Transparent display device and transparent display panel comprising same

Abstract

A transparent display device according to an embodiment comprises: a substrate; a light-emitting element; a lower wiring disposed on the substrate; a first insulating layer disposed on the lower wiring; an adhesive layer disposed between the first insulating layer and the light-emitting element; a first electrode disposed on the adhesive layer and electrically connected to the light-emitting element; a second insulating layer covering the light-emitting element and the first electrode; a light-transmitting second electrode disposed on the light-emitting element and electrically connected to the light-emitting element; and an upper wiring electrically connected to the light-transmitting second electrode, wherein the light-transmitting second electrode may be formed of a plurality of layers.

Description

Transparent display device and transparent display panel including the same

[0001] The present invention relates to a transparent display device and a transparent display panel including the same.

[0002] In the past, development has been made on transparent display devices that can display images without obstructing the view by allowing light to pass through from the front and back.

[0003] However, the opacity of metal electrodes limits their application, creating a growing need for transparent electrodes. Furthermore, as electronic devices become increasingly miniaturized and sophisticated, their applications are diversifying, leading to a growing demand for transparent electrodes beyond the aforementioned devices.

[0004] Transparent conductive oxides (TCOs) are highly versatile materials used as transparent electrodes. Indium tin oxide (ITO), a type of transparent conductive oxide, has been widely used as a candidate material for these transparent electrodes.

[0005] However, indium tin oxide (ITO) has relatively high sheet resistance compared to general metals, so its electrical conductivity is low, which may cause problems with the yield of display panels when used as general wiring.

[0006] Therefore, it is necessary to develop a transparent electrode that can increase transmittance while lowering surface resistance.

[0007]

[0008] Fig. 1 is a cross-sectional view of a display device according to internal technology, and Fig. 2 is a plan view of a display device according to internal technology.

[0009] A transparent display device according to internal technology may include a substrate (100), a lower wiring (110), a first insulating layer (120), an adhesive layer (130), a first electrode (140), a light-emitting element (150), a second insulating layer (170), a second electrode (180), and an upper wiring (190). The light-emitting element (150) may be arranged in multiples in consideration of redundancy.

[0010] In order to increase the light transmittance of the display device, the internal technology forms the second electrode (180) with a transparent conductive material. Typically, the transparent conductive material may include a metal oxide such as indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, or titanium oxide.

[0011] If the second electrode (180) is formed of ITO according to the internal technology, the transparent display device according to the comparative example may have improved light transmittance, but may have a problem of increased surface resistance. In addition, since the upper wiring (190) is formed of a metal material according to the internal technology, a problem of reduced light transmittance occurs.

[0012] The technical problem of the present invention is to provide a transparent display device having improved light transmittance while reducing surface resistance, and a transparent display panel including the same.

[0013] Another technical object of the present invention is to provide a transparent display device including a transparent electrode formed of a plurality of layers and a transparent display panel including the same.

[0014] Another technical problem of the present invention is to provide a transparent display device having improved light transmittance, electrical conductivity and mechanical strength of a transparent electrode formed of a plurality of layers, and a transparent display panel including the same.

[0015] A transparent display device according to an embodiment includes a substrate having lower wiring, a light-emitting element disposed on the substrate, a first electrode electrically connecting the lower wiring and the light-emitting element, a light-transmitting second electrode disposed on the light-emitting element and electrically connected to the light-emitting element, and an upper wiring electrically connected to the light-transmitting second electrode, wherein the light-transmitting second electrode may be formed in a plurality of layers.

[0016] In addition, a transparent display device according to an embodiment may include a substrate having lower wiring, a light-emitting element disposed on the substrate, a first electrode electrically connected to the light-emitting element, a light-transmitting second electrode disposed on the light-emitting element and electrically connected to the light-emitting element, and an upper wiring electrically connected to the light-transmitting second electrode.

[0017] The above lower wiring may include a first lower wiring layer, a second lower wiring layer, and a third lower wiring layer that are arranged sequentially.

[0018] The first electrode, the first lower wiring layer, and the second lower wiring layer may include any one of indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, and titanium oxide.

[0019] The second lower wiring layer may include at least one metal selected from the group consisting of chromium (Cr), nickel (Ni), copper (Cu), aluminum (Al), silver (Ag), molybdenum (Mo), gold (Au), titanium (Ti), and alloys thereof.

[0020] In addition, a transparent display device according to an embodiment may include a substrate having lower wiring, a light-emitting element disposed on the substrate, a first electrode electrically connected to the light-emitting element, and a light-transmitting second electrode disposed on the light-emitting element and electrically connected to the light-emitting element, wherein the light-transmitting second electrode may include a 2-1 electrode layer in contact with the second semiconductor layer, a 2-2 electrode layer disposed on the 2-1 electrode layer, and a 2-3 electrode layer disposed on the 2-2 electrode layer.

[0021]

[0022] A transparent display device according to an embodiment includes a substrate, a light-emitting element, a lower wiring disposed on the substrate, a first insulating layer disposed on the lower wiring, an adhesive layer disposed between the first insulating layer and the light-emitting element, a first electrode disposed on the adhesive layer and electrically connected to the light-emitting element, a second insulating layer covering the light-emitting element and the first electrode, a light-transmitting second electrode disposed on the light-emitting element and electrically connected to the light-emitting element, and an upper wiring electrically connected to the light-transmitting second electrode, wherein the light-transmitting second electrode may be formed of a plurality of layers.

[0023] In addition, the light-emitting element may include a first semiconductor layer electrically connected to the first electrode by contact, a light-emitting layer disposed on the first semiconductor layer, a second semiconductor layer disposed on the light-emitting layer and in contact with the light-transmitting second electrode; and a passivation layer disposed on a surface of the light-emitting element.

[0024] In addition, the above-mentioned light-transmitting second electrode is a second-first electrode layer in contact with the second semiconductor layer and

[0025] It may include a 2-2 electrode layer disposed on the 2-1 electrode layer and in contact with the upper wiring.

[0026] In addition, the 2-1 electrode layer may include any one of indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, and titanium oxide, and the 2-2 electrode layer may include any one of graphene and silver (Ag).

[0027] In another embodiment, the light-transmitting second electrode may include a 2-1 electrode layer in contact with the second semiconductor layer, a 2-2 electrode layer disposed on the 2-1 electrode layer, and a 2-3 electrode layer disposed on the 2-2 electrode layer and in contact with the upper wiring.

[0028] In addition, the 2-1 electrode layer and the 2-3 electrode layer may include any one of indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, and titanium oxide, and the 2-2 electrode layer may include graphene.

[0029] A display device according to another embodiment includes a substrate, a light-emitting element, a lower wiring disposed on the substrate, a first insulating layer disposed on the lower wiring, an adhesive layer disposed between the first insulating layer and the light-emitting element, a first electrode disposed on the adhesive layer and electrically connected to the light-emitting element, a second insulating layer covering the light-emitting element and the first electrode, a light-transmitting second electrode disposed on the light-emitting element and electrically connected to the light-emitting element, and an upper wiring electrically connected to the light-transmitting second electrode, wherein the lower wiring includes a first lower wiring layer, a second lower wiring layer, and a third lower wiring layer, wherein the first electrode, the first lower wiring layer, and the second lower wiring layer include any one of indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, and titanium oxide, and the second lower wiring layer includes chromium (Cr), nickel (Ni), copper (Cu), aluminum (Al), silver (Ag), It may include at least one metal selected from the group consisting of molybdenum (Mo), gold (Au), titanium (Ti) and alloys thereof.

[0030] According to another embodiment, a display device may include a substrate, a light-emitting element, a lower wiring disposed on the substrate, a first insulating layer disposed on the lower wiring, an adhesive layer disposed between the first insulating layer and the light-emitting element, a first electrode disposed on the adhesive layer and electrically connected to the light-emitting element, a second insulating layer covering the light-emitting element and the first electrode, and a light-transmitting second electrode disposed on the light-emitting element and electrically connected to the light-emitting element, wherein the light-transmitting second electrode may include a 2-1 electrode layer in contact with the second semiconductor layer, a 2-2 electrode layer disposed on the 2-1 electrode layer, and a 2-3 electrode layer disposed on the 2-2 electrode layer.

[0031] Additionally, the lower wiring may include a first lower wiring layer, a second lower wiring layer, and a third lower wiring layer.

[0032] Additionally, the first electrode, the first lower wiring layer, and the second lower wiring layer may include ITO, and the second lower wiring layer may include Ag.

[0033] In addition, the upper wiring may include an upper wiring layer disposed on the second transparent electrode, and the upper wiring may include a first upper wiring layer in contact with the second-third electrode layer, a second upper wiring layer disposed on the first upper wiring layer, and a third upper wiring layer disposed on the second upper wiring layer.

[0034] In addition, the first upper wiring layer and the third upper wiring layer may include any one of indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, and titanium oxide, and the second upper wiring layer may include at least one metal of chromium (Cr), nickel (Ni), copper (Cu), aluminum (Al), silver (Ag), molybdenum (Mo), gold (Au), titanium (Ti), and alloys thereof.

[0035] The transparent display panel of the present invention may include a transparent display device according to claims 1 to 12.

[0036] Additionally, it includes a thin film transistor, and the thin film transistor includes a source, a gate, a drain and a gate electrode, and may include a contact electrode in contact with the light-transmitting second electrode (180) and the drain.

[0037] Additionally, the contact electrode extends from the 2-1 electrode layer (180a) and may be formed of the same material as the 2-1 electrode layer (180a).

[0038] According to a transparent display device and a transparent display panel including the same according to an embodiment, light transmittance can be improved while reducing surface resistance.

[0039] Additionally, according to an embodiment, the mechanical strength can be improved while the upper electrode includes a transparent conductive material.

[0040] The technical effects of the embodiments are not limited to those described in this article, but include those that can be understood throughout the specification.

[0041] Figure 1 is a cross-sectional view of a display device according to internal technology.

[0042] Figure 2 is a plan view of a display device according to internal technology.

[0043] Figure 3 is a cross-sectional view of a transparent display device according to a first embodiment of the present invention.

[0044] FIG. 4 is an exemplary diagram showing a light-transmitting second electrode included in a transparent display device according to the first embodiment.

[0045] Figure 5 is a plan view according to an embodiment of the present invention.

[0046] Figure 6 is a cross-sectional view of a transparent display device according to a second embodiment of the present invention.

[0047] Fig. 7 is an exemplary diagram showing a light-transmitting second electrode of a transparent display device according to a second embodiment.

[0048] Figure 8 is a cross-sectional view of a transparent display device according to a third embodiment of the present invention.

[0049] Figure 9 is a cross-sectional view of a transparent display device according to a fourth embodiment of the present invention.

[0050] FIG. 10 is a cross-sectional view of a transparent display panel including a transparent display device according to another embodiment of the present invention.

[0051] Figure 11 is a graph comparing the surface resistance and light transmittance of a comparative example and an embodiment of the present invention according to internal technology.

[0052] Figure 12 is a cross-sectional image of a display device according to a comparative example and an embodiment of the present invention according to internal technology.

[0053] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the technical concept of the present invention is not limited to the described embodiments, but may be implemented in various different forms. Within the scope of the technical concept of the present invention, one or more of the components of the embodiments may be selectively combined or substituted for use.

[0054] In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0055] In addition, the terms used in the embodiments of the present invention are for the purpose of describing the embodiments and are not intended to limit the present invention. In this specification, the singular may also include the plural unless specifically stated in the phrase, and when it is described as “and (and) at least one (or more) of B, C,” it may include one or more of all combinations that can be combined with A, B, and C.

[0056] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and are not intended to limit the nature, order, or sequence of the components.

[0057] And, when a component is described as being 'connected', 'coupled' or 'connected' to another component, it may include not only cases where the component is directly connected, coupled or connected to the other component, but also cases where the component is 'connected', 'coupled' or 'connected' by another component between the component and the other component.

[0058] Additionally, when it is described as being formed or disposed "above or below" each component, above or below includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or disposed between the two components.

[0059] Additionally, when expressed as “upper or lower,” it can include the meaning of not only the upward direction but also the downward direction based on one component.

[0060]

[0061] FIG. 3 is a cross-sectional view of a transparent display device according to a first embodiment of the present invention, FIG. 4 is an exemplary view showing a light-transmitting second electrode included in a transparent display device according to the first embodiment, and FIG. 5 is a plan view according to an embodiment of the present invention.

[0062] Referring to FIGS. 3 and 4, the transparent display device according to the first embodiment of the present invention may have some configurations identical to those of the comparative example.

[0063] A transparent display device (10) according to the first embodiment may include a substrate (100), a lower wiring (110), a first insulating layer (120), an adhesive layer (130), a first electrode (140), a light-emitting element (150), a second insulating layer (170), a light-transmitting second electrode (180), and an upper wiring (190).

[0064] The above substrate (100) is configured to support various components included in the transparent display device (10) and may be made of an insulating material. For example, the substrate (100) may be made of glass or resin, etc. In addition, the substrate (100) may be made of a polymer or plastic, or may be made of a material having flexibility.

[0065] The lower wiring (110) may be arranged on the substrate (100). The lower wiring (110) may be connected to the first electrode (140) and electrically connected to the light-emitting element (150). The lower wiring may include a metal material. For example, it may be formed of at least one of titanium (Ti), chromium (Cr), nickel (Ni), aluminum (Al), platinum (Pt), gold (Au), tungsten (W), and molybdenum (Mo), or an alloy thereof.

[0066] The first insulating layer (120) may be placed on the lower wiring (110). The first insulating layer (120) may include an oxide film or a nitride film, but is not limited thereto.

[0067] The above adhesive layer (130) is disposed on the first insulating layer (120) and can be in contact with the light-emitting element (150).

[0068] The above light-emitting elements (150) may be formed in multiple units. For example, any one of the above light-emitting elements may function as a redundant light-emitting element.

[0069] The light-emitting element (150) may include a first semiconductor layer (151), a light-emitting layer (152), and a second semiconductor layer (153). The first semiconductor layer (151) and the second semiconductor layer (153) may be layers formed by doping a specific material with n-type and p-type impurities. For example, the first semiconductor layer (151) and the second semiconductor layer (153) may include an AlInGaP-based semiconductor layer, and may be a layer in which a material such as indium aluminum phosphide (InAlP), gallium arsenide (GaAs), etc. is doped with p-type or n-type impurities. In addition, the p-type impurity may be magnesium, zinc (Zn), beryllium (Be), etc., and the n-type impurity may be silicon (Si), germanium (Ge), tin (Sn), etc., but is not limited thereto. The above light-emitting layer (152) can emit light by receiving holes and electrons from the first semiconductor layer (151) and the second semiconductor layer (153). The light-emitting layer (152) can be formed of a single layer or a multi-quantum well (MQW) structure, and can be formed of, for example, indium gallium nitride (InGaN) or gallium nitride (GaN), but is not limited thereto.

[0070] The first electrode (140) is disposed on the adhesive layer (130) and may be electrically connected to the light emitting element (150). The first electrode (140) may be disposed on the lower surface of the first semiconductor layer (151). Accordingly, the first electrode (140) may be referred to as a lower electrode. The first electrode (140) may be formed of a conductive material. For example, the first electrode (140) may be formed of, but is not limited to, tin (Sn), indium (In), zinc (Zn), lead (Pb), nickel (Ni), gold (Au), platinum (Pt), copper (Cu), or the like.

[0071] The passivation layer (160) may be formed on the surface of the light-emitting element (150). The passivation layer (160) may be formed so that a portion of the second semiconductor layer (153) is exposed.

[0072] The second insulating layer (170) may be disposed on the first electrode (140) and the light emitting element (150). The second insulating layer (170) may be formed on the passivation layer (160). The second insulating layer (170) may be an oxide film, a nitride film, or the like, but is not limited thereto.

[0073]

[0074] The above-mentioned light-transmitting second electrode (180) is disposed on the light-emitting element (150) and may be electrically connected to the light-emitting element (150). The above-mentioned light-transmitting second electrode (180) may be referred to as an upper electrode. The above-mentioned light-transmitting second electrode (180) may be in contact with the second semiconductor layer (153) that is exposed because the passivation layer (160) is not formed. The above-mentioned light-transmitting second electrode (180) may include a transparent conductive material.

[0075] The above-mentioned light-transmitting second electrode (180) may be formed of a plurality of layers. The above-mentioned light-transmitting second electrode (180) may include a 2-1 electrode layer (180a) and a 2-2 electrode layer (180b). The 2-1 electrode layer (180a) may be connected to the second semiconductor layer (153). The 2-2 electrode layer (180b) may be disposed on the 2-1 electrode layer (180a) and may be electrically connected to the upper wiring.

[0076] The above 2-1 electrode layer (180a) and the 2-2 electrode layer (180b) may include a transparent conductive material. For example, the 2-1 electrode layer (180a) may include a metal oxide such as indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, or titanium oxide. The 2-2 electrode layer (180b) may include any one of graphene and silver (Ag). The light transmittance of the light-transmitting second electrode (180) may be 88% or more, and the sheet resistance may be 5Ω or less.

[0077] For example, the 2-1 electrode layer (180a) may be an ITO layer, and the 2-2 electrode layer (180b) may be a graphene layer.

[0078] At this time, the contact between the two layers may be unstable, resulting in peeling. To address this issue, the following process may be performed in the embodiment.

[0079] First, after depositing the ITO layer, O2 plasma treatment is performed to make the surface hydrophilic and remove micro-contaminants on the surface.

[0080] Next, graphene synthesized by CVD on the ITO layer can be transferred using a wet transfer method, so that both layers are in contact in a hydrophilic state, thereby improving adhesive strength. Subsequently, heat treatment can be performed to remove moisture between the interfaces, thereby stabilizing and strengthening the bonding strength. This can enhance the mechanical strength of the light-transmitting second electrode (180).

[0081] The upper wiring (190) may be electrically connected to the light-transmitting second electrode (180). The upper wiring (190) may include a metal material. For example, it may be formed of at least one of titanium (Ti), chromium (Cr), nickel (Ni), aluminum (Al), platinum (Pt), gold (Au), tungsten (W), and molybdenum (Mo), or an alloy thereof.

[0082]

[0083] FIG. 6 is a cross-sectional view of a transparent display device according to a second embodiment of the present invention, and FIG. 7 is an exemplary view showing a light-transmitting second electrode of a transparent display device according to the second embodiment.

[0084] The transparent display device according to the second embodiment may have the same configuration as the first embodiment except for the configuration of the light-transmitting second electrode (180). Hereinafter, the same configuration will be omitted and the description will focus on the different configuration.

[0085] The above-mentioned light-transmitting second electrode (180) is disposed on the light-emitting element (150) and may be electrically connected to the light-emitting element (150). The above-mentioned light-transmitting second electrode (180) may be referred to as an upper electrode. The above-mentioned light-transmitting second electrode (180) may be in contact with the second semiconductor layer (153) that is exposed because the passivation layer (160) is not formed. The above-mentioned light-transmitting second electrode (180) may include a transparent conductive material.

[0086] The above-mentioned light-transmitting second electrode (180) may be formed of a plurality of layers. The above-mentioned light-transmitting second electrode (180) may include a 2-1 electrode layer (180a), a 2-2 electrode layer (180b), and a 2-3 electrode layer (180c). The 2-1 electrode layer (180a) may be connected to the second semiconductor layer (153). The 2-2 electrode layer (180b) may be disposed on the 2-1 electrode layer (180a). The 2-3 electrode layer (180c) may be electrically connected to the upper wiring.

[0087] The above 2-1 electrode layer (180a), the 2-2 electrode layer (180b), and the 2-3 electrode layer (180c) may include a transparent conductive material. For example, the 2-1 electrode layer (180a) and the 2-3 electrode layer may include a metal oxide such as indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, or titanium oxide. The 2-2 electrode layer (180b) may include any one of graphene and silver (Ag).

[0088] For example, the 2-1 electrode layer (180a) and the 2-3 electrode layer (180c) may be ITO layers, and the 2-2 electrode layer (180b) may be a graphene layer. The process of forming the light-transmitting second electrode (180) may be performed as follows. First, after depositing the 2-1 electrode layer (180a), an O2 plasma treatment may be performed to make the surface hydrophilic and remove surface microcontaminants. Next, the 2-2 electrode layer (180b) synthesized by the CVD method may be transferred onto the 2-1 electrode layer (180a) by a wet transfer method so that both layers come into contact in a hydrophilic state, thereby improving adhesive strength. Next, the 2-3 electrode layer (180c) whose surface has been treated to be hydrophilic may be covered on the 2-2 electrode layer (180b). Thereafter, the moisture between the interfaces can be removed through heat treatment to stabilize and strengthen the bonding strength of the transparent second electrode (180). As a result, the mechanical strength of the transparent second electrode (180) can be improved.

[0089]

[0090] FIG. 8 is a cross-sectional view of a transparent display device according to a third embodiment of the present invention, and FIG. 9 is a cross-sectional view of a transparent display device according to a fourth embodiment of the present invention.

[0091] Referring to FIG. 8, a transparent display device according to a third embodiment may include a substrate (100), lower wiring (110), a first insulating layer (120), an adhesive layer (130), a first electrode (140), a light-emitting element (150), a second insulating layer (170), and a light-transmitting second electrode (180).

[0092] The above substrate (100) is configured to support various components included in the transparent display device (10) and may be made of an insulating material. For example, the substrate (100) may be made of glass or resin, etc. In addition, the substrate (100) may be made of a polymer or plastic, or may be made of a material having flexibility.

[0093] The lower wiring (110) may be arranged on the substrate (100). The lower wiring (110) may be formed of a plurality of layers. The lower wiring (110) may include a first lower wiring layer (111), a second lower wiring layer (112), and a third lower wiring layer (113). The first lower wiring layer (111) may be arranged on the substrate. The second lower wiring layer (112) may be arranged on the first lower wiring layer (111). The third lower wiring layer (113) may be arranged on the second lower wiring layer (112) and may be in contact with the first electrode (140). The lower wiring and the first electrode (140) may be electrically connected.

[0094] The lower wiring (110) of the third embodiment may include a transparent conductive material. For example, the first lower wiring layer (111) and the third lower wiring layer (113) may include a metal oxide such as indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, or titanium oxide. The second lower wiring layer (112) may include at least one of titanium (Ti), chromium (Cr), nickel (Ni), aluminum (Al), platinum (Pt), gold (Au), tungsten (W), and molybdenum (Mo), or an alloy thereof. For example, the first lower wiring layer (111) and the third lower wiring layer (113) may be formed of indium tin oxide (ITO), and the second lower wiring layer (112) may be formed of silver (Ag).

[0095] Since the first lower wiring layer (111) and the third lower wiring layer (113) are formed of a transparent conductive material, the light transmittance of the transparent display device (10) can be improved. In addition, since the second lower wiring layer (112) is formed of a metal material, the electrical conductivity of the lower wiring layer (113) can be improved.

[0096] The first insulating layer (120) may be disposed on the lower wiring (110). In detail, the first insulating layer (120) may be disposed on the third lower wiring layer (113). The first insulating layer (120) may include an oxide film or a nitride film, but is not limited thereto.

[0097] The above adhesive layer (130) is disposed on the first insulating layer (120) and can be in contact with the light-emitting element (150).

[0098] The above light-emitting elements (150) may be formed in multiple units. For example, any one of the above light-emitting elements may function as a redundant light-emitting element.

[0099] The light-emitting element (150) may include a first semiconductor layer (151), a light-emitting layer (152), and a second semiconductor layer (153). The first semiconductor layer (151) and the second semiconductor layer (153) may be layers formed by doping a specific material with n-type and p-type impurities. For example, the first semiconductor layer (151) and the second semiconductor layer (153) may include an AlInGaP-based semiconductor layer, and may be a layer in which a material such as indium aluminum phosphide (InAlP), gallium arsenide (GaAs), etc. is doped with p-type or n-type impurities. In addition, the p-type impurity may be magnesium, zinc (Zn), beryllium (Be), etc., and the n-type impurity may be silicon (Si), germanium (Ge), tin (Sn), etc., but is not limited thereto. The above light-emitting layer (152) can emit light by receiving holes and electrons from the first semiconductor layer (151) and the second semiconductor layer (153). The light-emitting layer (152) can be formed of a single layer or a multi-quantum well (MQW) structure, and can be formed of, for example, indium gallium nitride (InGaN) or gallium nitride (GaN), but is not limited thereto.

[0100] The first electrode (140) is disposed on the adhesive layer (130) and may be electrically connected to the light emitting element (150). The first electrode (140) may be disposed on the lower surface of the first semiconductor layer (151). Accordingly, the first electrode (140) may be referred to as a lower electrode. For example, the first electrode (140) may include a transparent conductive material. For example, the first lower wiring layer (111) and the third lower wiring layer (113) may include a metal oxide such as indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, or titanium oxide. In this case, the first electrode (140) may be formed integrally with the third lower wiring layer (113). When the first electrode (140) is formed of a transparent conductive material, the light transmittance of the transparent display device (10) can be improved. As another example, the first electrode (140) can be formed of a conductive material. For example, the first electrode (140) can be formed of tin (Sn), indium (In), zinc (Zn), lead (Pb), nickel (Ni), gold (Au), platinum (Pt), copper (Cu), or the like, but is not limited thereto.

[0101] The passivation layer (160) may be formed on the surface of the light-emitting element (150). The passivation layer (160) may be formed so that a portion of the second semiconductor layer (153) is exposed.

[0102] The second insulating layer (170) may be disposed on the first electrode (140) and the light emitting element (150). The second insulating layer (170) may be formed on the passivation layer (160). The second insulating layer (170) may be an oxide film, a nitride film, or the like, but is not limited thereto.

[0103] The above-mentioned light-transmitting second electrode (180) is disposed on the light-emitting element (150) and may be electrically connected to the light-emitting element (150). The above-mentioned light-transmitting second electrode (180) may be referred to as an upper electrode. The above-mentioned light-transmitting second electrode (180) may be in contact with the second semiconductor layer (153) that is exposed because the passivation layer (160) is not formed. The above-mentioned light-transmitting second electrode (180) may include a transparent conductive material.

[0104] The above-mentioned light-transmitting second electrode (180) may be formed of a plurality of layers. The above-mentioned light-transmitting second electrode (180) may include a 2-1 electrode layer (180a), a 2-2 electrode layer (180b), and a 2-3 electrode layer (180c). The 2-1 electrode layer (180a) may be arranged to be in contact with the second semiconductor layer (153) and may be electrically connected to the second semiconductor layer (153). The 2-2 electrode layer (180b) may be arranged on the 2-1 electrode layer (180a), and the 2-3 electrode layer (180c) may be arranged on the 2-2 electrode layer (180b).

[0105] According to a third embodiment, the upper wiring is omitted, and the light-transmitting second electrode (180) can include the function of the upper wiring. Accordingly, the light-transmitting second electrode (180) can connect one light-emitting element (150) and an adjacent redundant light-emitting element (150).

[0106] The 2-1 electrode layer (180a) and the 2-2 electrode layer (180b) may include a transparent conductive material. For example, the 2-1 electrode layer (180a) and the 2-3 electrode layer (180c) may include a metal oxide such as indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, or titanium oxide. The 2-2 electrode layer (180b) may include any one of graphene and silver (Ag). For example, the 2-1 electrode layer (180a) and the 2-3 electrode layer (180c) may be ITO layers, and the 2-2 electrode layer (180b) may be a graphene layer. The light transmittance of the above-mentioned light-transmitting second electrode (180) may be 88% or more, and the surface resistance may be 5Ω or less.

[0107]

[0108] Referring to FIG. 9, the transparent display device according to the fourth embodiment may have the same configuration as the first embodiment except that an upper wiring (190) is additionally added on the second transparent electrode (180).

[0109] The upper wiring (190) according to the fourth embodiment may include a transparent conductive material.

[0110] The upper wiring (190) may include a first upper wiring layer (190a), a second upper wiring layer (190b), and a third upper wiring layer (190c). The first upper wiring layer (190a) may be in contact with and electrically connected to the second-third electrode layer (180c). The second upper wiring layer (190b) may be disposed on and electrically connected to the first upper wiring layer (190a). The third upper wiring layer (190c) may be disposed on and electrically connected to the second upper wiring layer (190b).

[0111] The first upper wiring layer (190a) and the third upper wiring layer (190c) may include a metal oxide such as indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, or titanium oxide. The second-second electrode layer (180b) may include any one of graphene and silver (Ag). The second upper wiring layer (190b) may include at least one metal among chromium (Cr), nickel (Ni), copper (Cu), aluminum (Al), silver (Ag), molybdenum (Mo), gold (Au), titanium (Ti), and alloys thereof. For example, the first upper wiring layer (190a) and the third upper wiring layer (190c) may be formed of ITO, and the second upper wiring layer (190b) may be formed of silver (Ag).

[0112]

[0113] FIG. 10 is a cross-sectional view of a transparent display panel including a transparent display device according to another embodiment of the present invention.

[0114] Referring to FIG. 10, a transparent display panel (1) may include a transparent display device (10) and a thin film transistor (20). Although FIG. 10 discloses a transparent display device (10) according to a third embodiment, a transparent display device (10) according to another embodiment may be applied.

[0115] The above thin film transistor (20) may be placed on the same substrate (100) as the transparent display device (10). The above thin film transistor (20) may be composed of a gate (22), a semiconductor layer (24), a source (26), a drain (28), and a gate insulating layer (25) formed on the substrate (100).

[0116] The gate insulating layer (25) may be formed of the same material as the first insulating layer (120). A protective layer (40) may be formed to cover the thin film transistor (20). The light-emitting element (150) and the first electrode (140) may be disposed on the protective layer (40), and the first electrode (140) and the light-emitting element (150) may be electrically connected. Although not shown, the first electrode (140) may include a transparent conductive material according to the above-described embodiment.

[0117] The second insulating layer (170) can mold the thin film transistor (20) and the light emitting element (150). A portion of the second insulating layer (170) can be etched to form a via hole exposing the drain (28).

[0118] A light-transmitting second electrode (180) according to an embodiment may be disposed on the light-emitting element (150) and electrically connected to a second semiconductor layer (153) of the light-emitting element (150). The light-transmitting second electrode (180) may include a contact electrode (180d) formed in the via hole. The contact electrode (180d) may extend from a lower portion of the 2-1 electrode layer (180a). The contact electrode (180d) may be formed of the same material as the 2-1 electrode layer (180a). For example, the contact electrode (180d) may include a transparent conductive material. As another example, the contact electrode (180d) may include a metal material. As yet another example, the contact electrode (180d) may include graphene. The above contact electrode (180d) can be electrically connected to the drain (28).

[0119] The light transmittance of the transparent display panel (10) can be improved by the transparent display device (10).

[0120]

[0121] Fig. 11 is a graph comparing the surface resistance and light transmittance of a comparative example according to an internal technology and an embodiment of the present invention, and Fig. 12 is a cross-sectional image of a display device according to a comparative example according to an internal technology and an embodiment of the present invention.

[0122] Referring to FIG. 11, a comparative example according to an internal technology shows the sheet resistance and light transmittance of a display device including a light-transmitting second electrode formed of 200 nm indium tin oxide (ITO). The display device according to the comparative example can have a sheet resistance of 15Ω and a light transmittance of 89%. On the other hand, the display device according to the embodiment can have a sheet resistance of 5Ω and a light transmittance of 88%.

[0123] In the case of conventional ITO, the transmittance decreases rapidly as the resistance decreases. However, in the case of the transparent electrode having the graphene / ITO structure according to the embodiment, the transmittance decrease is small while the resistance decrease is significantly effective. Accordingly, according to the embodiment, there may be a difference between the sheet resistance value and the light transmittance value, but the value of the decrease in sheet resistance may be significantly greater than the value of the decrease in light transmittance.

[0124]

[0125] Referring to FIG. 12, FIG. 12(a) is a cross-sectional image of a comparative example according to internal technology, and FIG. 12(b) is a cross-sectional image according to an embodiment of the present invention.

[0126] A comparative example according to internal technology has the problem that when only indium tin oxide (ITO) is included in the light-transmitting second electrode (180), it is vulnerable to external impact due to the brittle nature of ITO.

[0127] However, when a transparent second electrode (180) having a Graphene / ITO structure is formed according to an embodiment of the present invention, a structurally more stable transparent electrode can be formed, thereby increasing panel yield and ensuring reliability.

[0128] In addition, in a comparative example according to internal technology, there is a tendency for the panel brightness to increase or decrease depending on the height of the first electrode (140) on the side of the light-emitting element (150). In other words, as the height of the first electrode (140) increases, the light generated from the light-emitting layer (152) is reflected by the first electrode (140), which causes a problem of decreased brightness. Accordingly, when lowering the height of the first electrode (140) to increase brightness, there was a limit to lowering the height of the first electrode (140) that must be in contact with the first semiconductor layer (151).

[0129] On the other hand, in accordance with an embodiment of the present invention, when the first electrode (140) is formed of a transparent conductive material, even if the first electrode (140) is formed higher than the height of the light-emitting layer (152), light can be transmitted, thereby increasing the luminance. In addition, by ensuring a sufficient height of the first electrode (140), there is an effect of improving reliability.

[0130]

[0131] The above detailed description should not be construed as limiting in any respect and should be considered illustrative only. The scope of the embodiments should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalency range of the embodiments are intended to be included within the scope of the embodiments.

[0132]

[0133] [Explanation of symbols]

[0134] 10: Transparent display device 100: Substrate

[0135] 110: Lower wiring 120: First insulation layer

[0136] 130: Adhesive layer 140: First electrode

[0137] 150: Light-emitting element 160: Passivation layer

[0138] 170: Second insulating layer 180: Light-transmitting second electrode

[0139] 190: Top wiring

[0140] The embodiment can be applied to display devices such as TVs and signage.

[0141] For example, the embodiments may be applied to, but are not limited to, liquid crystal displays (LCDs), organic light-emitting diode (OLED) displays, and micro-LED displays. The embodiments may also be applied to digital signage.

Claims

1. A substrate having lower wiring; A light emitting element disposed on the substrate; A first electrode electrically connecting the lower wiring and the light-emitting element; A light-transmitting second electrode disposed on the light-emitting element and electrically connected to the light-emitting element; and including an upper wiring electrically connected to the above-mentioned light-transmitting second electrode; The above-mentioned light-transmitting second electrode is characterized in that it is formed of a plurality of layers. Transparent display device.

2. In paragraph 1, The above light emitting element, A first semiconductor layer electrically connected to the first electrode A light-emitting layer disposed on the first semiconductor layer; A second semiconductor layer disposed on the light-emitting layer and in contact with the second light-transmitting electrode; and Including a passivation layer disposed on the surface of the light emitting element, Transparent display device.

3. In paragraph 2, The above-mentioned second transparent electrode is, A second-first electrode layer in contact with the second semiconductor layer; and A 2-2 electrode layer disposed on the 2-1 electrode layer and in contact with the upper wiring, Transparent display device.

4. In paragraph 3, The above 2-1 electrode layer includes any one of indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, and titanium oxide, The above 2-2 electrode layer comprises either graphene or silver (Ag). Transparent display device.

5. In paragraph 2, The above-mentioned second transparent electrode is, A second-first electrode layer in contact with the second semiconductor layer; A 2-2 electrode layer disposed on the 2-1 electrode layer; and A 2-3 electrode layer is disposed on the 2-2 electrode layer and is in contact with the upper wiring. Transparent display device.

6. In paragraph 5, The above 2-1 electrode layer and the 2-3 electrode layer include any one of indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, and titanium oxide, The above 2-2 electrode layer contains graphene. Transparent display device.

7. A substrate having lower wiring; A light emitting element disposed on the substrate; A first electrode electrically connected to the light-emitting element; A light-transmitting second electrode disposed on the light-emitting element and electrically connected to the light-emitting element; and including an upper wiring electrically connected to the above-mentioned light-transmitting second electrode; The above lower wiring is, It comprises a first lower wiring layer, a second lower wiring layer, and a third lower wiring layer arranged sequentially, The first electrode, the first lower wiring layer, and the second lower wiring layer include any one of indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, and titanium oxide. The second lower wiring layer comprises at least one metal selected from the group consisting of chromium (Cr), nickel (Ni), copper (Cu), aluminum (Al), silver (Ag), molybdenum (Mo), gold (Au), titanium (Ti) and alloys thereof. Transparent display device.

8. A substrate having lower wiring; A light emitting element disposed on the substrate; A first electrode electrically connected to the light-emitting element; A light-transmitting second electrode disposed on the light-emitting element and electrically connected to the light-emitting element; The above-mentioned second transparent electrode is, A second-first electrode layer in contact with the second semiconductor layer; A 2-2 electrode layer disposed on the 2-1 electrode layer; and Including a 2-3 electrode layer disposed on the 2-2 electrode layer Transparent display device.

9. In paragraph 8, The above lower wiring is, It includes a first lower wiring layer, a second lower wiring layer, and a third lower wiring layer arranged sequentially. Transparent display device.

10. In paragraph 9, The first electrode, the first lower wiring layer and the second lower wiring layer comprise ITO, The second lower wiring layer comprises Ag. Transparent display device.

11. In paragraph 8, Including an upper wiring disposed on the above-mentioned light-transmitting second electrode, The above upper wiring is, A first upper wiring layer in contact with the second-third electrode layers; A second upper wiring layer disposed on the first upper wiring layer; and A third upper wiring layer disposed on the second upper wiring layer. Transparent display device.

12. In paragraph 11, The first upper wiring layer and the third upper wiring layer include any one of indium tin oxide, indium zinc oxide, copper oxide, tin oxide, zinc oxide, and titanium oxide. The second upper wiring layer comprises at least one metal selected from the group consisting of chromium (Cr), nickel (Ni), copper (Cu), aluminum (Al), silver (Ag), molybdenum (Mo), gold (Au), titanium (Ti) and alloys thereof. Transparent display device.

13. A transparent display panel comprising a transparent display device according to any one of claims 1 to 12.

14. In paragraph 13, Further comprising a thin film transistor driving the transparent display device, The above thin film transistor It includes a source, gate, drain and gate electrodes, A transparent display panel including a contact electrode in contact with the above-described second light-transmitting electrode (180) and the drain.

15. In paragraph 14, A transparent display panel in which the contact electrode extends from the 2-1 electrode layer (180a) and is formed of the same material as the 2-1 electrode layer (180a).

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