Display device and manufacturing method thereof

Abstract

A display device and a method of manufacturing the same are provided. The display device includes: a pixel electrode configured to supply power to a sub-pixel; a common electrode; an organic transparent substrate; a driving layer provided on the organic transparent substrate and electrically connected to the pixel electrode, the driving layer including a driving device configured to control a power switch of the sub-pixel; and a light emitting unit provided on the driving layer and including an inorganic material, the light emitting unit including a first semiconductor layer, an active layer, and a second semiconductor layer.

Description

Technical Field

[0001] Example embodiments of the present disclosure relate to a flexible high-resolution display device and a method of manufacturing the same. Background Art

[0002] Liquid crystal displays (LCDs), organic light emitting diode (OLED) displays, and light emitting diode (LED) displays are widely used as display devices. Recently, interest in flexible display devices has increased. In general, OLED displays have been widely used as flexible devices, but OLED displays have relatively weak brightness compared to inorganic LED displays. Summary of the invention

[0003] Example embodiments of the present disclosure provide a flexible high-resolution display device.

[0004] Example embodiments of the present disclosure provide a method of manufacturing a flexible high-resolution display device.

[0005] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the presented embodiments of the disclosure.

[0006] According to one aspect of the present disclosure, a display device is provided, which includes: a pixel electrode configured to supply power to a sub-pixel; a common electrode; an organic transparent substrate; a driving layer provided on the organic transparent substrate and electrically connected to the pixel electrode, the driving layer including a driving device configured to control a power switch of the sub-pixel; and a light-emitting unit provided on the driving layer and including an inorganic material, the light-emitting unit including a first semiconductor layer, an active layer, and a second semiconductor layer.

[0007] The organic transparent substrate may include at least one of polyimide, polymethyl methacrylate (PMMA), organic glass, polyethylene terephthalate (PET), transparent polypropylene, polycarbonate, polyethylene naphthalate, polyarylate (PAR), polyetherimide or any combination thereof.

[0008] The display device may be a flexible display device or a rollable display device.

[0009] The display device may further include a coupling layer between the organic transparent substrate and the driving layer.

[0010] The coupling layer may include at least one of benzocyclobutene (BCB), epoxy, or spin-on-glass (SOG).

[0011] The light emitting unit may include a light emitting diode (LED) array structure.

[0012] The driving layer may have a thickness of about 2 μm or less.

[0013] The light emitting unit may have a thickness of about 2 μm to about 3 μm.

[0014] The display device may have a pixel integration level greater than or equal to 2000 pixels per inch (ppi).

[0015] The driving layer and the light emitting unit may have a monolithic integrated structure.

[0016] The light emitting unit may include a partition structure partitioning at least a portion of the light emitting structure based on the sub-pixel.

[0017] The display device may further include a current blocking layer in a region corresponding to the separation structure on the driving layer.

[0018] The display device may further include a plurality of color conversion layers configured to convert the light emitted from the light emitting unit into light with different colors.

[0019] According to another aspect of the present disclosure, a method for manufacturing a display device is provided, the method comprising: forming a first semiconductor layer on an epitaxial substrate; forming an active layer on the first semiconductor layer, the active layer comprising an inorganic material; forming a second semiconductor layer on the active layer; separating the active layer based on sub-pixels by forming a separation structure on the active layer at intervals corresponding to the sub-pixels; forming a first electrode on the second semiconductor layer based on the sub-pixels; forming a driving layer including a driving device, the driving device being electrically connected to the first electrode; positioning the driving layer to face downward and connecting the driving layer to an organic transparent substrate; removing the epitaxial substrate; and forming a second electrode on the first semiconductor layer.

[0020] Separating the active layer on a sub-pixel basis may include forming an ion implantation region.

[0021] The organic transparent substrate may include at least one of polyimide, polymethyl methacrylate (PMMA), organic glass, polyethylene terephthalate (PET), transparent polypropylene, polycarbonate, polyethylene naphthalate, polyarylate (PAR), polyetherimide, or any combination thereof.

[0022] The organic transparent substrate may be a flexible transparent substrate.

[0023] Forming the Driving Layer The driving layer may be formed to have a thickness of about 2 μm or less.

[0024] Forming the first semiconductor layer, forming the active layer, and forming the second semiconductor layer may form a light emitting unit having a thickness of about 2 μm to about 3 μm.

[0025] Forming the separation structure and forming the first electrode may be based on a sub-pixel basis corresponding to a pixel integration degree greater than or equal to 2,000 pixels per inch (ppi). BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0027] Figure 1 schematically shows a display device according to an embodiment;

[0028] Figure 2 Shows Figure 1 The display device shown further includes an example of a color conversion layer,;

[0029] Figure 3 An example in which the display device is applied to a flexible display device according to an embodiment is shown;

[0030] Figure 4 An example in which the display device according to the embodiment is applied to a contact lens type display device is shown;

[0031] Figure 5 An example in which the display device is applied to a rollable display device according to an embodiment is shown;

[0032] Figure 6 A display device according to an embodiment is shown;

[0033] Figure 7 Shown in Figure 6 The structure shown further includes a display device with a color conversion layer;

[0034] Figure 8 The electrode structure is shown in Figure 7 An example of a display device modified from the display device shown;

[0035] Figures 9 to 18 A method of manufacturing a display device according to an embodiment is shown;

[0036] Fig.19 A method of forming a transparent electrode of a display device according to an embodiment is shown; and

[0037] Fig. 20 Shown in Fig.18 A method of forming a color conversion layer in the structure shown. DETAILED DESCRIPTION

[0038] Embodiments will now be mentioned in detail, examples of which are shown in the accompanying drawings, wherein the same reference numerals always refer to the same elements. In this regard, example embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Therefore, example embodiments are described below only by reference to the accompanying drawings to illustrate various aspects. As used herein, the term "and / or" includes any and all combinations of one or more related listed items. When following a column of elements, expressions such as "at least one" modify the entire column of elements without modifying the individual elements in the column.

[0039] Hereinafter, a display device and a method for manufacturing the same according to various example embodiments will be described in detail with reference to the accompanying drawings. In the following drawings, the same reference numerals refer to the same components, and the size of each component in the drawings may be exaggerated for clarity and convenience of description. Terms such as "first" and "second" are used here only to describe various components, but these components are not limited by these terms. These terms are only used to distinguish one component from another component.

[0040] The singular form is also intended to include the plural form, unless the context clearly indicates otherwise. When a part "includes" a component, this means that the part may further include another component, rather than excluding another component, unless otherwise clearly disclosed. For the sake of clarity of description, the size and thickness of each component may be exaggerated. In addition, when a material layer is described as being on a substrate or another layer, the material layer may exist in direct contact with the substrate or another layer, or another third layer may exist therebetween. In the following embodiments, the materials constituting each layer are exemplary, so other materials may be used.

[0041] In the case where a component is described as being “connected” or “coupled” to another component, it should be understood that, although the component may be directly connected or coupled to the other component, yet another component may be “connected” or “coupled” between the two components.

[0042] Here, the expression “disposed on” includes a case where one element is disposed on another element to be in direct contact, and a case where the element is disposed over another element without being in direct contact with the element (for example, another element is interposed between the two elements).

[0043] Terms such as “unit” or “module” need to be understood as a unit that processes at least one function or operation, and as a unit that can be implemented by hardware, software, or a combination of hardware and software.

[0044] Certain implementations described in the example embodiments are for illustrative purposes only and do not limit the technical scope of the present disclosure in any way. In order to simplify the specification, descriptions of existing electronic configurations, control systems, software, and other functional aspects of the system may be omitted. In addition, the connections or connecting members of the lines between the components shown in the drawings are examples of functional connections and / or physical connections or circuit connections, and are replaced or expressed as various functional connections, physical connections or circuit connections in actual devices.

[0045] The use of the term "the" and similar terms can correspond to both the singular and the plural.

[0046] The operations of the method may be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by the context. In addition, the use of all exemplary terms (eg, etc.) is to simply illustrate the technical spirit, and these terms do not limit the scope unless limited by the claims.

[0047] Figure 1 A display device 100 according to an embodiment is shown.

[0048] refer to Figure 1 , the display device 100 includes a plurality of pixels. For convenience, Figure 1 Only one pixel is shown in FIG. A pixel may be a unit for displaying an image. Each pixel may include sub-pixels that emit light having different colors. An image may be displayed by controlling the color and light intensity of each sub-pixel. For example, each pixel may include a first sub-pixel SP1, a second sub-pixel SP2, and a third sub-pixel SP3.

[0049] The display device 100 may include an organic transparent substrate 110 , a driving layer 130 provided on the organic transparent substrate 110 , and a light emitting unit 140 provided in the driving layer 130 .

[0050] The organic transparent substrate 110 has flexibility and may be a substrate for supporting the driving layer 130 and the light emitting unit 140 disposed on or above the organic transparent substrate 110. That is, the organic transparent substrate 110 may not be a growth substrate. For example, the organic transparent substrate 110 may be a flexible transparent substrate and may include, for example, polyimide, polymethyl methacrylate (PMMA), organic glass, polyethylene terephthalate (PET), transparent polypropylene, polycarbonate, polyethylene naphthalate, polyarylate (PAR), polyetherimide, or any combination thereof.

[0051] The driving layer 130 may include a driving device 135 configured to electrically drive the light emitting unit 140. The driving device 135 may control the power switch of the sub-pixel (that is, control the power supply based on the sub-pixel). The driving device 135 may include, for example, a transistor, a thin film transistor, or a high electron mobility transistor (HEMT). The driving layer 130 may further include at least one insulating layer 132.

[0052] A coupling layer 120 may be provided between the organic transparent substrate 110 and the drive layer 130. The coupling layer 120 may be used to couple the drive layer 130 to the organic transparent substrate 110, and may include, for example, an adhesive layer or a direct bonding layer. The adhesive layer may include, for example, epoxy resin, spin-on glass (SOG), or benzocyclobutene (BCB). The direct bonding layer may be formed, for example, by plasma or ion beam treatment. The coupling layer 120 may be used to physically couple the drive layer 130 to the organic transparent substrate 110, and the drive layer 130 may be coupled to the organic transparent substrate 110 using a bonding method without electrical connection.

[0053] The light emitting unit 140 may include a micro light emitting diode (LED) array. The light emitting unit 140 may include a first semiconductor layer 142, an active layer 143, and a second semiconductor layer 145 stacked in a specified order. The first semiconductor layer 142, the active layer 143, and the second semiconductor layer 145 may form a light emitting structure.

[0054] The first semiconductor layer 142 may include a first type semiconductor. For example, the first semiconductor layer 142 may include a p-type semiconductor. The first semiconductor layer 142 may include a III-V group p-type semiconductor, such as p-GaN. The first semiconductor layer 142 may have a single layer or a multi-layer structure.

[0055] The active layer 143 may be provided on the upper surface of the first semiconductor layer 142. The active layer 143 may include an inorganic material and may emit light by combining electrons and holes. The active layer 143 may have a multi-quantum well (MQW) or single quantum well (SQW) structure. The active layer 143 may include a III-V semiconductor, such as GaN.

[0056] The second semiconductor layer 145 may be provided on the upper surface of the active layer 143. The second semiconductor layer 145 may include a second type semiconductor. The second semiconductor layer 145 may include, for example, an n-type semiconductor. In an example, the second semiconductor layer 145 may include a p-type semiconductor. The second semiconductor layer 145 may include a III-V group n-type semiconductor, such as n-GaN. The second semiconductor layer 145 may have a single layer or a multilayer structure.

[0057] The light emitting unit 140 may have a partition structure 147 so that light from the active layer 143 is emitted on a sub-pixel basis. In other words, the light emitting unit 140 may have a partition structure 147 between adjacent sub-pixels. The partition structure 147 may be, for example, an ion implantation region. Here, the ions may include, for example, nitrogen (N) ions, boron (B) ions, argon (Ar) ions, or phosphorus (P) ions. Current is not injected into the ion implantation region, so light is not emitted from the ion implantation region, and when the partition structure 147 is configured as an ion implantation region, the light emitting unit 140 may be formed without a mesa structure. In other words, the light emitting unit 140 can realize a micro-light emitting device array structure by using the partition structure 147 without an etching process. Because the etching process is not used, sub-pixels with small sizes can be manufactured, and thus a micro-light emitting device array with high resolution can be manufactured. For example, the display device 100 may have a pixel integration of 2,000ppi or more.

[0058] The driving layer 130 and the light emitting unit 140 may have a monolithic integrated structure. Since the thickness and pixel size of the display device 100 are reduced according to these structural characteristics, the organic transparent substrate 110 may support the driving layer 130 and the light emitting unit 140, and the flexible or rollable characteristics of the display device 100 may be achieved. For example, the driving layer 130 may have a thickness of about 0 μm to about 2 μm or less. For example, the light emitting unit 140 may have a thickness of about 2 μm to about 3 μm. The display device 100 may include an inorganic light emitting unit 140, but may have flexibility so that the display device 100 may be applied to a flexible display device or a rollable display device.

[0059] The display device 100 may include a first electrode 141 electrically connected to the first semiconductor layer 142 and a second electrode 146 electrically connected to the second semiconductor layer 145. The first electrode 141 may be a pixel electrode, and the second electrode 146 may be a common electrode. When the first semiconductor layer 142 and the second semiconductor layer 145 include a p-type semiconductor and an n-type semiconductor, respectively, the first electrode 141 and the second electrode 146 may be a p-type electrode and an n-type electrode, respectively. The driving device 135 may be electrically connected to the first electrode 141, and may control power switches of the first electrode 141 and the second electrode 146. Therefore, the driving device 135 may selectively drive at least one desired sub-pixel among the plurality of sub-pixels SP1, SP2, and SP3.

[0060] The first electrode 141 may include a reflective material to reflect light emitted from the active layer 143 in a downward direction (that is, toward the organic transparent substrate 110). The first electrode 141 may include, for example, Ag, Au, Al, Cr, Ni, or an alloy thereof. The second electrode 146 may be a transparent electrode or an opaque electrode. The transparent electrode may include, for example, indium tin oxide (ITO), ZnO, indium zinc oxide (IZO), or IGZO. When the second electrode 146 is formed as a transparent electrode, the second electrode 146 may be arranged to completely cover the second semiconductor layer 145. When the second electrode 146 is an opaque electrode, the display device 100 may further include a window area 149 to allow light emitted from the active layer 143 to pass through. Figure 1 An example is shown in which the display device 100 includes a window area 149 .

[0061] Figure 2 Shows Figure 1 The display device 100 shown further includes an example of a color conversion layer. Figure 1 Description of the differences Figure 2 .

[0062] A plurality of color conversion layers 151, 152, and 153 configured to emit light of different colors by using light emitted from the active layer 143 may be provided above the light emitting unit 140. The active layer 143 may emit light, such as blue light. However, the light emitted from the active layer 143 is not limited thereto, and any light having other wavelengths may be used as long as the light excites the color conversion layers 151, 152, and 153. The plurality of color conversion layers 151, 152, and 153 may be provided to correspond to the sub-pixels SP1, SP2, and SP3, respectively. The plurality of color conversion layers 151, 152, and 153 may include, for example, a blue conversion layer, a green conversion layer, and a red conversion layer. The blue conversion layer 151 may be provided to correspond to the blue sub-pixel, the green conversion layer 152 may be provided to correspond to the green sub-pixel, and the red conversion layer 153 may be provided to correspond to the red sub-pixel.

[0063] The blue conversion layer 151 may include a material for emitting blue light, or may be a transmission layer for transmitting blue light emitted from the active layer 143 .

[0064] When blue light is emitted from the active layer 143, the blue conversion layer 151 may transmit the light emitted from the active layer 143 and emit the light to the outside. The blue conversion layer 151 may further include a light scattering agent or a photoresist having a high transmission characteristic.

[0065] The green conversion layer 152 can convert the light emitted from the active layer 143 into green light and emit green light. The green conversion layer 152 may include, for example, quantum dots (QD) of a certain size, which are excited by blue light and emit green light. The QD may have a core-shell structure having a core portion and a shell portion, and may also have a particle structure without a shell. The core-shell structure may have a single shell or multiple shells. The multiple shells may be, for example, double shells.

[0066] The QD may include, for example, at least one of a II-VI semiconductor, a III-V semiconductor, a IV-VI semiconductor, a IV semiconductor, and a graphene QD. For example, the QD may include at least one of Cd, Se, Zn, S, and InP, but is not limited thereto. The diameter of each QD may be equal to or less than tens of nm, such as a diameter equal to or less than 10 nm. The green conversion layer 152 may include a phosphor that is excited by light emitted from the active layer 143 and emits green light. The green conversion layer 152 may further include a photoresist having high transmittance characteristics or a light scatterer that uniformly emits green light.

[0067] The red conversion layer 153 may convert the blue light emitted from the active layer 143 into red light and emit the converted red light. The red conversion layer 153 may include QDs having a certain size, which are excited by the blue light and emit red light. In addition, the red conversion layer 153 may include a phosphor that is excited by the blue light emitted from the active layer 143 and emits red light. The red conversion layer 153 may further include a photoresist and / or a light scattering agent.

[0068] The barrier wall 10 may be provided between the blue conversion layer 151, the green conversion layer 152, and the red conversion layer 153. A reflective film 155 may be further provided on the side surface of the barrier wall 150 to increase the extraction efficiency of light converted from each color conversion layer. Optionally, the barrier wall 150 may be configured as a black matrix for light absorption. The black matrix may improve contrast by preventing crosstalk between the blue conversion layer 151, the green conversion layer 152, and the red conversion layer 153.

[0069] In the structure as described above, for example, when the driving device 135 corresponding to the blue sub-pixel applies a certain voltage between the first electrode 141 corresponding to the blue sub-pixel and the second electrode 146 as the common electrode, for example, blue light may be emitted from the active layer 143 located below the blue conversion layer 151, and when light is incident on the blue conversion layer 151, the blue conversion layer 151 emits the blue light to the outside. For example, when the driving device 135 corresponding to the green sub-pixel applies a certain voltage between the first electrode 141 and the second electrode 146 corresponding to the green sub-pixel, blue light may be emitted from the active layer 143 located below the green conversion layer 152, and when the blue light thus emitted is incident on the green conversion layer 152, the green conversion layer 152 emits green light to the outside.

[0070] For example, when the driving device 135 corresponding to the red sub-pixel applies a certain voltage between the first electrode 141 and the second electrode 146 corresponding to the red sub-pixel, blue light can be emitted from the active layer 143 located below the red conversion layer 153, and when the blue light emitted in this way is incident on the red conversion layer 153, the red conversion layer 153 emits red light to the outside.

[0071] According to example embodiments, a high-resolution display device with improved light efficiency can be realized. According to the related art, in order to realize a display device, a driving layer and a light-emitting unit can be manufactured separately and can be connected to each other. In this case, it may not be easy to electrically connect the driving layer and the light-emitting unit, and when the size of the sub-pixel is reduced to improve the resolution, the alignment error rate of the driving layer and the light-emitting unit may increase. On the other hand, according to example embodiments, the driving layer 130 and the light-emitting unit 140 are manufactured using a monolithic integration method, so the electrical connection characteristics of the driving layer 130 and the light-emitting unit 140 can be excellent, and the size of the sub-pixel can be reduced based on the partition structure 147 of the light-emitting unit 140, thereby improving the resolution. The thickness of each of the driving layer 130 and the light-emitting unit 140 can be minimized.

[0072] The display device according to an embodiment includes a partition structure 147 between adjacent sub-pixels, so that the current injected from the first electrode can be prevented from spreading to the adjacent sub-pixels. No mesa etching process is required to separate the sub-pixels, so the internal quantum efficiency of the display device can be improved. The driving layer 130 is disposed below the light-emitting unit 140, so the light-emitting area can be increased, thereby improving the light-emitting efficiency.

[0073] Figure 3 An example in which the display device 100 is flexibly bent according to an embodiment is shown. When the display device 100 has flexibility, the display device 100 can be effectively applied to a wearable display device such as a smart watch, augmented reality (AR) glasses, virtual reality (VR) glasses, or mixed reality (MR) glasses.

[0074] Figure 4 An example in which the display device 100 is applied to a contact lens type display device according to an embodiment is shown. The display device 100 is very thin and flexible, and thus can be applied to a contact lens type display device that is worn and used on the user's eyes. The contact lens type display device 150 may include the display device 100, an antenna 151 included in the organic transparent substrate 110 of the display device 100, and a power management integrated circuit (IC) 152 connected to the antenna 151. A sensor 156 and a display driver chip 154 ​​may be connected to the power management IC 152. The sensor 156 may include a synchronous positioning and mapping (SLAM) device. The sensor 156 may match a virtual image and a real image with each other. For example, the antenna 151 may receive wireless communication data from a wireless communication device 170 such as a smartphone. The display driver chip 154 ​​may be connected to the display device 100 so that the display device 100 forms an image. A power supply 158 may be connected to the power management IC 152. The power supply 158 may include, for example, a solar cell or a super capacitor. The power supply 158 may supply power to the power management IC 152. A contact lens 160 may be further provided on the organic transparent substrate 110. The user's vision may be corrected by using the contact lens 160. The contact lens type display device 150 may be formed by integrating the display device 100 having flexibility into a contact lens, and may be worn by the user like a contact lens.

[0075] Figure 5 An example in which the display device 100 is applied to a rollable display device according to an embodiment is shown. The display device 100 may be rolled up and stored, and when the display device 100 is used, the display device 100 may be unfolded to display an image.

[0076] Figure 6 A display device 200 according to an embodiment is shown.

[0077] The display device 200 may include a first sub-pixel SP1, a second sub-pixel SP2, and a third sub-pixel SP3. The first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3 may emit light of different colors. The display device 200 may include an organic transparent substrate 210, a driving layer 230 provided on the organic transparent substrate 210, and a light emitting unit 240 based on an inorganic material provided on the driving layer 230.

[0078] The organic transparent substrate 210 may not be a growth substrate, but a substrate for supporting the driving layer 230 on the organic transparent substrate 210. The driving layer 230 may include a driving device 235, which is configured to electrically drive the light-emitting unit 240 of each sub-pixel. The driving device 235 may include, for example, a transistor, a thin film transistor (TFT), or a high electron mobility transistor (HEMT). For example, the driving device 235 may include a gate electrode G, a source electrode S, and a drain electrode D. The driving layer 230 may further include at least one insulating layer. For example, at least one insulating layer may include a first insulating layer 231 and a second insulating layer 232. The second insulating layer 232 may be, for example, a gate oxide. A third insulating layer 237 may be further disposed between the driving layer 230 and the light-emitting unit 240.

[0079] The coupling layer 220 may be disposed between the organic transparent substrate 210 and the driving layer 230. The coupling layer 220 may be used to couple the driving layer 230 to the organic transparent substrate 210, and may include, for example, an adhesive layer or a direct bonding layer. The coupling layer 220 may be used to physically couple the driving layer 230 to the organic transparent substrate 210, and may couple the driving layer 230 to the organic transparent substrate 210 by using a bonding method without electrical connection. During the bonding process, the coupling layer 220 may cover, for example, the source electrode S and the drain electrode D.

[0080] The light emitting unit 240 may include, for example, a micro LED array. The light emitting unit 240 may include a first semiconductor layer 242, an active layer 243, and a second semiconductor layer 245 stacked in a specified order.

[0081] The first semiconductor layer 242 may include a first type semiconductor. For example, the first semiconductor layer 242 may include a p-type semiconductor. The first semiconductor layer 242 may include a III-V group p-type semiconductor, such as p-GaN. The first semiconductor layer 242 may have a single layer or a multi-layer structure.

[0082] The active layer 243 may be provided on the upper surface of the first semiconductor layer 241. The active layer 243 may generate light by combining electrons and holes. The active layer 243 may have a multi-quantum well (MQW) or a single quantum well (SQW) structure. The active layer 243 may include a III-V semiconductor, such as GaN. The active layer 243 may include a two-dimensional thin film structure or a three-dimensional structure, such as a rod or pyramid structure.

[0083] The second semiconductor layer 245 may be provided on the upper surface of the active layer 243. The second semiconductor layer 245 may include, for example, an n-type semiconductor. The second semiconductor layer 245 may include a III-V group n-type semiconductor, such as n-GaN. The second semiconductor layer 245 may have a single layer or a multi-layer structure.

[0084] The light emitting unit 240 may include, for example, a micro-LED array based on an inorganic material. A micro-LED may be provided for each sub-pixel. The light emitting unit 240 may have a partition structure 247 so that light from the active layer 243 is emitted on a sub-pixel basis. In other words, the light emitting unit 240 may have a partition structure 247 between adjacent sub-pixels. The micro-LED structures may be spaced apart from each other by the partition structure 247. The partition structure 247 may be, for example, an ion implantation region. Current is not injected into the ion implantation region, so light is not emitted therefrom. The ion implantation region may be formed by implanting ions such as nitrogen ions or boron ions, and may have insulating properties. For example, about 10 12 Ions / cm 2 to about 10 20 Ions / cm 2 Ions of a dose of 100 Å may be implanted into the ion implantation region. However, this is an example and the present disclosure is not limited thereto.

[0085] The display device 200 may include a first electrode 241 electrically connected to the first semiconductor layer 242 and a second electrode 246 electrically connected to the second semiconductor layer 245. The first electrode 241 may be a pixel electrode, and the second electrode 246 may be a common electrode. When the first semiconductor layer 242 and the second semiconductor layer 245 include a p-type semiconductor and an n-type semiconductor, respectively, the first electrode 241 and the second electrode 246 may be a p-type electrode and an n-type electrode, respectively. The driving device 235 may be electrically connected to the first electrode 241, and may control a power switch of the first electrode 241. Therefore, the driving device 235 may selectively drive at least one desired sub-pixel among the plurality of sub-pixels SP1, SP2, and SP3.

[0086] The first electrode 241 may include a refractive material to reflect light emitted from the active layer 243 in a downward direction (that is, toward the organic transparent substrate 210). The first electrode 241 may include, for example, Ag, Au, Al, Cr, Ni, or an alloy thereof. The first electrode 241 is a pixel electrode that can operate the sub-pixels independently. The first electrodes 241 may be spaced apart from each other and may be arranged to face the active layer 243. A current blocking layer 244 may be further provided at both ends of the first electrode 241. The current blocking layer 244 may prevent current from leaking to another adjacent sub-pixel region. The current blocking layer 244 may be formed of, for example, silicon oxide or silicon nitride. The current blocking layer 244 may be provided between the lower surface of the separation structure 247 and the first electrode 241. The current blocking layer 244 may be arranged to correspond to the lower portion of the separation structure 247.

[0087] A third insulating layer 237 may be further provided between the driving layer 230 and the light emitting unit 240. A via hole 238 may be further provided in the third insulating layer 237 to electrically connect the driving device 235 and the first electrode 241 to each other. A metal electrode 239 may be further provided between the first electrode 241 and the via hole 238. The metal electrode 239 may be provided to improve the light emitting efficiency of the light emitting unit 240 by improving the electrical efficiency.

[0088] The second electrode 246 may be formed as a transparent electrode or an opaque electrode. The transparent electrode may include, for example, indium tin oxide (ITO), ZnO, indium zinc oxide (IZO) or IGZO. When the second electrode 246 is formed as a transparent electrode, the second electrode 246 may be arranged to completely cover the second semiconductor layer 245. This will be described in more detail later. When the second electrode 246 is an opaque electrode, the display device 200 may further include a window area 249, and the light emitted from the active layer 243 is transmitted through the window area 249. The window area 249 may be provided at a position corresponding to the active layer 243.

[0089] The second semiconductor layer 245 may include a fine pattern structure 248. The fine pattern structure 248 may increase light extraction efficiency. The fine pattern structure 248 may be provided in a region corresponding to the active layer 243.

[0090] The separation structure 247 may be provided with a certain thickness from the first semiconductor layer 242. The separation structure 247 may have a thickness for preventing the current injected into the first semiconductor layer 242 through the first electrode 241 from spreading to the adjacent sub-pixel. The current injected from the first electrode 241 needs to be controlled on a sub-pixel basis so as not to be injected into the first semiconductor layer 242 of the adjacent sub-pixel, and the current may be injected into the entire second semiconductor layer 245, so the separation structure 247 may not need to reach the top surface of the second semiconductor layer 245. For example, the thickness of the separation structure 247 may be equal to or greater than the sum of the thickness of the first semiconductor layer 242 and the thickness of the active layer 243. Alternatively, the separation structure 247 may have a thickness for separation from the first semiconductor layer 242 to the second semiconductor layer 245.

[0091] In this embodiment, among the light emitted from the active layer 243, the light guided downward (that is, toward the organic transparent substrate 210) can be reflected by the first electrode 241 and guided upward, and the light guided in the lateral direction from the active layer 243 can be guided upward without being absorbed or scattered because the partition structure 247 does not have a mesa structure. Therefore, the luminous efficiency can be improved. Based on the partition structure 247, the size of the sub-pixel can be reduced, which can improve the resolution. The fine pattern structure 248 can be provided in the second semiconductor layer 245 to increase the external quantum efficiency. The fine pattern structure 248 can be provided in the window area 249. In addition, the present embodiment can have a vertical electrode structure, in which the first electrode 241 and the second electrode 246 are arranged up and down based on the active layer 243. The second electrode 246 can be arranged on one side of the active layer 243, and the second electrode 246 can be manufactured without a via hole process, and therefore, the electrode can be formed without a mesa structure.

[0092] Figure 7 Shown in Figure 6 The structure shown further includes a display device 200A having a color conversion layer. Figure 7 In, use Figure 6 Components with the same reference numerals as in Figure 6 The components described in have basically the same functions and configurations, so their detailed description is omitted here.

[0093] The display device 200A may include an organic transparent substrate 210 , a driving layer 230 , an inorganic material-based light emitting unit 240 , and color conversion layers 251 , 252 , and 253 .

[0094] A plurality of color conversion layers 251, 252, and 253 that emit light having different colors by using light emitted from the active layer 243 of the light emitting unit 240 may be provided on or above the light emitting unit 240. The active layer 243 may emit, for example, blue light. However, this is merely an example, and light having other wavelengths that may excite the color conversion layers 251, 252, and 253 may also be emitted. A plurality of color conversion layers 251, 252, and 253 may be provided to correspond to the sub-pixels SP1, SP2, and SP3, respectively. The plurality of color conversion layers 251, 252, and 253 may include, for example, a blue conversion layer, a green conversion layer, and a red conversion layer. The blue conversion layer 251 may correspond to a blue sub-pixel, the green conversion layer 252 may correspond to a green sub-pixel, and the red conversion layer 253 may correspond to a red sub-pixel. The blue conversion layer 251, the green conversion layer 252, and the red conversion layer 253 are Figure 2 The blue conversion layer 151 , the green conversion layer 152 , and the red conversion layer 153 described in are substantially the same, and thus a detailed description thereof is omitted.

[0095] The color conversion layers 251, 252, and 253 may have a cross-sectional shape that widens upward. The barrier wall 250 may be provided between adjacent color conversion layers 251, 252, and 253. A reflective film 255 may be further provided on the side surface of the barrier wall 250 to increase the extraction efficiency of light converted from each color conversion layer. Optionally, the barrier wall 250 may be configured as a black matrix for light absorption. The black matrix may improve contrast by preventing crosstalk between the blue conversion layer 251, the green conversion layer 252, and the red conversion layer 253.

[0096] For example, blue light may be emitted from each sub-pixel of the light emitting unit 240, and based on the blue light, colored light corresponding to the color conversion layer of each sub-pixel may be emitted. The light intensity may be controlled by the amount of current injected into the first electrode 241 and the second electrode 246, and colored light may be emitted through the color conversion layer in the sub-pixel, so a color image may be displayed. According to example embodiments, even if the size of the sub-pixel is reduced, light leakage to adjacent sub-pixels may be reduced or prevented by the separation structure, thereby improving the resolution of the display device.

[0097] Figure 8 An example of a display device 200B is shown, in which the structure of the second electrode is similar to Figure 7 Compared to that, there has been a change.

[0098] refer to Figure 8 , the second electrode 246B may be formed as a transparent electrode in the display device 200B. The second electrode 246B may include, for example, indium tin oxide (ITO), ZnO, indium zinc oxide (IZO), or IGZO. The second electrode 246B may be a common electrode and may be provided in one plate. The second electrode 246B may be arranged to completely cover the second semiconductor layer 245. In this case, when the second electrode 246B is configured as a transparent electrode, the manufacturing process may be simplified because a window area that allows light to pass through is not required.

[0099] The display device according to the embodiment may be applied to, for example, a flexible display, a rollable display, a head-up display, a contact lens type display, virtual reality (VR) glasses, or augmented reality (AR) glasses. The display device according to the embodiment may be applied to various products.

[0100] Hereinafter, a method of manufacturing a display device according to an embodiment will be described.

[0101] refer to Fig. 9, the first semiconductor layer 420, the first layer 425, and the second semiconductor layer 427 may be grown on the epitaxial substrate 410. The epitaxial substrate 410 may be, for example, a silicon substrate or a sapphire substrate. However, the epitaxial substrate 410 is not limited thereto, and various epitaxial substrates may be used. The first semiconductor layer 420 may include an n-type semiconductor layer. However, in some cases, the first semiconductor layer 420 may include a p-type semiconductor layer. For example, the first semiconductor layer 420 may include n-type GaN. The first layer 425 is a layer on which an active layer is formed, and may include GaN, for example. The buffer layer 415 may be formed between the epitaxial substrate 410 and the first semiconductor layer 420. The buffer layer 415 may include a single layer or a multilayer structure, and may promote the growth of the first semiconductor layer 420. The buffer layer 415 may include, for example, AlN. An undoped semiconductor layer (not shown), such as u-GaN, may be further provided between the buffer layer 415 and the first semiconductor layer 420.

[0102] refer to Fig. 9 and Fig.10 , the separation structure 430 can be formed on the first layer 425 and the second semiconductor layer 427 using a mask 428. The mask 428 can be, for example, an ion implantation mask. For example, the separation structure 430 can be formed by implanting ions into a certain area of ​​the first layer 425 and the second semiconductor layer 427. The ions can include, for example, nitrogen (N) ions, boron (B) ions, argon (Ar) ions, or phosphorus (P) ions. However, the ions are not limited thereto. Fig.10 An example in which the partition structure 430 is formed on the first layer 425 and the second semiconductor layer 427 is shown, but the thickness of the partition structure 430 may be variously determined. For example, the partition structure 430 may be formed from the second semiconductor layer 427 to a local depth of the first semiconductor layer 420. The active layer 425a and the second semiconductor layer 427a spaced apart from each other by the partition structure 430 may be formed. The active layer 425a and the second semiconductor layer 427a spaced apart from each other may define a sub-pixel area. A micro LED array may be formed based on the partition structure 430.

[0103] When the sub-pixels are electrically separated by the ion implantation area, the edge portion of the active layer 425a (where defects may exist) can be disabled by ion implantation, thereby inducing light emission only from the inside of the active layer 425a. The pixels (or sub-pixels) can be electrically isolated by the ion implantation area, thereby preventing local contrast reduction. Local contrast reduction occurs when light is unintentionally emitted to adjacent pixels (sub-pixels) at the boundary of pixels (sub-pixels) of a horizontal tableless structure, in which structural separation between pixels (sub-pixels) is not achieved. However, in this embodiment, the contrast can be improved by using a tableless separation structure to prevent current from spreading to adjacent pixels (sub-pixels).

[0104] refer to Fig.11 , the current blocking layer 433 may be deposited on or above the separation structure 430. The current blocking layer 433 may be formed by a photoresist and etching process. The current blocking layer 433 may be formed of an insulating material. The current blocking layer 433 may electrically insulate the first electrode to be formed later. In an embodiment, the current blocking layer 433 may be omitted.

[0105] refer to Fig.12 , you can Fig.11 A conductive material is deposited on the structure shown to form first electrodes 435 spaced apart from each other based on sub-pixels by etching. The first electrode 435 can be a pixel electrode that operates based on sub-pixels. The first electrode 435 can be formed of a reflective conductive material. The first electrode 435 can include, for example, Ag, Au, Al, Cr, Ni or an alloy thereof. The first electrode 435 can be an opaque electrode.

[0106] refer to Fig.13 , a first insulating layer 437 may be formed to cover the first electrode 435. The first insulating layer 437 may include, for example, SiO 2 、SiN、Al 2 O 3 or TiO 2 , but not limited to this.

[0107] refer to Fig.14 , the first insulating layer 437 may be etched and a conductive material may be deposited to form a via hole 440 and an electrode pad 443. The via hole 440 may contact the first electrode 435. Optionally, before forming the via hole 440, a metal electrode 439 may be formed to contact a portion of the first electrode 435. The via hole 440 may contact the metal electrode 439.

[0108] refer to Fig.15 , a second insulating layer 445 may be formed on the first insulating layer 437, and a gate electrode 446 may be formed on the second insulating layer 445. A third insulating layer 447 may be formed on the second insulating layer 445 and the gate electrode 446. A source electrode 448 and a drain electrode 449 may be formed by etching the second insulating layer 445 and the third insulating layer 447. The gate electrode 446, the source electrode 448, and the drain electrode 449 may constitute a driving device. Here, a method of forming a thin film transistor as an example of a driving device is described. The source electrode 448 may be connected to the electrode pad 443, and the drain electrode 449 may be connected to the via hole 440. Thus, a driving layer 444 may be formed.

[0109] refer to Fig.16 , Fig.15The structure shown can be inverted so that the epitaxial substrate 410 is located on top, and the structure can be arranged such that the third insulating layer 447 faces the organic transparent substrate 450. The organic transparent substrate 450 can be a substrate for supporting Fig.15 the structure shown, and the organic transparent substrate 450 can be a flexible transparent substrate, for example, it can include polyimide, polymethyl methacrylate (PMMA), plexiglass, polyethylene terephthalate (PET), transparent polypropylene, polycarbonate, polyethylene naphthalate, polyaryl compound (PAR), polyetherimide, or any combination thereof. Referring to Fig.17 , the organic transparent substrate 450 and the third insulating layer 447 can be coupled to each other through a coupling layer 455. The coupling layer 455 can include, for example, an adhesive layer or a direct bonding layer. The organic transparent substrate 450 may not require electrical connection and can support the structure. The organic material transparent substrate 450 and Fig.15 the structure shown can be physically coupled to each other via simple bonding. For example, the thickness of the coupling layer 455 can be in the range of about 0.1 nm to about 10 μm.

[0110] After the driving layer 444 is coupled to the organic transparent substrate 450, the epitaxial substrate 410 can be removed. For example, the epitaxial substrate 410 can be removed by laser lift-off or polishing. The polishing method can be used together with a dry etching method. For example, when the epitaxial substrate 410 is a sapphire substrate, the epitaxial substrate 410 can be removed by laser lift-off, and when the epitaxial substrate 410 is a silicon substrate, the epitaxial substrate 410 can be removed by polishing.

[0111] When the epitaxial substrate 410 is mechanically removed, the total grinding force F can be divided into a normal grinding force Fn and a tangential grinding force Ft.

[0112] F = Fn + Ft

[0113] As shown below, when Ft is less than the adhesion force G at the interface of the transparent inorganic substrate, there is no peeling of the organic transparent substrate during mechanical polishing.

[0114] Ft < G

[0115] The tangential grinding force Ft can monotonically increase with an increase in the wafer rotation speed, an increase in the wheel feed rate, and a decrease in the wheel rotation speed. Ft is related to the sliding force, and through the system's molecular dynamics simulation of steering, G increases according to the sliding speed. Based on this, by appropriately selecting an organic transparent substrate with high rigidity and low coefficient of thermal expansion (such as polyimide), exposing it to ultraviolet (UV) radiation, and controlling the polyimide curing time, the absolute value of G can be kept high. Therefore, Ft and G can increase together with an increase in the sliding speed while maintaining Ft < G to sufficiently increase the process window.

[0116] Wheel feed speed <150 (μm / min)

[0117] Wheel speed>1000rpm

[0118] Wafer rotation speed <400rpm

[0119] Under the above conditions, the epitaxial substrate 410 can be removed without peeling off the polyimide film.

[0120] For example, the epitaxial substrate 410 may be polished in two stages.

[0121] <Phase 1>

[0122] Wheel feed rate: 1.5 to 2 μm / sec,

[0123] Wheel speed: 1500rpm

[0124] Chip speed: 250rpm

[0125] <Phase 2>

[0126] Wheel feed rate: 0.5μm / sec

[0127] Wheel speed: 2800rpm,

[0128] Chip rotation speed: 150rpm.

[0129] The buffer layer 415 may be selectively removed. Fig.17 An example is shown in which the buffer layer 415 is removed. The first semiconductor layer 420 may be etched to reduce its thickness. For example, the first semiconductor layer 420 may have a thickness of about 0.5 μm to about 3.0 μm. Fig.18 , a fine pattern structure 465 may be formed in the first semiconductor layer 420 by a wet etching process. The fine pattern structure 465 may be formed to correspond to a region from which light is emitted. For example, the fine pattern structure 465 may be formed at a position corresponding to the active layer 427a. The fine pattern structure 465 may increase light extraction efficiency. The second electrode 460 may be formed on the first semiconductor layer 420. The second electrode 460 may be formed as an opaque electrode. When the second electrode 460 is an opaque electrode, the second electrode 460 may be etched to form a window region 463 allowing light to be emitted therefrom.

[0130] and Fig.18 different, Fig.19An example of a second electrode 460 formed of a transparent electrode is shown. The second electrode 460 may include, for example, indium tin oxide (ITO), ZnO, indium zinc oxide (IZO), or IGZO. When the second electrode 460 is a transparent electrode, the second electrode 460 may be arranged to completely cover the second semiconductor layer 420. The window area may not be required because the transparent electrode allows light to pass through without change. The second electrode 460 may be a common electrode, and its structure is simple, so the second electrode 460 can be simply manufactured, and the manufacturing error can be reduced. A driving layer including a thin film transistor may be arranged below the active layer 427a, and the second electrode 460 as a common electrode may be arranged above the active layer 427a, so that the area from which light is emitted can be easily ensured. The first electrode 435 may be arranged below the active layer 427a, so that the light emitted downward from the active layer 427a is reflected by the first electrode 435, thereby improving the luminous efficiency.

[0131] refer to Fig. 20 , a plurality of color conversion layers, such as first, second, and third color conversion layers 481, 482, and 483, may be formed on the second electrode 460. The first, second, and third color conversion layers 481, 482, and 483 may be separated by a barrier wall 477. The barrier wall layer 470 may be stacked on the second electrode 460, a first hole 471 for the first color conversion layer 481 may be formed using a first mask (not shown), and the first color conversion layer 481 may be deposited on the first hole 471. Before depositing the first color conversion layer 481, a reflective film 475 may be formed on the sidewall of the first hole 471. A second hole 472 for the second color conversion layer 482 may be formed using a second mask (not shown), and the second color conversion layer 482 may be deposited on the second hole 472. Before depositing the second color conversion layer 482, a reflective film 475 may be formed on the sidewall of the second hole 472. A third hole 473 for a third color conversion layer 483 may be formed using a third mask (not shown), and the third color conversion layer 483 may be deposited on the third hole 473. Before depositing the third color conversion layer 483, a reflective film 475 may be formed on a sidewall of the third hole 473. Through the above process, a barrier wall 477 may be formed between adjacent color conversion layers.

[0132] In the method for manufacturing a display according to an embodiment, a light-emitting unit based on an inorganic material can be connected to an organic transparent substrate. The driving layer and the light-emitting unit can be formed by a monolithic integration method, so they can be very thin and the pixel size can be reduced. In the method for manufacturing a display according to an embodiment, the epitaxial substrate can be flipped to the top and connected to the organic transparent substrate, and then a vertical electrode structure without a mesa structure can be formed by a flip-chip manufacturing process. During the flip-chip manufacturing process, the organic material transparent substrate can support the driving layer and the light-emitting unit without damage, so a flexible display device can be manufactured. In the method for manufacturing a display according to an embodiment, the manufacturing process can be simplified by shortening the via hole etching process for forming the electrode, and there is no mesa structure, so the reduction of the internal quantum efficiency due to the mesa structure can be prevented. At least one of the first electrode and the second electrode can be used as a reflective film to improve the luminous efficiency.

[0133] The display device according to the embodiment may have flexibility by coupling the inorganic light emitting unit to the organic transparent substrate. In the display device according to the embodiment, the driving layer and the light emitting unit have a monolithic integrated structure, thereby reducing the pixel size and improving the resolution.

[0134] The method of manufacturing a display device according to an embodiment may provide a method of coupling an inorganic light emitting unit to an organic transparent substrate.

[0135] The above exemplary embodiments are merely illustrative, and various modifications and other equivalent embodiments may be made by those skilled in the art. Therefore, the true scope of the embodiments should be determined by the technical spirit of the disclosure defined by the claims and their equivalents.

[0136] It should be understood that the embodiments described herein are considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments.

[0137] Although one or more example embodiments have been described with reference to the drawings, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the appended claims and their equivalents.

[0138] CROSS-REFERENCE TO RELATED APPLICATIONS

[0139] This application is based on and claims the priority of U.S. Patent Application No. 63 / 521,750 filed in the United States Patent and Trademark Office on June 19, 2023 and Korean Patent Application No. 10-2023-0113737 filed in the Korean Intellectual Property Office on August 29, 2023, and the disclosures of these two patent applications are incorporated herein by reference in their entirety.

Claims

1. A display device, include: a pixel electrode configured to supply power to the sub-pixel; Common electrode; Organic transparent substrate; a driving layer provided on the organic transparent substrate and electrically connected to the pixel electrode, the driving layer comprising a driving device configured to control a power switch of the sub-pixel; as well as The light emitting unit is provided on the driving layer and includes an inorganic material, wherein the light emitting unit includes a first semiconductor layer, an active layer and a second semiconductor layer.

2. The display device according to claim 1, The organic transparent substrate includes at least one of polyimide, polymethyl methacrylate, organic glass, polyethylene terephthalate, transparent polypropylene, polycarbonate, polyethylene naphthalate, polyarylate, polyetherimide or any combination thereof.

3. The display device according to claim 1, in, The display device is a flexible display device or a rollable display device.

4. The display device according to claim 1, further comprising: include: A coupling layer is provided between the organic transparent substrate and the driving layer.

5. The display device according to claim 4, The connection layer includes at least one of benzocyclobutene, epoxy resin or spin-on-glass.

6. The display device according to claim 1, The light emitting unit comprises a light emitting diode array structure.

7. The display device according to claim 1, The driving layer has a thickness of 2 μm or less.

8. The display device according to claim 1, The light emitting unit has a thickness of 2 μm to 3 μm.

9. The display device according to claim 1, The display device has a pixel integration level greater than or equal to 2000 pixels per inch.

10. The display device according to claim 1, The driving layer and the light emitting unit have a monolithic integrated structure.

11. The display device according to claim 1, The light emitting unit includes a partition structure for partitioning at least a portion of the light emitting structure based on sub-pixels.

12. The display device according to claim 11, further comprising: include: A current blocking layer is provided on the driving layer in a region corresponding to the separation structure.

13. The display device according to claim 1, further comprising: include: A plurality of color conversion layers are configured to convert the light emitted from the light emitting unit into light of different colors.

14. A method for manufacturing a display device, the method include: forming a first semiconductor layer on an epitaxial substrate; forming an active layer on the first semiconductor layer, wherein the active layer comprises an inorganic material; forming a second semiconductor layer on the active layer; partitioning the active layer on a sub-pixel basis by forming partition structures on the active layer at intervals corresponding to the sub-pixels; forming a first electrode on the second semiconductor layer based on a sub-pixel; forming a driving layer including a driving device, the driving device being electrically connected to the first electrode; positioning the drive layer to face downward and coupling the drive layer to an organic transparent substrate; removing the epitaxial substrate; as well as A second electrode is formed on the first semiconductor layer.

15. The method according to claim 14, Wherein dividing the active layer based on sub-pixels includes forming ion implantation regions.

16. The method according to claim 14, The organic transparent substrate includes at least one of polyimide, polymethyl methacrylate, organic glass, polyethylene terephthalate, transparent polypropylene, polycarbonate, polyethylene naphthalate, polyarylate, polyetherimide or any combination thereof.

17. The method according to claim 14, The organic transparent substrate is a flexible transparent substrate.

18. The method according to claim 14, Wherein forming the driving layer forms the driving layer to have a thickness of 2 μm or less.

19. The method according to claim 14, The forming of the first semiconductor layer, the forming of the active layer, and the forming of the second semiconductor layer form a light emitting unit having a thickness of 2 μm to 3 μm.

20. The method according to claim 14, Wherein forming the partition structure and forming the first electrode are based on a sub-pixel basis corresponding to a pixel integration degree greater than or equal to 2,000 pixels per inch.

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