light-emitting layer 232b3 disposed on the second-second sub-light-emitting layer 232b2.

[0096] The multiple second sub-light-emitting layers can be made of aluminum gallium indium phosphide (AlGaInP). Meanwhile, the multiple second sub-light-emitting layers can have different aluminum contents. In this case, the aluminum contents of the multiple second sub-light-emitting layers can increase in one direction. For example, the aluminum contents of the multiple second sub-light-emitting layers can increase in the upward direction. For example, in the case where the n-type semiconductor layer is disposed on the lower side of the light-emitting element ED2 and the p-type semiconductor layer is disposed on the upper side of the light-emitting element ED2, the aluminum contents of the multiple second sub-light-emitting layers can increase as the multiple second sub-light-emitting layers get closer to the p-type semiconductor layer. The aluminum content of the second-first sub-light-emitting layer 232b1 can be 0.16% to 0.17% by weight, the aluminum content of the second-second sub-light-emitting layer 232b2 can be 0.17% to 0.18% by weight, and the aluminum content of the second-third sub-light-emitting layer 232b3 can be 0.18% to 0.19% by weight.

[0097] Therefore, the emission wavelengths of the plurality of second sub-light-emitting layers can increase in one direction. Specifically, the emission wavelengths of the plurality of second sub-light-emitting layers can increase in the downward direction. For example, in the case where the n-type semiconductor layer is disposed on the lower side of the light-emitting element ED2 and the p-type semiconductor layer is disposed on the upper side of the light-emitting element ED2, the emission wavelengths of the plurality of second sub-light-emitting layers can increase as the plurality of second sub-light-emitting layers become closer to the n-type semiconductor layer. The second-first sub-light-emitting layer 232b1 can emit light having a wavelength of about 620 nm, the second-second sub-light-emitting layer 232b2 can emit light having a wavelength of about 618 nm, and the second-third sub-light-emitting layer 232b3 can emit light having a wavelength of about 616 nm. However, the present specification is not limited thereto.

[0098] Meanwhile, the materials constituting the plurality of second sub-light-emitting layers and the emission bands of the plurality of second sub-light-emitting layers are not limited thereto.

[0099] The light-emitting element ED2 according to another embodiment of the present specification includes a first light-emitting layer 232a including a plurality of first sub-light-emitting layers and a second light-emitting layer 232b including a plurality of second sub-light-emitting layers. Therefore, the brightness of the light-emitting element ED2 can be improved, and the luminous efficiency of the light-emitting element ED2 can be improved.

[0100] In addition, the plurality of first sub-light-emitting layers and the plurality of second sub-light-emitting layers of the light-emitting element ED2 according to another embodiment of the present specification emit light beams having different wavelengths. Therefore, the color reproduction range of the light-emitting element ED2 can be improved.

[0101] In addition, in the light-emitting element ED2 according to another embodiment of the present specification, the plurality of first sub-light-emitting layers and the plurality of second sub-light-emitting layers emit red light having different wavelengths. Therefore, the light-emitting element ED2 according to another embodiment of the present specification can solve the problem of brightness deviation according to color, and can easily adjust the emission wavelengths of the plurality of first sub-light-emitting layers and the plurality of second sub-light-emitting layers of the red light-emitting element.

[0102] In addition, in the light-emitting element ED2 according to another embodiment of the present specification, the aluminum content of the plurality of first sub-light-emitting layers and the plurality of second sub-light-emitting layers can increase in one direction. Therefore, the difference in lattice parameters occurring at the interface between the plurality of first sub-light-emitting layers and the plurality of second sub-light-emitting layers can be reduced.

[0103] In addition, in the light-emitting element ED2 according to another embodiment of the present specification, the emission wavelengths of the plurality of first sub-light-emitting layers and the plurality of second sub-light-emitting layers may decrease in the upward direction of the light-emitting element ED2. In a general light-emitting element, the transmittance of a light-emitting layer that emits light in a long wavelength band is lower than that of a light-emitting layer that emits light in a short wavelength band. Therefore, in the light-emitting element ED2 according to another embodiment of the present specification, the first-first sub-light-emitting layer 232a1 provided on the lower side of the light-emitting element ED2 emits light in the longest wavelength band, and the second-third sub-light-emitting layer 232b3 provided on the upper side of the light-emitting element ED2 emits light in the shortest wavelength band. Therefore, the transmittance of the light-emitting element ED2 can be improved.

[0104] Figure 3A And Figure 3B are views for explaining the effects of the light-emitting elements according to various embodiments of the present specification. Figure 3A Shows the emission spectrum simulation results related to the comparative embodiment and Embodiments 1 and 2. In Figure 3A the maximum luminance of the comparative embodiment is assumed to be 1. Figure 3B Shows the CIE coordinate systems of the comparative embodiment and Embodiments 1 and 2.

[0105] The comparative embodiment relates to a general light-emitting element, that is, a light-emitting element in which a light-emitting layer that emits light of a single wavelength is provided. Embodiment 1 relates to Figure 1 the light-emitting element ED1 in which the aluminum content of the plurality of first sub-light-emitting layers and the plurality of second sub-light-emitting layers increases as the plurality of first sub-light-emitting layers and the plurality of second sub-light-emitting layers become closer to the n-type semiconductor layer among the n-type semiconductor layer and the p-type semiconductor layer. Embodiment 1 includes a first-first sub-light-emitting layer configured to emit light having a wavelength of 616 nm, a first-second sub-light-emitting layer configured to emit light having a wavelength of 618 nm, a first-third sub-light-emitting layer configured to emit light having a wavelength of 620 nm, a second-first sub-light-emitting layer configured to emit light having a wavelength of 626 nm, a second-second sub-light-emitting layer configured to emit light having a wavelength of 628 nm, and a second-third sub-light-emitting layer configured to emit light having a wavelength of 630 nm. Embodiment 2 relates to Figure 2The light-emitting element ED2 therein, wherein the aluminum content of the plurality of first sub-light-emitting layers and the plurality of second sub-light-emitting layers increases as the plurality of first sub-light-emitting layers and the plurality of second sub-light-emitting layers become closer to the p-type semiconductor layer among the n-type semiconductor layer and the p-type semiconductor layer. Embodiment 2 includes a first-first sub-light-emitting layer configured to emit light having a wavelength of 630 nm, a first-second sub-light-emitting layer configured to emit light having a wavelength of 628 nm, a first-third sub-light-emitting layer configured to emit light having a wavelength of 626 nm, a second-first sub-light-emitting layer configured to emit light having a wavelength of 620 nm, a second-second sub-light-emitting layer configured to emit light having a wavelength of 618 nm, and a second-third sub-light-emitting layer configured to emit light having a wavelength of 616 nm.

[0106] First, referring to Figure 3A , it can be determined that the maximum brightness in the comparative embodiment is 1, the maximum brightness in Embodiment 1 is about 1.1, and the maximum brightness in Embodiment 2 is about 1.16. Therefore, it can be determined that the maximum brightness in Embodiments 1 and 2 is higher than the maximum brightness in the comparative embodiment. It can be determined that the maximum brightness in Embodiment 2 is higher than the maximum brightness in Embodiment 1.

[0107] In addition, referring to Figure 3A , it can be determined that the wavelength widths in Embodiments 1 and 2 are greater than the wavelength width in the comparative embodiment. It can be determined that the wavelength width in Embodiment 2 is greater than the wavelength width in Embodiment 1.

[0108] Next, referring to Figure 3B , it can be determined that the x-coordinates in Embodiments 1 and 2 are further moved in the + direction compared to the x-coordinate in the comparative embodiment, and the y-coordinates in Embodiments 1 and 2 are further moved in the - direction compared to the y-coordinate in the comparative embodiment. Therefore, it can be determined that the red region in Embodiments 1 and 2 is expanded.

[0109] Hereinafter, a description will be made with reference to Table 1.

[0110] Table 1 shows the color reproduction ranges in the comparative embodiment and Embodiments 1 and 2. Table 1 shows the color reproduction ranges in the comparative embodiment and Embodiments 1 and 2 based on BT.2020.

[0111] Table 1

[0112] Color reproduction range (%) Comparative embodiment 87.4 Embodiment 1 90.4 Embodiment 2 90.4

[0113] Referring to Table 1, it can be determined that the color reproduction ranges in Embodiments 1 and 2 are about 3% higher than the color reproduction range in the comparative embodiment. Therefore, it can be determined that the color reproduction ranges in Embodiments 1 and 2 are greater than the color reproduction range in the comparative embodiment.

[0114] Figure 4 It is a schematic configuration diagram of a display device according to an embodiment of the present specification. For ease of description, Figure 4 only the display panel PN, the gate driving unit GD, the data driving unit DD, and the timing controller TC among various components of the display device 1000 are shown. The gate driving unit GD and the data driving unit DD are configured to drive the display panel PN.

[0115] The gate driving unit GD supplies a plurality of scan signals to a plurality of scan lines SL in response to a plurality of gate control signals provided from the timing controller TC. Figure 4 It is shown that a single gate driving unit GD is provided to be spaced apart from one side of the display panel PN. However, the number and arrangement of the gate driving units GD are not limited thereto.

[0116] The data driving unit DD converts the image data input from the timing controller TC into a data voltage by using a reference gamma voltage in response to a plurality of data control signals provided from the timing controller TC. The data driving unit DD may supply the converted data voltage to a plurality of data lines DL.

[0117] The timing controller TC aligns the image data input from the outside and supplies the image data to the data driving unit DD. The timing controller TC may generate a gate control signal and a data control signal by using synchronization signals, namely a dot clock signal, a data enable signal, and a horizontal / vertical synchronization signal input from the outside. In addition, the timing controller TC may control the gate driving unit GD and the data driving unit DD by supplying the generated gate control signal and data control signal to the gate driving unit GD and the data driving unit DD.

[0118] The display panel PN is configured to display an image to a user and includes a plurality of sub-pixels SP. In the display panel PN, a plurality of scan lines SL and a plurality of data lines DL cross each other, and each of the plurality of sub-pixels SP is connected to the scan line SL and the data line DL. In addition, although not shown in the drawings, the plurality of sub-pixels SP may be respectively connected to a high-potential power line, a low-potential power line, a reference line, etc.

[0119] The display panel PN may have a display area AA and a non-display area NA configured to surround the display area AA. The non-display area NA may completely or only partially surround the display area AA.

[0120] The display area AA is the area where the display device 1000 displays an image. The display area AA may include a plurality of sub-pixels SP that constitute a plurality of pixels PX and a circuit configured to operate the plurality of sub-pixels SP. The plurality of sub-pixels SP are the smallest units that constitute the display area AA. n sub-pixels SP may constitute a single pixel. A light-emitting element, a thin-film transistor for operating the light-emitting element, etc. may be provided in each of the plurality of sub-pixels SP. Depending on the type of the display panel PN, the plurality of light-emitting elements may be defined in different ways. For example, in the case where the display panel PN is an inorganic light-emitting display panel, the light-emitting element may be a light-emitting diode (LED) or a micro light-emitting diode (micro LED).

[0121] A plurality of lines for sending various types of signals to the plurality of sub-pixels SP are provided in the display area AA. For example, the plurality of lines may include a plurality of data lines DL for supplying a data voltage to the plurality of sub-pixels SP and a plurality of scan lines SL for supplying a scan signal to the plurality of sub-pixels SP. The plurality of scan lines SL may extend in one direction in the display area AA and be connected to the plurality of sub-pixels SP. The plurality of data lines DL may extend in a direction different from one direction in the display area AA and may be connected to the plurality of sub-pixels SP. In addition, a low-potential power line, a high-potential power line, etc. may also be provided in the display area AA. However, this specification is not limited thereto.

[0122] The non-display area NA may be defined as an area that does not display an image, that is, an area extending from the display area AA. The non-display area NA may include link lines and pad electrodes for sending signals to the sub-pixels SP in the display area AA. Alternatively, the non-display area NA may include drive ICs, such as a gate driver IC and a data driver IC.

[0123] However, the non-display area NA may be located on the rear surface of the display panel PN, that is, the surface on which no sub-pixels SP exist. Alternatively, the non-display area NA may not be included. However, this specification is not limited to the configuration shown in the drawings.

[0124] Meanwhile, drive units such as a gate drive unit GD, a data drive unit DD, and a timing controller TC may be connected to the display panel PN in various ways. For example, the gate drive unit GD may be installed in the non-display area NA by an in-panel gate (GIP) method or between a plurality of sub-pixels SP in the display area AA by an in-active area gate (GIA) method. For example, the data drive unit DD and the timing controller TC may be formed on a separate flexible film and a printed circuit board PCB. The data drive unit DD and the timing controller TC may be electrically connected to the display panel PN by bonding the flexible film and the printed circuit board PCB to pad electrodes formed in the non-display area NA of the display panel PN.

[0125] When the gate driving unit GD is installed by the GIP method and the data driving unit DD and the timing controller TC send signals to the display panel PN through the pad electrodes in the non-display area NA, it is necessary to ensure that the area of the non-display area NA is at a predetermined level or higher in order to set the gate driving unit GD and the pad electrodes, which may increase the bezel.

[0126] Alternatively, when the gate driving unit GD is installed in the display area AA by the GIA method and side lines are formed to connect the signal lines on the front surface of the display panel PN to the pad electrodes on the rear surface of the display panel PN to bond the flexible film and the printed circuit board to the rear surface of the display panel PN, the non-display area NA on the front surface of the display panel PN can be minimized. That is, when the gate driving unit GD, the data driving unit DD, and the timing controller TC are connected to the display panel PN by the above method, a zero bezel with substantially no bezel can be achieved.

[0127] Hereinafter, one sub-pixel SP of the display device 1000 according to an embodiment of the present specification will be described with reference to Figure 5 The display device 1000 may have a plurality of sub-pixels, and each sub-pixel has the configuration shown in Figure 5 .

[0128] Figure 5 is a cross-sectional view of a sub-pixel according to an embodiment of the present specification. For ease of description, Figure 5 only the substrate 110, the buffer layer 111, the gate insulating layer 112, the first interlayer insulating layer 113, the second interlayer insulating layer 114, the passivation layer 115, the first planarization layer 116a, the second planarization layer 116b, the bank BB, the protective layer 117, the cover layer 160, the optical film MF, the transistor DT, the light blocking layer BSM, the reflector RF, the light emitting element ED1, the power line VL, the connection electrode CE, and the bonding layer BDL are shown.

[0129] Referring to Figure 5 , the substrate 110 may be a substrate, that is, an insulating substrate configured to support the components disposed above the display device 1000. For example, the substrate 110 may be made of glass, resin, etc. In addition, the substrate 110 may include a polymer or plastic. In several embodiments, the substrate 110 may be made of a flexible plastic material.

[0130] A plurality of pixels may be formed on the substrate 110 so that an image can be displayed.

[0131] First, a light-blocking layer BSM can be provided on the substrate 110. The light-blocking layer BSM can block light from entering the active layer ACT of multiple transistors, thereby minimizing leakage current. For example, the light-blocking layer BSM can be provided under the active layer ACT of the transistor DT and block light from entering the active layer ACT. When light is emitted to the active layer ACT, leakage current occurs, which may reduce the reliability of the transistor. Therefore, a light-blocking layer BSM for blocking light can be provided on the substrate 110, thereby improving the reliability of the transistor DT. The light-blocking layer BSM can be made of an opaque conductive material such as copper (Cu), aluminum (Al), molybdenum (Mo), nickel (Ni), titanium (Ti), chromium (Cr), or an alloy thereof. However, this specification is not limited thereto.

[0132] A buffer layer 111 can be provided on the light-blocking layer BSM. For example, the buffer layer 111 can be configured as a single layer or multiple layers made of silicon oxide (SiOx) or silicon nitride (SiNx). However, this specification is not limited thereto. The buffer layer 111 can reduce the penetration of moisture or impurities through the substrate 110. However, depending on the type of the first substrate 110 or the type of the transistor, the buffer layer 111 may not be included. However, this specification is not limited thereto.

[0133] A transistor DT including an active layer ACT, a gate electrode GE, a source electrode SE, and a drain electrode DE can be provided on the buffer layer 111.

[0134] Meanwhile, although not shown in Figure 5 , an additional buffer layer can be provided between the substrate 110 and the light-blocking layer BSM. For example, similar to the buffer layer 111, the additional buffer layer can be configured as a single layer or multiple layers made of silicon oxide (SiOx) or silicon nitride (SiNx) to reduce the penetration of moisture or impurities through the substrate 110. However, this specification is not limited thereto.

[0135] First, the active layer ACT of the transistor DT can be provided on the buffer layer 111. The active layer ACT can be made of a semiconductor material such as an oxide semiconductor, amorphous silicon, or polycrystalline silicon. However, this specification is not limited thereto.

[0136] In addition, although not shown in the drawings, other transistors such as switching transistors, sensing transistors, and light-emitting control transistors can be additionally provided in addition to the transistor DT. The active layers of these transistors can be made of a semiconductor material such as an oxide semiconductor, amorphous silicon, or polycrystalline silicon. However, this specification is not limited thereto. In addition, the active layers of the transistors such as the transistor DT, the switching transistor, the sensing transistor, and the light-emitting control transistor included in the pixel circuit can be made of the same material or different materials.

[0137] A gate insulating layer 112 may be provided on the active layer ACT. The gate insulating layer 112 may be an insulating layer for electrically insulating the active layer ACT and the gate electrode GE. The gate insulating layer 112 may be configured as a single layer or multiple layers made of silicon oxide (SiOx) or silicon nitride (SiNx). However, the present specification is not limited thereto.

[0138] A gate electrode GE may be provided on the gate insulating layer 112. The gate electrode GE may be made of a conductive material such as copper (Cu), aluminum (Al), molybdenum (Mo), nickel (Ni), titanium (Ti), chromium (Cr), or an alloy thereof. However, the present specification is not limited thereto.

[0139] In addition, an intermediate electrode CNT may be provided on the gate insulating layer 112. The intermediate electrode CNT may be made of the same material as the gate electrode GE. For example, the intermediate electrode CNT may be made of copper (Cu), aluminum (Al), molybdenum (Mo), nickel (Ni), titanium (Ti), chromium (Cr), or an alloy thereof. The intermediate electrode CNT may be electrically connected to the source electrode SE. However, the present specification is not limited thereto.

[0140] A first interlayer insulating layer 113 and a second interlayer insulating layer 114 may be provided on the gate electrode GE. Contact holes through which the source electrode SE and the drain electrode DE are connected to the active layer ACT are formed in the first interlayer insulating layer 113 and the second interlayer insulating layer 114. The first interlayer insulating layer 113 and the second interlayer insulating layer 114 are insulating layers for protecting components provided below the first interlayer insulating layer 113 and the second interlayer insulating layer 114. The first interlayer insulating layer 113 and the second interlayer insulating layer 114 may each be configured as a single layer or multiple layers made of silicon oxide (SiOx) or silicon nitride (SiNx). However, the present specification is not limited thereto.

[0141] The source electrode SE and the drain electrode DE electrically connected to the active layer ACT may be provided on the second interlayer insulating layer 114. The drain electrode DE may be electrically connected to the first electrode 134 of the light-emitting element ED1, and the source electrode SE may be connected to another component of the pixel circuit. The source electrode SE and the drain electrode DE may each be made of a conductive material such as copper (Cu), aluminum (Al), molybdenum (Mo), nickel (Ni), titanium (Ti), chromium (Cr), or an alloy thereof. However, the present specification is not limited thereto.

[0142] A power line VL may be provided on the second interlayer insulating layer 114. The power line VL may be a low-potential power line. In the present specification, a configuration for supplying a low-potential voltage to the power line VL is described. However, the present specification is not limited thereto. The power line VL may be a high-potential power line. The power line VL may be made of the same material as the source electrode SE and the drain electrode DE. However, the present specification is not limited thereto.

[0143] The power line VL can be connected to the connection electrode CE. The power line VL can be connected to the second electrode 135 of the light-emitting element ED1 through the connection electrode CE. Therefore, the power line VL can transmit a low-potential voltage to the connection electrode CE and the second electrode 135 of the light-emitting element ED1.

[0144] A passivation layer 115 can be provided on the source electrode SE, the drain electrode DE, and the power line VL. The passivation layer 115 is an insulating layer for protecting the components provided below the passivation layer 115. The passivation layer 115 can be made of an inorganic material such as silicon oxide (SiOx) or silicon nitride (SiNx). However, the present specification is not limited thereto.

[0145] A first planarization layer 116a can be provided on the passivation layer 115. The first planarization layer 116a can planarize the upper part of the pixel circuit including the transistor DT. The first planarization layer 116a can be configured as a single layer or multiple layers and is made of, for example, benzocyclobutene or an acrylic-based organic material. However, the present specification is not limited thereto.

[0146] A plurality of reflectors RF can be provided on the first planarization layer 116a. The plurality of reflectors RF can be provided below the plurality of light-emitting elements ED1 and are electrically connected to the plurality of light-emitting elements ED1. The plurality of reflectors RF can be configured to reflect the light emitted from the plurality of light-emitting elements ED1 toward the upper side of the substrate 110 and have a shape corresponding to each of the plurality of sub-pixels SP. The plurality of reflectors RF can be used to reflect the light emitted from the plurality of light-emitting elements ED1 and serve as electrodes for electrically connecting the plurality of light-emitting elements ED1 and the pixel circuit. Specifically, the plurality of reflectors RF can be electrically connected to the drain electrode DE of the transistor DT through the contact holes in the passivation layer 115 and the first planarization layer 116a. That is, the plurality of reflectors RF can be electrically connected to the first electrode 134 of the plurality of light-emitting elements ED1 and the transistor DT.

[0147] Therefore, considering the light reflection efficiency and resistance, the plurality of reflectors RF can include various conductive layers. For example, the plurality of reflectors RF can be made by using an opaque conductive layer made of silver (Ag), aluminum (Al), molybdenum (Mo), titanium (Ti), or an alloy thereof, and a transparent conductive layer made of indium tin oxide (ITO). However, the structure of the plurality of reflectors RF is not limited thereto.

[0148] A plurality of bonding layers BDL may be provided on the plurality of reflection plates RF. The plurality of bonding layers BDL may fix the plurality of light emitting elements ED1 provided on the plurality of reflection plates RF. In addition, the plurality of bonding layers BDL may include a conductive material to electrically connect the plurality of reflection plates RF and the first electrodes 134 of the plurality of light emitting elements ED1. However, the present specification is not limited thereto. In the case where a conductive material is separately provided to electrically connect the plurality of reflection plates RF and the first electrodes 134 of the plurality of light emitting elements ED1, the plurality of bonding layers BDL may be made of an insulating material.

[0149] A plurality of light emitting elements ED1 may be disposed on a plurality of bonding layers BDL in each of a plurality of sub-pixels SP. A plurality of light emitting elements ED1 may be disposed on a plurality of bonding layers BDL and electrically connected to the reflective plate RF. Specifically, the first electrodes 134 of the plurality of light emitting elements ED1 and the reflective plate RF may be electrically connected through the plurality of bonding layers BDL.

[0150] The plurality of light emitting elements ED1 may be elements configured to emit light by current, and include a first light emitting element configured to emit red light, a second light emitting element configured to emit green light, and a third light emitting element configured to emit blue light. The combination of the light emitting elements ED1 may realize various colors including white. For example, the light emitting element ED1 may be a light emitting diode (LED) or a micro LED. However, the present specification is not limited thereto.

[0151] The plurality of light emitting elements ED1 may each include a first electrode 134, a first contact layer CTL1, a first-first type cladding layer CLa1, a first barrier layer B1, a first light emitting layer 132a, a second barrier layer B2, a second-first type cladding layer CLb1, a tunnel layer TL, a first-second type cladding layer CLa2, a third barrier layer B3, a second light emitting layer 132b, a fourth barrier layer B4, a second-second type cladding layer CLb2, a window layer WL, a second contact layer CTL2, and a second electrode 135. In the following, it is assumed that the plurality of light emitting elements ED1 have a vertical structure for description. However, the type of the plurality of light emitting elements ED1 is not limited thereto. In addition, in Figure 5 In the embodiment, the plurality of light emitting elements ED1 are described as adopting reference Figure 1 However, the present specification is not limited thereto. Figure 2 All the light emitting elements ED2 according to another embodiment of the present specification are described. Figure 1 The plurality of light emitting elements ED1 are described in detail, so a repeated description will be omitted.

[0152] Next, an encapsulation film 136 may be provided to surround the plurality of light emitting elements ED1. The encapsulation film 136 may be made of an insulating material, and protects the first electrode 134, the first contact layer CTL1, the first-first type cladding layer CLa1, the first barrier layer B1, the first light emitting layer 132a, the second barrier layer B2, the second-first type cladding layer CLb1, the tunnel layer TL, the first-second type cladding layer CLa2, the third barrier layer B3, the second light emitting layer 132b, the fourth barrier layer B4, the second-second type cladding layer CLb2, the window layer WL, the second contact layer CTL2, and the second electrode 135. Contact holes through which the first electrode 134 and the second electrode 135 are exposed may be formed in the encapsulation film 136. Therefore, the plurality of bonding layers BDL and the connection electrode CE may be electrically connected to the first electrode 134 and the second electrode 135.

[0153] Next, the second planarization layer 116b may be provided to surround the plurality of light emitting elements ED1. The second planarization layer 116b may be provided to surround the top and side surfaces of the plurality of light emitting elements ED1, and fix and protect the plurality of light emitting elements ED1. For example, the second planarization layer 116b may be made of an organic material such as benzocyclobutene or acrylic. However, the present specification is not limited thereto.

[0154] A connection electrode CE may be disposed on the second planarization layer 116b and the plurality of light emitting elements ED1. The connection electrode CE may contact the second electrode 135 disposed on the upper side of the plurality of light emitting elements ED1 and electrically connect the second electrode 135 of the plurality of light emitting elements ED1 and the power line VL. Specifically, the connection electrode CE may be electrically connected to the power line VL through a contact hole formed in the passivation layer 115, the first planarization layer 116a, and the second planarization layer 116b.

[0155] The connection electrode CE may be made of a conductive material, for example, a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) or an opaque conductive material such as titanium (Ti), gold (Au), silver (Ag), copper (Cu) or an alloy thereof. However, the present specification is not limited thereto.

[0156] A bank BB may be provided on the connection electrode CE. The bank BB may be provided to be spaced apart from the light emitting element ED1 at a predetermined interval and at least partially overlap the plurality of reflection plates RF. For example, the bank BB may cover a portion of the connection electrode CE formed on the passivation layer 115, the first planarization layer 116a, and the second planarization layer 116b.

[0157] The bank BB may be made of an opaque material such as a black resin to reduce color mixing between the plurality of sub-pixels SP. However, the present specification is not limited thereto.

[0158] A protective layer 117 may be disposed on the connection electrode CE and the bank BB. The protective layer 117 is a layer for protecting components disposed below the protective layer 117. The protective layer 117 may be configured as a single layer or multiple layers. For example, the protective layer 117 may be made of benzocyclobutene, a light-transmitting epoxy resin, a photoresist, or an acrylic-based organic material. However, the present specification is not limited thereto.

[0159] The optical film MF may be provided in the entire region of the upper portion of the substrate 110 and cover the upper portion of the cover layer 160. The optical film MF may be provided on the protective layer 117. The optical film MF may be a functional film that realizes an image with higher image quality while protecting the display device 1000. For example, the optical film MF may include an anti-scattering film, an anti-glare film, an anti-reflection film, a low-reflection film, an OLED transmittance controllable film, or a polarizing plate. However, the present specification is not limited thereto.

[0160] Meanwhile, a bonding portion may be disposed above the substrate 110 and disposed between the protective layer 117 and the optical film MF. The bonding portion may be formed on the front surface of the substrate 110 and bond the protective layer 117 to the optical film MF. The bonding portion may be made of a photocurable bonding material that can be cured by light. For example, the bonding portion may be made of an acrylic-based material including a photosensitizer. However, the present specification is not limited thereto.

[0161] Exemplary embodiments of the present disclosure may also be described as follows:

[0162] According to aspects of the present disclosure, a light-emitting element is provided. The light-emitting element includes: a first semiconductor layer; a first light-emitting layer disposed on the first semiconductor layer; a tunnel layer disposed on the first light-emitting layer; a second light-emitting layer disposed on the tunnel layer, and the second light-emitting layer is configured to emit light having a wavelength different from the wavelength of light emitted from the first light-emitting layer; and a second semiconductor layer disposed on the second light-emitting layer, wherein the first light-emitting layer includes a plurality of first sub-light-emitting layers configured to emit light having different wavelengths, and wherein the second light-emitting layer includes a plurality of second sub-light-emitting layers configured to emit light having different wavelengths.

[0163] The multiple first sub-light emitting layers may include: a first-first sub-light emitting layer; a first-second sub-light emitting layer arranged on the first-first sub-light emitting layer; and a first-third sub-light emitting layer arranged on the first-second sub-light emitting layer, wherein the multiple second sub-light emitting layers may include: a second-first sub-light emitting layer; a second-second sub-light emitting layer arranged on the second-first sub-light emitting layer; and a second-third sub-light emitting layer arranged on the second-second sub-light emitting layer, and wherein the multiple first sub-light emitting layers and the multiple second sub-light emitting layers may be made of aluminum gallium indium phosphide (AlGaInP).

[0164] The plurality of first sub-light emitting layers and the plurality of second sub-light emitting layers may have different aluminum contents.

[0165] The aluminum contents of the plurality of first sub-light emitting layers and the plurality of second sub-light emitting layers may increase in one direction.

[0166] The first semiconductor layer may be an n-type semiconductor layer, and the second semiconductor layer may be a p-type semiconductor layer.

[0167] The aluminum contents of the plurality of first sub light emitting layers and the plurality of second sub light emitting layers may increase as the plurality of first sub light emitting layers and the plurality of second sub light emitting layers become closer to the first semiconductor layer.

[0168] The aluminum contents of the plurality of first sub light emitting layers and the plurality of second sub light emitting layers may increase as the plurality of first sub light emitting layers and the plurality of second sub light emitting layers become closer to the second semiconductor layer.

[0169] The emission wavelengths of the plurality of first sub light emitting layers and the plurality of second sub light emitting layers may increase in one direction.

[0170] The first semiconductor layer may be an n-type semiconductor layer, and the second semiconductor layer may be a p-type semiconductor layer.

[0171] The emission wavelengths of the plurality of first sub light emitting layers and the plurality of second sub light emitting layers may increase as the plurality of first sub light emitting layers and the plurality of second sub light emitting layers become closer to the second semiconductor layer.

[0172] The emission wavelengths of the plurality of first sub light emitting layers and the plurality of second sub light emitting layers may increase as the plurality of first sub light emitting layers and the plurality of second sub light emitting layers become closer to the first semiconductor layer.

[0173] The first-first sub-light emitting layer may emit light having a wavelength of about 616nm, the first-second sub-light emitting layer may emit light having a wavelength of about 618nm, the first-third sub-light emitting layer may emit light having a wavelength of about 620nm, the second-first sub-light emitting layer may emit light having a wavelength of about 626nm, the second-second sub-light emitting layer may emit light having a wavelength of about 628nm, and the second-third sub-light emitting layer may emit light having a wavelength of about 630nm.

[0174] The first-first sub-light emitting layer may emit light having a wavelength of about 630nm, the first-second sub-light emitting layer may emit light having a wavelength of about 628nm, the first-third sub-light emitting layer may emit light having a wavelength of about 626nm, the second-first sub-light emitting layer may emit light having a wavelength of about 620nm, the second-second sub-light emitting layer may emit light having a wavelength of about 618nm, and the second-third sub-light emitting layer may emit light having a wavelength of about 616nm.

[0175] The light emitting element may further include: a cladding layer disposed between the tunnel layer and the first light emitting layer; and a window layer disposed above the second semiconductor layer.

[0176] The first semiconductor layer may be an n-type semiconductor layer made of aluminum indium phosphide (AlInP) doped with silicon (Si), and the second semiconductor layer may be a p-type semiconductor layer made of aluminum indium phosphide (AlInP) doped with magnesium (Mg).

[0177] The plurality of first sub-light emitting layers and the plurality of second sub-light emitting layers configured to emit red light having different wavelengths may have a smaller band gap than the light emitting layers of the light emitting elements configured to emit light having other colors.

Claims

1. A light emitting element, comprising: a first semiconductor layer; a first light emitting layer on the first semiconductor layer; a tunnel layer on the first light-emitting layer; a second light emitting layer on the tunnel layer, the second light emitting layer configured to emit light having a wavelength different from a wavelength of light emitted from the first light emitting layer; as well as a second semiconductor layer on the second light emitting layer, wherein the first light emitting layer includes a plurality of first sub-light emitting layers configured to emit light having different wavelengths, and The second light-emitting layer includes a plurality of second sub-light-emitting layers configured to emit light with different wavelengths.

2. The light-emitting element according to claim 1, wherein The plurality of first sub-light-emitting layers include: first - a first sub-light emitting layer; a first-second sub-light emitting layer on the first-first sub-light emitting layer; and first to third sub-light-emitting layers on the first to second sub-light-emitting layers, Wherein, the plurality of second sub-light-emitting layers include: second-first sub-light emitting layer; a second-second sub-light-emitting layer on the second-first sub-light-emitting layer; and a second-third sub-light emitting layer on the second-second sub-light emitting layer, and The plurality of first sub-light emitting layers and the plurality of second sub-light emitting layers are made of aluminum gallium indium phosphide (AlGaInP).

3. The light-emitting element according to claim 2, wherein: The plurality of first sub-light emitting layers and the plurality of second sub-light emitting layers have different aluminum contents.

4. The light-emitting element according to claim 2, wherein Aluminum contents of the plurality of first sub-light emitting layers and the plurality of second sub-light emitting layers increase in one direction.

5. The light emitting element according to claim 4, wherein The first semiconductor layer is an n-type semiconductor layer, and the second semiconductor layer is a p-type semiconductor layer.

6. The light-emitting element according to claim 5, wherein Aluminum contents of the plurality of first sub-light emitting layers and the plurality of second sub-light emitting layers increase as the plurality of first sub-light emitting layers and the plurality of second sub-light emitting layers become closer to the first semiconductor layer.

7. The light-emitting element according to claim 5, wherein The aluminum contents of the plurality of first sub-light emitting layers and the plurality of second sub-light emitting layers increase as the plurality of first sub-light emitting layers and the plurality of second sub-light emitting layers become closer to the second semiconductor layer.

8. The light-emitting element according to claim 2, wherein The aluminum content of the first-first sub-light-emitting layer is 0.18% to 0.19%, the aluminum content of the first-second sub-light-emitting layer is 0.17% to 0.18%, the aluminum content of the first-third sub-light-emitting layer is 0.16% to 0.17%, the aluminum content of the second-first sub-light-emitting layer is 0.13% to 0.14%, the aluminum content of the second-second sub-light-emitting layer is 0.12% to 0.13%, and the aluminum content of the second-third sub-light-emitting layer is 0.11% to 0.12%.

9. The light-emitting element according to claim 2, wherein: The aluminum content of the first-first sub-light-emitting layer is 0.11% to 0.12%, the aluminum content of the first-second sub-light-emitting layer is 0.12% to 0.13%, the aluminum content of the first-third sub-light-emitting layer is 0.13% to 0.14%, the aluminum content of the second-first sub-light-emitting layer is 0.16% to 0.17%, the aluminum content of the second-second sub-light-emitting layer is 0.17% to 0.18%, and the aluminum content of the second-third sub-light-emitting layer is 0.18% to 0.19%.

10. The light emitting element according to claim 2, wherein Emission wavelengths of the plurality of first sub-light emitting layers and the plurality of second sub-light emitting layers increase in one direction.

11. The light emitting element according to claim 10, wherein The first semiconductor layer is an n-type semiconductor layer, and the second semiconductor layer is a p-type semiconductor layer.

12. The light emitting element according to claim 11, wherein Emission wavelengths of the plurality of first sub light emitting layers and the plurality of second sub light emitting layers increase as the plurality of first sub light emitting layers and the plurality of second sub light emitting layers become closer to the second semiconductor layer.

13. The light emitting element according to claim 11, wherein Emission wavelengths of the plurality of first sub light emitting layers and the plurality of second sub light emitting layers increase as the plurality of first sub light emitting layers and the plurality of second sub light emitting layers become closer to the first semiconductor layer.

14. The light emitting element according to claim 2, wherein The first-first sub-light emitting layer emits light having a wavelength of about 616nm, the first-second sub-light emitting layer emits light having a wavelength of about 618nm, the first-third sub-light emitting layer emits light having a wavelength of about 620nm, the second-first sub-light emitting layer emits light having a wavelength of about 626nm, the second-second sub-light emitting layer emits light having a wavelength of about 628nm, and the second-third sub-light emitting layer emits light having a wavelength of about 630nm.

15. The light emitting element according to claim 2, wherein The first-first sub-light emitting layer emits light having a wavelength of about 630nm, the first-second sub-light emitting layer emits light having a wavelength of about 628nm, the first-third sub-light emitting layer emits light having a wavelength of about 626nm, the second-first sub-light emitting layer emits light having a wavelength of about 620nm, the second-second sub-light emitting layer emits light having a wavelength of about 618nm, and the second-third sub-light emitting layer emits light having a wavelength of about 616nm.

16. The light emitting element according to claim 1, further comprising: a cladding layer disposed between the tunnel layer and the first light-emitting layer; as well as A window layer is disposed above the second semiconductor layer.

17. The light emitting element according to claim 1, wherein The first semiconductor layer is an n-type semiconductor layer made of aluminum indium phosphide (AlInP) doped with silicon (Si), and the second semiconductor layer is a p-type semiconductor layer made of aluminum indium phosphide (AlInP) doped with magnesium (Mg).

18. The light emitting element according to claim 1, wherein The plurality of first sub-light emitting layers and the plurality of second sub-light emitting layers are configured to emit red light having different wavelengths.

19. The light emitting element according to claim 18, wherein The plurality of first sub-light emitting layers and the plurality of second sub-light emitting layers configured to emit red light having a different wavelength have a smaller band gap than a light emitting layer of a light emitting element configured to emit light having other colors.

20. A display device, comprising: A display panel including a plurality of sub-pixels, the display panel being configured to display an image, wherein each of the plurality of sub-pixels comprises the light-emitting element according to claim 1; and A gate driving part and a data driving part are configured to drive the display panel.

Images