Organic light emitting display device and method of manufacturing the same

Abstract

An organic light emitting display device includes a first display area having a plurality of sub-pixel areas therein and a second display area having a plurality of sub-pixel areas and a plurality of transmission areas therein. The organic light emitting display device includes a plastic substrate including a first portion corresponding to the first display area and a second portion corresponding to the second display area, a plurality of thin film transistors on the plastic substrate to correspond to the plurality of sub-pixel areas, and a plurality of organic light emitting elements on the plurality of thin film transistors to correspond to the plurality of sub-pixel areas, wherein the second portion includes a polyimide and a ligand compound and the first portion includes the polyimide without the ligand compound.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit and priority of Korean Patent Application No. 10-2020-0188251, filed in Korea on December 30, 2020, the entire contents of which are expressly incorporated herein by reference. Technical Field

[0003] This disclosure relates to an organic light-emitting display device and a method for manufacturing the same, and more specifically, to an organic light-emitting display device and a method for manufacturing the same, the organic light-emitting display device comprising a plastic substrate that uses inexpensive materials and has selectively improved transmittance through a simple process compared to related technologies while maintaining high reliability of the display device. Background Technology

[0004] Recently, as our society moves towards an information society, the field of display devices for visually representing electrical information signals has developed rapidly. Various display devices with excellent performance in terms of thinness, light weight, and low power consumption are also under development. Plastic organic light-emitting display devices, by using plastic films instead of thick glass as substrates, are thin, light, and possess excellent flexibility, thus allowing them to be easily applied to various forms such as flexible displays.

[0005] Meanwhile, the display device includes a display area in which an image is substantially displayed, and a border area that is a non-display area in which an image is substantially not displayed due to being covered by a light-blocking member or the like. Display elements for displaying images are disposed in the display area, and various lines or drive circuits for driving the display elements are disposed in the border area. The display includes a camera, speakers, various sensors, etc., to provide various functions, and these components are also disposed in the border area.

[0006] Recently, research has been actively conducted to reduce the bezel area in order to improve the aesthetics of display designs and provide the widest possible screen within a limited display size. Accordingly, techniques have been proposed to replace components such as cameras and sensors, previously located in the bezel area, with those components in the display area. For example, it has been proposed to place these components on the rear surface of the display to enable smooth image display. Summary of the Invention

[0007] The advantage of polyimide films, which are most widely used as plastic substrates, is that they have excellent mechanical properties, specifically excellent heat resistance, so that they will not deform even during deposition processes performed at high temperatures above 300°C, such as those used in thin-film transistors.

[0008] However, a drawback of polyimide is that it forms charge-transfer complexes (CTCs) through intra-chain and inter-chain interactions, exhibiting a significant coloration ranging from pale yellow to dark brown. Here, polyimide contains an amine as an electron donor and a carbonyl group as an electron acceptor in its backbone, and it is stable while pushing electrons from the amine (electron donor) to the carbonyl group (electron acceptor), thus forming charge-transfer complexes. This occurs not only within a single chain but also between adjacent chains. The stacking between chains is caused by this interaction, resulting in a high chain density. The charge-transfer complexes are due to the transfer of π electrons within the polyimide, and with the transfer of π electrons, the energy level decreases. Therefore, the limitation is that visible light (especially visible light in the 400 nm to 500 nm wavelength band) is absorbed, resulting in yellow and brown light as complementary colors, and reduced transmittance.

[0009] On the other hand, when cameras or sensors are mounted on the back surface of a display to reduce the bezel area, the area where the camera is mounted needs to have a predetermined level of transmittance for smooth operation. Therefore, when using a polyimide film as a substrate, transmittance is ensured by forming thin-film transistors and light-emitting elements on the polyimide film, and then using high energy, such as a laser, to irradiate the polyimide in the area where the camera is mounted to remove it. However, polyimide byproducts contaminate the panel, and the incomplete removal of polyimide residue limits the improvement of transmittance. Furthermore, the high energy during laser irradiation can damage the thin-film transistors and moisture barrier layer, thus reducing the reliability of the display panel.

[0010] Therefore, transparent polyimide films with improved transmittance were developed by introducing organic groups containing highly electronegative elements such as trifluoromethyl, sulfone, and ether into the polyimide backbone to reduce CTC formation. However, the developed transparent polyimide requires complex synthesis, which limits its cost to a significantly higher unit cost compared to existing colored polyimides, thus increasing material costs.

[0011] Therefore, embodiments of this disclosure relate to an organic light-emitting display device and a method of manufacturing the same, which substantially eliminates one or more problems caused by the limitations and disadvantages of related technologies.

[0012] Therefore, one aspect of this disclosure is to provide an organic light-emitting display device and a method for manufacturing the same, the organic light-emitting display device comprising a plastic substrate that uses low-cost materials and has improved light transmittance through a simple process compared to related technologies.

[0013] Another aspect of this disclosure is to provide an organic light-emitting display device and a method for manufacturing the same, which can selectively increase the transmittance of a polyimide film without irradiating it with high energy such as lasers, thereby minimizing or reducing damage or contamination to the display panel caused by the aforementioned polyimide residues.

[0014] Another aspect of this disclosure is to selectively increase the light transmittance of a specific region of a polyimide film through a simple process, and to reduce the bezel area by placing a camera or sensor on the back surface of the polyimide film with the increased transmittance.

[0015] Another aspect of this disclosure is the use of inexpensive materials and a simple process to selectively increase light transmittance while maintaining high reliability of the display device, compared to related technologies.

[0016] Additional features and aspects will be set forth in the description which follows and will become apparent in part from the specification, or may be learned by practicing the inventive concept provided herein. Other features and aspects of the inventive concept may be realized and obtained by means of the structures specifically pointed out in the written description or derivatives thereof, the claims of this disclosure, and the accompanying drawings.

[0017] To achieve these and other aspects of the inventive concept, as presented and generally described herein, an organic light-emitting display device comprising a first display region having a plurality of sub-pixel regions and a second display region having a plurality of sub-pixel regions and a plurality of transmissive regions includes: a plastic substrate including a first portion corresponding to the first display region and a second portion corresponding to the second display region; a plurality of thin-film transistors located on the plastic substrate to correspond to the plurality of sub-pixel regions; and a plurality of organic light-emitting elements located on the plurality of thin-film transistors to correspond to the plurality of sub-pixel regions, wherein the second portion comprises polyimide and a ligand compound, and the first portion comprises polyimide but does not contain a ligand compound.

[0018] In another aspect, a method for manufacturing an organic light-emitting display device according to exemplary embodiments of the present disclosure includes: manufacturing a plastic substrate comprising polyimide; forming a plurality of thin-film transistors on the plastic substrate; forming organic light-emitting elements on the plurality of thin-film transistors; and coating a ligand solution onto at least a portion of the rear surface of the plastic substrate and drying the ligand solution.

[0019] Further details of the exemplary embodiments are included in the detailed description and accompanying drawings.

[0020] According to this disclosure, the transmittance of a plastic substrate containing inexpensive colored polyimide can be selectively increased by using a simple process of treating the substrate with a ligand solution without irradiating it with high energy such as a laser.

[0021] Furthermore, since the limitations of the laser irradiation method mentioned above are solved by replacing the process of irradiating with high energy such as laser, the transmittance of the plastic substrate can be selectively improved while maintaining the high reliability of the organic light-emitting display device.

[0022] Furthermore, by selectively mounting cameras and / or various sensors on the rear surface of a plastic substrate with improved transmittance, it is possible to provide an organic light-emitting display device with a reduced bezel area.

[0023] Furthermore, by treating the entire surface of the plastic substrate with a ligand solution, the light transmittance of the entire surface of the organic light-emitting display device can be improved, thereby making it easy to realize a transparent display device.

[0024] It should be understood that the general description above and the detailed description below are exemplary and illustrative, and are intended to provide further explanation of the claimed inventive concept. Attached Figure Description

[0025] This disclosure includes accompanying drawings, which are incorporated in and constitute a part of this application, to provide a further understanding of the disclosure and illustrate embodiments thereof, and together with the description serve to explain various principles.

[0026] Figure 1 This is a schematic plan view of an organic light-emitting display device according to exemplary embodiments of the present disclosure.

[0027] Figure 2 yes Figure 1 A schematic enlarged plan view of region A in the diagram.

[0028] Figure 3 yes Figure 1 A schematic enlarged plan view of region B in the diagram.

[0029] Figure 4 This is a schematic plan view of a plastic substrate in an organic light-emitting display device according to an exemplary embodiment of the present disclosure.

[0030] Figure 5 It is along Figure 2 A schematic cross-sectional view taken from line I-I' in the diagram.

[0031] Figure 6 It is along Figure 3 A schematic cross-sectional view taken from line II-II' in the diagram.

[0032] Figure 7A This is a graph showing the yellow index (YI) of colored polyimide films treated with ligand solutions in or out of the presence of ligands.

[0033] Figure 7BThis is a graph showing the light transmittance of colored polyimide films treated with ligand solutions, depending on whether they are present or absent.

[0034] Figure 8 This is a process flow diagram illustrating a method for manufacturing an organic light-emitting display device according to an exemplary embodiment of the present disclosure. Detailed Implementation

[0035] The advantages and features of this disclosure, as well as methods for achieving these advantages and features, will become apparent from the exemplary embodiments and accompanying drawings described in detail below. However, this disclosure is not limited to the exemplary embodiments disclosed herein, but will be implemented in various forms. The exemplary embodiments are provided by way of example only so that those skilled in the art can fully understand the disclosure and scope of this disclosure. Therefore, this disclosure will be limited only by the scope of the appended claims.

[0036] The shapes, dimensions, ratios, angles, quantities, etc., shown in the accompanying drawings used to describe exemplary embodiments of this disclosure are merely examples, and this disclosure is not limited thereto. Throughout the specification, similar reference numerals generally denote similar elements. Furthermore, in the following description of this disclosure, detailed explanations of known related technologies may be omitted to avoid unnecessarily obscuring the subject matter of this disclosure. Terms such as “comprising,” “having,” and “consisting of” as used herein are generally intended to allow for the addition of additional components, unless these terms are used in conjunction with the term “only.” Unless otherwise expressly stated, any reference to the singular may include the plural.

[0037] Even if not explicitly stated, components are interpreted as including a normal error range.

[0038] When using terms such as “on top of,” “above,” “below,” and “near” to describe the positional relationship between two parts, one or more parts may be located between the two parts, unless these terms are used in conjunction with the terms “close to” or “directly.”

[0039] When one element or layer is placed "on" another element or layer, a third layer or third element can be directly inserted on the other element or between one element and another.

[0040] Although the terms "first," "second," etc., are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from other components. Therefore, the first component mentioned below can be a second component under the technical concept of this disclosure.

[0041] Throughout the specification, similar reference numerals generally denote similar elements.

[0042] For ease of description, the dimensions and thickness of each component shown in the accompanying drawings are illustrated, and this disclosure is not limited to the dimensions and thickness of the components shown.

[0043] The features of the various embodiments of this disclosure may be partially or wholly attached to or combined with each other, and may be associated and operated in various technical ways, and these embodiments may be performed independently or in relation to each other.

[0044] Unless otherwise stated herein, the yellow index is a value measured using a colorimeter, and the light transmittance is a value measured using a UV-Vis spectrophotometer.

[0045] In the following description, an organic light-emitting display device and a method of manufacturing the same according to various exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0046] Figures 1 to 6 This is a view used to explain an organic light-emitting display device according to exemplary embodiments of the present disclosure. Figure 1 This is a schematic plan view of an organic light-emitting display device according to exemplary embodiments of the present disclosure. Figure 2 yes Figure 1 A schematic enlarged plan view of region A in the diagram. Figure 3 yes Figure 1 A schematic enlarged plan view of region B in the diagram. Figure 4 This is a schematic plan view of a plastic substrate in an organic light-emitting display device according to an exemplary embodiment of the present disclosure. Figure 5 It is along Figure 2 A schematic cross-sectional view taken from line I-I' in the diagram. Figure 6 It is along Figure 3 A schematic cross-sectional view taken from line II-II' in the diagram.

[0047] refer to Figures 1 to 6 An organic light-emitting display device 100 according to an exemplary embodiment of the present disclosure includes a plastic substrate 110, a thin-film transistor (TFT), a planarization layer 134, a diaphragm 135, an organic light-emitting element 140, an encapsulation layer 150, and a camera module 160. The various components will be described in detail below.

[0048] First, refer to Figure 1 The organic light-emitting display device 100 is divided into display areas DA1 and DA2 and a non-display area NDA. Display areas DA1 and DA2 are areas in which multiple sub-pixels are configured to substantially display an image. Multiple sub-pixels for displaying the image, as well as various driving elements and driving circuits for driving the sub-pixels, can be disposed in display areas DA1 and DA2. A sub-pixel is a sub-pixel that serves as an element for displaying a color, and includes a light-emitting area that emits light and a non-light-emitting area that does not emit light.

[0049] The non-display area NDA surrounds the display areas DA1 and DA2. The non-display area NDA is the region in which images are essentially not displayed and can be referred to as the border area. Various lines, driver ICs, printed circuit boards, etc., used to drive the sub-pixels and driving elements located in the display areas DA1 and DA2 are located in the non-display area NDA. For example, various ICs such as gate driver ICs and data driver ICs can be located in the non-display area.

[0050] Furthermore, display areas DA1 and DA2 can be divided into a first display area DA1 and a second display area DA2. The first display area DA1 surrounds the second display area DA2. Additionally, the area of ​​the second display area DA2 is smaller than the area of ​​the first display area DA1. Figure 1 The second display area DA2 is shown to be located at the center of the upper end of the entire display area, but this disclosure is not limited thereto. The position, shape, and size of the second display area DA2 can be changed as needed.

[0051] refer to Figures 1 to 3 The first display area DA1 includes multiple sub-pixel areas SPA1, and the second display area DA2 includes multiple sub-pixel areas SPA2 and multiple transmissive areas TA. In the accompanying drawings, different reference numerals are used to distinguish the multiple sub-pixel areas of the first display area and the multiple sub-pixel areas of the second display area, but they may be substantially identical to each other. Furthermore, the drawings show that each of the multiple sub-pixel areas and the multiple transmissive areas has a rectangular shape, but this disclosure is not limited thereto.

[0052] Subpixels are formed in each of the plurality of subpixel regions SPA1 in the first display area DA1 and the plurality of subpixel regions SPA2 in the second display area DA2. Each subpixel can be any one of a red subpixel, a green subpixel, a blue subpixel, and a white subpixel. Subpixels are not located in the transmissive region TA of the second display area DA2; therefore, the transmissive region TA does not emit light and can be transparent.

[0053] The first display area DA1 and the second display area DA2 can have different resolutions. The first display area DA1 is configured to include multiple sub-pixel areas SPA1, and the second display area DA2 is configured to include multiple sub-pixels SPA2 and multiple transmissive areas TA. Furthermore, comparing the first display area DA1 and the second display area DA2 with the same area, the number of sub-pixel areas in the second display area DA2 is less than the number of sub-pixel areas in the first display area DA1. That is, based on the same area, the number of sub-pixels contained in the second display area DA2 is less than the number of sub-pixels contained in the first display area DA1; therefore, the resolution of the second display area DA2 can be lower than the resolution of the first display area DA1. In other words, the second display area DA2 includes multiple transmissive areas TA, making it have a lower resolution and a higher light transmittance than the first display area DA1.

[0054] The organic light-emitting display device 100 may include components such as a camera module, an infrared sensor, an illuminance sensor, an object sensor, and / or a biosensor to provide users with various functions and conveniences. These components may be disposed on the rear surface of the plastic substrate 110 to overlap with the second display area DA2. Since the second display area DA2 includes multiple sub-pixel areas SPA2 and multiple transmissive areas TA, images are displayed through the second display area DA2. Simultaneously, the second display area DA2 has high light transmittance, allowing the aforementioned camera module and / or various sensors to be disposed therein.

[0055] According to related technologies, camera modules, various sensors, etc., are located in the non-display area, thereby limiting the reduction of the non-display area. According to an exemplary embodiment of this disclosure, a second display area DA2 with relatively high light transmittance can be provided, allowing components such as camera modules to be configured to overlap with the second display area DA2. Therefore, the non-display area NDA can be reduced.

[0056] although Figure 1The illustration shows a display area divided into a first display area DA1 and a second display area DA2, but this disclosure is not limited thereto. For example, when implementing a transparent organic light-emitting display device, it is necessary to ensure a light transmittance of a predetermined level or higher over the entire area of ​​the display device. In this case, the display area may consist solely of a second display area comprising multiple sub-pixels and multiple transmissive areas. As another example, the display area may further include a third display area. The third display area may include multiple sub-pixel areas and multiple transmissive areas, and therefore may have a lower resolution than the first display area. The resolution of the third display area may be the same as or different from the resolution of the second display area. When a third display area is further included, a camera module may be configured to overlap with the second display area, and another camera module or various sensors may be configured to overlap with the third display area, but this disclosure is not limited thereto.

[0057] The plastic substrate 110 supports various components constituting the organic light-emitting display device 100. (Reference) Figure 4 The plastic substrate 110 includes a first portion 110a and a second portion 110b. The first portion 110a corresponds to a first display area DA1, and the second portion 110b corresponds to a second display area DA2. A detailed description will be provided later.

[0058] The plastic substrate 110 contains polyimide. Polyimide has excellent mechanical properties, specifically excellent heat resistance, so that it will not undergo thermal decomposition or thermal deformation even under high-temperature processes in which components such as thin-film transistors are formed on the plastic substrate.

[0059] For example, polyimide may contain repeating units represented by Formula 1 below.

[0060] [Formula 1]

[0061]

[0062] In Equation 1, X1 can be a tetravalent organic group, and X1 can be a divalent aromatic organic group. n can be an integer between 10 and 1000, but is not limited to this.

[0063] As described above, polyimides form charge-transfer complexes through intra-chain and inter-chain interactions. Specifically, as shown in Formula 1, polyimides consist of repeating units comprising an amine as an electron donor and a carbonyl group as an electron acceptor. Thus, a charge-transfer complex is formed that is stabilized while pushing electrons from the amine to the carbonyl group, and through this interaction, chain stacking occurs, resulting in a characteristic of a fairly high chain density. Furthermore, as the charge-transfer complex is stabilized by this charge transfer, the energy level decreases, causing the charge-transfer complex to absorb visible light in the wavelength range of 400 nm to 500 nm and exhibiting a color ranging from pale yellow to dark brown. Polyimides exhibiting characteristic colors due to the formation of charge-transfer complexes as described above are generally referred to as colored polyimides. Colored polyimides have limited applications due to their unique color when high transmittance is required. To ensure transmittance, transparent polyimide films can be used, but these are considerably more expensive than colored polyimides, leading to a significant increase in material costs.

[0064] According to this disclosure, the transmittance of the plastic substrate 110 can be selectively increased. Therefore, considering the reduction in material costs, using a colored polyimide as the plastic substrate 110 can be advantageous. The colored polyimide can be a polyimide with a light transmittance (450 nm) of 40% or less, which can be distinguished from a transparent polyimide with a light transmittance (450 nm) of 60% or more. As another example, the colored polyimide can be a polyimide with a yellow index of 90 or more, which can be distinguished from a transparent polyimide with a yellow index of 20 or less.

[0065] As a specific example, polyimide comprises repeating units represented by Formula 1, wherein, X1 is an organic group represented by formula 2a or 2b, and X1 may be an organic group represented by formula 3a or 3b, but this disclosure is not limited thereto.

[0066] [Equation 2a]

[0067]

[0068] In formula 2a, Ar1 can be a cycloalkyl group having 4 to 10 carbon atoms or an aryl group having 6 to 12 carbon atoms, R1 can be an alkyl group having 1 to 10 carbon atoms, and m can be 0 or 2.

[0069] [Equation 2b]

[0070]

[0071] In formula 2b, Ar2 and Ar3 can each be independently an aryl group having 6 to 12 carbon atoms or an aryloxy group having 6 to 12 carbon atoms, and L1 can be selected from single bonds, -O-, -S-, -C(R2)(R3)-, -C(=O)-, -C(=O)O-, -C(=O)NH- and phenyl, wherein R2 and R3 can each be independently selected from hydrogen and alkyl groups having 1 to 10 carbon atoms.

[0072] [Equation 3a]

[0073] *-R4-Ar4-R5-*

[0074] In formula 3a, Ar4 can be an aryl group having 6 to 12 carbon atoms, and R4 and R5 can each be an alkyl group having 1 to 10 carbon atoms.

[0075] [Formula 3b]

[0076] *-Ar5-L2-Ar6-*

[0077] In formula 3b, Ar5 and Ar6 can each be an aryl group having 6 to 12 carbon atoms or an aryloxy group having 6 to 12 carbon atoms, and L2 can be selected from single bond, -O-, -S-, -C(R2)(R3)-, -C(=O)-, -C(=O)O-, -C(=O)NH- and phenyl.

[0078] In the case of the organic light-emitting display device 100 according to an exemplary embodiment of the present disclosure, components such as the camera module 160 are arranged to overlap with the second display area DA2. Therefore, the second display area DA2 needs to have a transmittance of a predetermined level or higher. However, when the aforementioned colored polyimide is used as the plastic substrate 110, there is a drawback of reduced transmittance in the second display area.

[0079] refer to Figures 4 to 6 In the organic light-emitting display device 100 of this disclosure, the plastic substrate 110 includes a first portion 110a and a second portion 110b with different light transmittances. As described above, the first portion 110a corresponds to a first display region DA1, and the second portion 110b corresponds to a second display region DA2. The first portion 110a and the second portion 110b are integrally formed by containing the same polyimide. In this case, the second portion 110b, which needs to have a transmittance of a predetermined degree or higher, further contains a ligand compound. The ligand compound permeates between the chains of the polyimide and widens the distance between the chains, thereby preventing the formation of charge transfer complexes between the chains. Therefore, the second portion 110b, which further contains a ligand compound, has a higher transmittance than the first portion 110a.

[0080] The second part 110b suppresses the formation of the charge-transfer complex by including a ligand compound. Therefore, even though the first part 110a and the second part 110b are integrally formed using the same polyimide, the second part 110b exhibits physical properties different from those of the first part 110a. For example, the yellow index of the second part 110b is lower than that of the first part 110a. Furthermore, the light transmittance of the second part 110b in the 400 nm to 500 nm wavelength band is higher than that of the first part 110a in the same wavelength band. As described above, in the second part 110b, the energy level changes are minimized and the formation of the charge-transfer complex is suppressed due to the ligand compound penetrating into the polyimide chain. Therefore, in the 400 nm to 500 nm wavelength band (the visible light absorbed during the formation of the charge-transfer complex), the light transmittance of the second part 110b is higher than that of the first part 110a. Furthermore, due to reduced absorption of visible light in the wavelength band, the second portion 110b has a lower yellow index and higher light transmittance compared to the first portion 110a. For example, the light transmittance (450 nm) of the first portion 110a can be less than 40%, while the light transmittance (450 nm) of the second portion 110b can be more than 50%. Although the first portion 110a and the second portion 110b are integrally formed from the same polyimide, the second portion 110b can be selectively treated with a ligand solution to achieve higher light transmittance characteristics. By including a plastic substrate 110 with the above-described characteristics, the transmittance of the second display region DA2 of the organic light-emitting display device 100 can be improved. Meanwhile, when the transparent region is selectively formed by patterning colored polyimide and transparent polyimide respectively, even if the colored polyimide and transparent polyimide are patterned with the same thickness, steps are generated and the flatness is inevitably reduced. In other words, as in the exemplary embodiments of this disclosure, the plastic substrate integrally formed with the first portion 110a and the second portion 110b has the advantage of excellent flatness.

[0081] The second portion of the plastic substrate can be modified as needed. For example, when realizing a transparent organic light-emitting display device, it is necessary to ensure high transmittance over the entire display area. Therefore, the plastic substrate is not divided into a first portion and a second portion, and its entire area can contain polyimide and ligand compounds. That is, the second portion can be modified to correspond to at least a portion or the entire area that requires a predetermined level of transmittance for the display device.

[0082] Figure 7A This is a graph showing the yellow index (YI) of colored polyimide films treated with ligand solutions in or out of the presence of ligands. Figure 7BThis is a graph showing the light transmittance of colored polyimide films treated with a ligand solution, depending on the presence or absence of the ligand. Specifically, two colored polyimide films were prepared. One colored polyimide film was immersed in a ligand solution prepared by dissolving oleic amine, which serves as the ligand compound, in dimethylformamide for a predetermined period of time to prepare sample 1. The other colored polyimide film was immersed in dimethylformamide for the same period of time to prepare sample 2.

[0083] The yellow index was measured 5 times for each sample. Figure 7A This is a graph showing the yellow index values ​​of Sample 1 and Sample 2 in their respective measurement order. As a result of the yellow index measurement, it can be confirmed that the average yellow index value of Sample 1 is 50.5, and the average yellow index value of Sample 2 is 57.1. This indicates that the yellow index (YI) value of Sample 1, prepared by immersion in the ligand solution, is lower than that of Sample 2. Furthermore, refer to... Figure 7B It can be confirmed that the light transmittance of sample 1 is significantly higher than that of sample 2 in the range of 400 nm to 500 nm (which is the absorption wavelength of the charge transfer complex). In addition, it can be confirmed that sample 1, after being treated with ligand solution, exhibits higher transmittance than sample 2 in the entire visible light region (400 nm to 700 nm), thus demonstrating excellent transparency.

[0084] according to Figure 7A and Figure 7B The results show that the ligand compound inhibits the formation of charge-transfer complexes between polyimide chains, thus improving the transmittance of the polyimide. Although not shown in the figures, it is confirmed that Sample 1 has a light transmittance of 86.1% over the entire visible light region. This corresponds to the level of transparent polyimide films according to related technologies, and according to this disclosure, optical properties equivalent to those of transparent polyimide can be achieved by using colored polyimide.

[0085] The ligand compound can be a material that does not absorb visible light. Specifically, it is preferable to use a material that does not absorb light in the wavelength range of 400 nm to 500 nm as the ligand compound. As mentioned above, polyimide absorbs visible light in the wavelength range of 400 nm to 500 nm due to the formation of charge-transfer complexes, resulting in reduced transmittance. Therefore, it is preferable to use a ligand compound that does not absorb light in this wavelength band. For example, the ligand compound can have a light transmittance of more than 90% in the wavelength range of 400 nm to 500 nm.

[0086] For example, the ligand compound can be at least one selected from amino compounds and carboxylic acid compounds. For example, the amino compound can be an alkyl amine having 3 to 20 carbon atoms. In this case, the alkyl group may contain at least one unsaturated bond. For example, the carboxylic acid compound can be a carboxylic acid having 3 to 20 carbon atoms. In this case, the alkyl group may contain at least one unsaturated bond. In this disclosure, the carboxylic acid compound includes esterified products of carboxylic acids or carboxylic acid derivatives such as carboxylic anhydrides.

[0087] Amine compounds can act as electron donors, and carboxylic acid compounds can act as electron acceptors. Therefore, when amine and / or carboxylic acid compounds are used as ligand compounds, they interact with the polyimide chains and can suppress charge transfer between adjacent polyimide chains. This minimizes the formation of charge-transfer complexes between polyimide chains.

[0088] More preferably, the ligand compound can be an amine or carboxylic acid having an alkyl group containing 15 to 20 carbon atoms. In this case, when the ligand compound permeates into the polyimide chain, the distance between the polyimide chains increases further, making charge transfer between chains more difficult. Therefore, the formation of the charge transfer complex is further suppressed, and the optical properties of the second part 110b can be further improved.

[0089] According to related technologies, transmittance is ensured by removing polyimide from the corresponding area of ​​a plastic substrate that corresponds to the second display area through high-energy laser irradiation, or by using a transparent polyimide film as the plastic substrate. However, as mentioned above, the laser irradiation method requires expensive laser equipment, and its ability to improve transmittance is limited by contamination from byproducts and polyimide residues generated during laser irradiation. Furthermore, laser damage to the display panel can occur, making it difficult to maintain the display quality and reliability of the display device. Moreover, transparent polyimide is a considerably more expensive material compared to colored polyimide, resulting in a significant increase in material costs.

[0090] The plastic substrate 110 according to an exemplary embodiment of the present disclosure enables selective enhancement of transmittance by treating the portion corresponding to the second display region DA2 with a ligand solution, thereby maintaining high display quality and reliability even when using low-cost materials.

[0091] refer to Figure 5 and Figure 6 A barrier layer 121 is disposed on the plastic substrate 110. The barrier layer 121 can prevent deterioration caused by moisture seeping into the lower part of the organic light-emitting display device 100 by enhancing the moisture permeability and oxygen resistance of the plastic substrate 110. For example, it can be deposited by depositing materials such as silicon nitride (SiN). x ), silicon oxide (SiO)x ), silicon nitride oxide (SiON), aluminum oxide (Al) x O y The barrier layer 121 may be formed using inorganic materials such as amorphous silicon (a-Si), but is not limited to these. The barrier layer 121 is substantially transparent because it is formed as a very thin film through a deposition process. Therefore, even if the barrier layer 121 is formed on the entire surface of the plastic substrate 110, the transmittance will not be significantly reduced.

[0092] An auxiliary substrate layer 122 is disposed on the barrier layer 121. When a plastic substrate 110 is used instead of a glass substrate, its rigidity is relatively lower than that of glass. Therefore, when forming devices such as thin-film transistors (TFTs), it is difficult to control the process, and deformations such as sagging may occur. The auxiliary substrate layer 122 enhances the rigidity of the plastic substrate 110. For example, the auxiliary substrate layer 122 may comprise polyimide, polycarbonate, polyethersulfone, etc. Preferably, the auxiliary substrate layer 122 may be formed of polyimide, which has excellent rigidity and heat resistance.

[0093] An auxiliary substrate layer 122 may be formed on the barrier layer 121 to correspond to the plurality of sub-pixel regions SPA1 and SPA2. That is, the auxiliary substrate layer 122 may not be formed in the transmissive region TA. When the auxiliary substrate layer 122 is formed on the barrier layer 121 corresponding to the transmissive region TA, the transmittance of the second display region DA2 may decrease. However, this is not a limitation. When a material with high transparency is used as the auxiliary substrate layer 122, the auxiliary substrate layer 122 may be disposed on the entire surface of the barrier layer 121.

[0094] Thin-film transistors (TFTs) are disposed on an auxiliary substrate layer 122 to correspond to a plurality of sub-pixel regions SPA1 and SPA2. The TFTs are components for driving the sub-pixels formed in the plurality of corresponding sub-pixel regions SPA1 and SPA2. Therefore, the TFTs correspond to each of the plurality of sub-pixel regions SPA1 of the first display region DA1 and the plurality of sub-pixel regions SPA2 of the second display region DA2. In the accompanying drawings, only driving TFTs are shown for ease of description, but this disclosure is not limited thereto and may further include switching TFTs, etc.

[0095] A buffer layer 131 may be disposed between the auxiliary substrate layer 122 and the thin-film transistor (TFT). The buffer layer 131 prevents oxygen or moisture from seeping in from the outside and prevents impurities remaining on the plastic substrate 110 from flowing into the device. Although the figures show the buffer layer 131 formed corresponding to multiple sub-pixel regions, this disclosure is not limited thereto. The buffer layer 131 may also be formed in the transmission region TA when it does not reduce the transmittance of the transmission region TA. Furthermore, if the influence of external air such as moisture or impurities is absent, the buffer layer 131 may be omitted, and if necessary, the buffer layer 131 may be formed from multiple layers.

[0096] A thin-film transistor (TFT) comprising a gate (G), an active layer (ACT), a source (S), and a drain (D) is disposed on a buffer layer 131. For example, the active layer ACT is formed on the buffer layer 131, and a gate insulating layer 133 for insulating the gate (G) is formed on the active layer ACT. Furthermore, an interlayer insulating layer 132 is formed for insulating the gate (G), the source (S), and the drain (D), respectively, and the source (S) and drain (D) are formed on the active layer ACT, respectively, and are in contact with the active layer ACT. However, this is not the only option. The configuration and arrangement of the thin-film transistor (TFT) can be changed as needed.

[0097] A planarization layer 134 is disposed on the thin-film transistor TFT. The planarization layer 134 flattens the upper portion of the thin-film transistor TFT. Furthermore, the planarization layer 134 covers the step between the area where the thin-film transistor TFT is disposed and the area where the thin-film transistor TFT is not disposed. That is, the planarization layer 134 is formed over the entire surface to correspond to the plurality of sub-pixel regions SPA1 and SPA2 and the plurality of transmissive regions TA. Since the auxiliary substrate layer 122, the buffer layer 131, and the thin-film transistor TFT are not disposed in the transmissive regions TA, the planarization layer 134 directly contacts the barrier layer 121 in the transmissive regions TA. For example, the planarization layer 134 can be formed of a transparent insulating resin. The planarization layer 134 includes contact holes for electrically connecting the thin-film transistor TFT and the organic light-emitting element 140.

[0098] An organic light-emitting element 140 is disposed on a planarization layer 134. The organic light-emitting element 140 is disposed on the planarization layer 134 to correspond to a plurality of sub-pixel regions SPA1 and SPA2, thereby being electrically connected to a thin-film transistor (TFT). The organic light-emitting element 140 includes an anode 141, an organic light-emitting layer 142, and a cathode 143.

[0099] An anode 141 is disposed on a planarization layer 134. The anode 141 is disposed on the planarization layer 134 to correspond to a plurality of sub-pixel regions SPA1 and SPA2. Furthermore, the anodes 141 can be formed spaced apart from each other in the plurality of sub-pixels. That is, the anodes 141 can be configured to overlap at least a portion of each of the plurality of sub-pixel regions SPA1 and SPA2. In this case, color mixing of light emitted from adjacent sub-pixel regions SPA1 and SPA2 can be prevented.

[0100] The anode 141 can be formed of a material with a high work function to supply holes to the organic light-emitting layer 142. For example, the anode 141 can be formed of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), or indium tin zinc oxide (ITZO), but is not limited thereto. Although the anode 141 is formed of a transparent conductive material as shown in the transmission region TA in the figure, when the organic light-emitting display device 100 is driven in a top-emitting manner, the anode 141 can be configured to further include a reflective layer.

[0101] The anode 141 is electrically connected to the thin-film transistor TFT through the contact holes of the planarization layer 134. For example, the anode 141 may be electrically connected to the source S of the thin-film transistor TFT, but is not limited thereto.

[0102] A cathode 143 is disposed on the anode 141. The cathode 143 supplies electrons to the organic light-emitting layer 142. For example, the cathode 143 may be formed of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), zinc oxide (ZnO), and tin oxide (TO), or a metallic material including calcium (Ca), barium (Ba), aluminum (Al), silver (Ag), magnesium (Mg), ytterbium (Yb), etc., but is not limited thereto.

[0103] The cathode 143 can be formed corresponding to multiple sub-pixel regions SPA1 and SPA2. Within the multiple sub-pixels, the cathode 143 can be formed connected rather than spaced apart. Furthermore, although the accompanying drawings show the cathode 143 not formed in the transmission region TA, this disclosure is not limited thereto. When the cathode 143 is formed of a transparent material without reducing transmittance, for ease of handling, the cathode 143 can be formed as a single layer over the multiple sub-pixel regions SPA1 and SPA2 and the multiple transmittance regions TA.

[0104] An organic light-emitting layer 142 is disposed between an anode 141 and a cathode 143. The organic light-emitting layer 142 is configured to emit light of the same color as the sub-pixels corresponding to the organic light-emitting layer 142. The organic light-emitting layer 142 may be spaced apart among a plurality of corresponding sub-pixels and disposed on the anode 141.

[0105] A dam 135 is disposed on the anode 141 and the planarization layer 134. The dam 135 is used to distinguish adjacent sub-pixels. Furthermore, the dam 135 is used to separate adjacent sub-pixel regions SPA1 and SPA2 and the transmission region TA. The dam 135 includes a plurality of openings that expose at least a portion of the planarization layer 134. For example, the dam 135 includes a plurality of first openings OA1 and a plurality of second openings OA2.

[0106] Each of the first openings OA1 is formed to overlap at least a portion of each of the plurality of sub-pixel regions SPA1 and SPA2. Each of the plurality of organic light-emitting elements 140 is disposed on the planarization layer 134 exposed by the first openings OA1. Thus, the embankment 135 divides adjacent sub-pixels.

[0107] Each of the second openings OA2 is formed to overlap at least a portion of each of the plurality of transmission regions TA. Therefore, the transmittance of the transmission regions TA can remain high without decreasing. However, this is not a limitation. When the embankment 135 is formed of transparent resin and does not reduce the transmittance of the transmission regions TA, the second openings OA2 may not be formed.

[0108] An encapsulation layer 150 is disposed on the organic light-emitting element 140. The encapsulation layer 150 protects the organic light-emitting element 140 from deterioration due to externally absorbed moisture or other contaminants. Furthermore, the encapsulation layer 150 flattens the upper portion of the organic light-emitting element 140. Additionally, the encapsulation layer 150 covers the step between the area where the organic light-emitting element 140 is disposed and the area where the organic light-emitting element 140 is not disposed. The encapsulation layer 150 can be formed as a single layer or multiple layers. For example, the encapsulation layer 150 may include a first inorganic encapsulation layer 151, an organic encapsulation layer 152, and a second inorganic encapsulation layer 153. In sub-pixel regions SPA1 and SPA2, the first inorganic encapsulation layer 151 is in direct contact with the upper portion of the cathode 143, and in the transmission region TA, the first inorganic encapsulation layer 151 is formed on the planarization layer 134 exposed by the second opening OA2 for direct contact with it. The organic encapsulation layer 152 is configured to flatten the upper portion of the first inorganic encapsulation layer 151, and the second inorganic encapsulation layer 153 is deposited on the organic encapsulation layer 152. For example, the first inorganic encapsulation layer 151 and the second inorganic encapsulation layer 153 can be deposited by depositing silicon nitride (SiN). x ), silicon oxide (SiO) x ), silicon nitride oxide (SiON), aluminum oxide (Al) x O y The materials used may be formed independently, but are not limited to these. For example, the organic encapsulation layer 152 may be formed of a transparent resin selected from acrylic resin, epoxy resin, polyethylene resin, etc., but is not limited to these.

[0109] If necessary, a color filter substrate can be selectively disposed on the encapsulation layer 150. The color filter substrate includes a color filter layer and a black matrix. The color filter layer includes multiple color filters overlapping each of the multiple sub-pixel regions SPA1 and SPA2. The black matrix distinguishes the multiple color filters and prevents color mixing between adjacent sub-pixels. To maintain high transmittance in the transmission region TA, the color filter layer and the black matrix are not formed in the transmission region TA.

[0110] An organic light-emitting display device 100 according to an exemplary embodiment of the present disclosure includes a plurality of sub-pixel regions SPA2 and a plurality of transmissive regions TA in a second display region DA2. A second portion 110b of a plastic substrate 110 corresponding to the second display region DA2 contains polyimide and a ligand compound, and exhibits a low yellow index and high light transmittance due to the ligand compound. Therefore, it has the effect of displaying images through the second display region DA2 while maintaining excellent light transmittance.

[0111] Therefore, the camera module 160 can be disposed on the rear surface of the plastic substrate 110 corresponding to the second portion 110b, which has high light transmittance. Although the camera module 160 is disposed on the rear surface of the plastic substrate 110, images of objects, etc., can be captured due to the high transmittance of the second display area DA2. For ease of description, the placement of the camera module has been illustrated by way of example, but this disclosure is not limited thereto. In addition to the camera module 160, various sensors can also be disposed. Even if these sensors are disposed on the rear surface of the plastic substrate 110 corresponding to the second portion 110b, they can detect the surrounding environment.

[0112] In the following text, reference will be made to Figure 8 Describe a method for manufacturing an organic light-emitting display device. Figure 8 This is a process flow diagram illustrating a method for manufacturing an organic light-emitting display device according to an exemplary embodiment of the present disclosure. (Reference) Figure 8 A method for manufacturing an organic light-emitting display device according to an exemplary embodiment of the present disclosure includes: in step S110, manufacturing a plastic substrate comprising polyimide; in step S120, forming a plurality of thin-film transistors on the plastic substrate; in step S130, forming organic light-emitting elements on the plurality of thin-film transistors; and in step S140, coating a ligand solution onto at least a portion of the back surface of the plastic substrate and drying the ligand solution. The manufacturing method according to an exemplary embodiment of the present disclosure relates to... Figures 1 to 6 The manufacturing method of the organic light-emitting display device 100 shown will therefore be omitted from the reference. Figures 1 to 6 The description is a repetitive description.

[0113] First, in step S110, a plastic substrate containing polyimide is manufactured.

[0114] A polyimide precursor solution is formed on a carrier substrate and subjected to an imidization reaction to produce a plastic substrate 110 containing polyimide. The polyimide precursor solution can be a polyamic acid solution. Polyimide has very low solubility because the solvent has difficulty penetrating into the polyimide due to the formation of charge transfer complexes between the chains. Therefore, a polyamic acid with a higher solubility than polyimide is prepared and subjected to an imidization reaction to prepare a polyimide in the form of a film. Polyamic acid can be synthesized by polymerization of diamine and dicarboxylic anhydride.

[0115] For example, polyamic acid may contain repeating units represented by Formula 4 below, but is not limited thereto.

[0116] [Formula 4]

[0117]

[0118] in, X1 and n are defined as in Equation 1 above.

[0119] The polyamic acid prepared as described above is dissolved in a solvent to prepare a polyimide precursor solution. For example, the solvent may be selected from sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, pyrrolidone solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, formamide solvents such as N,N-dimethylformamide and N,N-diethylformamide, acetamide solvents such as N,N-dimethylacetamide and N,N-diethylacetamide, phenolic solvents such as phenol, o-cresol, m-cresol, and p-cresol, tetrahydrofuran, etc., but is not limited thereto.

[0120] The polyimide precursor solution is formed into a film on a carrier substrate and then subjected to heat treatment to imidize the polyamic acid. For example, the heat treatment can be performed in a temperature range of 200°C to 400°C. The polyimide prepared as described above may contain repeating units represented by Formula 1.

[0121] Next, in step S120, a plurality of thin-film transistors are formed on the plastic substrate.

[0122] Before forming multiple thin-film transistors (TFTs), a barrier layer 121 and an auxiliary substrate layer 122 can be formed on the plastic substrate 110. This can be achieved by depositing materials such as silicon nitride (SiN). x ), silicon oxide (SiO) x ), silicon nitride oxide (SiON), aluminum oxide (Al) x O yThe barrier layer 121 may be formed from inorganic materials such as amorphous silicon (a-Si). For example, the barrier layer 121 may be formed by known deposition methods such as chemical vapor deposition, electron beam evaporation, atomic layer deposition, etc., but is not limited thereto.

[0123] The auxiliary substrate layer 122 can be formed by the following steps: forming a polyimide precursor solution on the entire surface of the barrier layer 121; subjecting the polyimide precursor solution to an imidization reaction to form a polyimide film; and etching the polyimide film. For ease of description, the auxiliary substrate layer 122 is illustrated by way of example as being formed of polyimide, but this disclosure is not limited thereto.

[0124] For reference Figures 1 to 6 The auxiliary substrate layer 122 is formed on the barrier layer 121 to correspond to the plurality of sub-pixel regions SPA1 and SPA2. Therefore, after forming a polyimide film on the entire surface of the barrier layer 121, the polyimide film in the portion excluding the plurality of sub-pixel regions SPA1 and SPA2, i.e., the polyimide film in the transmission region TA, is removed by etching. For example, etching can be performed by a plasma etching method, but is not limited thereto.

[0125] Furthermore, the method may further include forming a buffer layer on an auxiliary substrate layer. The buffer layer 131 may be formed to correspond to the entire surface of the plastic substrate 110, and if necessary, may be partially formed to correspond to a plurality of sub-pixel regions SPA1 and SPA2.

[0126] A thin-film transistor (TFT) is formed on the buffer layer 131. For example, the TFT is formed by the following steps: forming an active layer ACT on the buffer layer 131, forming a gate insulating layer 133 on the active layer ACT, forming a gate G on the gate insulating layer 133, forming an interlayer insulating layer 132 on the gate G, and forming a source S and a drain D on the interlayer insulating layer 132. However, this disclosure is not limited thereto, and the TFT can be formed using various methods known in the art, depending on the configuration and structure of the organic light-emitting display device.

[0127] After forming the thin-film transistor (TFT), the method may include forming a planarization layer 134 to protect the TFT and planarize its upper surface. Furthermore, after forming the planarization layer 134, contact holes are formed to electrically connect the TFT and the organic light-emitting element 140.

[0128] Next, in step S130, organic light-emitting elements are formed on a plurality of thin-film transistors.

[0129] The organic light-emitting element 140 can be formed by the following steps: forming an anode 141 on a planarization layer 134, forming an organic light-emitting layer 142 on the anode 141, and forming a cathode 143 on the organic light-emitting layer 142.

[0130] As described above, the anodes 141 are formed spaced apart from each other in multiple sub-pixels. With a mask such as a fine metal mask provided, the anodes 141 can be formed by depositing a transparent conductive material using known deposition methods such as sputtering or vapor deposition.

[0131] After forming the anode 141, the method may include forming a dam 135 on the anode 141 and the planarization layer 134. For example, the dam 135 may be formed of a transparent insulating resin and may be patterned using a photolithography method to have a first opening OA1 and a second opening OA2.

[0132] For example, an organic light-emitting layer 142 can be formed by depositing an organic light-emitting material using a fine metal mask, the organic light-emitting material emitting light of a color corresponding to each of the sub-pixel regions SPA1 and SPA2. As another example, the organic light-emitting layer 142 can be formed by dripping ink of a color corresponding to each of the sub-pixel regions SPA1 and SPA2 using an inkjet method, and then curing the ink.

[0133] For example, the cathode 143 can be formed by setting a mask on the organic light-emitting layer 142 and then depositing a metallic material such as aluminum by methods known in the art, such as sputtering, vapor deposition or atomic layer unit deposition.

[0134] After forming the organic light-emitting element 140, the method may include forming an encapsulation layer 150 to protect the organic light-emitting element 140 and flatten its top surface.

[0135] Next, in step S140, the ligand solution is coated onto at least a portion of the rear surface of the plastic substrate 110 and dried.

[0136] First, a ligand solution is prepared. This solution can be prepared by dissolving the ligand compound in a solvent. As described above, a compound with a light transmittance of 90% or more in the 400 nm to 500 nm wavelength band can be used as the ligand compound. The polyimide constituting the plastic substrate 110 absorbs visible light in the 400 nm to 500 nm wavelength range due to the formation of a charge transfer complex, resulting in reduced transmittance. The ligand compound is used to suppress the formation of the charge transfer complex, thereby increasing transmittance. Therefore, to improve the effectiveness of this disclosure, a ligand compound that does not absorb light in the 400 nm to 500 nm wavelength range can be used.

[0137] As a solvent, solvents capable of dissolving the ligand compound and swelling the polyimide can be used. A detailed description will be provided later. For example, the solvent can be selected from sulfoxide-based solvents such as dimethyl sulfoxide and diethyl sulfoxide; pyrrolidone-based solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone; formamide-based solvents such as N,N-dimethylformamide and N,N-diethylformamide; acetamide-based solvents such as N,N-dimethylacetamide and N,N-diethylacetamide; phenolic solvents such as phenol, o-cresol, m-cresol, and p-cresol; tetrahydrofuran; and other solvents, but are not limited thereto.

[0138] After preparing the ligand solution, the rear surface of the plastic substrate 110 is turned upwards, and the ligand solution is coated onto at least a portion of the area requiring relatively high transmittance. The ligand solution can be selectively coated without limitation, as long as the area is where high transmittance should be ensured. That is, the ligand solution can be selectively coated onto a specific area of ​​the rear surface of the plastic substrate 110, or it can be coated onto the entire area. This increases the transmittance of the specific area coated with the ligand solution. Therefore, a camera module or the like can be mounted on the rear surface of the plastic substrate with increased transmittance. Furthermore, when the ligand solution is coated onto the entire area, the transmittance of the entire area of ​​the plastic substrate is increased, and a transparent organic light-emitting display device can be manufactured without using expensive transparent polyimide.

[0139] For example, the organic light-emitting display device 100 may include a first display area DA1 and a second display area DA2 with a resolution lower than that of the first display area DA1. The second display area DA2 may be an area requiring a transmittance of a predetermined level or higher in order to mount an imaging module on the rear surface of the plastic substrate 110. Therefore, a ligand solution is coated onto the rear surface of the plastic substrate 110 corresponding to the second display area DA2 of the organic light-emitting display device 100.

[0140] For example, ligand solutions can be applied to specific areas using a drop-down method with an inkjet device, but this is not the only possibility.

[0141] When the ligand solution is coated onto the rear surface of the plastic substrate 110 corresponding to the second display region DA2, the solvent diffuses between the polyimide chains, and the polyimide swells. As the solvent diffuses, the ligand compound permeates between the polyimide chains, increasing the distance between them. Therefore, a solvent capable of swelling polyimide (e.g., partially dissolving polyimide) can be used as a solvent for preparing the ligand solution.

[0142] After the ligand solution is coated onto a specific area of ​​the plastic substrate 110 and dried, the solvent evaporates, leaving the ligand compound between the polyimide chains and inhibiting the formation of charge-transfer complexes. Due to the inhibition of charge-transfer complex formation, the plastic substrate 110 in the ligand-coated area exhibits a lower yellow index and higher light transmittance compared to the uncoated area. In this step, the plastic substrate 110, integrally formed by containing the same polyimide, is divided into a first portion 110a and a second portion 110b. The first portion 110a is the area untreated with the ligand solution and corresponds to the first display area DA1. The second portion 110b contains the ligand compound through treatment with the ligand solution and corresponds to the second display area DA2.

[0143] As described above, in the method for manufacturing an organic light-emitting display device according to exemplary embodiments of the present disclosure, the transmittance of a plastic substrate containing polyimide can be partially increased without using expensive equipment such as laser devices. Therefore, the limitations of the aforementioned laser radiation method can be overcome, and process costs are reduced by avoiding the use of expensive equipment. Furthermore, even when using colored polyimide, transmittance can be partially increased through a ligand solution treatment process. Therefore, compared to the case of using expensive transparent polyimide, the same effect can be achieved while significantly reducing material costs.

[0144] Next, the method may include setting the camera module 160 to correspond to the region where the transmittance is partially increased, namely the second portion 110b of the plastic substrate 110.

[0145] As described above, with the increase in light transmittance in a specific area, images can be captured successfully even if the camera module 160 is disposed on the rear surface of the plastic substrate 110. Furthermore, various sensors can be used instead of the camera module 160, and if necessary, both the camera module and sensors can be disposed simultaneously to correspond to the second part 110b.

[0146] Furthermore, in the coating and drying of the ligand solution, by coating the entire back surface of the plastic substrate, the light transmittance of the entire area can be improved. In this case, the light transmittance of the entire area of ​​the organic light-emitting display device is improved, making it easy to realize a transparent organic light-emitting display device.

[0147] Exemplary embodiments of this disclosure can also be described as follows:

[0148] According to one aspect of this disclosure, an organic light-emitting display device includes a first display area comprising a plurality of sub-pixel regions and a second display area comprising the plurality of sub-pixel regions and a plurality of transmissive regions. The organic light-emitting display device includes: a plastic substrate including a first portion corresponding to the first display area and a second portion corresponding to the second display area; a plurality of thin-film transistors disposed on the plastic substrate to correspond to the plurality of sub-pixel regions; and a plurality of organic light-emitting elements disposed on the plurality of thin-film transistors to correspond to the plurality of sub-pixel regions, wherein the first portion comprises polyimide, and the second portion comprises polyimide and a ligand compound.

[0149] According to another aspect of this disclosure, an organic light-emitting display device comprising a first display area having a plurality of sub-pixel regions and a second display area having a plurality of sub-pixel regions and a plurality of transmissive regions includes: a plastic substrate including a first portion corresponding to the first display area and a second portion corresponding to the second display area; a plurality of thin-film transistors located on the plastic substrate to correspond to the plurality of sub-pixel regions; and a plurality of organic light-emitting elements located on the plurality of thin-film transistors to correspond to the plurality of sub-pixel regions, wherein the second portion comprises polyimide and a ligand compound, and the first portion comprises polyimide but does not contain a ligand compound.

[0150] The first and second parts can be integrally formed by including polyimide.

[0151] The yellow index of the second part can be lower than that of the first part, and the light transmittance of the second part in the 400nm to 500nm range can be greater than that of the first part in the 400nm to 500nm range.

[0152] The light transmittance of the first part (450nm) can be less than 40%, and the light transmittance of the second part (450nm) can be more than 50%.

[0153] The ligand compound can have a light transmittance of over 90% in the wavelength range of 400 nm to 500 nm.

[0154] The ligand compound may contain at least one selected from amino compounds and carboxylic acid compounds.

[0155] The amine compound can be an amine having an alkyl group containing 3 to 20 carbon atoms, and the carboxylic acid compound can be a carboxylic acid having an alkyl group containing 3 to 20 carbon atoms.

[0156] The resolution of the second display area can be lower than that of the first display area.

[0157] The organic light-emitting display device may further include a planarization layer disposed between a plurality of thin-film transistors and a plurality of organic light-emitting elements to planarize the upper parts of the plurality of thin-film transistors, wherein the planarization layer may be disposed on a plastic substrate to directly contact the plastic substrate in the transmission region.

[0158] The organic light-emitting display device may further include a barrier layer disposed between a plastic substrate and a plurality of thin-film transistors, and an auxiliary substrate layer disposed on the barrier layer to correspond to a plurality of sub-pixel regions.

[0159] The organic light-emitting display device may further include a planarization layer disposed between a plurality of thin-film transistors and a plurality of organic light-emitting elements to planarize the upper parts of the plurality of thin-film transistors, wherein the planarization layer may be disposed on a barrier layer to directly contact the barrier layer in the transmission region.

[0160] The organic light-emitting display device may further include a dam disposed on a planarization layer and including a plurality of openings exposing at least a portion of the planarization layer, wherein the dam may include at least one first opening and at least one second opening, the first opening being formed to overlap at least a portion of each of the sub-pixel regions, and the second opening being formed to overlap at least a portion of each of the transmissive regions, wherein each of the plurality of organic light-emitting elements may be disposed on the planarization layer exposed by the first opening.

[0161] The organic light-emitting display device may further include an encapsulation layer disposed on the embankment and multiple organic light-emitting elements to make the upper surfaces of the multiple organic light-emitting elements flat.

[0162] In the transmissive region, the encapsulation layer can be in direct contact with the planarization layer.

[0163] At least one of the camera module and the sensor may be disposed on the rear surface of the plastic substrate corresponding to the second part.

[0164] According to another aspect of this disclosure, a method for manufacturing an organic light-emitting display device includes: manufacturing a plastic substrate comprising polyimide; forming a plurality of thin-film transistors on the plastic substrate; forming organic light-emitting elements on the plurality of thin-film transistors; and coating a ligand solution onto at least a portion of the back surface of the plastic substrate and drying the ligand solution.

[0165] According to another aspect of this disclosure, a method for manufacturing an organic light-emitting display device includes: providing a plastic substrate comprising polyimide; forming a plurality of thin-film transistors on the plastic substrate; forming organic light-emitting elements on the plurality of thin-film transistors; and coating a ligand solution onto at least a portion of the rear surface of the plastic substrate and drying the ligand solution.

[0166] The ligand solution may contain a solvent and a ligand compound having a light transmittance of more than 90% in the wavelength range of 400 nm to 500 nm.

[0167] During the coating and drying process of the ligand solution, the ligand compound can penetrate between the polymer chains of the polyimide, resulting in a decrease in the yellow index and an increase in light transmittance in at least a portion of the plastic substrate.

[0168] The ligand compound may contain at least one selected from amino compounds and carboxylic acid compounds.

[0169] An organic light-emitting display device may include a first display area and a second display area with a resolution lower than that of the first display area, wherein, during the coating and drying process of the ligand solution, the ligand solution may be coated onto the back surface of a plastic substrate corresponding to the second display area.

[0170] Although exemplary embodiments of the present disclosure have been described in detail with reference to the accompanying drawings, the present disclosure is not limited thereto and may be implemented in many different forms without departing from the technical concept of the present disclosure. Therefore, the exemplary embodiments of the present disclosure are provided for illustrative purposes only and are not intended to limit the technical concept of the present disclosure. The scope of the technical concept of the present disclosure is not limited thereto. Therefore, it should be understood that the above exemplary embodiments are illustrative in all respects and do not limit the present disclosure. The scope of protection of the present disclosure should be interpreted based on the following claims, and all technical concepts within the equivalent scope thereof should be interpreted as falling within the scope of the present disclosure.

Claims

1. An organic light-emitting display device, comprising a first display area having a plurality of sub-pixel regions and a second display area having a plurality of sub-pixel regions and a plurality of transmissive regions, the organic light-emitting display device comprising: A plastic substrate, the plastic substrate comprising a first portion corresponding to the first display area and a second portion corresponding to the second display area; Multiple thin-film transistors are located on the plastic substrate and correspond to the multiple sub-pixel regions; as well as Multiple organic light-emitting elements are located on the multiple thin-film transistors and correspond to the multiple sub-pixel regions. The second portion comprises a polyimide and a ligand compound, while the first portion comprises a polyimide but does not contain the ligand compound. The ligand compound has a light transmittance of over 90% in the wavelength range of 400 nm to 500 nm.

2. The organic light-emitting display device according to claim 1, wherein, The first portion and the second portion are integrally formed by comprising polyimide.

3. The organic light-emitting display device according to claim 1, wherein, The yellow index of the second part is lower than that of the first part, and the light transmittance of the second part in the range of 400 nm to 500 nm is greater than that of the first part in the range of 400 nm to 500 nm.

4. The organic light-emitting display device according to claim 1, wherein, The first part has a light transmittance of less than 40% at 450nm, while the second part has a light transmittance of more than 50% at 450nm.

5. The organic light-emitting display device according to claim 1, wherein, The ligand compound comprises at least one selected from amino compounds and carboxylic acid compounds.

6. The organic light-emitting display device according to claim 5, wherein, The amine compound is an amine having an alkyl group containing 3 to 20 carbon atoms, and the carboxylic acid compound is a carboxylic acid having an alkyl group containing 3 to 20 carbon atoms.

7. The organic light-emitting display device according to claim 1, wherein, The resolution of the second display area is lower than that of the first display area.

8. The organic light-emitting display device according to claim 7, further comprising: A planarization layer is provided, located between the plurality of thin-film transistors and the plurality of organic light-emitting elements, to planarize the upper portion of the plurality of thin-film transistors. In the transmission region, the planarization layer is in direct contact with the plastic substrate.

9. The organic light-emitting display device according to claim 1, further comprising: A barrier layer is located between the plastic substrate and the plurality of thin-film transistors; as well as An auxiliary base layer is located on the blocking layer and corresponds to the plurality of sub-pixel regions.

10. The organic light-emitting display device according to claim 9, further comprising: A planarization layer is located between the plurality of thin-film transistors and the plurality of organic light-emitting elements, making the upper part of the plurality of thin-film transistors flat, wherein the planarization layer is in direct contact with the barrier layer in the transmission region.

11. The organic light-emitting display device according to claim 8 or 10, further comprising: A dam portion, located on the planarization layer, includes a plurality of openings exposing at least a portion of the planarization layer, wherein the dam portion includes at least one first opening overlapping at least a portion of the sub-pixel region and at least one second opening overlapping at least a portion of the transmissive region, and Each of the plurality of organic light-emitting elements is located on the planarization layer exposed by the first opening.

12. The organic light-emitting display device according to claim 11, further comprising: An encapsulation layer is located on the embankment and the plurality of organic light-emitting elements to make the upper surfaces of the plurality of organic light-emitting elements flat.

13. The organic light-emitting display device according to claim 12, wherein, In the transmission region, the encapsulation layer is in direct contact with the planarization layer.

14. The organic light-emitting display device according to claim 1, wherein, At least one of the camera module and the sensor is located on the rear surface of the plastic substrate corresponding to the second portion.

15. A method for manufacturing an organic light-emitting display device, the method comprising: Provides a plastic substrate containing polyimide; Multiple thin-film transistors are formed on the plastic substrate; Organic light-emitting elements are formed on the plurality of thin-film transistors; as well as The ligand solution is coated onto at least a portion of the back surface of the plastic substrate and then dried. The ligand solution comprises a solvent and a ligand compound having a light transmittance of more than 90% in the wavelength range of 400 nm to 500 nm.

16. The manufacturing method according to claim 15, wherein, During the coating and drying process of the ligand solution, the ligand compound penetrates between the polymer chains of the polyimide, resulting in a decrease in the yellow index and an increase in light transmittance in at least a portion of the plastic substrate.

17. The manufacturing method according to claim 15, wherein, The ligand compound comprises at least one selected from amino compounds and carboxylic acid compounds.

18. The manufacturing method according to claim 15, wherein, The organic light-emitting display device includes a first display area and a second display area with a resolution lower than that of the first display area. During the coating and drying process of the ligand solution, the ligand solution is coated onto the rear surface of the plastic substrate corresponding to the second display area.

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