Display devices and multi-panel display devices

Abstract

This disclosure relates to display devices and multi-panel display devices. A display device according to an exemplary embodiment of this disclosure includes: a plurality of signal lines, each disposed on an upper surface of a first substrate and electrically connected to a display unit; a plurality of connecting lines, each disposed below the first substrate; and a plurality of side lines, each disposed on a side surface of the first substrate and connecting the plurality of signal lines and the plurality of connecting lines. Each of the plurality of side lines includes: a first conductive layer disposed on the side surface of the first substrate and formed of first conductive particles; and a second conductive layer covering the first conductive layer and formed of second conductive particles with a particle size larger than that of the first conductive particles. According to this exemplary embodiment of the disclosure, while minimizing the bezel area, the contact resistance of the side lines is reduced and mechanical properties are improved.

Description

TECHNICAL FIELD

[0001] The disclosure relates to a display apparatus and a multi-panel display apparatus, and more particularly, to a display apparatus and a multi-panel display apparatus capable of implementing a narrow bezel with excellent power efficiency and high reliability. BACKGROUND

[0002] Recently, as the information age has come, the field of display apparatuses expressing electrical information signals visually has been rapidly developed, and in response thereto, various display apparatuses having excellent performances such as a thin thickness, a light weight, and low power consumption have been developed. Specific examples of such display apparatuses include a liquid crystal display apparatus (LCD), a plasma display panel apparatus (PDP), a field emission display apparatus (FED), and an organic light emitting display apparatus (OLED).

[0003] In general, a display apparatus includes a display panel having a display area displaying an image and a non-display area defined along a circumference of the display area, a plurality of driving circuits provided in the non-display area, and a printed circuit board (PCB) providing a control signal to the plurality of driving circuits. A plurality of connection lines connecting the display panel and the driving circuits are provided in the non-display area. The non-display area is blocked by a black matrix or a housing of the display panel so that the image is not substantially displayed, and this area is generally referred to as a bezel area. In order to increase an effective display screen size with the same area, the driving circuits and the connection lines are provided in a lower portion of the display panel corresponding to the non-display area, and side portion lines are provided on a side surface to electrically connect the display panel and the driving circuits.

[0004] Meanwhile, the size and shape of a display are gradually diversifying, and in recent years, a super large size display is attracting attention. In the super large size display, it is difficult to implement a super large size screen with one panel, and thus a multi-panel display apparatus in which a plurality of display panels are connected is currently used. Such a multi-panel display apparatus can implement a super large size screen by providing a plurality of display panels in a tile pattern. However, in the multi-panel display apparatus, a joint is formed between the connected display panels due to a bezel area of the adjacent display panels. The joint can be visually recognized by a user, so that when one image is displayed on the entire screen, a feeling of discontinuity and awkwardness can be felt. Therefore, it is required to minimize the bezel area of each display panel. In addition, as the brightness and the circuit integration increase, power consumption is great, and thus it is required to design the multi-panel display apparatus to improve power efficiency. SUMMARY

[0005] One object of the disclosure is to provide a display apparatus and a multi-panel display apparatus capable of implementing a narrow bezel with excellent power efficiency and high reliability.

[0006] An object of the disclosure is to provide a structure capable of improving mechanical properties while reducing the linear resistance and contact resistance of side lines.

[0007] The objects of the disclosure are not limited to the above objects, and other objects not mentioned above will be clearly understood by those skilled in the art from the following description.

[0008] According to one aspect of the disclosure, a display device includes a first substrate including a display area and a non-display area surrounding the display area, a display unit including an organic light emitting diode disposed on an upper surface of the first substrate, a plurality of signal lines disposed on the upper surface of the first substrate and electrically connected to the display unit, a plurality of connection lines disposed under the first substrate, and a plurality of side lines disposed on a side surface of the first substrate and connecting the plurality of signal lines and the plurality of connection lines, each of the plurality of side lines including a first conductive layer disposed on the side surface of the first substrate and formed of first conductive particles, and a second conductive layer covering the first conductive layer and formed of second conductive particles having a particle size greater than that of the first conductive particles.

[0009] According to another aspect of the disclosure, a multi-panel display device includes a plurality of display devices disposed adjacent to each other, wherein each of the plurality of display devices includes a first substrate including a display area and a non-display area surrounding the display area, a display unit including an organic light emitting diode disposed on an upper surface of the first substrate, a plurality of signal lines disposed on the upper surface of the first substrate and electrically connected to the display unit, a plurality of connection lines disposed under the first substrate, a plurality of side lines disposed on a side surface of the first substrate and connecting the plurality of signal lines and the plurality of connection lines, and a protective layer covering the plurality of side lines and including a black material, each of the plurality of side lines including a first conductive layer disposed on the side surface of the first substrate and formed of first conductive particles, and a second conductive layer covering the first conductive layer and formed of second conductive particles having a particle size greater than that of the first conductive particles.

[0010] Other details of the example embodiments are included in the detailed description and the accompanying drawings.

[0011] According to the disclosure, in a display device, mechanical properties can be improved while reducing the contact resistance of side lines. Accordingly, the power efficiency and reliability of the display device are improved.

[0012] According to the disclosure, a multi-panel display apparatus can be provided that reduces a bezel area to improve image quality and reduce power consumption.

[0013] According to the disclosure, migration of the side portion lines is inhibited, and adhesion is improved to provide excellent reliability.

[0014] Effects according to the disclosure are not limited to the above examples, and more various effects are included in the present specification. BRIEF DESCRIPTION OF DRAWINGS

[0015] The above and other aspects, features, and other advantages of the disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0016] Figure 1 is a cross-sectional view of a display apparatus according to one exemplary embodiment of the disclosure;

[0017] Figure 2 is a plan view of a first substrate in a display apparatus according to one exemplary embodiment of the disclosure;

[0018] Figure 3 is a side view of a display apparatus according to one exemplary embodiment of the disclosure;

[0019] Figure 4A is a view showing a state before performing a heat treatment during a process of forming a first conductive layer and a second conductive layer in a display apparatus according to another exemplary embodiment of the disclosure;

[0020] Figure 4B is a view showing a state after performing a heat treatment on a first conductive layer and a second conductive layer in a display apparatus according to another exemplary embodiment of the disclosure;

[0021] Figure 5 is a plan view of a first substrate in a display apparatus according to another exemplary embodiment of the disclosure;

[0022] Figure 6 is a side view of a display apparatus according to another exemplary embodiment of the disclosure;

[0023] Figure 7 is a cross-sectional view of a display apparatus according to still another exemplary embodiment of the disclosure;

[0024] Figure 8 is a side view of a display apparatus according to still another exemplary embodiment of the disclosure;

[0025] Figure 9 is a plan view of a first substrate in a display apparatus according to still another exemplary embodiment of the disclosure;

[0026] Figure 10 This is a plan view of a multi-panel display device according to an exemplary embodiment of the present disclosure;

[0027] Figure 11 yes Figure 10 A magnified planar view of region X; and

[0028] Figure 12 It is along Figure 11 The cross-sectional view taken from line I-I'. Detailed Implementation

[0029] The advantages and features of this disclosure, as well as methods for achieving these advantages and features, will be illustrated by referring to the exemplary embodiments described in detail below with reference to the accompanying drawings. 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 to enable those skilled in the art to fully understand the disclosure and scope of this disclosure. Therefore, this disclosure will be limited only by the scope of the appended claims.

[0030] 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, the same reference numerals generally denote the same 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 other 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.

[0031] Even if not explicitly stated, the components will be interpreted as including the normal error range.

[0032] When using terms such as “above,” “over,” “below,” and “beside” to describe the positional relationship between two parts, one or more parts may be located between the two parts, unless these terms are used with the terms “immediately adjacent” or “directly.”

[0033] When one element or layer is disposed "on" another element or layer, the element or layer may be located directly on the other element or layer, or another layer or element may be inserted between them.

[0034] 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 in the technical concept of this disclosure.

[0035] Throughout the specification, the same reference numerals generally denote the same elements.

[0036] The dimensions and thickness of each component shown in the accompanying drawings are illustrated for ease of description, and this disclosure is not limited to the dimensions and thickness of the components shown.

[0037] Features of the various embodiments of this disclosure may be attached or combined with each other in part or in whole, and may be interlocked and operated in various technical ways, and these embodiments may be performed independently or in association with each other.

[0038] In the following, a display device according to an exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0039] Throughout this specification, unless otherwise stated, the particle size is the particle size at the point (D50) where the cumulative amount in the cumulative particle size distribution is 50%.

[0040] Figures 1 to 3 This is a view used to explain a display device according to an exemplary embodiment of the present disclosure. Figure 1 This is a schematic cross-sectional view of a display device according to an exemplary embodiment of the present disclosure. Figure 2 This is a schematic top view of a first substrate in a display device according to an exemplary embodiment of the present disclosure. Figure 3 This is a side view of a display device according to an exemplary embodiment of the present disclosure.

[0041] Reference Figures 1 to 3 According to an exemplary embodiment of the present disclosure, a display device 100 includes a first substrate 110, a display unit 120, a sealant 170, a second substrate 130, multiple signal lines 140, multiple connecting lines 150, multiple side lines 160, and a protective layer 180. The side lines 160 include a first conductive layer 161 and a second conductive layer 162.

[0042] The first substrate 110 is a base substrate used to support various components of the display unit. The first substrate 110 may be formed of an insulating material. For example, the first substrate 110 may be made of glass or plastic. The first substrate 110 may be a flexible plastic film that can be bent as needed.

[0043] In the first substrate 110, a display area DA and a non-display area NDA surrounding the display area DA can be defined. The display area DA is the area in the display device where an image is actually displayed, and a display unit 120, which will be described below, is disposed in the display area DA. The non-display area NDA is the area where no image is actually displayed, such that the non-display area NDA can be defined as the edge region of the first substrate 110 surrounding the display area DA. Various wirings can be disposed in the non-display area NDA, such as gate lines and data lines of thin-film transistors connected to the display unit 120 disposed in the display area DA. Furthermore, driving circuitry, such as a data driving integrated circuit chip or a gate driving integrated circuit chip, can be disposed in the non-display area NDA, and multiple pads can be disposed, but not limited thereto.

[0044] A plurality of pixels PX are defined in the display area DA of the first substrate 110. Each of the plurality of pixels PX is an independent unit that emits light and includes red, green, and blue pixels. If desired, white pixels may be included. A display unit 120 is formed in each of the plurality of pixels PX.

[0045] Display unit 120 displays an image. For example, display unit 120 includes an organic light-emitting diode (OLED) and circuitry for driving the OLED. Specifically, the OLED may include an anode, at least one organic layer, and a cathode, such that electrons and holes are coupled to emit light. The organic layer includes, but is not limited to, an organic light-emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer. For example, the circuitry may include multiple thin-film transistors, capacitors, and multiple wirings to drive the OLED.

[0046] When the display device 100 is driven in a top-emitting mode, a circuit unit is provided on the first substrate 110, and an organic light-emitting diode is provided on the circuit unit. Specifically, a thin-film transistor is provided on the first substrate 110, a planarization layer is provided on the thin-film transistor, and an anode, a plurality of organic layers including an organic light-emitting layer, and a cathode are sequentially provided on the planarization layer to form a display unit 120.

[0047] The second substrate 130 is disposed on the display unit 120, opposite to the first substrate 110. The second substrate 130 is an encapsulation substrate that protects the display unit 120 from external moisture or air penetration or physical impact. For example, the second substrate 130 may be selected from metal foil and plastic substrate, but is not limited to these, and may be an encapsulation layer formed by coating with organic and / or inorganic materials.

[0048] A sealant 170 is disposed between the first substrate 110 and the second substrate 130 in the non-display area NDA. The sealant 170 is disposed around the outer periphery of the display unit 120 and bonds the first substrate 110 and the second substrate 130. The sealant 170 prevents moisture and oxygen from penetrating from the side surfaces of the display unit 120 and is referred to as a dam. The sealant 170 may be omitted when the second substrate 130 does not have a plate-like shape (e.g., glass, metal foil, or plastic substrate) but can be formed as an encapsulation layer coated with organic and / or inorganic materials.

[0049] Multiple signal lines 140 are provided on the upper surface of the first substrate 110, and multiple connection lines 150 are provided on the rear surface of the first substrate 110. The multiple signal lines 140 are electrically connected to the components of the display unit 120 to transmit signals to the display unit 120. The multiple connection lines 150 are wirings connecting the multiple signal lines formed on the upper surface of the first substrate 110 to the driving circuit.

[0050] Specifically, common reference Figure 1 and Figure 2 The multiple signal lines 140 disposed on the upper surface of the first substrate 110 may be multiple gate lines GL and multiple data lines DL. The multiple gate lines GL and multiple data lines DL are electrically connected to the thin-film transistors of the display unit 120 disposed in the display area DA to transmit gate signals and data signals.

[0051] Meanwhile, the multiple connection lines 150 disposed on the rear surface of the first substrate 110 can be multiple gate connection lines and multiple data connection lines. The multiple gate connection lines are wiring connecting the multiple gate lines GL disposed on the upper surface of the first substrate 110 to the gate driving circuit. The multiple data connection lines are wiring connecting the multiple data lines DL disposed on the upper surface of the first substrate 110 to the data driving circuit. The multiple gate connection lines and multiple data connection lines can extend from the end of the rear surface of the first substrate 110 to the center of the rear surface of the first substrate 110.

[0052] Furthermore, on the rear surface of the first substrate 110, a gating drive circuit is electrically connected to multiple gating connection lines, and a data drive circuit is electrically connected to multiple data connection lines. In this case, the gating drive circuit and the data drive circuit can be directly formed on the rear surface of the first substrate 110, and can be disposed on the rear surface of the first substrate 110 in a chip-on-film manner. As another example, the gating drive circuit and the data drive circuit can be connected to a printed circuit board. The printed circuit board can transmit various signals to the multiple signal lines 140 and the display unit 120 formed on the first substrate 110.

[0053] Refer again Figure 1Each of the multiple signal lines 140 may include a first pad unit PAD1, and each of the multiple connection lines 150 may include a second pad unit PAD2. The first pad unit PAD1 and the second pad unit PAD2 are areas that contact the side line 160. The first pad unit PAD1 may be a conductive layer extending from the multiple signal lines 140, and the second pad unit PAD2 may be a conductive layer extending from the multiple connection lines 150. The first substrate 110 protrudes outward from the second substrate 130. The ends of the multiple signal lines 140 disposed on the upper surface of the first substrate 110 (i.e., the upper surface of the first pad unit PAD1) are exposed. Therefore, the side line 160, which electrically connects the multiple signal lines 140 and the multiple connection lines 150, can contact not only the side surface of the signal lines 140 but also the upper surface. As described above, when the contact area between the side line 160 and the signal line 140 increases, the current transmitted to the signal line 140 via the side line increases significantly. Therefore, it is easy to realize large-size display devices.

[0054] Continue to refer to Figure 1 Multiple side lines 160 are provided on the side surface of the first substrate 110. The multiple side lines 160 are electrically connected to multiple signal lines 140 provided on the upper surface of the first substrate 110 and multiple connection lines 150 provided on the rear surface of the first substrate 110.

[0055] Multiple side lines 160 are configured to cover the ends of multiple signal lines 140 disposed on the upper surface of the first substrate 110, the side surface of the first substrate 110, and the ends of multiple connection lines 150 disposed on the rear surface of the first substrate 110. That is, the multiple side lines 160 are configured to continuously cover the first pad unit PAD1 of the multiple signal lines 140, the side surface of the first substrate 110, and the second pad unit PAD2 of the multiple connection lines 150. Furthermore, the multiple side lines 160 are in direct contact with the first pad unit PAD1, the side surface of the first substrate 110, and the second pad unit PAD2.

[0056] Specifically, the multiple side lines 160 may include a first side line and a second side line. The first side line connects the gate line GL formed on the upper surface of the first substrate 110 and the gate connection line formed on the rear surface of the first substrate 110. The second side line connects the data line DL formed on the upper surface of the first substrate 110 and the data connection line formed on the rear surface of the first substrate 110.

[0057] Each of the multiple side lines 160 includes a first conductive layer 161 and a second conductive layer 162.

[0058] The first conductive layer 161 is configured to continuously cover the ends of the signal lines 140 formed on the upper surface of the first substrate 110, the side surfaces of the first substrate 110, and the ends of the connection lines 150 formed on the rear surface of the first substrate 110. That is, the first conductive layer 161 is configured to be in direct contact with the upper and side surfaces of the first pad unit PAD1, the side surface of the first substrate 110, and the lower and side surfaces of the second pad unit PAD2.

[0059] The second conductive layer 162 is configured to cover the first conductive layer 161. The second conductive layer 162 is configured to continuously cover the upper surface of the first pad unit PAD1 and the lower surface of the first conductive layer 161 and the second pad unit PAD2. The second conductive layer 162 can be configured to directly contact the upper surface of the first pad unit PAD1 that is not covered by the first conductive layer 161 and thus exposed, as well as the lower surfaces of the first conductive layer 161 and the second pad unit PAD2. That is, the second conductive layer 162 completely covers the first conductive layer 161, so that the first conductive layer 161 is not exposed.

[0060] The side lines 160 are patterned to connect multiple corresponding signal lines 140 and multiple corresponding connection lines 150 to each other. That is, the first conductive layer 161 is patterned to connect multiple corresponding signal lines 140 and multiple corresponding connection lines 150 to each other. Furthermore, similar to the first conductive layer 161, the second conductive layer 162 is patterned to connect multiple corresponding signal lines 140 and multiple corresponding connection lines 150 to each other. For example, the first conductive layer 161 and the second conductive layer 162 can be formed by a pad printing method, but are not limited thereto. Steps are formed on the side surface of the first substrate 110 on which the first conductive layer 161 and the second conductive layer 162 are to be formed. However, the pad printing method uses a resilient silicone rubber pad (e.g., PDMS), allowing the conductive layer to be easily formed on the stepped surface.

[0061] The first conductive layer 161 and the second conductive layer 162 may include conductive particles. The first conductive layer includes first conductive particles, and the second conductive layer includes second conductive particles. For example, the first and second conductive particles may include one or more metals selected from silver (Ag), gold (Au), platinum (Pt), palladium (Pd), and copper (Cu). For example, the first and second conductive particles may include silver (Ag) or an alloy thereof, which is hardly oxidized and has excellent electrical properties.

[0062] The size of the first conductive particles included in the first conductive layer 161 is smaller than the size of the second conductive particles included in the second conductive layer 162. For example, the particle size of the first conductive particles can be 10nm to 400nm, 10nm to 300nm, 10nm to 150nm, 10nm to 100nm, 20nm to 100nm, or 100nm to 300nm. The particle size of the second conductive particles can be 1μm to 5μm, 1.5μm to 4μm, 1μm to 3.5μm, or 3μm to 5μm.

[0063] The particle size of the second conductive particles can be 5 to 20 times, 10 to 20 times, or 5 to 15 times that of the first conductive particles. Within this range, the advantage is that the electrical and mechanical properties of the side wire 160 can be excellent.

[0064] The side line 160 has a structure in which a first conductive layer 161 formed of first conductive particles and a second conductive layer 162 formed of second conductive particles with a particle size smaller than the first conductive particles are laminated. Therefore, contact resistance can be reduced, electrical characteristics improved, and mechanical properties enhanced. In this way, power consumption is reduced and mechanical properties are significantly improved, thereby providing a display device with high reliability and excellent display quality.

[0065] Each of the first conductive layer 161 and the second conductive layer 162 may further comprise a resin. The resin provides adhesion between the interfaces. For example, the resin may be an epoxy resin. Epoxy resin improves the adhesion between the interfaces and has strong resistance to stress changes after curing, and protects the first conductive layer 161 and the second conductive layer 162 from physical impacts. For example, based on the total amount of the first conductive particles and the resin, the first conductive layer 161 may comprise 10% to 30% by weight of resin. For example, based on the total amount of the second conductive particles and the resin, the second conductive layer 162 may comprise 20% to 40% by weight of resin. However, the resin content ratio is not limited to these and may vary depending on the particle size of the first and second conductive particles and the method of patterning the conductive layers.

[0066] The first conductive layer 161 can be formed from a first paste comprising first conductive particles and a curable resin. The second conductive layer 162 can be formed from a second paste comprising second conductive particles and a curable resin. For example, the first conductive layer 161 can be formed by pad printing the first paste, and the second conductive layer 162 can be formed by pad printing the second paste. A first paste layer is formed on a side surface of the first substrate by pad printing the first paste, and a second paste layer is laminated to cover the first paste layer by pad printing the second paste. Thereafter, a heat treatment is performed together to form the first and second conductive layers. (See attached...) Figure 4A andFigure 4B It is described in detail.

[0067] When the first and second slurry layers are laminated and then subjected to heat treatment, the first conductive particles included in the first slurry layer are sintered, and the curable resin is cured to form the first conductive layer. Similarly, the second conductive particles included in the second slurry layer are sintered, and the curable resin is cured to form the second conductive layer. Under the same heat treatment conditions, the degree of sintering of the first and second conductive particles can differ due to the difference in particle size. The first conductive particles with relatively smaller particle size have a greater degree of sintering, while the second conductive particles with relatively larger particle size have a smaller degree of sintering. Therefore, during heat treatment, the viscosity of the first conductive particles with relatively smaller particle size decreases rapidly, i.e., the first conductive particles melt to increase the contact area at the interface. Therefore, the first conductive layer 161 formed by sintering the first conductive particles has a larger contact area with the signal line 140 and the connection line 150, resulting in lower contact resistance (interface resistance) and better adhesion. Furthermore, the first conductive particles are rapidly melted through heat treatment to sinter into individual lumps, thereby reducing the linear resistance of the first conductive layer 161. As described above, with the reduction in the contact resistance and linear resistance of the first conductive layer 161, the current transmitted to the signal line 140 and the connecting line 150 via the side line 160 can be significantly increased.

[0068] Simultaneously, a second conductive layer 162 is formed by sintering second conductive particles with a particle size relatively larger than that of the first conductive layer 161. Due to the relatively large particle size, the viscosity of the second conductive particles decreases relatively slowly during the same heat treatment, thereby sintering at a density lower than that of the first conductive layer 161. Therefore, the second conductive layer 162, having a relatively low density, can have a higher surface hardness than the first conductive layer 161. Thus, the second conductive layer can protect the first conductive layer 161 and improve the rigidity of the side line 160.

[0069] The total thickness (t1+t2) of the side lines 160, including the first conductive layer 161 and the second conductive layer 162, is very thin, ranging from 4μm to 10μm, 4.5μm to 7μm, or 4μm to 6μm. Therefore, a narrow-bezel display device with high power efficiency and high reliability can be achieved while reducing the bezel area.

[0070] Because the thickness t1 of the first conductive layer 161 is designed to be thinner, the sintering degree of the first conductive particles increases during the formation of the first conductive layer 161, thereby improving conductivity. However, as the thickness t1 of the first conductive layer 161 becomes thinner, the resin content included in the first conductive layer 161 decreases, which may reduce the adhesion of the first conductive layer 161. As a result, the first conductive layer 161 may separate from the side surface of the first substrate 110. Furthermore, when the resin content in the first conductive layer 161 is low, moisture penetration increases, which may accelerate the ionization of conductive particles due to moisture. Ionized particles cause migration, thereby causing wiring defects. Therefore, it is desirable to form a first conductive layer 161 with a thickness t1 of 1 μm or greater.

[0071] For example, the thickness t1 of the first conductive layer 161 can be 1 μm to 6 μm, 1.5 μm to 5 μm, 1.5 μm to 3 μm or 1.5 μm to 2 μm, and within this range, the adhesion is excellent, the contact resistance is low, and the wiring defects are minimized.

[0072] Meanwhile, the thickness t2 of the second conductive layer 162 can be 2μm to 8μm, 2.5μm to 6μm, or 3μm to 5μm. Within this range, the advantage is that the surface hardness is improved, while the electrical properties of the side line 160 remain high.

[0073] Furthermore, the thickness t2 of the second conductive layer 162 can be equal to or greater than the thickness t1 of the first conductive layer 161. For example, the ratio of the thickness t2 of the second conductive layer 162 to the thickness t1 of the first conductive layer 161 can be from 1:0.3 to 1:1. As described above, as the first conductive layer 161 becomes thinner, the contact resistance is further reduced to improve electrical properties, but adhesion may decrease, or migration may be accelerated. Therefore, in order to minimize migration while maintaining high electrical properties and adhesion, the ratio of the thickness t2 of the second conductive layer 162 to the thickness t1 of the first conductive layer 161 can be formed in the range of 1:0.4 to 1:0.7.

[0074] There is no specific limitation on the width of the first conductive layer 161 and the second conductive layer 162, but it is desirable that they be greater than the width of the signal line 140 and the connecting line 150 in order to increase the contact area between the wiring.

[0075] The protective layer 180 is formed to cover multiple side lines 160. The protective layer 180 comprises a black material, making the side lines 160 invisible from the outside. The multiple side lines 160 are formed of a metallic material with glossy properties (e.g., silver (Ag)), so that external light or light emitted from the display unit 120 is reflected and recognized by the user. Therefore, the protective layer 180 is formed of an insulating material comprising the black material. That is, the protective layer 180 can be an insulating layer comprising the black material.

[0076] For example, the sum of the thickness t1 of the first conductive layer 161, the thickness t2 of the second conductive layer 162, and the thickness t3 of the protective layer 180 can be 15 μm or less, or 5 μm to 15 μm. In this case, the bezel area is minimized to achieve a narrow bezel display device.

[0077] A display device 100 according to an exemplary embodiment of the present disclosure includes a plurality of side lines 160 electrically connecting a plurality of signal lines 140 disposed on the upper surface of a first substrate 110 and a plurality of connection lines disposed on the lower surface of the first substrate 110. Each of the plurality of side lines 160 includes a first conductive layer 161 and a second conductive layer 162. The first conductive layer 161 has first conductive particles, and the second conductive layer 162 is configured to cover the first conductive layer 161 and is formed of second conductive particles with a particle size larger than the first conductive particles. The first conductive layer 161 includes first conductive particles with a smaller particle size, resulting in lower linear resistance and lower contact resistance with the signal lines 140 and connection lines 150. Furthermore, the second conductive layer 162 complements the surface hardness of the first conductive layer 161 to simultaneously improve the electrical characteristics and mechanical properties of the side lines 160. Therefore, the power efficiency and reliability of the display device 100 are improved. Furthermore, without increasing the thickness of the side line 160, a first conductive layer 161 and a second conductive layer 162 formed of conductive particles with different particle sizes are laminated to achieve a narrow bezel display device.

[0078] Figure 4A and Figure 4B This is a view used to explain a display device according to another exemplary embodiment of the present disclosure. Figure 4A This is a view showing the state of a display device according to another exemplary embodiment of the present disclosure before heat treatment during the process of forming the first conductive layer and the second conductive layer, and Figure 4B This is a cross-sectional view of the display device after heat treatment. Figure 4A and Figure 4B The structures of the first and second conductive layers in the exemplary embodiment shown are different. Figures 1 to 3 The structure of the exemplary embodiment shown is similar, but other components are substantially the same. Therefore, redundant descriptions will be omitted.

[0079] existFigure 4A The image shows that the first conductive particle 261a and the second conductive particle 262a are spherical, but are not limited to this.

[0080] As described above, the first conductive layer 261 and the second conductive layer 262 can be patterned by a pad printing method. Specifically, the first conductive layer 261 and the second conductive layer 262 can be formed by a pad printing method including the following steps: i) applying a first slurry including first conductive particles 261a and curable resin 261b to a metal plate in which an engraved pattern portion is formed, and removing the first slurry applied to the portion other than the engraved pattern portion. ii) after smearing the pattern of the first slurry filling the engraved pattern portion using a silicon pad, setting the pattern of the first slurry to contact the signal line 140, the side surface of the first substrate 110, and the connection line 150 of the first substrate 110 to form a first slurry layer 265. iii) then performing simple drying (or simple curing). Steps i) to iii) can be repeated depending on the desired thickness. iv) Using a second slurry comprising second conductive particles 262a and curable resin 262b, a second slurry layer 266 is formed by the same process as steps i) to iii) to cover the first slurry layer 265. Similarly, the second slurry layer 266 may be further formed according to the desired thickness. v) The laminated first slurry layer 265 and second slurry layer 266 are heat-treated to form a first conductive layer 261 and a second conductive layer 262. This pad printing method is exemplary but not limited thereto.

[0081] Reference Figure 4A and Figure 4B When the first slurry layer 265 is heat-treated, the first conductive particles 261a, which have a relatively smaller particle size, melt rapidly. Therefore, the first conductive particles 261a of the first conductive layer 261 do not maintain a spherical shape, but melt into individual blocks to form the first conductive portion 261a'. The curable resin 261b of the first slurry layer 265 cures during the heat treatment process to form the first cured resin portion 261b'.

[0082] Conversely, under the same heat treatment conditions, the second conductive particles 262a with a relatively larger particle size may not melt easily. Therefore, the second conductive particles 262a of the second conductive layer 262 partially contact each other while maintaining a slightly spherical shape to aggregate, thereby forming a plurality of second conductive portions 262a'. The plurality of second conductive portions 262a' contact with their adjacent second conductive portions 262a' to be conductive.

[0083] In each of the second conductive portions 262a', the second conductive particles 262a are partially melted and then fixed at the portions where the second conductive particles 262a are in contact with each other to form a neck structure.

[0084] Furthermore, in the second conductive layer 262, some second conductive particles 262a exist without melting while maintaining a close distance between the particles. As described above, some of the unmelted second conductive particles 262a are surrounded by the second curable resin portion 262b', thus preventing them from contacting each other.

[0085] In the first conductive layer 261, most of the first conductive particles 261a are melted and then fused (fixed) into a bulk to form the first conductive portion 261a'. Therefore, the linear resistance is reduced, and the contact resistance with the signal line 140 and the connecting line 150 is reduced, and thus, the amount of current transmitted to the signal line 140 and the connecting line 150 is significantly increased. The second conductive layer 262 includes a plurality of second conductive portions 262a', in which the second conductive particles 262a maintain a slightly spherical shape and are partially in contact with each other to have a neck structure formed by the fused contact portions. In this way, an uneven structure is formed on the surface of the side line 260 to improve surface hardness. Therefore, the power efficiency of the display device 200B is improved, and the mechanical properties are also improved.

[0086] Figure 5 This is a top view of a first substrate in a display device according to another exemplary embodiment of the present disclosure. Figure 6 This is a side view of a display device according to another exemplary embodiment of the present disclosure. Figures 1 to 3 Compared to the display device shown, except Figure 5 and Figure 6 Apart from the placement structure of the protective layer in the exemplary embodiment shown, the other components are basically the same. Therefore, redundant descriptions will be omitted.

[0087] Reference Figure 5 and Figure 6 In a display device 300 according to another exemplary embodiment of the present disclosure, a protective layer 380 is patterned to cover a plurality of side lines 160 patterned to connect corresponding signal lines 140 and connection lines 150 to each other. That is, unlike the protective layer 180, which is formed as a continuous layer along the corner of the first substrate 110 to cover all the plurality of side lines 160, Figure 5 and Figure 6 The protective layer 380 has a structure patterned to correspond to multiple side lines 160.

[0088] Specifically, the protective layer 380 may include a first protective pattern and a second protective pattern. The first protective pattern covers the side lines 160 of the gate line GL formed on the upper surface of the first substrate 110 and the gate connection line formed on the rear surface of the first substrate 110. The second protective pattern covers the side lines of the data line DL formed on the upper surface of the first substrate 110 and the data connection line formed on the rear surface of the first substrate 110.

[0089] For example, the protective layer 380 can be formed by laser transfer to have a structure patterned on the side lines 160 provided on the side surface of the first substrate 110, but is not limited thereto.

[0090] Figures 7 to 9 This is a view used to explain a display device according to yet another exemplary embodiment of the present disclosure. Figure 7 This is a cross-sectional view of a display device according to yet another exemplary embodiment of the present disclosure. Figure 8 This is a side view of a display device according to yet another exemplary embodiment of the present disclosure. Figure 9 This is a top view of a first substrate in a display device according to yet another exemplary embodiment of the present disclosure.

[0091] and Figures 1 to 3 Compared to the display device shown, Figures 7 to 9 The exemplary embodiment shown also includes a third substrate located on the rear surface of the first substrate, and has a different structure with multiple connecting lines, multiple side lines, and a protective layer. However, other components are substantially the same, so redundant descriptions will be omitted.

[0092] Common Reference Figures 7 to 9 A third substrate 490 is disposed on the rear surface of the first substrate 110. The third substrate 490 is an auxiliary substrate supporting components below the display device 400. The third substrate 490 may be formed of an insulating material. For example, the third substrate 490 may be made of glass or plastic. The third substrate 490 may be formed of the same material as the first substrate 110.

[0093] An adhesive layer 495 is disposed between the first substrate 110 and the third substrate 490. The adhesive layer 495 bonds the first substrate 110 and the third substrate 490. The adhesive layer 495 may be disposed on either the first substrate 110 or the third substrate 490 to correspond to the non-display area NDA of the first substrate 110. However, it is not limited thereto, and the adhesive layer 495 may be disposed in the entire area between the first substrate 110 and the third substrate 490.

[0094] exist Figures 1 to 3In the case of the display device 100 shown, the display unit 120 and multiple signal lines 140 are disposed on the upper surface of the first substrate 110, and the connection line 150 and the drive circuit are disposed on the rear surface of the first substrate 110. When components are disposed on both surfaces of a substrate as described above, it is difficult to ensure the stability of the process during the process of disposing of some components on one surface and then disposing of other components on the other surface.

[0095] Therefore, the display device 400 can be easily manufactured by joining the first substrate 110 and the third substrate 490 after the display unit 120 and signal line 140 are disposed on the first substrate 110 and the connection line 450 and the drive circuit are disposed on the third substrate 490. Furthermore, this is beneficial for process stability and product reliability.

[0096] Common Reference Figure 7 and Figure 8 Multiple connection lines 450 are formed on the rear surface of the third substrate 490. Specifically, multiple gate connection lines and multiple data connection lines are formed on the rear surface of the third substrate 490. Furthermore, on the rear surface of the third substrate 490, a gate driving circuit is configured to be electrically connected to the multiple gate connection lines, and a data driving circuit is configured to be electrically connected to the multiple data connection lines.

[0097] Multiple side lines 460 are provided on the side surfaces of the first substrate 110 and the third substrate 490. The multiple side lines 460 are configured to cover the ends of multiple signal lines provided on the upper surface of the first substrate 110, the side surfaces of the first substrate 110 and the third substrate 490, and the ends of multiple connecting lines 450 provided on the rear surface of the third substrate 490.

[0098] Specifically, the first conductive layer 461 is configured to directly contact a plurality of signal lines 140 disposed on the upper surface of the first substrate 110, a side surface of the first substrate 110, a side surface of the third substrate 490, and a plurality of connection lines 450 disposed on the rear surface of the third substrate 490. The second conductive layer 462 is configured to directly contact the upper surface of the plurality of signal lines 140 that is not covered by the first conductive layer 461 and thus exposed, as well as the plurality of connection lines 450 disposed on the first conductive layer 461 and the rear surface of the third substrate 490.

[0099] Common Reference Figures 7 to 9 A protective layer 480 is continuously provided to completely cover the second conductive layer 462 from one end to the other end.

[0100] Figures 10 to 12 This is a view used to explain a multi-panel display device according to an exemplary embodiment of the present disclosure. Figure 10This is a plan view of a multi-panel display device according to an exemplary embodiment of the present disclosure. Figure 11 yes Figure 10 A magnified planar view of region X, and Figure 12 It is along Figure 11 The cross-sectional view taken from line I-I'.

[0101] Reference Figure 10 A multi-panel display device 1000 according to an exemplary embodiment of the present disclosure includes a plurality of display devices 400A, 400B, 400C, and 400D. The plurality of display devices 400A, 400B, 400C, and 400D are arranged in an m×n tiled pattern to be implemented as a single multi-panel display device 1000. Although for ease of description... Figure 10 The illustration shows 20 display devices arranged in a 5×4 tile pattern, but this disclosure is not limited thereto, so that an appropriate number of display devices can be arranged as needed.

[0102] Reference magnification Figure 10 Region X Figure 11 Multiple display devices can be arranged to be in contact with each other vertically or horizontally. For example, multiple display devices 400A, 400B, 400C, and 400D include a first display device 400A, a second display device 400B, a third display device 400C, and a fourth display device 400D. The first display device 400A and the second display device 400B are arranged to be in contact with each other horizontally, and the third display device 400C and the fourth display device 400D are arranged to be in contact with each other vertically.

[0103] Figure 12 It is along Figure 11 The cross-sectional view taken from line I-I'. (Refer to...) Figure 12 In the multi-panel display device 1000 according to this exemplary embodiment of the present disclosure, the first display device 400A and the second display device 400B are arranged to be horizontally contacting each other. The display devices 400A and 400B are... Figure 7 The display device 400 shown is basically the same, so redundant descriptions will be omitted.

[0104] Reference Figure 12 Each of the first display device 400A and the second display device 400B includes a side line 460, which includes a first conductive layer 461 and a second conductive layer 462. The first conductive layer 461 includes first conductive particles with a relatively small particle size, and the second conductive layer 462 includes second conductive particles with a larger particle size than the first conductive particles.

[0105] A first conductive layer 461 is formed by sintering first conductive particles with a relatively small particle size to reduce the contact resistance and linear resistance with the signal line 140 and the connection line 450. Therefore, the amount of current transmitted to the signal line 140 and the connection line 450 can be significantly increased by means of the first conductive layer.

[0106] The second conductive layer 462 is configured to cover the first conductive layer 461 to protect the first conductive layer 461. Furthermore, the second conductive layer 462 is formed by sintering second conductive particles with a relatively larger particle size to compensate for the low surface hardness of the first conductive layer 461, thereby improving the mechanical properties of the side line 460.

[0107] Because multi-panel display devices include multiple display devices, increased brightness and circuit integration inevitably lead to increased power consumption. However, the multi-panel display device 1000 of this disclosure employs a side line (460) structure in which a first conductive layer 461 and a second conductive layer 462 are laminated, which significantly increases the current transmitted to the signal line 140 and the connecting line 150 via the side line 460. In this way, power efficiency is improved.

[0108] Furthermore, the multi-panel display device 1000 according to this disclosure is manufactured by laminating a first conductive layer 461 to improve electrical properties without increasing the thickness of the side lines 460, and a second conductive layer 462 to improve the mechanical properties of the side lines. Therefore, the bezel area B is not increased. Furthermore, the seams S are minimized, allowing an image to be displayed on the multi-panel display device 1000 without discontinuity or awkwardness due to the seams S. In addition, a high-quality multi-panel display device 1000 with improved power efficiency and improved reliability is provided.

[0109] The effects of this disclosure will be described in more detail below with reference to examples. However, although the following examples are illustrated to illustrate this disclosure, its scope is not limited thereto.

[0110] Example 1

[0111] A first slurry comprising 80 wt% silver nanoparticles with a particle size D50 of 200 nm to 300 nm and 20 wt% epoxy-based curable resin was prepared. The first slurry was applied to ITO glass. The first slurry was briefly dried on the ITO glass. Next, a second slurry was prepared, comprising 70 wt% silver nanoparticles with a particle size D50 of 2 μm to 3 μm and 30 wt% epoxy-based curable resin. The second slurry was applied onto the first slurry laminated on the ITO glass. Then, a wiring with a first conductive layer (2.5 μm) and a second conductive layer (2.5 μm) laminated on it was fabricated by heat treatment at 200°C for 30 to 180 minutes.

[0112] Example 2

[0113] Except for applying the first and second pastes at different thicknesses, wiring with a first conductive layer (2.0 μm) and a second conductive layer (3.0 μm) laminated on it is manufactured by the same method as in Example 1.

[0114] Example 3

[0115] Except for applying the first and second pastes at different thicknesses, wiring with a first conductive layer (1.5 μm) and a second conductive layer (3.5 μm) laminated on it is manufactured by the same method as in Example 1.

[0116] Comparative Example 1

[0117] Except for the process of not applying the first paste and applying the second paste at a different thickness, the wiring consisting of a second conductive layer (5.0 μm) is manufactured by the same method as in Example 1.

[0118] Comparative Example 2

[0119] The mixed slurry was prepared by mixing the first slurry and the second slurry in a 50:50 weight ratio, instead of applying the first slurry and then the second slurry on top of it as in Example 1. The mixed slurry was then applied to ITO glass. The fabrication process involves heat treatment at 200°C for 30 to 180 minutes to create wiring consisting of a single conductive layer (5.0 μm).

[0120] Comparative Example 3

[0121] A first slurry was prepared comprising 80 wt% silver nanoparticles with a particle size D50 of 200 nm to 300 nm and 20 wt% epoxy-based curable resin. The first slurry was applied to ITO glass. Next, a heat treatment is performed at 200°C for 30 to 180 minutes to create wiring consisting of a single conductive layer (5.0 μm).

[0122] Comparative Example 4

[0123] Except that the first and second pastes are laminated in a different order, wiring lines on which a second conductive layer (2.5 μm) and a first conductive layer (2.5 μm) are sequentially laminated are manufactured by the same method as in Example 1.

[0124] Experimental Example

[0125] The linear resistance, contact resistance, and surface hardness of the wiring according to the example, reference, and comparative examples are measured using the following methods, and reliability is evaluated through a migration test.

[0126] 1. Linear resistance and contact resistance

[0127] The linear resistance at room temperature (2.5 μm thickness and 40 mm) was measured using a four-point probe-type surface resistance measurement unit. 2 The linear resistance and contact resistance were measured at the same heat treatment temperature of 200°C for 30 minutes, 60 minutes, and 180 minutes. The results are shown in Table 1 below.

[0128] 2. Surface hardness

[0129] A 500g load was applied to the sample while the sample surface was scratched with a pencil, and the surface scratches were then measured visually. Surface hardness was measured at the same heat treatment temperature of 200°C for 30, 60, and 180 minutes. The results are shown in Table 1 below.

[0130] 3. Reliability (Migration Testing)

[0131] The time it took for a short circuit to form in the electrode due to silver (Ag) migration was measured while a constant voltage was applied to the sample in a chamber with high temperature (85°C) and high humidity (85%). The results are shown in Table 1 below.

[0132] [Table 1]

[0133]

[0134] (In Table 1, NPs are conductive layers formed by a first slurry containing silver nanoparticles with a size of 200 nm to 300 nm, MPs are conductive layers formed by a second slurry containing micron particles with a size of 2 μm to 3 μm, and NPs+MPs are conductive layers formed by a mixed slurry containing silver nanoparticles and silver micron particles).

[0135] Referring to Table 1, it can be confirmed that the wiring in Examples 1 to 3, in which the first conductive layer and the second conductive layer are laminated, has low linear resistance, low contact resistance, high pencil hardness, and excellent reliability. Specifically, it can be confirmed that Examples 2 and 3, in which the second conductive layer formed by silver micron particles with relatively larger particle size has a greater thickness, have electrical and surface hardness characteristics equal to those of Example 1, and even better reliability.

[0136] The wiring in Comparative Example 1 is formed from a single conductive layer composed of silver micron-sized particles with a relatively larger particle size. The wiring in Comparative Example 1 comprises particles with a relatively large particle size, which are less fused under the same sintering conditions. Therefore, it should be understood that the linear resistance and contact resistance are larger, and in particular, the contact resistance is significantly larger compared to the examples.

[0137] The wiring of Comparative Example 2, formed from a mixed slurry comprising both silver nanoparticles and silver microparticles, includes silver nanoparticles that are rapidly melted through heat treatment. Therefore, it was confirmed that the linear resistance and contact resistance were reduced compared to Comparative Example 1. However, it was also confirmed that the linear resistance and contact resistance were significantly higher, while the surface hardness was significantly lower, and silver (Ag) migration was more likely to occur compared to Examples 1 to 3.

[0138] Furthermore, according to Comparative Example 3, the monolayer wiring formed by the first slurry was composed of silver nanoparticles, resulting in a larger contact area and thus confirming the lowest linear resistance, with the contact resistance being equal to that in each example. However, it was confirmed that the surface hardness was 1H or lower, which is very low and easily affected by moisture penetration, thus causing silver migration most rapidly.

[0139] In Comparative Example 4, which has a different lamination sequence than Example 1, the conductive layer formed by the first slurry with excellent electrical properties is located on top, resulting in a lower linear resistance. However, it was confirmed that the contact resistance was very low and the surface hardness was very poor.

[0140] Summarizing the experimental results, the first conductive layer was formed from silver nanoparticles with a particle size (D50) of 200 nm to 300 nm, and the second conductive layer was laminated onto the first conductive layer using a paste containing silver microparticles with a particle size (D50) of 2 μm to 3 μm. Therefore, it was confirmed that surface hardness was improved, silver migration was suppressed, and both the linear resistance and contact resistance of the wiring were reduced.

[0141] Therefore, when the laminated structure of the first conductive layer and the second conductive layer is applied to the side electrodes of the display device, the current flow of the side electrodes is increased, thereby improving the power efficiency of the display device. Furthermore, the surface hardness of the side lines is increased, and migration is suppressed to prevent short circuits in the electrodes, thus providing a display device with improved reliability. Moreover, compared to existing technologies, wiring with the first and second conductive layers laminated on it can simultaneously improve electrical characteristics and surface hardness without increasing the thickness of the wiring. Therefore, this wiring can realize narrow-bezel display devices and can be applied to multi-panel display devices.

[0142] Exemplary embodiments of this disclosure can also be described as follows:

[0143] According to one aspect of this disclosure, a display device includes: a first substrate including a display area and a non-display area surrounding the display area; a display unit including an organic light-emitting diode disposed on an upper surface of the first substrate; a plurality of signal lines disposed on the upper surface of the first substrate and electrically connected to the display unit; a plurality of connecting lines disposed below the first substrate; and a plurality of side lines disposed on a side surface of the first substrate and connecting the plurality of signal lines and the plurality of connecting lines, each of the plurality of side lines including: a first conductive layer disposed on a side surface of the first substrate and formed of first conductive particles; and a second conductive layer covering the first conductive layer and formed of second conductive particles with a particle size larger than that of the first conductive particles.

[0144] The particle size of the first conductive particle can be from 10 nm to 400 nm, and the particle size of the second conductive particle can be from 1 μm to 5 μm.

[0145] The sum of the thicknesses of the first conductive layer and the second conductive layer can be from 4 μm to 10 μm, and the thickness of the first conductive layer can be from 1 μm to 6 μm.

[0146] The ratio of the thickness of the second conductive layer to the thickness of the first conductive layer can be from 1:0.3 to 1:1.

[0147] The first conductive layer may include a first conductive portion formed by sintering first conductive particles, and the second conductive layer may include a second conductive portion formed by sintering second conductive particles.

[0148] The second conductive portion may have a structure in which the second conductive particles contact each other to aggregate.

[0149] The second conductive portion may have a neck structure in the portion where the second conductive particles are in contact with each other.

[0150] The first conductive layer may include first conductive particles and resin, and the second conductive layer may include second conductive particles and resin.

[0151] Based on the total amount of the first conductive particles and the resin, the first conductive layer may include 10% to 30% by weight of the resin, and based on the total amount of the second conductive particles and the resin, the second conductive layer may include 20% to 40% by weight of the resin.

[0152] The first conductive layer can directly contact multiple signal lines, the side surface of the first substrate, and multiple connection lines, and the second conductive layer can cover the first conductive layer and can directly contact multiple signal lines and multiple connection lines.

[0153] The display device may also include a protective layer that covers the plurality of side lines and comprises a black material.

[0154] The protective layer can be formed as a single layer to surround the entire side surface of the first substrate and cover all of the multiple side lines, or it can be patterned to correspond to each of the multiple side lines.

[0155] The display device may further include: a second substrate disposed on the display unit opposite to the first substrate, wherein the first substrate may protrude outward from the second substrate, a plurality of signal lines may be disposed on the protruding first substrate, and a plurality of side lines may be configured to contact the exposed upper and side surfaces of the plurality of signal lines.

[0156] The display device may further include: a third substrate disposed below the first substrate, wherein multiple connecting lines may be disposed on the lower surface of the third substrate, and multiple side lines may be configured to cover the side surfaces of the multiple signal lines, the side surfaces of the first substrate, the side surfaces of the third substrate, and the side surfaces of the multiple connecting lines.

[0157] According to another aspect of this disclosure, a multi-panel display device includes: a plurality of display devices disposed adjacent to each other, wherein each of the plurality of display devices includes: a first substrate, the first substrate including a display area and a non-display area surrounding the display area; a display unit including an organic light-emitting diode disposed on an upper surface of the first substrate; a plurality of signal lines disposed on the upper surface of the first substrate and electrically connected to the display unit; a plurality of connecting lines disposed below the first substrate; a plurality of side lines disposed on a side surface of the first substrate and connecting the plurality of signal lines and the plurality of connecting lines; and a protective layer covering the plurality of side lines and comprising a black material, each of the plurality of side lines including: a first conductive layer disposed on a side surface of the first substrate and formed of first conductive particles; and a second conductive layer covering the first conductive layer and formed of second conductive particles with a particle size larger than that of the first conductive particles.

[0158] The particle size of the first conductive particle can be from 10 nm to 400 nm, and the particle size of the second conductive particle can be from 1 μm to 5 μm.

[0159] The combined thickness of the first conductive layer and the second conductive layer can be from 4 μm to 10 μm, and the thickness of the first conductive layer can be 1 μm or greater.

[0160] The ratio of the thickness of the second conductive layer to the thickness of the first conductive layer can be from 1:0.3 to 1:1.

[0161] The first conductive layer may include a first conductive portion formed by sintering first conductive particles, and the second conductive layer may include a second conductive portion formed by sintering second conductive particles.

[0162] The second conductive portion may have a structure in which the second conductive particles can contact each other to aggregate.

[0163] The second conductive portion may have a neck structure in the part where the second conductive particles can contact each other.

[0164] Each of the first conductive layer and the second conductive layer may further include resin. Based on the total amount of the first conductive particles and the resin, the first conductive layer may include 10% to 30% by weight of resin, and based on the total amount of the second conductive particles and the resin, the second conductive layer may include 20% to 40% by weight of resin.

[0165] 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 can 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 merely for illustrative purposes 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 appended claims, and all technical concepts within the equivalent scope thereof should be interpreted as falling within the scope of the present disclosure.

[0166] Cross-reference to related applications

[0167] This application claims priority to Korean Patent Application No. 10-2020-0114718, filed on September 8, 2020, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

Claims

1. A display device comprising: a first substrate including a display area and a non-display area surrounding the display area; a display unit including an organic light emitting diode disposed on an upper surface of the first substrate; a plurality of signal lines disposed on the upper surface of the first substrate and electrically connected to the display unit; a plurality of connection lines disposed under the first substrate, and a plurality of side lines disposed on a side surface of the first substrate and connecting the plurality of signal lines and the plurality of connection lines, each of the plurality of side lines includes: a first conductive layer disposed on the side surface of the first substrate and including first conductive particles; and a second conductive layer covering the first conductive layer and including second conductive particles having a particle size greater than that of the first conductive particles. The first conductive particles have a particle size of 10 nm to 400 nm, and the second conductive particles have a particle size of 1 µm to 5 µm.

2. The display device according to claim 1, wherein The sum of the thicknesses of the first conductive layer and the second conductive layer is 4 µm to 10 µm, and the thickness of the first conductive layer is 1 µm to 6 µm.

3. The display device according to claim 1, wherein The ratio of the thickness of the second conductive layer to the thickness of the first conductive layer is 1:0.3 to 1:

1.

4. The display device according to claim 1, wherein The first conductive layer includes a first conductive portion formed by sintering the first conductive particles, and the second conductive layer includes a second conductive portion formed by sintering the second conductive particles.

5. The display device according to claim 1, wherein The second conductive portion has a structure in which the second conductive particles contact each other to be aggregated.

6. The display device of claim 5, wherein, The second conductive portion has a neck structure in a portion in which the second conductive particles contact each other.

7. The display device of claim 6, wherein, The first conductive layer includes the first conductive particles and a resin, and the second conductive layer includes the second conductive particles and a resin.

8. The display device according to claim 1, wherein The first conductive layer includes 10 wt% to 30 wt% of the resin based on the total of the first conductive particles and the resin, and the second conductive layer includes 20 wt% to 40 wt% of the resin based on the total of the second conductive particles and the resin.

9. The display device of claim 8, wherein, The first conductive layer is in direct contact with the plurality of signal lines, the side surface of the first substrate, and the plurality of connection lines, and the second conductive layer covers the first conductive layer and is in direct contact with the plurality of signal lines and the plurality of connection lines.

10. The display device according to claim 1, wherein 11.The display device of claim 1, further comprising: a protective layer covering the plurality of side lines and including a black material. The protective layer is formed as one layer to surround all side surfaces of the first substrate and cover all of the plurality of side lines, or the protective layer is patterned to correspond to each of the plurality of side lines.

12. The display device of claim 11, wherein, 13.The display device of claim 1, further comprising: a second substrate disposed on the display unit to be opposite to the first substrate, ​ The first substrate protrudes outward from the second substrate, the plurality of signal lines are disposed on the protruding first substrate, and the plurality of side lines are disposed in contact with exposed upper surfaces and side surfaces of the plurality of signal lines. 14.The display device of claim 1, further comprising: a third substrate disposed below the first substrate, wherein the plurality of connection lines are disposed on a lower surface of the third substrate, and the plurality of side lines are disposed to cover side surfaces of the plurality of signal lines, side surfaces of the first substrate, side surfaces of the third substrate, and side surfaces of the plurality of connection lines. 15.A multi-panel display device comprising: a plurality of display devices disposed adjacent to each other, wherein each of the plurality of display devices comprises: a first substrate including a display area and a non-display area surrounding the display area; a display unit including an organic light emitting diode disposed on an upper surface of the first substrate; a plurality of signal lines disposed on the upper surface of the first substrate and electrically connected to the display unit; a plurality of connection lines disposed below the first substrate; a plurality of side lines disposed on side surfaces of the first substrate and connecting the plurality of signal lines and the plurality of connection lines; and a protective layer covering the plurality of side lines and including a black material, each of the plurality of side lines includes: a first conductive layer disposed on the side surface of the first substrate and including first conductive particles; and a second conductive layer covering the first conductive layer and including second conductive particles having a particle size greater than a particle size of the first conductive particles.

16. The multi-panel display apparatus of claim 15, wherein, The particle size of the first conductive particles is 10 nm to 400 nm, and the particle size of the second conductive particles is 1 µm to 5 µm.

17. The multi-panel display apparatus of claim 15, wherein, The sum of thicknesses of the first conductive layer and the second conductive layer is 4 µm to 10 µm, and the thickness of the first conductive layer is 1 µm or more.

18. The multi-panel display apparatus of claim 15, wherein, The ratio of the thickness of the second conductive layer to the thickness of the first conductive layer is 1:0.3 to 1:

1.

19. The multi-panel display apparatus of claim 15, wherein, The first conductive layer includes a first conductive portion formed by sintering the first conductive particles, and the second conductive layer includes a second conductive portion formed by sintering the second conductive particles.

20. The multi-panel display apparatus of claim 19, wherein, The second conductive portion has a structure in which the second conductive particles contact each other to be aggregated.

21. The multi-panel display apparatus of claim 20, wherein, The second conductive portion has a neck structure in a portion in which the second conductive particles contact each other.

22. The multi-panel display apparatus of claim 15, wherein, Each of the first conductive layer and the second conductive layer further includes a resin, the first conductive layer includes 10 wt% to 30 wt% of the resin based on the sum of the first conductive particles and the resin, and the second conductive layer includes 20 wt% to 40 wt% of the resin based on the sum of the second conductive particles and the resin.

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