CN110660833B - Electroluminescent display device and method for manufacturing the same - Google Patents
Electroluminescent display device and method for manufacturing the same Download PDFInfo
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Abstract
The invention discloses an electroluminescent display device and a preparation method thereof. The electronic light-emitting display device comprises a bottom-emitting light-emitting device and a top-emitting light-emitting device which are arranged in a stacked mode, wherein the bottom-emitting light-emitting device comprises a bottom-emitting substrate, the bottom-emitting substrate is provided with a plurality of first light-emitting pixel areas and a plurality of first blank pixel areas on one side facing the top-emitting light-emitting device, the first light-emitting pixel areas comprise first light-emitting diodes, the top-emitting light-emitting device comprises a top-emitting substrate, the top-emitting substrate is provided with a plurality of second light-emitting pixel areas and a plurality of second blank pixel areas on one side facing the bottom-emitting light-emitting device, the second light-emitting pixel areas comprise second light-emitting diodes, the second light-emitting pixel areas correspond to the first blank pixel areas, and the second blank pixel areas correspond to the first light-emitting pixel areas.
Description
Technical Field
The present invention relates to an electroluminescent display device and a method of manufacturing the same.
Background
Organic Light Emitting Diode (OLED) display devices have many advantages such as self-luminescence, low driving voltage, high luminous efficiency, short response time, high definition and contrast, viewing angle of approximately 180 °, wide temperature range, flexible display, and large-area full-color display, and are considered as the most promising display devices in the industry.
The OLED display device belongs to self-luminous display equipment and generally comprises a pixel electrode, a common electrode and a functional layer, wherein the pixel electrode and the common electrode are respectively used as an anode and a cathode, the functional layer is arranged between the pixel electrode and the common electrode and generally comprises a hole injection layer arranged on the anode, a hole transport layer arranged on the hole injection layer, a light emitting layer arranged on the hole transport layer, an electron transport layer arranged on the light emitting layer and an electron injection layer arranged on the electron transport layer.
A quantum dot light emitting diode (QLED) is a new technology applied to the field of display technology, and is mainly different from an OLED in that a material of a light emitting layer is a quantum dot light emitting material. The quantum dot luminescent material obeys the quantum dot size effect, the property of the quantum dot luminescent material changes along with the size change of the quantum dot, when the quantum dot is stimulated by light or electricity, the quantum dot can emit colored light, the color of the light is related to the property of the light, and therefore the light emitted by the quantum dot can be controlled by changing the size of the quantum dot. The quantum dot luminescent material has the advantages of concentrated luminescent spectrum, high color purity and the like. The quantum dot light-emitting material is used in the technical field of display, so that the color gamut of the traditional display can be greatly improved, and the color reduction capability of the display is enhanced.
The research direction of the display device formed by the blue light OLED, the red light QLED and the green light QLED is that: the blue light emitting layer is arranged in the blue pixel area, and the light emitting layer of the red light QLED and the light emitting layer of the green light QLED are correspondingly arranged in the red pixel area and the green pixel area respectively. The blue light emitting layer can be manufactured by an evaporation technology, and the problems of low light emitting efficiency and short service life caused by manufacturing the blue light QLED by a wet film forming technology are solved. The red light emitting layer and the green light emitting layer are manufactured through a wet film process, the problem of high production cost of an evaporation film forming technology is solved, the production cost can be reduced under the condition that the luminous efficiency and the service life of a luminous display device are not influenced, and the competitiveness of a product in the aspects of color gamut and color reduction capability is improved.
However, the difference between OLED and QLED processes and the difference between manufacturing raw materials easily affect the overall performance.
Disclosure of Invention
The inventor finds that when the electroluminescent devices with two structures are manufactured on the substrate by using two processes of evaporation and solution methods, the manufacturing processes are easy to influence each other, and the best effect of the electroluminescent devices with the two structures cannot be guaranteed. For example, it is a technical difficulty to match the materials of the common layer when evaporating OLED and printing QLED on the substrate. In addition, during the fabrication of OLED and QLED devices, the devices fabricated later will always affect the devices already fabricated, for example: when the QLED red light device or the green light device is manufactured by a wet film process after the OLED blue light device is manufactured, each functional layer is baked to be a film at the temperature of 80-150 ℃, and the performance of the OLED blue light device is easily influenced by multiple times of baking; if the QLED red light or green light device is manufactured by using a wet film firstly and then the OLED blue light device is manufactured by using an evaporation process and a mask plate, the QLED red light or green light device is scratched by the mask plate, so that the final performance of the device is influenced.
In order to overcome the above-mentioned disadvantages, an object of the present invention is to provide an electroluminescent display device and a method for manufacturing the same, which solve the problem in the prior art that materials of a common layer are difficult to match when two types of light emitting diodes are manufactured on the same substrate.
Another objective of the present invention is to provide an electroluminescent display device and a method for manufacturing the same, which solve the problem that the manufacturing process of the later manufactured light emitting diode affects the performance of the manufactured light emitting diode when two types of light emitting diodes are manufactured in the prior art.
According to an aspect of the present invention, there is provided an electroluminescent display device comprising a bottom emission light emitting device and a top emission light emitting device which are arranged in a stack, wherein,
the bottom emission light emitting device includes a bottom emission substrate having a plurality of first light emitting pixel regions and a plurality of first dummy pixel regions on a side facing the top emission light emitting device, the first light emitting pixel regions including first light emitting diodes,
the top emission light emitting device includes a top emission substrate having a plurality of second light emitting pixel regions and a plurality of second dummy pixel regions on a side facing the bottom emission light emitting device, the second light emitting pixel regions including second light emitting diodes, the second light emitting pixel regions corresponding to the first dummy pixel regions, the second dummy pixel regions corresponding to the first light emitting pixel regions.
In one embodiment, the first light emitting diode is a quantum dot light emitting diode and the second light emitting diode is an organic light emitting diode; or the first light-emitting diode is an organic light-emitting diode, and the second light-emitting diode is a quantum dot light-emitting diode.
In one embodiment, the plurality of quantum dot light emitting diodes include a light emitting diode for emitting red light and a light emitting diode for emitting green light, and the organic light emitting diode emits blue light.
In one embodiment, the quantum dot light emitting diode includes a quantum dot light emitting layer, and the organic light emitting diode includes an organic light emitting layer.
In one embodiment, one of the first blank pixel regions is disposed opposite to one or more of the second light-emitting pixel regions, and one of the second blank pixel regions is disposed opposite to one or more of the first light-emitting pixel regions.
In one embodiment, the orthographic projection of the second light-emitting pixel region on the bottom emission substrate does not overlap with the first light-emitting pixel region.
In one embodiment, a transparent electrode material is or is not disposed in the first blank pixel region, or a reflective electrode material is or is not disposed in the second blank pixel region.
According to another aspect of the present invention, there is provided a method of manufacturing an electroluminescent display device, comprising the steps of:
providing a bottom emission substrate with a plurality of first pixel pits and a plurality of second pixel pits on the surface, and preparing a first light-emitting diode in each first pixel pit to obtain a bottom emission light-emitting device;
providing a top emission substrate with a plurality of third pixel pits and a plurality of fourth pixel pits on the surface, and preparing a second light emitting diode in each third pixel pit to obtain a top emission light emitting device;
aligning the bottom emission light emitting device and the top emission light emitting device such that the second light emitting diode within the third pixel pit is opposite to an opening of the second pixel pit, and then sealing the bottom emission light emitting device and the top emission light emitting device.
In one embodiment, the first light emitting diode is prepared in the first pixel pit at least once by a wet process, and the second light emitting diode is prepared in the third pixel pit only by an evaporation process; or, the first light emitting diode is prepared in the first pixel pit only by adopting an evaporation process, and the second light emitting diode is prepared in the third pixel pit at least once by adopting a wet process.
In one embodiment, the light-emitting layer of the first light-emitting diode is made of quantum dot light-emitting materials, and the light-emitting layer of the second light-emitting diode is made of organic small molecule light-emitting materials; or, the light-emitting layer of the first light-emitting diode is prepared by adopting an organic small molecule light-emitting material, and the light-emitting layer of the second light-emitting diode is prepared by adopting a quantum dot light-emitting material.
In one embodiment, before the bottom-emission light-emitting device and the top-emission light-emitting device are sealed, an encapsulation material is arranged at a frame position of the bottom-emission light-emitting device or the top-emission light-emitting device, and after the bottom-emission light-emitting device and the top-emission light-emitting device are aligned, the bottom-emission light-emitting device and the top-emission light-emitting device are sealed by the encapsulation material.
Compared with the prior art, the invention has the beneficial effects that: in the invention, two different light-emitting diodes are respectively manufactured on the two substrates, and the material matching of a shared layer is not required to be considered when the two light-emitting diodes are manufactured on the same substrate by adopting different processes; when the evaporation process is adopted to manufacture one of the light-emitting diodes, the mask plate does not need to be worried about damaging other structures, and when the wet process is adopted to manufacture one of the light-emitting diodes, the high-temperature baking does not need to be worried about damaging the other light-emitting diode; the pixel size, device structure, etc. of the corresponding substrate can be optimized according to the specific process of the light emitting diode manufactured on the substrate.
Drawings
FIG. 1A is a schematic longitudinal sectional view of a first embodiment of an electroluminescent display device of the present invention, in which solid arrows indicate the light-emitting directions of light-emitting diodes;
FIG. 1B is a cross-sectional view A-A of the embodiment shown in FIG. 1A;
FIG. 1C is a schematic cross-sectional view B-B of the embodiment shown in FIG. 1A;
FIG. 2 is a schematic longitudinal sectional view of a second embodiment of an electroluminescent display device according to the invention, in which the solid arrows indicate the light exit direction of the light-emitting diodes;
FIG. 3 is a schematic longitudinal sectional view of a third embodiment of an electroluminescent display device according to the invention, in which the solid arrows indicate the light exit direction of the light-emitting diodes;
FIG. 4 is a schematic longitudinal sectional view of a fourth embodiment of an electroluminescent display device according to the invention, in which the solid arrows indicate the light exit direction of the light-emitting diodes;
FIG. 5A is a schematic diagram of a first sub-pixel cell of one embodiment of an electroluminescent display device of the present invention;
FIG. 5B is a schematic diagram of a second sub-pixel unit corresponding to the first sub-pixel unit of FIG. 5A;
FIG. 6A shows one embodiment of a bottom emitting substrate provided with a first pixel defining structure;
FIG. 6B shows an embodiment of a first light emitting diode fabricated on the bottom emitting substrate of FIG. 6A;
FIG. 6C shows one embodiment of a top emitting substrate provided with a second pixel defining structure;
FIG. 6D shows an embodiment of a second light emitting diode fabricated on the top emitting substrate of FIG. 6C;
FIG. 6E shows a schematic view of a bottom-emitting light-emitting device aligned with a top-emitting light-emitting device;
in the figure:
100. a bottom-emitting light-emitting device; 101. a first sub-pixel unit; 110. a bottom emission substrate; 111. a first light emitting pixel region; 112. a first blank pixel region; 120. a first light emitting diode; 121. a first hole injection layer; 122. a first hole transport layer; 123. a first light-emitting layer; 124. a first electron transport layer; 125. a first electron injection layer; 126. a first electrode; 130. a first pixel defining structure; 11. a first pixel pit; 12. a second pixel pit;
200. a top-emitting light emitting device; 201. a second sub-pixel unit; 210. a top emission substrate; 211. a second light emitting pixel region; 212. a second blank pixel region; 220. a second light emitting diode; 221. a reflective anode; 222. a second hole injection layer; 223. a second hole transport layer; 224. a second light emitting layer; 225. a second electron transport layer; 226. a second electron injection layer; 227. a second electrode; 230. a second pixel defining structure; 23. a third pixel pit; 24. a fourth pixel pit;
3. and (5) packaging the material.
Detailed Description
The present invention is further described below with reference to specific embodiments, and it should be noted that, without conflict, any combination between the embodiments or technical features described below may form a new embodiment.
In the description of the present invention, it should be noted that, for the terms of orientation, such as "central", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., it indicates that the orientation and positional relationship shown in the drawings are based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, but does not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated without limiting the specific scope of protection of the present invention.
It is noted that the terms first, second and the like in the description and in the claims of the present application are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the application described herein may be used. Moreover, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
As shown in fig. 1A to 4, the present invention provides an electroluminescent display device including a bottom-emitting light-emitting device 100 and a top-emitting light-emitting device 200 which are stacked, wherein:
the bottom emission light emitting device 100 includes a bottom emission substrate 110, the bottom emission substrate 110 having a plurality of first light emitting pixel regions 111 and a plurality of first blank pixel regions 112 on a side facing the top emission light emitting device 200, the first light emitting pixel regions 111 including first light emitting diodes 120;
the top emission light emitting device 200 includes a top emission substrate 210, the top emission substrate 210 having a plurality of second light emitting pixel regions 211 and a plurality of second blank pixel regions 212 at a side facing the bottom emission light emitting device 100, the second light emitting pixel regions 211 including second light emitting diodes 220;
the first light emitting pixel region 111 corresponds to the second blank pixel region 212, and the second light emitting pixel region 211 corresponds to the first blank pixel region 112, so that light emitted from the second light emitting diode 220 can pass through the first blank pixel region 112 and exit from the bottom emission substrate 110 side.
As will be understood by those skilled in the art, a bottom emission light emitting device means that the light emitting direction of the light emitting device is one side of the substrate, and a top emission light emitting device means that the light emitting direction of the light emitting device is the other side away from the substrate. The bottom-emitting light-emitting device 100 and the top-emitting light-emitting device 200 are stacked, and the bottom-emitting substrate 110 and the top-emitting substrate 210 both face outward, so that the bottom-emitting light-emitting device 100 and the top-emitting light-emitting device 200 emit light in the same direction. In addition, in the first blank pixel region 112, a non-transparent layer is not disposed on the bottom emission substrate 110, so that light emitted from the second light emitting diode 220 can pass through the first blank pixel region 112 and be emitted from the bottom emission substrate 110.
The bottom emission light emitting device 100 and the top emission light emitting device 200 of the electroluminescent display device are independently manufactured respectively, and after the manufacture is finished, the bottom emission light emitting device and the top emission light emitting device are stacked to obtain a complete display device. The first light emitting diode 120 of the bottom emission light emitting device 100 and the second light emitting diode 220 of the top emission light emitting device 200 may be different types of light emitting diodes, for example, a quantum dot light emitting diode and an organic light emitting diode, respectively. Since the first light emitting diode 120 and the second light emitting diode 220 are fabricated on different substrates, the fabrication processes will not affect each other, which is beneficial to obtaining high performance light emitting diodes. In addition, since the first and second light emitting diodes 120 and 220 do not have a common layer, there is no need to consider the material matching problem of the common layer. The quantum dot light-emitting diode is generally manufactured by adopting a wet process, such as ink-jet printing, slit coating and the like, the preparation cost is low, and the performance of the quantum dot light-emitting diode in the aspects of color gamut and color reduction capability is excellent; the organic light emitting diode is generally manufactured by adopting an evaporation process, such as physical vapor deposition and the like, the manufacturing cost is relatively high, but the manufactured organic light emitting diode has high luminous efficiency and long service life.
In some embodiments, the first light emitting diode 120 is a quantum dot light emitting diode and the second light emitting diode 220 is an organic light emitting diode. In other embodiments, the first light emitting diode 120 is an organic light emitting diode and the second light emitting diode 220 is a quantum dot light emitting diode.
The luminescent layer of the quantum dot light-emitting diode is a quantum dot luminescent layer, the thickness of the quantum dot luminescent layer is 20 nm-60 nm, the luminescent material is a quantum dot luminescent material, and the quantum dot light-emitting diode is preferably used for emitting red light and green light. The organic light emitting diode has light emitting layer of 20-70 nm thickness and light emitting material of small organic molecule, and preferably emits blue light.
In the embodiment shown in fig. 1A, first light emitting diode 120 is a quantum dot light emitting diode, that is, first light emitting layer 123 is a quantum dot light emitting layer, and the plurality of quantum dot light emitting diodes includes a light emitting diode for emitting red light and a light emitting diode for emitting green light. The second light emitting diode 220 is an organic light emitting diode for emitting blue light, i.e., the second light emitting layer 224 is an organic light emitting layer.
In the embodiment shown in fig. 2, the first light emitting diode 120 is an organic light emitting diode for emitting blue light. The second light emitting diode 220 is a quantum dot light emitting diode, and the plurality of quantum dot light emitting diodes include a light emitting diode for emitting red light and a light emitting diode for emitting green light.
One second blank pixel region 212 may be disposed opposite to one or more first light-emitting pixel regions 111, or a plurality of second blank pixel regions 212 may be disposed opposite to one first light-emitting pixel region 111. One first blank pixel region 112 may be opposite to one or more second light emitting pixel regions 211, or a plurality of first blank pixel regions 112 may be opposite to one second light emitting pixel region 211.
In the embodiment shown in fig. 1A or 2 or 4, one first blank pixel region 112 is disposed opposite one second emissive pixel region 211. The area of the second light emitting pixel region 211 may be larger than, equal to, or smaller than the area of the opposite first blank pixel region 112, so as to ensure that at least part of the light of the second light emitting diode 220 can enter the opposite first blank pixel region 112. In a preferred embodiment, the area of the second light emitting pixel region 211 is larger than the area of the opposing first blank pixel region 112, as shown in FIG. 4.
In the embodiment shown in fig. 3, one first blank pixel region 112 is disposed opposite to a plurality of second light-emitting pixel regions 211. When the second light emitting diode 220 of one second light emitting pixel region 211 opposite to the first blank pixel region 112 is abnormal, the second light emitting diodes 220 of other second light emitting pixel regions 211 can ensure the normal use of the electroluminescent display device, thereby being beneficial to reducing the probability of the abnormality of the electroluminescent display device and prolonging the service life of the electroluminescent display device. In a preferred embodiment, the total area of the plurality of second light emitting pixel regions 211 is greater than the area of the first blank pixel region 112 opposite thereto.
The bottom emission substrate 110 is provided with a first pixel defining structure 130 thereon, and the first pixel defining structure 130 defines a plurality of first pixel pits 11 and a plurality of second pixel pits 12 on the bottom emission substrate 110. No other structure is provided in the second pixel pit 12, that is, the area of the second pixel pit 12 is the first blank pixel area 112. In the first pixel pit, a first hole injection layer 121, a first hole transport layer 122, a first light emitting layer 123, a first electron transport layer 124, a first electron injection layer 125, and a first electrode 126 are sequentially disposed on the bottom emission substrate 110, so that the first light emitting diode 120 is formed in the first pixel pit 11, that is, the region of the first pixel pit 11 is the first light emitting pixel region 111. It should be noted that the anode of the first light emitting diode 120 is formed on the bottom emission substrate 110, and the first electrode 126 is a cathode.
In some embodiments, the first electrode 126 is a transparent electrode, i.e., the first light emitting diode 120 can also emit light in the direction of the top-emission light emitting device 200. At this time, in order to avoid mixing of the light of the first light emitting diode 120 and the light of the second light emitting diode 220, it is preferable that the orthographic projection of the second light emitting pixel region 211 on the bottom emission substrate 110 does not overlap the first light emitting pixel region 111, or the orthographic projection of the first light emitting pixel region 111 on the top emission substrate 210 does not overlap the second light emitting pixel region 211, so that the light of the second light emitting pixel region 211 and the light of the first light emitting pixel region 111 do not affect each other.
The material of which the transparent first electrode 126 is made may be, but is not limited to, ITO, ZnO, graphene, Ag, Al, etc. When the transparent first electrode 126 is prepared using metallic Ag, the thickness of the first electrode 126 is preferably 10nm to 20nm, and more preferably 15 nm.
Further, when the first electrode 126 is a transparent electrode, a reflective electrode material is preferably disposed in the second blank pixel area 212, and the reflective electrode material is used to reflect light emitted from the first light emitting diode 120 into the second blank pixel area 212.
When the electrode material is evaporated on the entire upper surface of the bottom emission substrate 110 by using the evaporation process to prepare the transparent first electrode 126, the opening of the second pixel pit 12 may be covered by using a mask plate, so as to prevent the electrode material from entering the second pixel pit 12, that is, the transparent electrode material is not disposed in the first blank pixel region 111; of course, the second pixel pits may not be covered, and the electrode material deposited in the second pixel pits forms a transparent layer which does not block light from passing through, i.e., the transparent electrode material is disposed in the first blank pixel region 111.
In other embodiments, the first electrode 126 is an opaque electrode. When the first electrode 126 is an opaque electrode, the first light emitting pixel region 111 and the second light emitting pixel region 211 may or may not overlap, and light of the first light emitting diode 120 and light of the second light emitting diode 220 are not mixed. The material of which the opaque first electrode 126 is made may be, but is not limited to, Ag, Al, etc. When the opaque first electrode 126 is prepared using metallic Ag, the thickness of the first electrode 126 is preferably 80nm to 200nm, and more preferably 150 nm.
When the electrode material is entirely evaporated above the bottom emission substrate 110 by using the evaporation process to prepare the opaque first electrode 126, the opening of the second pixel hole 12 needs to be covered by using a mask plate, so that the electrode material is prevented from entering the second pixel hole 12.
The top emission substrate 210 is provided with a second pixel defining structure 230, and the second pixel defining structure 230 defines a plurality of third pixel pits 23 and a plurality of fourth pixel pits 24 on the top emission substrate 210. No other structure is provided in fourth pixel pit 24, that is, the area of fourth pixel pit 24 is second blank pixel area 212. In third pixel pit 23, reflective anode 221, second hole injection layer 222, second hole transport layer 223, second light emitting layer 224, second electron transport layer 225, second electron injection layer 226, and second electrode 227 are sequentially disposed on top emission substrate 210, so that second light emitting diode 220 is formed in third pixel pit 23, that is, the region of third pixel pit 23 is second light emitting pixel region 211. The second electrode 227 is a transparent electrode.
It should be noted that, in some embodiments, the electron injection layer may not be included in each of the light emitting diodes.
The material for preparing the transparent second electrode 227 may be, but is not limited to, ITO, ZnO, graphene, Ag, Al, etc. When the transparent second electrode 227 is prepared using metallic Ag, the thickness of the second electrode 227 is preferably 10nm to 20nm, more preferably 12 nm.
When the evaporation process is adopted to evaporate the electrode material on the whole upper surface of the top emission substrate 210 to prepare the transparent second electrode 227, the mask plate can be used to cover the opening of the fourth pixel pit, so that the electrode material is prevented from entering the fourth pixel pit; of course, the electrode material may be deposited in the fourth pixel pit without covering the fourth pixel pit.
Further, the bottom emission device 100 includes a plurality of first sub-pixel units 101 disposed in an array, and each of the first sub-pixel units 101 includes a number of first light emitting pixel regions 111 and a number of first blank pixel regions 112. Similarly, the top emission device 200 includes a plurality of second sub-pixel units 201 arranged in an array, and each second sub-pixel unit 201 includes a plurality of second light-emitting pixel regions 211 and a plurality of second blank pixel regions 212. The first sub-pixel units 101 of the bottom emission device 100 correspond to the second sub-pixel units 201 of the top emission device 200 one by one, and the second light emitting pixel regions 211 of the second sub-pixel units 201 correspond to the first blank pixel regions 112 of the first sub-pixel units 101.
In one embodiment, as shown in fig. 1B and 1C, the first sub-pixel unit 101 includes two first light-emitting pixel regions 111 and one first blank pixel region 112, and three pixel regions of the first sub-pixel unit 101 are arranged in a row in parallel. The second sub-pixel unit 201 includes one second light-emitting pixel region 211 and two second blank pixel regions 212, and the three pixel regions of the second sub-pixel unit 201 are arranged in parallel in one row. The second emission pixel region 211 is opposite to the first blank pixel region 112, and the two second blank pixel regions 212 are respectively opposite to the two first emission pixel regions 111. The light emitting diodes in the two first light emitting pixel regions 111 of the first sub-pixel unit 101 emit red light and green light, respectively, and the light emitting diodes in the second light emitting pixel region 211 emit blue light.
In another embodiment, as shown in fig. 5A and 5B, the first sub-pixel unit 101 includes two first light-emitting pixel regions 111 and one first blank pixel region 112, wherein the two first light-emitting pixel regions 111 are arranged in parallel in one row, and the first blank pixel regions 112 are individually arranged in one row. The second sub-pixel unit 201 includes two second light-emitting pixel regions 211 and two second blank pixel regions 212, wherein the two second light-emitting pixel regions 211 are arranged in parallel in a row, the two second blank pixel regions 212 are arranged in parallel in a row, the two second light-emitting pixel regions 211 are both opposite to the first blank pixel region 112, and the two second blank pixel regions 212 are respectively opposite to the two first light-emitting pixel regions 111. The light emitting diodes of the two second light emitting pixel regions 211 emit blue light, and the light emitting diodes of the two first light emitting pixel regions 111 emit red light and green light, respectively.
In some embodiments, the top-emitting device 200 is a single-layer or multi-layer series structure.
The invention also provides a preparation method of the electroluminescent display device, which comprises the following steps:
providing a bottom emission substrate 110 having a plurality of first pixel pits 11 and a plurality of second pixel pits 12 on the surface, as shown in fig. 6A, preparing a first light emitting diode 120 in each first pixel pit 11, and obtaining a bottom emission light emitting device 100, as shown in fig. 6B;
providing a top emission substrate 210 having a plurality of third pixel pits 23 and a plurality of fourth pixel pits 24 on the surface, as shown in fig. 6C, and fabricating a second light emitting diode 220 in each third pixel pit 23 to obtain a top emission light emitting device 200, as shown in fig. 6D;
the bottom emission light emitting device 100 and the top emission light emitting device 200 are aligned such that the second light emitting diode 220 within the third pixel pit 23 is opposite to the opening of the second pixel pit 12, and then the bottom emission light emitting device 100 and the top emission light emitting device 200 are sealed.
The first light emitting diode 120 and the second light emitting diode 220 are independently manufactured on the two substrates, so that the manufacturing process of the first light emitting diode 120 does not affect the second light emitting diode 220, and the manufacturing process of the second light emitting diode 220 does not affect the first light emitting diode 120.
In some embodiments, the first light emitting diode 120 is fabricated at least once in the first pixel pit 11 by a wet process, and the second light emitting diode 220 is fabricated in the third pixel pit 13 by an evaporation process. In other embodiments, only the evaporation process is used to fabricate the first light emitting diode 120 in the first pixel pit 11, and the wet process is used at least once to fabricate the second light emitting diode 220 in the third pixel pit 13.
The invention discloses a method for preparing a light-emitting diode at least once by adopting a wet process, which comprises the following steps: when each functional layer of the light-emitting diode is prepared, at least one functional layer is prepared by adopting a wet process, and after a film layer is prepared by adopting the wet process, a baking step is required, so that the preparation process of the light-emitting diode is equivalent to that of the light-emitting diode, and at least one time of drying is required. The invention discloses a method for preparing a light-emitting diode by only adopting a vapor deposition process, which comprises the following steps: when all functional layers of the light-emitting diode are prepared, all the functional layers are prepared by adopting an evaporation process, so that the drying is not needed in the preparation process of the light-emitting diode.
In the present invention, the wet process is a method of making a solution containing a functional material enter into corresponding pixel pits by various means, and then drying to obtain a functional layer, and the wet process may be, but is not limited to, inkjet printing, slit coating, and the like. The evaporation process is a method for making the functional material enter the corresponding pixel pit by vapor deposition, so as to form the functional layer, and the evaporation process can be, but is not limited to, vacuum evaporation, sputtering coating, plasma coating and the like.
The preparation method of the invention can give consideration to the advantages of preparing different light-emitting diodes by a wet process and an evaporation process, and can avoid the influence of the subsequent preparation process on the light-emitting diode which is prepared firstly when two light-emitting diodes are prepared on the same substrate in sequence, namely the method of the invention can ensure that the first light-emitting diode 120 and the second light-emitting diode 220 both keep good light-emitting performance, thereby obtaining the electroluminescent display device with the performance superior to that of the prior art.
In some embodiments, the light emitting layer of the first light emitting diode 120 is made of a quantum dot light emitting material, and the light emitting layer of the second light emitting diode 220 is made of a small organic molecule light emitting material. In other embodiments, the light emitting layer of the first light emitting diode 120 is made of an organic small molecule light emitting material, and the light emitting layer of the second light emitting diode 220 is made of a quantum dot light emitting material.
The method of sealing the bottom emission light emitting device 100 and the top emission light emitting device 200 may be, but is not limited to, packaging using a curing paste or packaging using a laser sintering process.
In some embodiments, before the bottom-emission light-emitting device 100 and the top-emission light-emitting device 200 are sealed, an encapsulating material 3 with good light transmittance is disposed on the entire surface of the bottom-emission light-emitting device 100 or the top-emission light-emitting device 200, as shown in fig. 6E, after the bottom-emission light-emitting device 100 and the top-emission light-emitting device 200 are aligned, the space between the bottom-emission light-emitting device 100 and the top-emission light-emitting device 200 is sealed by the encapsulating material 3, and the encapsulating material 3 has good light transmittance, so that the light extraction performance of the devices is less affected. The sealing material 3 generally has a certain fluidity, and when the pixel pits are blank as opposed to the sealing material 3, the sealing material 3 enters the pixel pits.
When the package material 3 is a light-curing adhesive, after the package material 3 is disposed on the bottom emission light-emitting device 100 or the top emission light-emitting device 200, a liquid desiccant is preferably disposed at the frame, and the liquid desiccant can prevent external water and oxygen from penetrating through the package material 3 to affect the normal use of the light-emitting device.
In some embodiments, after aligning the bottom-emitting light emitting device 100 with the top-emitting light emitting device 200, the cavity between the two is evacuated and then the bottom-emitting light emitting device 100 and the top-emitting light emitting device 200 are sealed.
In one embodiment, a method of fabricating an electroluminescent display device includes the steps of:
first, preparing a bottom emission light emitting device
(1) Providing a bottom emission substrate, wherein a pixel defining structure is arranged on the bottom emission substrate, the pixel defining structure defines and forms a plurality of pixel pits on the bottom emission substrate, every three pixel pits form a sub-pixel unit, and the three pixel pits of each sub-pixel unit are respectively a red pixel pit, a green pixel pit and a blank pixel pit;
(2) a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer and an electron injection layer are sequentially manufactured in each red pixel pit by adopting a wet film forming process, then a cathode is manufactured on the electron injection layer by adopting an evaporation process, wherein the quantum dot light-emitting layer is made of red light quantum dot materials, and thus a red light-emitting diode is manufactured in each red pixel pit;
(3) the method for preparing the light-emitting diode emitting green light in each green pixel pit refers to the preparation method in a red pixel pit, and is characterized in that the material of the quantum dot light-emitting layer is a green light quantum dot material;
(4) no other structure is arranged in each blank pixel pit, in order to prevent the preparation materials in the steps (2) and (3) from entering the blank pixel pits, a shielding plate can be adopted to cover the opening of the blank pixel pit when the light-emitting diode is prepared,
if the cathodes for vapor deposition are transparent electrodes in the steps (2) and (3), the vapor deposition can also be directly carried out on the whole surface, the cathode material entering the blank pixel pits forms a transparent layer, the passing of light rays is not influenced,
if the cathodes of the evaporation are all opaque electrodes in the steps (2) and (3), the openings of the blank pixel pits need to be covered by the shielding plates so as to prevent the evaporation material from entering the blank pixel pits.
Secondly, preparing a top-emitting luminescent device
(5) Providing a top emission substrate, wherein a pixel defining structure is arranged on the top emission substrate, the pixel defining structure defines and forms a plurality of pixel pits on the top emission substrate, every three pixel pits form a sub-pixel unit, and the three pixel pits of each sub-pixel unit are a blue pixel pit and two blank pixel pits;
(6) a hole injection layer, a hole transport layer, an organic light-emitting layer, an electron transport layer, an electron injection layer and a transparent cathode are sequentially manufactured in the blue pixel pit by adopting an evaporation process, the organic light-emitting layer is made of a blue organic micromolecule light-emitting material, and therefore a blue light-emitting diode is manufactured in the blue pixel pit;
(7) and (3) no other structures are arranged in each blank pixel pit, and in order to prevent the preparation material in the step (6) from entering the blank pixel pits, a shielding plate can be adopted to cover the openings of the blank pixel pits during the preparation of the light-emitting diode.
Thirdly, preparing an electroluminescent display device:
(8) arranging light-transmitting light-curing glue on the whole top surface (namely the surface of one side far away from the top emission substrate) of the top emission light-emitting device;
(9) moving the substrate of the bottom emission light-emitting device upwards to the position above the top emission light-emitting device, keeping the distance between the substrate of the bottom emission light-emitting device and the top emission light-emitting device to be 0.1mm, and then adjusting the alignment marks of the bottom emission light-emitting device and the top emission light-emitting device to be overlapped by utilizing a machine vision system, so that the sub-pixel units of the top emission light-emitting device and the sub-pixel units of the bottom emission light-emitting device are in one-to-one correspondence, and the opening of the blue pixel pit of the top emission light-emitting device is opposite to the opening of the blank pixel pit of the bottom emission light-emitting device;
(10) evacuating a cavity between a bottom-emitting light-emitting device and a top-emitting light-emitting device to 5 x 10-3torr, then restored to 8 x 10-2torr；
(11) And pressing the bottom emission light-emitting device on the top emission light-emitting device, and turning on a light source to cure the light-curing adhesive.
The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are within the protection scope of the present invention.
Claims (11)
1. An electroluminescent display device comprising a bottom-emitting light-emitting device and a top-emitting light-emitting device which are arranged in a stack, wherein,
the bottom emission light emitting device includes a bottom emission substrate having a plurality of first light emitting pixel regions and a plurality of first dummy pixel regions on a side facing the top emission light emitting device, the first light emitting pixel regions including first light emitting diodes,
the top emission light emitting device includes a top emission substrate having a plurality of second light emitting pixel regions and a plurality of second dummy pixel regions on a side facing the bottom emission light emitting device, the second light emitting pixel regions including second light emitting diodes, the second light emitting pixel regions corresponding to the first dummy pixel regions, the second dummy pixel regions corresponding to the first light emitting pixel regions.
2. An electroluminescent display device according to claim 1, wherein the first light emitting diode is a quantum dot light emitting diode and the second light emitting diode is an organic light emitting diode;
or the first light-emitting diode is an organic light-emitting diode, and the second light-emitting diode is a quantum dot light-emitting diode.
3. The device of claim 2, wherein the plurality of quantum dot light emitting diodes comprise a light emitting diode for emitting red light and a light emitting diode for emitting green light, and the organic light emitting diode emits blue light.
4. An electroluminescent display device according to claim 2, wherein the quantum dot light emitting diode comprises a quantum dot light emitting layer and the organic light emitting diode comprises an organic light emitting layer.
5. An electroluminescent display device according to any one of claims 1 to 4, wherein one of the first blank pixel regions is disposed opposite to one or more of the second light-emitting pixel regions, and one of the second blank pixel regions is disposed opposite to one or more of the first light-emitting pixel regions.
6. An electroluminescent display device according to any of claims 1 to 4, wherein the orthographic projection of the second light-emitting pixel region on the bottom-emitting substrate does not overlap with the first light-emitting pixel region.
7. An electroluminescent display device according to any of claims 1 to 4, characterized in that the first blank pixel area is provided with or without a transparent electrode material or the second blank pixel area is provided with or without a reflective electrode material.
8. A method for manufacturing an electroluminescent display device, comprising the steps of:
providing a bottom emission substrate with a plurality of first pixel pits and a plurality of second pixel pits on the surface, and preparing a first light-emitting diode in each first pixel pit to obtain a bottom emission light-emitting device;
providing a top emission substrate with a plurality of third pixel pits and a plurality of fourth pixel pits on the surface, and preparing a second light emitting diode in each third pixel pit to obtain a top emission light emitting device;
aligning the bottom emission light emitting device and the top emission light emitting device such that the second light emitting diode within the third pixel pit is opposite to an opening of the second pixel pit, and then sealing the bottom emission light emitting device and the top emission light emitting device.
9. The method of claim 8, wherein the first light emitting diode is fabricated at least once in the first pixel pit by a wet process, and the second light emitting diode is fabricated in the third pixel pit by an evaporation process only;
or, the first light emitting diode is prepared in the first pixel pit only by adopting an evaporation process, and the second light emitting diode is prepared in the third pixel pit at least once by adopting a wet process.
10. The method of claim 8, wherein the light-emitting layer of the first light-emitting diode is made of a quantum dot light-emitting material, and the light-emitting layer of the second light-emitting diode is made of an organic small molecule light-emitting material;
or, the light-emitting layer of the first light-emitting diode is prepared by adopting an organic small molecule light-emitting material, and the light-emitting layer of the second light-emitting diode is prepared by adopting a quantum dot light-emitting material.
11. The method of manufacturing an electroluminescent display device according to claim 8, wherein before the bottom emission light emitting device and the top emission light emitting device are sealed, an encapsulating material is provided at a position of a frame of the bottom emission light emitting device or the top emission light emitting device, and after the bottom emission light emitting device and the top emission light emitting device are aligned, the bottom emission light emitting device and the top emission light emitting device are sealed by using the encapsulating material.
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| CN106098954A (en) * | 2016-06-30 | 2016-11-09 | 京东方科技集团股份有限公司 | A kind of organic electroluminescence device and preparation method thereof, display device |
| CN106340597A (en) * | 2016-08-31 | 2017-01-18 | 纳晶科技股份有限公司 | Light emitting device |
| CN106784386A (en) * | 2017-01-13 | 2017-05-31 | 纳晶科技股份有限公司 | Encapsulating structure, method for packing and electroluminescent device |
| CN107681040A (en) * | 2017-10-14 | 2018-02-09 | 施伟强 | Display panel and constructional device |
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| KR102291619B1 (en) * | 2014-02-26 | 2021-08-23 | 삼성디스플레이 주식회사 | Organic light emiiting dispaly device |
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| CN106098954A (en) * | 2016-06-30 | 2016-11-09 | 京东方科技集团股份有限公司 | A kind of organic electroluminescence device and preparation method thereof, display device |
| CN106340597A (en) * | 2016-08-31 | 2017-01-18 | 纳晶科技股份有限公司 | Light emitting device |
| CN106784386A (en) * | 2017-01-13 | 2017-05-31 | 纳晶科技股份有限公司 | Encapsulating structure, method for packing and electroluminescent device |
| CN107681040A (en) * | 2017-10-14 | 2018-02-09 | 施伟强 | Display panel and constructional device |
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