CN114005359A - Display device and method for manufacturing the same - Google Patents

Abstract

A display device according to an embodiment includes: a display panel including a plurality of panel pads; a flexible circuit board including a plurality of coupling pads corresponding to the panel pads; and a bonding layer disposed between the display panel and the flexible circuit board, wherein the bonding layer includes a conductive portion disposed on the panel pad and including a first base portion and a plurality of conductive particles dispersed in the first base portion, and a non-conductive portion disposed between the coupling pads above the conductive portion and including a second base portion but not including the conductive particles, so that improved reliability can be achieved.

Description

Display device and method for manufacturing the same

Technical Field

The present invention relates to a display device and a method of manufacturing the same. More particularly, the present invention relates to a display device including a bonding layer bonding a display panel and a circuit board and having conductive particles, and a method of manufacturing the same.

Background

An electronic device such as a display device includes a plurality of circuit wirings and a plurality of electronic elements connected to the plurality of circuit wirings, and operates by being applied with an electric signal. The plurality of circuit wirings and the electronic component are electrically connected using a conductive bonding member. For example, a display panel, a circuit board, and the like of a display device are electrically connected using an Anisotropic Conductive Film (ACF) or the like.

In addition, as the display device requires high resolution, a bonding member for bonding high-precision circuit wiring is required.

Disclosure of Invention

Solves the technical problem

An object of the present invention is to provide a display device having improved reliability by controlling arrangement of a conductive portion and a non-conductive portion included in a bonding layer.

Further, it is another object of the present invention to provide a method of manufacturing a display device with improved reliability, the method including a step of forming a bonding layer including conductive portions and non-conductive portions having different arrangement characteristics in a region overlapping with a pad and a region not overlapping with the pad.

Solving means

An embodiment provides a display device including: a display panel including a plurality of panel pads; a flexible circuit board including a plurality of coupling pads corresponding to the panel pads; and a bonding layer disposed between the display panel and the flexible circuit board, wherein the bonding layer includes a conductive portion and a non-conductive portion, wherein the conductive portion is disposed on the panel pad and includes a first base portion and a plurality of conductive particles dispersed in the first base portion, and the non-conductive portion is disposed between the bonding pads above the conductive portion and includes a second base portion but does not include the conductive particles.

The non-conductive portion may be spaced apart from the panel pad.

The ratio of the thickness of the conductive portion to the non-conductive portion may be 1: 2 to 1: 5.

The bonding layer may include: an overlapping portion overlapping with the panel pad and the coupling pad corresponding to each other; and a non-overlapping portion that does not overlap the panel pad and the coupling pad.

The overlapping portion may include a conductive portion, and the non-overlapping portion may include a conductive portion disposed adjacent to the display panel and a non-conductive portion disposed on the conductive portion and spaced apart from the display panel.

The conductive portion included in the overlapping portion and the conductive portion included in the non-overlapping portion may be integrally arranged on the display panel, and in the non-overlapping portion, the non-conductive portion may be filled between the conductive portion and the flexible circuit board.

The distribution density of the conductive particles in the overlapping portion may be greater than the distribution density of the conductive particles in the non-overlapping portion.

The conductive particles included in the conductive portion may not overlap in the thickness direction.

The display device may further include: an input sensing part disposed on the display panel and including a plurality of sensing pads; a sensing flexible circuit board including sensing coupling pads corresponding to the sensing pads; and a sensing bonding layer disposed between the input sensing portion and the sensing flexible circuit board, and including a sensing conductive portion and a sensing non-conductive portion, wherein the sensing conductive part is disposed on the sensing pad and includes a first sensing base part and a plurality of sensing conductive particles dispersed in the first sensing base part, and a sensing non-conductive part disposed between the sensing bond pads above the sensing conductive part, the sensing non-conductive part including the second sensing base part, but not including the sensing conductive particles, wherein the sensing bonding layer further includes a sensing overlapping portion and a sensing non-overlapping portion, the sensing overlapping portion overlapping the sensing pad and the sensing coupling pad corresponding to each other, and the sensing non-overlapping portion does not overlap the sensing pad and the sensing connection pad, the sensing overlapping portion includes a sensing conductive portion, but does not include a sensing non-conductive portion, and the sensing non-overlapping portion includes a sensing conductive portion and a sensing non-conductive portion disposed on the sensing conductive portion.

Another embodiment provides a method of manufacturing a display device, the method including: a step of providing a flexible circuit board including a plurality of coupling pads on a first stage; a step of providing a preliminary bonding layer on the flexible circuit board; heating the first stage and bonding the flexible circuit board and the preliminary bonding layer at a first temperature; a step of providing a display panel including a plurality of panel pads on a second stage; a step of disposing the joined flexible circuit board and preliminary joining layer onto the provided display panel; and a step of bonding the display panel, the preliminary bonding layer, and the flexible circuit board, which are sequentially stacked, by pressing at a second temperature. The preliminary bonding layer includes a preliminary non-conductive portion and a preliminary conductive portion stacked on the preliminary non-conductive portion, and the step of providing the preliminary bonding layer includes: a step of arranging the preliminary bonding layer so that the preliminary nonconductive portion is adjacent to the coupling pad, and a step of arranging the bonded flexible circuit board and the preliminary bonding layer includes: a step of arranging the joined flexible circuit board and preliminary joining layer so that the preliminary conductive portion is adjacent to the panel pad.

The step of bonding the flexible circuit board with the preliminary bonding layer may include: a step of filling the preliminary non-conductive portion between the bonding pads.

At the first temperature, the viscosity of the preliminary non-conductive portion may be lower than the viscosity of the preliminary conductive portion.

The step of bonding the flexible circuit board and the preliminary bonding layer may include: heat is provided to the preliminary non-conductive portion adjacent to the flexible circuit board to reduce the viscosity of the preliminary non-conductive portion to a first viscosity and to cool the exposed preliminary conductive portion to maintain the viscosity of the preliminary conductive portion at a second viscosity higher than the first viscosity.

The preliminary conductive portion may include a first base resin and a plurality of conductive particles dispersed in the first base resin, and the preliminary non-conductive portion may include a second base resin, but may not include the conductive particles.

The first temperature may be equal to or higher than a glass transition temperature of the second base resin, and may be equal to or lower than a curing start temperature of the second base resin.

The second temperature may be higher than the curing start temperature of the first base resin and the second base resin.

The curing start temperature of the first base resin may be higher than the curing start temperature of the second base resin.

The viscosity of the first base resin may be higher than that of the second base resin at the same temperature.

The step of bonding the display panel, the preliminary bonding layer, and the flexible circuit board may include: a bonding layer forming step of forming a conductive portion adjacent to the display panel by curing the preliminary conductive portion, and forming a non-conductive portion spaced apart from the display panel and filled between the bonding pads by curing the preliminary non-conductive portion.

The step of bonding the display panel, the preliminary bonding layer, and the flexible circuit board may include: a step of pressing the preliminary bonding layer using a pressing jig arranged above the flexible circuit board; and a curing step of converting the preliminary bonding layer into a bonding layer by supplying heat to the pressing jig.

Advantageous effects

The display device according to an embodiment includes the bonding layer in which the non-conductive portion including no conductive particle is disposed in the region not overlapping with the pad, whereby improved reliability characteristics can be achieved.

A manufacturing method of a display device according to an embodiment includes a process of controlling an arrangement of a non-conductive portion provided in a bonding layer between a display panel and a circuit board, whereby a display device having excellent reliability also in a case of high resolution can be provided.

Drawings

Fig. 1 is a perspective view of a display device according to an embodiment.

Fig. 2 is an exploded perspective view of a display device according to an embodiment.

FIG. 3 is a plan view of a portion of a display device according to an embodiment.

Fig. 4 is an exploded perspective view illustrating a portion of a display device according to an embodiment.

Fig. 5 is a cross-sectional view illustrating a portion of a display device according to an embodiment.

Fig. 6 is a cross-sectional view illustrating a portion of a display device according to an embodiment.

Fig. 7 is a cross-sectional view illustrating a portion of a display device according to an embodiment.

Fig. 8 is a plan view illustrating a portion of a display device according to an embodiment.

Fig. 9 is a cross-sectional view illustrating a portion of a display device according to an embodiment.

Fig. 10 is a flowchart illustrating a method of manufacturing a display device according to an embodiment.

Fig. 11 is a flowchart illustrating a part of a method of manufacturing a display device according to an embodiment.

Fig. 12a to 12e are flowcharts schematically showing a step of a method of manufacturing a display device according to an embodiment, respectively.

Fig. 13 is a graph showing viscosity as a function of temperature.

Fig. 14 is an image showing a part of a display device according to an embodiment.

Description of reference numerals

DD: display device DP: display panel

AP: bonding layer FB-DP: flexible circuit board

DPD: panel pad CPD: connection pad

And (3) CP: conductive particles

Detailed Description

The present invention may take various forms and modifications, and specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. However, it is not intended to limit the present invention to the particular forms disclosed, but rather, the present invention is to be construed as including all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention.

In this specification, when a component (or a region, a layer, a portion, or the like) is referred to as being "on", "connected to", or "coupled to" another component, it means that it may be directly arranged on, connected or coupled to the other component, or a third component may be arranged therebetween.

In addition, in the present application, "directly disposed" may mean that there is no additional layer, film, region, plate, or the like between the portion of the layer, film, region, plate, or the like and the other portion. For example, "directly disposed" may mean disposed between two layers or members without using an additional member such as an adhesive member.

Like reference numerals denote like constituent elements. In addition, in the drawings, thicknesses, ratios, and sizes of constituent elements are exaggerated for effective description of technical contents.

"and/or" includes all of one or more combinations that can be defined by the associated structure.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one constituent element from another constituent element. For example, a first component may be named a second component, and similarly, a second component may also be named a first component, without departing from the scope of the invention. Unless the context clearly dictates otherwise, expressions in the singular include expressions in the plural.

Further, terms such as "below", "lower", "above", "upper", and the like are used to describe an association relationship between the structures shown in the drawings. The above terms are relative concepts, and are described with reference to the directions shown in the drawings. In this specification, when it is referred to as "disposed on … …", it may mean both of the case of being disposed above and below a certain member.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, terms such as those defined in commonly used dictionaries should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will be interpreted as having a meaning that is expressly defined herein unless an ideal or excessively formal meaning is interpreted.

It will be understood that terms such as "including" or "having," etc., are intended to specify the presence of stated features, quantities, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, steps, operations, elements, components, or combinations thereof.

Hereinafter, a display device according to an embodiment of the present invention and a method of manufacturing the display device according to an embodiment will be described with reference to the accompanying drawings.

Fig. 1 is a perspective view of a display device according to an embodiment. Fig. 2 is an exploded perspective view of a display device according to an embodiment. FIG. 3 is a plan view of a portion of a display device according to an embodiment. FIG. 4 is an exploded perspective view of a portion of a display device according to an embodiment.

The display device DD may be a device that is activated in response to an electrical signal. The display device DD may include various embodiments. For example, the display device DD may be a personal computer, a notebook computer, a personal digital terminal, a vehicle navigation unit, a game machine, a smart phone, a tablet computer, a camera, or the like. Further, these are shown only as examples, and other display devices may be employed without departing from the concept of the present invention. In the present embodiment, the display device DD is exemplified as a smartphone.

In addition, the first direction axis DR1, the second direction axis DR2, and the third direction axis DR3 are shown in fig. 1 and the following drawings, and the directions indicated by the first direction axis DR1, the second direction axis DR2, and the third direction axis DR3 described in this specification are opposite concepts, and may be changed to other directions.

In this specification, for convenience of description, the direction of the third direction axis DR3 is defined as a direction in which an image is provided to a user. In addition, the first and second direction axes DR1 and DR2 may be perpendicular to each other, and the third direction axis DR3 may be a normal direction with respect to a plane defined by the first and second direction axes DR1 and DR 2.

The display device DD according to an embodiment may include a display panel DP, a panel driving part DP-M including a flexible circuit board FB-DP, and a bonding layer AP. The display device DD according to an embodiment may include: a display panel DP including a plurality of panel pads DPD; a flexible circuit board FB-DP including a plurality of connection pads CPD corresponding to the panel pads DPD; and a bonding layer AP disposed between the display panel DP and the flexible circuit board FB-DP. In addition, the display device DD according to an embodiment may further include an input sensing part ISU and a sensing driving part TP-M. The display device DD according to an embodiment may include a window WP and a case HAU, and the window WP and the case HAU may be combined to constitute an appearance of the display device DD.

Unlike the illustration in the drawings, the input sensing part ISU and the sensing driving part TP-M in the display device DD according to an embodiment may be omitted. In addition, unlike the illustration, the input sensing part ISU may be directly disposed on the display panel DP, and may be provided integrally with the display panel DP.

In an embodiment, the display device DD may display the image IM in a direction toward the third direction axis DR3 on a display surface FS parallel to a plane defined by the first direction axis DR1 and the second direction axis DR 2. The display surface FS displaying the image IM may correspond to a front surface of the display device DD, and may correspond to a front surface of the window WP. Hereinafter, the same reference numerals are used for the display surface, the front surface of the display device DD, and the front surface of the window WP. The image IM may include not only a dynamic image but also a still image. In fig. 1, the clock window and the application icon are shown as an example of the image IM.

In the display device DD according to an embodiment, the window WP may include an optically transparent insulating substance. The window WP may include a transmission area TA and a bezel area BZA. The front surface FS of the window WP including the transmissive area TA and the bezel area BZA corresponds to the front surface FS of the display device DD. The user can see an image IM provided through the transmissive area TA corresponding to the front surface FS of the display device DD.

The transmissive area TA may be an optically transparent area. The bezel area BZA may be an area having a relatively lower light transmittance than the transmissive area TA. The bezel area BZA may have a predetermined color. The bezel area BZA may be adjacent to the transmission area TA, and may surround the transmission area TA. The bezel area BZA may define the shape of the transmission area TA. However, the embodiment is not limited to the illustration, and the bezel area BZA may be disposed only on one side of the transmission area TA, or a part of the bezel area BZA may be omitted.

The display panel DP may be disposed below the window WP. In this specification, "below" may refer to a direction opposite to a direction in which the display panel DP provides an image.

In one embodiment, the display panel DP may be a structure that substantially generates the image IM. The image IM generated by the display panel DP IS displayed on the panel display surface IS and externally viewed by the user through the transmissive area TA.

In the display device DD according to an embodiment, the display panel DP may be a liquid crystal display panel or a light emitting type display panel. For example, the display panel DP may be a liquid crystal display panel including a liquid crystal element, an organic electroluminescence display panel including an organic electroluminescence element, a quantum dot light display panel including a quantum dot light emitting element, or the like. However, the embodiments are not limited thereto.

The display panel DP may include a display area DA and a non-display area NDA. In an embodiment, a display element such as a liquid crystal element, an organic electroluminescence element, or a quantum dot light emitting element may be arranged in the display area DA of the display panel DP.

The display panel DP includes a panel display surface IS having a display area DA and a non-display area NDA. The display area DA may be an area activated according to an electric signal. The non-display area NDA may be an area covered by the bezel area BZA. The non-display area NDA is adjacent to the display area DA. The non-display area NDA may surround the display area DA. A driving circuit or a driving wiring or the like for driving the display area DA may be arranged in the non-display area NDA. The panel pad area DPA may be disposed in the non-display area NDA.

The display panel DP may include a base substrate BS and a display layer DP-EL disposed on the base substrate BS. For example, when the display panel DP is a light-emitting type display panel, the display layer DP-EL may include a light-emitting element layer (not shown) and an encapsulation layer (not shown).

The base substrate BS may be a member providing a base surface for arranging the display layers DP-EL. The base substrate BS may be a glass substrate, a metal substrate, a plastic substrate, or the like. However, the embodiment is not limited thereto, and the base substrate BS may be an inorganic layer, an organic layer, or a composite material layer. The base substrate BS may be a flexible substrate that can be easily bent or folded.

For example, the base substrate BS may be a transparent glass substrate or a transparent polyimide substrate. Further, unlike this, the base substrate BS may be an opaque polyimide substrate.

The plurality of panel pads DPD may be disposed in the non-display area NDA of the display panel DP. The plurality of panel pads DPD may be arranged to be spaced apart from each other in the panel pad area DPA. Although in fig. 3 and 4 and the like, it is illustrated that the plurality of panel pads DPD are aligned in a row along the first direction axis DR1 and spaced apart at a constant interval, the embodiment is not limited thereto. For example, the plurality of panel pads DPD may be arranged in a plurality of columns (i.e., two or more columns) and aligned. In addition, the interval pitches between the plurality of panel pads DPD may be different from each other, or the plurality of panel pads DPD may be arranged to be aligned in the diagonal direction so as to have different inclination angles from each other with respect to the second direction axis DR 2.

The panel pad DPD may be connected to the display connection wiring DCL to be electrically connected to a circuit layer (not shown) of the display panel DP. A circuit layer (not shown) may be disposed on the base substrate BS, and may include switching transistors and driving transistors and the like for driving a plurality of display elements included in the display layers DP-EL.

The display device DD may include a panel driving part DP-M. The panel driving part DP-M may include a flexible circuit board FB-DP. The flexible circuit board FB-DP may be disposed at one side of the display panel DP. However, the embodiments are not limited thereto.

In addition, although not shown in the drawings, the panel driving part DP-M may be arranged to be bent toward a lower surface side of the display panel DP. The panel driving part DP-M may be bent toward a lower surface side of the display panel DP and accommodated in the case HAU.

The flexible circuit board FB-DP may include a plurality of connection pads CPD. The flexible circuit board FB-DP may include a base film BF and a plurality of connection pads CPD disposed on the base film BF. The base film BF may be formed of a flexible substance (e.g., polyimide).

The flexible circuit board FB-DP may include a landing pad area CPA. The plurality of coupling pads CPD may be arranged in the coupling pad area CPA to correspond to the plurality of panel pads DPD, respectively.

Referring to fig. 3 and 4, etc., in the display device DD according to an embodiment, the panel driving part DP-M may include a flexible circuit board FB-DP and a panel driving board MB-DP. The flexible circuit board FB-DP may be disposed between the display panel DP and the panel driving boards MB-DP, and electrically coupled to the display panel DP and the panel driving boards MB-DP.

The panel driving part DP-M may include a driving chip IC. The driving chip IC may be mounted on the flexible circuit board FB-DP. The driving chip IC may be coupled to the signal line CL of the flexible circuit board FB-DP to be electrically connected to the display panel DP. The driver chip IC may generate or process various electrical signals. The flexible circuit board FB-DP may also be referred to as a Chip On Film (COF).

The flexible circuit board FB-DP may be electrically and physically bonded to the display panel DP through the bonding layer AP. The bonding layer AP may be disposed between the display panel DP and the flexible circuit board FB-DP. Further, the display device DD according to an embodiment may include a driving bonding layer M-AP electrically and physically bonding the flexible circuit board FB-DP and the panel driving board MB-DP. The panel driving boards MB to DP may include a driving pad area MPA. The plurality of driving pads MPD may be arranged in the driving pad area MPA of the panel driving boards MB to DP. The driving bonding layer M-AP may bond the driving pad MPD and the coupling pads CPD respectively disposed corresponding to the driving pad MPD to each other.

The bonding layer AP may be disposed between the panel pad area DPA and the coupling pad area CPA. That is, the bonding layer AP may be disposed between the panel pad DPD and the coupling pad CPD, which face each other and are disposed correspondingly.

Fig. 5 and 6 are sectional views of a display device according to an embodiment, respectively. Fig. 5 is a sectional view showing a portion corresponding to a line I-I 'of fig. 3, and fig. 6 is a sectional view showing a portion AA' of fig. 5.

Referring to fig. 5 and 6, the bonding layer AP is disposed between the display panel DP and the flexible circuit board FB-DP. The bonding layer AP according to an embodiment may include conductive portions AC and non-conductive portions NC. The non-conductive part NC may be provided to be stacked on the conductive part AC. In an embodiment, the non-conductive part NC of the bonding layer AP may be disposed on the conductive part AC and spaced apart from the display panel DP.

The conductive part AC may include a first base part RS1 and a plurality of conductive particles CP, wherein the conductive particles CP may be dispersed in the first base part RS 1. The first base part RS1 may be filled between the conductive particles CP.

The non-conductive part NC may include the second base part RS 2. The non-conductive part NC may be a portion including the second base part RS2 but not including the conductive particles CP.

The conductive particles CP included in the bonding layer AP may be metal particles or alloy particles mixed with a plurality of metals, or the like. For example, the conductive particles CP may be metal including at least one of silver, copper, bismuth, zinc, indium, tin, nickel, cobalt, chromium, and iron or alloy particles including at least two metals selected from silver, copper, bismuth, zinc, indium, tin, nickel, cobalt, chromium, and iron. Further, the conductive particle CP may also include a coating layer having a core portion formed of a polymer resin or the like and a conductive substance surrounding the core portion.

The first base part RS1 and the second base part RS2 of the junction layer AP may each include at least one of an acrylic polymer, a silicon-based polymer, a polyurethane-based polymer, an epoxy-based polymer, and an imide-based polymer. For example, the first base part RS1 and the second base part RS2 may each independently include any one polymer substance selected from an acrylic polymer, a silicon-based polymer, a polyurethane-based polymer, an epoxy-based polymer, and an imide-based polymer, or a combination of selected plural polymer substances. The first base portion RS1 and the second base portion RS2 may be each formed of an acrylic resin, a silicon-based resin, a polyurethane-based resin, an epoxy-based resin, or an imide-based resin. For example, each of the first base portion RS1 and the second base portion RS2 may be a portion formed by heat curing or light curing a base resin such as an acrylic resin, a silicon resin, a polyurethane resin, an epoxy resin, or an imide resin.

The first base part RS1 and the second base part RS2 may be formed of different kinds of resin materials from each other. Further, the first base part RS1 and the second base part RS2 may be formed of the same kind of resin material, or of mixed materials having different molecular weights, different types of additives added, or different contents of additives added from each other. For example, the first base part RS1 and the second base part RS2 may be formed of epoxy-based resins having different molecular weights.

Alternatively, the first base part RS1 and the second base part RS2 may be formed of resin materials having viscosity values different from each other. For example, the viscosity of the resin material forming the first base part RS1 may be greater than the viscosity of the resin material forming the second base part RS2 under the same temperature condition in the temperature range of 50 ℃ to 100 ℃.

In an embodiment, the modulus values of the first and second base parts RS1 and RS2 may be different from each other under the same temperature condition. For example, the modulus value of the first base part RS1 may be greater than the modulus value of the second base part RS2 under the same temperature condition in the temperature range of 50 ℃ to 100 ℃.

In the display device DD according to an embodiment shown in fig. 5 and 6, the non-conductive part NC may be disposed above the conductive part AC. The non-conductive part NC may be disposed between the coupling pads CPD above the conductive part AC.

The non-conductive part NC may be disposed on the conductive part AC disposed between the non-conductive part NC and the display panel DP, and may be spaced apart from the display panel DP. For example, the non-conductive part NC may be spaced apart from the panel pad DPD.

In an embodiment, the conductive portions AC of the bonding layer AP may be arranged as a single layer on the display panel DP, and the non-conductive portions NC may be spaced apart from the display panel DP on the conductive portions AC and filled between the coupling pads CPD.

In an embodiment, the thickness of the non-conductive portion NC of the bonding layer AP may be greater than the thickness of the conductive portion AC. In addition, in the present specification, the thickness indicates the length in the direction of the third direction axis DR3, and the thicknesses of the non-conductive part NC and the conductive part AC indicate the length in the direction of the third direction axis DR3 between the display panel DP and the flexible circuit board FB-DP.

Thickness t of conductive part AC_AThickness t of non-conductive part NC_NThe ratio of (A) to (B) may be from 1: 2 to 1: 5. In addition, the thickness t of the conductive part AC_AAnd thickness t of non-conductive part NC_NThe average value of the thickness can be expressed. In the present specification, the thickness t of the conductive portion AC_AThe thickness t of the non-conductive part NC is the average thickness of the conductive part AC of the entire bonding layer AP_NThe average thickness of the non-conductive portion NC of the entire bonding layer AP is shown.

For example, in one embodiment, the thickness t of the conductive portion AC_AMay be about 4 μm or less, the thickness t of the non-conductive portion NC_NAnd may be about 10 μm or more. However, the embodiments are not limited thereto.

The attachment layer AP may include an overlapping portion AP-O and a non-overlapping portion AP-NO. The overlapping portion AP-O is a portion overlapping with the panel pad DPD and the coupling pad CPD, and the non-overlapping portion AP-NO is a portion not overlapping with both the panel pad DPD and the coupling pad CPD. In the bonding layer AP, the overlapping portion AP-O corresponds to a region overlapping with the opposing panel pad DPD and the coupling pad CPD. In the overlapping portion AP-O, the conductive particles CP are fixed between the corresponding panel pad DPD and the coupling pad CPD, and are electrically connected to the panel pad DPD and the coupling pad CPD. The non-overlapping portion AP-NO may be a portion disposed between the overlapping portions AP-O. Referring to fig. 5 and 6, the bonding layer AP may include overlapping portions AP-O and non-overlapping portions AP-NO alternately arranged in the direction of the first direction axis DR 1.

In the display device DD according to an embodiment, the overlapping portion AP-O may include the conductive portion AC, and the non-overlapping portion AP-NO may include the conductive portion AC and the non-conductive portion NC. In the non-overlapping portion AP-NO, the conductive portion AC may be disposed adjacent to the display panel DP, and the non-conductive portion NC may be disposed spaced apart from the display panel DP on the conductive portion AC so as not to contact the panel pad DPD.

For example, in the display device DD according to an embodiment, the bonding layer AP may be divided into an overlapping portion AP-O and a non-overlapping portion AP-NO. In an embodiment, the overlapping portion AP-O may include a conductive portion AC disposed between the panel pad DPD and the coupling pad CPD, and may not include a non-conductive portion NC, and the non-overlapping portion AP-NO may include the conductive portion AC and the non-conductive portion NC sequentially stacked between the display panel DP and the flexible circuit board FB-DP.

The conductive part AC included in the overlapping part AP-O and the conductive part AC included in the non-overlapping part AP-NO may be integrally disposed on the display panel DP. For example, the conductive part AC included in the overlapping part AP-O and the conductive part AC included in the non-overlapping part AP-NO may be directly arranged in a single layer on the display panel DP.

Further, in the non-overlapping section AP-NO, the non-conductive section NC may be filled between the conductive section AC and the flexible circuit board FB-DP.

The conductive particles CP included in the conductive part AC may not overlap in the thickness direction. In the bonding layer AP according to an embodiment, the conductive particles CP included in the conductive portions AC are dispersedly arranged on a plane parallel to a plane defined by the first direction axis DR1 and the second direction axis DR2, and are not stacked along the third direction axis DR 3. For example, the thickness of the overlap AP-O defined by the spacing between the panel pad DPD and the coupling pad CPD may be substantially the same as the diameter of the conductive particles CP disposed between the panel pad DPD and the coupling pad CPD, or the thickness of the overlap AP-O may be less than or equal to the diameter of the conductive particles CP disposed between the panel pad DPD and the coupling pad CPD.

The overlapping portion AP-O of the bonding layer AP has the conductive portion AC including the conductive particles CP, and the non-overlapping portion AP-NO has both the conductive portion AC including the conductive particles CP and the non-conductive portion NC not including the conductive particles CP, and therefore, the distribution density of the conductive particles CP in the bonding layer AP in the overlapping portion AP-O may be greater than the distribution density of the conductive particles CP in the bonding layer AP in the non-overlapping portion AP-NO.

In addition, although not shown, the difference in the distribution density of the conductive particles CP in the overlapping portion AP-O and the non-overlapping portion AP-NO may not be large when viewed on the plane defined by the first direction axis DR1 and the second direction axis DR 2. That is, in the non-overlapping portion AP-NO including the non-conductive portion NC, since the non-conductive portion NC is filled between the conductive portion AC and the flexible circuit board FB-DP, thereby restricting the movement of the conductive particles CP, the distribution densities of the conductive particles CP in the overlapping portion AP-O and the non-overlapping portion AP-NO may not be different similarly to the distribution density of the conductive particles CP when the bonding layer AP is initially provided.

In an embodiment, the thickness of the coupling pad CPD may be greater than that of the panel pad DPD. For example, the thickness t of the panel pad DPD_DPCan be about 0.5 μm to 0.6 μm, and the thickness t of the bonding pad CPD_CPMay be about 8 μm. + -. 1 μm. However, the thickness t of the panel pad DPD_DPAnd thickness t of connection pad CPD_CPThe numerical values of (a) are not limited to the examples.

In an embodiment, since the thickness of the coupling pad CPD provided is greater than that of the panel pad DPD, the non-conductive part NC having a relatively thick thickness in the bonding layer AP may be provided to the coupling pad CPD side. The non-conductive part NC having a relatively thick thickness is filled and disposed between the bonding pads CPD such that the non-conductive part NC restricts the flow of the conductive part AC, so that it is possible to minimize the case where the conductive particles CP of the conductive part AC move and are disposed between the bonding pads CPD.

Accordingly, the display device according to an embodiment may include a display panel, a flexible circuit board, and a bonding layer disposed between the display panel and the flexible circuit board, and the bonding layer may include a non-conductive portion disposed between the coupling pads of the flexible circuit board, whereby a situation in which conductive particles are disposed between the coupling pads may be minimized, and thus a characteristic of reducing a short-circuit phenomenon that may occur due to coupling of the coupling pads and the conductive particles may be achieved.

In an embodiment shown in fig. 5 and 6, the boundary IFL between the conductive portion AC and the non-conductive portion NC may be located at the same height level as the bottom surface CPD-BT of the coupling pad CPD. However, the embodiments are not limited thereto.

Fig. 7 is a sectional view illustrating a portion AA '-1 of the display device according to an embodiment, and it corresponds to a portion corresponding to the area AA' of fig. 6. The portion AA' -1 of the display device shown in fig. 7 is different from that of fig. 6 only in the position of the boundary IFL between the conductive portion AC and the non-conductive portion NC and the cross-sectional form of the boundary IFL portion.

Referring to fig. 7, in an embodiment, the positions of the boundaries IFL between the conductive parts AC and the non-conductive parts NC may be randomly formed. The boundary IFL between the conductive portion AC and the non-conductive portion NC may be located at an upper side with respect to the bottom surface CPD-BT of the coupling pad CPD or at a lower side with respect to the bottom surface CPD-BT. However, even in this case, the average thickness of the non-conductive part NC may be greater than that of the conductive part AC, and most of the space between the joining pads CPD may be filled with the non-conductive part NC.

In addition, the description of the bonding layer AP described with reference to fig. 5 to 7 and the like may be equally applied to the driving bonding layer M-AP. That is, among the conductive particles CP included in the driving bonding layer M-AP, the movement of the conductive particles CP in the region not overlapping the driving pad MPD is restricted by the non-conductive part NC filled between the coupling pads CPD, so that it is possible to minimize a short defect in the region not overlapping the driving pad MPD and the coupling pad CPD.

Fig. 8 is a plan view illustrating a portion of a display device according to an embodiment. Fig. 8 illustrates an input sensing part ISU and a sensing driving part TP-M included in a display device DD (fig. 2) according to an embodiment. Fig. 9 is a sectional view of a portion corresponding to line II-II' of fig. 8.

Referring to fig. 2, 8 and 9, in the display device DD according to an embodiment, the input sensing part ISU may be provided as a separate element on the display panel DP. However, unlike the illustration, the input sensing part ISU may be directly disposed on the display panel DP.

The input sensing part ISU may obtain the location or intensity information of the external input TC by sensing the external input TC (fig. 1). For example, the external input TC may include various forms of external input, such as a portion of a user's body, light, heat, or pressure. In addition, the input sensing part ISU may also sense an input in contact with the input sensing part ISU and an input close to or adjacent to the input sensing part ISU.

The input sensing part ISU may include a sensing area SA and a non-sensing area NSA. The sensing area SA may overlap the display area DA. The non-sensing area NSA is adjacent to the sensing area SA. The non-sensing area NSA may surround an edge of the sensing area SA. However, this is merely exemplary and the non-sensing area NSA may be adjacent to only a portion of the edge of the sensing area SA, or the non-sensing area NSA may be omitted, but is not limited to a certain embodiment.

The input sensing part ISU may include a plurality of sensing electrodes Tx and Rx, a plurality of sensing wires SL, and a plurality of sensing pads TPD. That is, the input sensing part ISU may include a plurality of first sensing electrodes Tx (hereinafter, referred to as first sensing electrodes), a plurality of second sensing electrodes Rx (hereinafter, referred to as second sensing electrodes), a plurality of first sensing wirings TL (hereinafter, referred to as first sensing wirings), a plurality of second sensing wirings RL (hereinafter, referred to as second sensing wirings), and a sensing pad TPD electrically connected to the first and second sensing wirings TL and RL.

The first and second sensing electrodes Tx and Rx may be disposed in the sensing region SA. The input sensing part ISU may obtain information about the external input TC through a change in mutual capacitance between the first and second sensing electrodes Tx and Rx.

Each of the first sensing electrodes Tx may include a plurality of first portions Tx-a (hereinafter, referred to as first portions) and second portions Tx-b defined between the first portions Tx-a adjacent to each other among the first portions Tx-a. The first portion Tx-a may be referred to as a sensing portion and the second portion Tx-b may be referred to as a connection portion or a crossing portion.

The first and second portions Tx-a and Tx-b may have an integral shape connected to each other. Accordingly, the second portion Tx-b may be defined as a portion of the first sensing electrode Tx crossing the second sensing electrode Rx. The first portion Tx-a and the second portion Tx-b may be disposed on the same layer as each other.

Each of the second sensing electrodes Rx may include a plurality of sensing patterns Rx-a (hereinafter, referred to as sensing patterns) and bridge patterns Rx-b electrically connected to two sensing patterns Rx-a adjacent to each other among the sensing patterns Rx-a. The sensing pattern Rx-a and the bridge pattern Rx-b may be arranged on different layers from each other. Although fig. 8 illustrates a case where the number of bridge patterns Rx-b connecting two sensing patterns Rx-a is 2, the number of bridge patterns Rx-b may be 1, or may be 3 or more.

The first and second portions Tx-a and Tx-b may be disposed on the same layer as the sensing pattern Rx-a. The layer in which the bridge pattern Rx-b is disposed may be a different layer from the layer in which the first portion Tx-a, the second portion Tx-b, and the sensing pattern Rx-a are disposed. However, as long as the bridge pattern Rx-b and the second portion Tx-b are disposed on different layers from each other, there is no particular limitation.

Each of the first and second sensing electrodes Tx and Rx may be electrically connected to a corresponding sensing wiring SL of the first and second sensing wirings TL and RL. For example, one first sensing electrode Tx may be connected to one first sensing wiring TL. One second sensing wiring RL may be electrically connected to one second sensing electrode Rx. However, the connection relationship of the first sensing electrode Tx or the second sensing electrode Rx with respect to the first and second sensing wirings TL and RL is not limited to the illustrated example. For example, one first sensing electrode Tx may be connected to two first sensing wirings TL. One first sensing wiring TL may be electrically connected to one end of the first sensing electrode Tx, and the other first sensing wiring TL may be electrically connected to the other end of the first sensing electrode Tx.

In addition, the shapes of the sensing electrodes Tx and Rx, the number of the sensing electrodes Tx and Rx, and the connection relationship of the sensing wiring SL shown in fig. 8 are only examples, and the embodiment is not limited thereto.

The sensing electrodes Tx and Rx may be disposed in the sensing area SA, and the sensing pad TPD may be disposed in the non-sensing area NSA. The sensing pad TPD may be disposed adjacent to one side end of the input sensing part ISU.

The sensing wiring SL may be connected to the sensing electrodes Tx and Rx, and may extend to the non-sensing region NSA to be connected to the sensing pad TPD. The sensing pad TPD may be connected to a sensing driving board MB-TP for driving the input sensing part ISU through a sensing flexible circuit board FB-TP.

The sensing electrodes Tx and Rx and the sensing wiring SL may be provided on the sensing base substrate BS-T. The sensing base substrate BS-T may be a glass substrate, a metal substrate, a plastic substrate, or the like. However, the embodiment is not limited thereto, and the sensing base substrate BS-T may be an inorganic layer, an organic layer, or a composite material layer.

In addition, when the input sensing part ISU is directly disposed on the display panel DP, the sensing base substrate BS-T may be omitted. In this case, the sensing electrodes Tx and Rx and the sensing wiring SL may be directly disposed on the display panel DP.

The sensing driving part TP-M may include a sensing flexible circuit board FB-TP and a sensing driving board MB-TP. Further, the sensing junction layer T-AP may be disposed between the input sensing part ISU and the sensing flexible circuit board FB-TP. The sensing flexible circuit board FB-TP may be disposed at one side of the input sensing part ISU, and may include sensing coupling pads CPD-T corresponding to the plurality of sensing pads TPD. The sensing flexible circuit board FB-TP may include a base film BF-T and a plurality of sensing connection pads CPD-T provided on one surface of the base film BF-T.

The sensing bonding layer T-AP may be disposed between the sensing pad TPD and the sensing coupling pad CPD-T. For the sensing junction layer T-AP, the same contents as those described above for the junction layer AP may be applied.

That is, the sensing junction layer T-AP may include conductive portions AC and non-conductive portions NC. The conductive part AC may include the first base part RS1 and the conductive particles CP, and the non-conductive part NC may include the second base part RS2 but not the conductive particles CP. Further, the sensing bonding layer T-AP may include an overlapping portion AP-O overlapping the sensing pad TPD and the sensing coupling pad CPD-T corresponding to each other and a non-overlapping portion AP-NO not overlapping the sensing pad TPD and the sensing coupling pad CPD-T.

In an embodiment, the non-conductive part NC of the sensing bonding layer T-AP is disposed between the sensing bonding pads CPD-T above the conductive part AC to restrict movement of the conductive particles CP of the conductive part AC, thereby improving a short circuit problem due to contact of the sensing bonding pads CPD-T and the conductive particles CP.

A display device according to an embodiment includes a bonding layer including a non-conductive portion disposed between the coupling pads to minimize the conductive particles from being disposed between the coupling pads, thereby achieving a characteristic of improving a short defect between the conductive particles and the coupling pads. Furthermore, even in a high-resolution display device in which the spacing distance (i.e., Pitch; Pitch) between adjacent pads is reduced, excellent reliability can be achieved by including a bonding layer that minimizes the placement of conductive particles between the coupling pads.

Hereinafter, a method of manufacturing a display device according to an embodiment will be described with reference to fig. 10 to 13 and the like. In the manufacturing method of the display device according to an embodiment described below, the content overlapping with the above description of the display device according to an embodiment is not described again, and the differences will be mainly described.

Fig. 10 and 11 are flowcharts respectively illustrating a method of manufacturing a display device according to an embodiment. Fig. 12a to 12e are views schematically showing a part of steps corresponding to those of the method of manufacturing a display device according to an embodiment shown in fig. 10 and 11, respectively. FIG. 13 is a graph showing the change in viscosity with temperature.

A method of manufacturing a display device according to an embodiment may include: a step S100 of providing a flexible circuit board including a plurality of coupling pads; a step S200 of providing a preliminary bonding layer on the flexible circuit board; a step S300 of bonding the flexible circuit board and the preliminary bonding layer; a step S400 of providing a display panel including a plurality of panel pads; a step S500 of disposing the joined flexible circuit board and preliminary joining layer onto the display panel; and a step S600 of bonding the display panel, the preliminary bonding layer, and the flexible circuit board. Further, the step S600 of bonding the display panel, the preliminary bonding layer, and the flexible circuit board may include a step S610 of pressurizing the preliminary bonding layer using a pressurizing jig and a curing step S620 of converting the preliminary bonding layer into a bonding layer.

Fig. 12a schematically shows a step S100 of providing a flexible circuit board comprising a plurality of bond pads and a step S200 of providing a preliminary bonding layer on the flexible circuit board.

The flexible circuit board FB-DP including a plurality of bonding pads CPD may be disposed on the first stage ST, and the preliminary bonding layer P-AP may be disposed on the bonding pads CPD of the flexible circuit board FB-DP. The preliminary bonding layer P-AP may include a preliminary conductive portion P-AC and a preliminary non-conductive portion P-NC. The preliminary conductive part P-AC may be distinguished from the preliminary non-conductive part P-NC, and the preliminary conductive part P-AC may be stacked on the preliminary non-conductive part P-NC while being spaced apart from the connection pad CPD. The thickness of the preliminary non-conductive portion P-NC may be greater than the thickness of the preliminary conductive portion P-AC. The contents regarding the thickness ratio of the non-conductive portions NC and the conductive portions AC described with reference to fig. 6 may be equally applied to the description of the thickness ratio of the preliminary non-conductive portions P-NC and the preliminary conductive portions P-AC. For example, the thickness ratio of the preliminary conductive portion P-AC to the preliminary non-conductive portion P-NC may be 1: 2 to 1: 5.

In addition, in this specification, the preliminary bonding layer P-AP refers to a state before transition to the final bonding layer AP that bonds the display panel DP and the flexible circuit board FB-DP to each other. In addition, the preliminary conductive portions P-AC and the preliminary non-conductive portions P-NC also indicate states before transition to the conductive portions AC and the non-conductive portions NC, respectively. Further, in the present specification, the upper surfaces of the first stage ST, the second stage B-ST, and the like may be parallel to a plane defined by the X axis (X) and the Y axis (Y). The Z axis (Z) may represent a normal direction with respect to a plane defined by the X axis (X) and the Y axis (Y).

In an embodiment, the preliminary conductive part P-AC may include a first base resin PS1 and a plurality of conductive particles CP, wherein the conductive particles CP are dispersed in the first base resin PS 1. The first base resin PS1 may be filled between the conductive particles CP.

The preliminary non-conductive portion P-NC may include the second base resin PS 2. The preliminary non-conductive portion P-NC may be composed of the second base resin PS2, and may be a portion excluding the conductive particles CP.

The conductive particles CP dispersed in the first base resin PS1 may be metal particles or alloy particles mixed with a plurality of metals, or the like. For example, the conductive particles CP may be metal including at least one of silver, copper, bismuth, zinc, indium, tin, nickel, cobalt, chromium, and iron or alloy particles including at least two metals selected from silver, copper, bismuth, zinc, indium, tin, nickel, cobalt, chromium, and iron. Further, the conductive particle CP may also have a core portion formed of a polymer resin or the like and a coating layer of a conductive substance surrounding the core portion.

The first base resin PS1 and the second base resin PS2 may each include at least one of an acrylic resin, a silicon-based resin, a polyurethane-based resin, an epoxy-based resin, and an imide-based resin. The first base resin PS1 and the second base resin PS2 may include different kinds of resin materials from each other. Further, unlike this, the first base resin PS1 and the second base resin PS2 may be the same kind of resin material or have different molecular weights. Alternatively, the first base resin PS1 and the second base resin PS2 may include resin materials of the same kind, and the kinds of additives added may be different from each other, or the contents of additives added may be different from each other.

The first base resin PS1 and the second base resin PS2 may have different viscoelasticity from each other. Under the same temperature condition, the viscosity of the first base resin PS1 may be higher than that of the second base resin PS 2. Further, the curing start temperature of the first base resin PS1 may be higher than that of the second base resin PS 2.

Fig. 13 is a graph showing viscosity as a function of temperature. In fig. 13, the viscosity change according to the temperatures of the preliminary bonding layer P-AP, the preliminary conductive portion P-AC, and the preliminary non-conductive portion P-NC is shown.

Referring to fig. 13, the viscosities of the preliminary bonding layer P-AP, the preliminary conductive portions P-AC, and the preliminary non-conductive portions P-NC decrease with an increase in temperature, and at a predetermined temperature or higher, the viscosities of the preliminary bonding layer P-AP, the preliminary conductive portions P-AC, and the preliminary non-conductive portions P-NC increase again. The temperature at which the viscosity begins to increase again can be considered asCorresponding to near the cure initiation temperature. For example, the temperature T at the point where the viscosity of the preliminary nonconductive portion P-NC increases again_NCMay correspond to the curing start temperature of the second base resin PS2 and the temperature T at the point where the viscosity of the preliminary conductive portion P-AC is increased again_ACMay correspond to the curing start temperature of the first base resin PS 1. For example, in one embodiment shown in fig. 13, the curing start temperature of the second base resin PS2 may be about 94 ℃, and the curing start temperature of the first base resin PS1 may be about 97 ℃. However, the embodiments are not limited thereto. The curing start temperature of the second base resin PS2 and the curing start temperature of the first base resin PS1 may vary depending on the material composition of the respective base resins. However, the curing start temperature of the first base resin PS1 may be maintained higher than that of the second base resin PS 2.

In addition, referring to fig. 13, it can be confirmed that the preliminary bonding layer P-AP has a characteristic of having a higher viscosity than the preliminary non-conductive portion P-NC and a lower viscosity than the preliminary conductive portion P-AC under the same temperature condition of 100 ℃ or lower.

Referring again to fig. 12a, the preliminary bonding layer P-AP may be disposed on the flexible circuit board FB-DP so that the preliminary non-conductive portion P-NC may contact the coupling pad CPD side. That is, the preliminary non-conductive part P-NC may be disposed adjacent to the coupling pad CPD of the flexible circuit board FB-DP, wherein the thickness of the preliminary non-conductive part P-NC is greater than that of the preliminary conductive part P-AC, and the preliminary non-conductive part P-NC has a relatively low viscosity under the same temperature condition.

Fig. 12b and 12c are diagrams schematically showing step S300 of bonding the flexible circuit board and the preliminary bonding layer. Fig. 12b and 12c are steps of bonding the flexible circuit board FB-DP and the preliminary bonding layer P-AP at a first temperature by heating the first stage ST. Fig. 12b exemplarily shows the flow of the preliminary non-conductive part P-NC, and fig. 12c exemplarily shows a case where the preliminary non-conductive part P-NC is filled and arranged between the coupling pads CPD.

In the step S300 of bonding the flexible circuit board and the preliminary bonding layer, the first stage ST may be heated to supply heat to the flexible circuit board FB-DP and the preliminary non-conductive portion P-NC of the preliminary bonding layer P-AP provided on the first stage ST. For example, the first station ST may be heated to about 100 ℃. However, the embodiment is not limited thereto, and the temperature of the first stage ST may vary according to the material composition of the preliminary bonding layer P-AP used. That is, the first stage ST may be heated to a temperature range in which the preliminary non-conductive portion P-NC of the preliminary bonding layer P-AP flows by supplying heat to the flexible circuit board FB-DP and the preliminary bonding layer P-AP sequentially stacked on the first stage ST, and the second base resin PS2 of the preliminary non-conductive portion P-NC may be maintained at a temperature before curing occurs.

In an embodiment, the first stage ST may be heated to a temperature range in which the first stage ST maintains room temperature in the step S100 of providing the flexible circuit board including the plurality of coupling pads and the step S200 of providing the preliminary bonding layer on the flexible circuit board, and heats the preliminary bonding layer P-AP to a first temperature in the step S300 of bonding the flexible circuit board and the preliminary bonding layer. However, the embodiment is not limited thereto, and the first stage ST may be heated before the step S200 of providing the preliminary bonding layer on the flexible circuit board.

The first station ST may be heated by an external heating unit (not shown), or the first station ST itself may be directly heated. For example, the first stage ST may be disposed on a heating unit (not shown) as a separate structure and heated, or may include an induction heating coil (not shown) or the like inside the first stage ST and directly heat.

In addition, in the steps exemplarily shown in fig. 12a to 12c, the preliminary conductive portions P-AC of the preliminary bonding layer P-AP may be spaced apart from the bonding pads CPD. In the step S300 of bonding the flexible circuit board and the preliminary bonding layer, the preliminary conductive portions P-AC may be exposed to the outside. In an embodiment, the heat transferred through the first stage ST may be used to reduce the viscosity of the preliminary non-conductive part P-NC, but since a part of the supplied heat is dissipated through the preliminary conductive part P-AC exposed to the outside, the viscosity is not reduced to such an extent that the first base resin PS1 flows. In addition, in an embodiment, the preliminary conductive portion P-AC may maintain a viscosity higher than or equal to the flow viscosity by cooling air CLA supplied from a separate cooling unit (not shown).

That is, the step S300 of bonding the flexible circuit board and the preliminary bonding layer may include the steps of: heat is supplied to the preliminary non-conductive portion P-NC adjacent to the flexible circuit board FB-DP to lower the viscosity of the preliminary non-conductive portion P-NC to a first viscosity lower than the viscosity at room temperature, and the exposed preliminary conductive portion P-AC is cooled to maintain the viscosity thereof at a second viscosity higher than the first viscosity. For example, in the step S300 of bonding the flexible circuit board and the preliminary bonding layer, the preliminary non-conductive portion P-NC may be heated to a temperature of about 80 ℃ to maintain a low viscosity, and the preliminary conductive portion P-AC may be maintained at a temperature of about 40 ℃ or less to achieve a high viscosity characteristic without fluidity. In addition, as described above, in order to keep the preliminary conductive part P-AC at the second viscosity, the preliminary conductive part P-AC may be placed in a state of being exposed to the outside, or may be cooled by a separate cooling unit (not shown).

By the first stage ST heated in the step S300 of bonding the flexible circuit board and the preliminary bonding layer, heat may be transferred to the preliminary non-conductive portion P-NC of the preliminary bonding layer P-AP, and the preliminary non-conductive portion P-NC may be heated to a first temperature capable of flowing.

In an embodiment, the first temperature may be equal to or higher than the glass transition temperature of the second base resin PS2 constituting the preliminary non-conductive part P-NC, and equal to or lower than the curing start temperature of the second base resin PS 2. For example, referring to fig. 13, the first temperature may be about 80 ℃. Further, the first temperature at this time may be less than about 94 ℃, which is a curing start temperature.

At the first temperature, the preliminary non-conductive portion P-NC may have fluidity and may be filled in the space OH between the coupling pads CPD. That is, the preliminary non-conductive portion P-NC may be disposed on the coupling pads CPD and may flow in the direction FL filling the space OH between the coupling pads CPD.

In addition, in step S300 of bonding the flexible circuit board and the preliminary bonding layer, since the viscosity of the preliminary non-conductive part P-NC is lower than that of the preliminary conductive part P-AC, the preliminary non-conductive part P-NC has fluidity and fills the gap between the bonding pads CPD, but since the fluidity of the preliminary conductive part P-AC is low, the movement of the conductive particles CP included in the preliminary conductive part P-AC can be restricted.

That is, in the step S300 of bonding the flexible circuit board and the preliminary bonding layer, the second base resin PS2 of the preliminary non-conductive part P-NC is heated to the first temperature to have a viscosity exhibiting fluidity, and the first base resin PS1 of the preliminary conductive part P-AC is maintained in a temperature range lower than the first temperature to have a higher viscosity than that of the second base resin PS2, so that a state having no fluidity can be maintained. Thus, the manufacturing method of the display device according to an embodiment can minimize the case where the conductive particles CP of the preliminary conductive part P-AC move to the space between the coupling pads CPD by preferentially filling the space between the coupling pads CPD using the preliminary non-conductive part P-NC including no conductive particles, so that it is possible to reduce short defects due to the conductive particles CP disposed in the region not overlapping with the coupling pads CPD.

Fig. 12d is a view schematically showing step S500 of disposing the bonded flexible circuit board and preliminary bonding layer onto the display panel. After the step S400 of providing the display panel including the plurality of panel pads on the second stage B-ST, the step S500 of disposing the bonded flexible circuit board and the preliminary bonding layer on the provided display panel may be performed.

The second station B-ST may be a separate structure from the first station ST shown in fig. 12a to 12 c. The flexible circuit board FB-DP and the preliminary bonding layer P-AP may be bonded on the first stage ST, and the display panel DP and the preliminary bonding layer P-AP may be bonded on the second stage B-ST.

In the step S300 of bonding the flexible circuit board and the preliminary bonding layer on the first stage ST, the preliminary non-conductive portion P-NC and the preliminary conductive portion P-AC of the preliminary bonding layer P-AP may be sequentially arranged in the Z-axis (Z) direction such that the preliminary non-conductive portion P-NC of the preliminary bonding layer P-AP is adjacent to the bonding pad CPD. Further, in step S500 of disposing the bonded flexible circuit board and preliminary bonding layer onto the display panel disposed on the second stage B-ST, the preliminary conductive portion P-AC may be disposed adjacent to the panel pad DPD.

That is, the combination of the flexible circuit board FB-DP and the preliminary bonding layer P-AP bonded on the first stage ST may be provided on the display panel DP disposed on the second stage B-ST, and at this time, the combination of the flexible circuit board FB-DP and the preliminary bonding layer P-AP may be provided on the display panel DP such that one side of the preliminary conductive portion P-AC originally exposed to the outside on the first stage ST is adjacent to the panel pad DPD.

The display panel DP, the preliminary conductive part P-AC, the preliminary non-conductive part P-NC, and the flexible circuit board FB-DP may be sequentially disposed on the second stage B-ST.

Fig. 12e is a diagram exemplarily showing a part of step S600 of bonding the display panel, the preliminary bonding layer, and the flexible circuit board. Referring to fig. 12d and 12e, etc., step S600 of bonding the display panel, the preliminary bonding layer, and the flexible circuit board may be performed on the second stage B-ST. The display panel DP, the preliminary bonding layer P-AP, and the flexible circuit board FB-DP, which are sequentially stacked, may be bonded by performing pressurization at a second temperature. For example, heat may be provided to the preliminary joining layer P-AP to bring the preliminary joining layer P-AP to the second temperature.

The step S600 of bonding the display panel, the preliminary bonding layer, and the flexible circuit board may include: a step S610 of pressing the preliminary bonding layer using a pressing jig arranged above the flexible circuit board; and a curing step S620 of converting the preliminary bonding layer into a bonding layer by supplying heat to the pressing jig. The step S610 of pressurizing the preliminary bonding layer using a pressurizing jig disposed above the flexible circuit board and the step S620 of curing to convert the preliminary bonding layer into a bonding layer by supplying heat to the pressurizing jig may be performed in the same step.

In the step S600 of bonding the display panel, the preliminary bonding layer, and the flexible circuit board, the display panel DP, the preliminary bonding layer P-AP, and the flexible circuit board FB-DP may be pressurized using a pressurizing jig JG. The direction PR in which the pressing jig JG presses may be a direction perpendicular to the second stage B-ST, and it may press and heat the display panel DP, the preliminary bonding layer P-AP, and the flexible circuit board FB-DP over the flexible circuit board FB-DP under high temperature and high pressure.

In an embodiment, the preliminary bonding layer P-AP may be heated to a second temperature, and the second temperature may be a temperature higher than a curing start temperature of the first and second base resins PS1 and PS 2. For example, the preliminary tie layer P-AP may be heated to a temperature in the range of about 170 ℃ ± 10 ℃.

Heat may be supplied to the preliminary junction layer P-AP, the flexible circuit board FB-DP, and the like by using the pressing jig JG. For example, a pressurized jig JG may be used to provide heat until the temperature of the primary bond layer P-AP reaches 170 ℃. + -. 10 ℃. That is, the pressing jig JG may be a portion capable of performing pressing and heating, whereby the display panel DP, the preliminary junction layer P-AP, and the flexible circuit board FB-DP may be thermocompressed by using the pressing jig JG.

The pressing jig JG may be heated to a temperature of about 300 ℃, and a pressure of about 7MPa may be provided to the display panel DP, the preliminary bonding layer P-AP, and the flexible circuit board FB-DP disposed between the second stage B-ST and the pressing jig JG by using the pressing jig JG.

The step S600 of bonding the display panel, the preliminary bonding layer, and the flexible circuit board may be a step of curing the base resins PS1 and PS2 of the preliminary bonding layer P-AP to be converted into the bonding layer AP. The step S600 of bonding the display panel, the preliminary bonding layer, and the flexible circuit board may include a bonding layer forming step of forming a conductive portion AC adjacent to the display panel DP by curing the preliminary conductive portion P-AC, and forming a non-conductive portion NC spaced apart from the display panel DP and filling a gap between the joining pads CPD by curing the preliminary non-conductive portion P-NC. That is, in the step S600 of bonding the display panel, the preliminary bonding layer, and the flexible circuit board, the first base resin PS1 and the second base resin PS2 are cured so that the preliminary bonding layer P-AP is converted into the bonding layer AP and fixed.

In the manufacturing method of the display device according to an embodiment, by making the preliminary non-conductive part P-NC flowable and preferentially arranged between the coupling pads CPD in the step S300 of bonding the flexible circuit board and the preliminary bonding layer, it is possible to minimize the movement of the conductive particles CP included in the preliminary conductive part P-AC between the coupling pads CPD in the step S600 of bonding the display panel, the preliminary bonding layer, and the flexible circuit board, which is performed later. Therefore, according to the manufacturing method of the display device of an embodiment, by preferentially filling between the coupling pads with the preliminary non-conductive portion and then electrically or physically bonding the coupling pads and the panel pads with the preliminary conductive portion, it is possible to achieve good reliability characteristics even in the case where the pitch (pitch) between the adjacent pads is reduced.

Fig. 14 is a plan view illustrating a portion of a display device manufactured by a manufacturing method of a display device according to an embodiment. An image of the bonding layer AP including an overlapping portion AP-O overlapping the panel pad DPD and the coupling pad CPD and a non-overlapping portion AP-NO arranged so as not to overlap the panel pad DPD and the coupling pad CPD is shown in fig. 14. When viewed in a plane, it can be confirmed that the conductive particles CP are randomly arranged in a similar distribution density without distinguishing the overlapping portion AP-O and the non-overlapping portion AP-NO. In addition, referring to the image of fig. 14, it can be confirmed that the conductive particles CP are not disposed on only the portion of the non-overlapping portion AP-NO where the non-conductive portion NC is disposed.

That is, in the case of the manufacturing method of a display device according to an embodiment, in the bonding layer including the conductive portion and the non-conductive portion provided in a stack, after the non-conductive portion is filled in the non-overlapping portion by utilizing a difference in fluidity of the conductive portion and the non-conductive portion, the step of fixing the conductive portion is performed, so that movement of the conductive particles can be minimized. Thus, in the display device manufactured by the manufacturing method of the display device according to an embodiment, unnecessary electrical contact between the coupling pad and the conductive particle may be blocked, thereby achieving improved reliability characteristics.

The manufacturing method of a display device according to one embodiment of the present invention includes a step of bonding the preliminary conductive portion and the display panel such that the panel pad is adjacent to the landing pad after performing the step of bonding the flexible circuit board and the preliminary bonding layer such that the preliminary non-conductive portion not including the conductive particles is filled between the landing pads, whereby movement of the conductive particles included in the preliminary bonding layer can be controlled, and thus can be used to manufacture a display device with good reliability.

Further, the display device according to an embodiment includes the non-conductive portion that does not overlap the pads and is disposed between the adjacent pads to space the conductive particles in the non-overlapping portion from the flexible circuit board by the non-conductive portion, so that excellent reliability characteristics can be achieved. In addition, in the display device according to an embodiment, the non-conductive part disposed between the adjacent pads is filled between the conductive part and the flexible circuit board and spaced apart from the display panel, so that it is possible to minimize the case where the conductive particles of the conductive part are disposed between the coupling pads, thereby achieving excellent reliability even in the case where pads aligned with high precision are included to achieve high resolution.

While the invention has been described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art or those skilled in the art that various modifications and changes may be made thereto without departing from the spirit and scope of the invention as set forth in the appended claims.

Therefore, the technical scope of the present invention is not limited to the contents described in the detailed description of the specification, but should be determined by the claims.

Claims (20)

1. A display device, comprising:

a display panel including a plurality of panel pads;

a flexible circuit board including a plurality of coupling pads corresponding to the panel pads; and

a bonding layer disposed between the display panel and the flexible circuit board,

wherein the bonding layer comprises:

a conductive portion disposed on the panel pad and including a first base portion and a plurality of conductive particles dispersed in the first base portion; and

a non-conductive portion disposed between the bond pads above the conductive portion, the non-conductive portion including the second base portion but not including the conductive particles.

2. The display device of claim 1, wherein the non-conductive portion is spaced apart from the panel pad.

3. The display device according to claim 1, wherein a thickness ratio of the conductive portion to the non-conductive portion is 1: 2 to 1: 5.

4. The display device according to claim 1, wherein the bonding layer comprises:

an overlapping portion overlapping the panel pad and the coupling pad corresponding to each other; and

a non-overlapping portion that does not overlap the panel pad and the coupling pad.

5. The display device according to claim 4,

the overlapping portion includes the conductive portion, an

The non-overlapping portion includes the conductive portion arranged adjacent to the display panel and the non-conductive portion arranged on the conductive portion to be spaced apart from the display panel.

6. The display device according to claim 4,

the conductive portion included in the overlapping portion and the conductive portion included in the non-overlapping portion are integrally arranged on the display panel, and

in the non-overlapping portion, the non-conductive portion is filled between the conductive portion and the flexible circuit board.

7. The display device according to claim 4,

the distribution density of the conductive particles in the overlapping portion is greater than the distribution density of the conductive particles in the non-overlapping portion.

8. The display device according to claim 1,

the conductive particles included in the conductive portion do not overlap in a thickness direction.

9. The display device according to claim 1, further comprising:

an input sensing part disposed on the display panel and including a plurality of sensing pads;

a sensing flexible circuit board including sensing coupling pads corresponding to the sensing pads; and

a sensing bonding layer disposed between the input sensing part and the sensing flexible circuit board,

wherein the sensing bonding layer comprises:

a sensing conductive part disposed on the sensing pad and including a first sensing base part and a plurality of sensing conductive particles dispersed in the first sensing base part; and

a sensing non-conductive portion disposed between the sensing bond pads above the sensing conductive portion, the sensing non-conductive portion including a second sensing base portion but not including the sensing conductive particles,

wherein the sensing bonding layer further includes a sensing overlapping portion overlapping the sensing pad and the sensing coupling pad corresponding to each other and a sensing non-overlapping portion not overlapping the sensing pad and the sensing coupling pad,

the sensing overlap includes the sensing conductive portion but not the sensing non-conductive portion, an

The sensing non-overlapping portion includes the sensing conductive portion and the sensing non-conductive portion disposed on the sensing conductive portion.

10. A method of manufacturing a display device, comprising:

a step of providing a flexible circuit board including a plurality of coupling pads on a first stage;

a step of providing a preliminary bonding layer on the flexible circuit board;

a step of heating the first stage and bonding the flexible circuit board and the preliminary bonding layer at a first temperature;

a step of providing a display panel including a plurality of panel pads on a second stage;

a step of disposing the flexible circuit board and the preliminary bonding layer bonded onto the display panel provided; and

a step of bonding the display panel, the preliminary bonding layer, and the flexible circuit board stacked in this order by pressing at a second temperature,

wherein the preliminary bonding layer includes a preliminary non-conductive portion and a preliminary conductive portion stacked on the preliminary non-conductive portion,

the step of providing the preliminary bonding layer includes: a step of arranging the preliminary bonding layer so that the preliminary non-conductive portion is adjacent to the bonding pad, an

The step of arranging the flexible circuit board and the preliminary bonding layer bonded includes: a step of arranging the joined flexible circuit board and the preliminary joining layer so that the preliminary conductive portion is adjacent to the panel pad.

11. The method for manufacturing a display device according to claim 10, wherein the step of bonding the flexible circuit board and the preliminary bonding layer includes:

a step of filling the preliminary non-conductive portion between the bonding pads.

12. The method for manufacturing a display device according to claim 10,

at the first temperature, a viscosity of the preliminary non-conductive portion is lower than a viscosity of the preliminary conductive portion.

13. The method for manufacturing a display device according to claim 10, wherein the step of bonding the flexible circuit board and the preliminary bonding layer comprises:

providing heat to the preliminary non-conductive portion adjacent to the flexible circuit board to reduce the viscosity of the preliminary non-conductive portion to a first viscosity and cooling the exposed preliminary conductive portion to maintain the viscosity of the preliminary conductive portion at a second viscosity higher than the first viscosity.

14. The method for manufacturing a display device according to claim 10,

the preliminary conductive portion includes a first base resin and a plurality of conductive particles dispersed in the first base resin, and

the preliminary nonconductive portion includes a second base resin, but does not include the conductive particles.

15. The method for manufacturing a display device according to claim 14,

the first temperature is equal to or higher than a glass transition temperature of the second base resin, and equal to or lower than a curing start temperature of the second base resin.

16. The method for manufacturing a display device according to claim 14,

the second temperature is higher than a curing start temperature of the first base resin and the second base resin.

17. The method for manufacturing a display device according to claim 14,

the curing start temperature of the first base resin is higher than the curing start temperature of the second base resin.

18. The method for manufacturing a display device according to claim 14,

the viscosity of the first base resin is higher than the viscosity of the second base resin at the same temperature.

19. The method for manufacturing the display device according to claim 10, wherein the step of bonding the display panel, the preliminary bonding layer, and the flexible circuit board comprises:

a bonding layer forming step of forming a conductive portion adjacent to the display panel by curing the preliminary conductive portion, and forming a non-conductive portion spaced apart from the display panel and filled between the bonding pads by curing the preliminary non-conductive portion.

20. The method for manufacturing the display device according to claim 10, wherein the step of bonding the display panel, the preliminary bonding layer, and the flexible circuit board comprises:

a step of pressing the preliminary bonding layer using a pressing jig arranged above the flexible circuit board; and

a curing step of converting the preliminary bonding layer into a bonding layer by supplying heat to the pressing jig.

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