Patent Description:
A display device displays various images through a display screen to provide a user with information. In general, the display device displays the information in an allocated screen area. A flexible display device including a flexible display panel that is able to be folded is being developed. Different from a rigid display device, the flexible display device is foldable, rollable, or bendable. The flexible display device, which is capable of being transformed into various shapes, is easy to carry and improves a user's convenience regardless of the original size of the display screen.

<CIT> discloses a display device in accordance with the features as summarized in the preamble of claim <NUM>.

Further reference is made to <CIT>, <CIT>, and <CIT>.

The present invention provides a display device having improved reliability with the features of claim <NUM>.

The present invention provides a method of manufacturing the display device to prevent appearance defects in a foldable area of the display device with the features of claim <NUM>.

The present invention provides a display device including a first non-foldable area, a second non-foldable area, and a foldable area. The display device includes a display module including a display panel, a support substrate supporting the display module, including an upper surface facing the display module and a lower surface opposite to the upper surface, and provided with at least a groove defined in the lower surface to overlap the foldable area in a thickness direction of the support substrate, a first support plate disposed under the support substrate, and a second support plate disposed under the support substrate and spaced apart from the first support plate in the foldable area. Thus, there is a distance between the first support plate and the second support plate in a direction crossing or perpendicular to the thickness direction within in the foldable area of the display device.

The at least one groove may overlap an entirety of the foldable area.

The support substrate further includes a protective coating layer disposed along the surface of the groove.

The protective coating layer may include an ultraviolet coating member.

The protective coating layer may include an anti-static material.

The support substrate may have a thickness in the thickness direction greater than a thickness of the first support plate and greater than a thickness of the second support plate.

A thickness of the support substrate may be in a range from about <NUM> millimeters (mm) to about <NUM>.

A depth of the groove in the thickness direction of the support substrate may be equal to or smaller than a half of a thickness of the support substrate.

The groove may be provided in plural, and the grooves may be arranged continuously or discontinuously in the foldable area.

The first support plate and the second support plate may include a metal material.

The display device may further include a first cushion member disposed under the first support plate and overlapping a portion of the foldable area and a portion of the first non-foldable area in the thickness direction and a second cushion member disposed under the second support plate and overlapping another portion of the foldable area and a portion of the second non-foldable area in the thickness direction.

Each of the first cushion member and the second cushion member may have a thickness from about <NUM> micrometers to about <NUM> micrometers.

The display device may further include a first auxiliary plate disposed under the first cushion member in the thickness direction and overlapping the first cushion member and a second auxiliary plate disposed under the second cushion member and overlapping the second cushion member in the thickness direction.

The display module may have a first state in which the display module is flat and a second state in which the display module in the foldable area is bent such that the first non-foldable area faces the second non-foldable area.

The present invention provides a method of manufacturing a display device including providing a display module including a first non-foldable area, a second non-foldable area, and a foldable area, providing a support substrate under the display module, and providing a first support plate and a second support plate to be spaced apart from each other in the foldable area under the support substrate. The support substrate includes an upper surface facing the display module and a lower surface opposite to the upper surface, and the support substrate is provided with a groove defined in the lower surface to overlap the foldable area in a thickness direction of the support substrate.

The providing of the support substrate may include providing a preliminary support substrate and defining the groove in the preliminary support substrate using a jig.

The providing of the preliminary support substrate may include coating a foam resin on a release film, and the defining of the groove may include drying the coated foam resin while pressing the preliminary support substrate with the jig.

The jig may include a coating layer formed on a surface of the jig and which makes contact with the preliminary support substrate.

The providing of the support substrate further includes coating a protective coating layer along the surface of the formed groove.

The jig may include protrusion formed on a surface of the jig and which makes contact with the preliminary support substrate to overlap the foldable area and to correspond to the groove in the thickness direction.

The providing of the support substrate may include disposing a first adhesive member on the upper surface of the support substrate and disposing the display module on the first adhesive member.

The providing of the first and second support plates may include disposing a second adhesive member on the lower surface of the support substrate to overlap the first non-foldable area and the second non-foldable area in the thickness direction and disposing the first and second support plates on the second adhesive member.

According to the above, the support substrate disposed under the display panel as a cushion layer may have a thick thickness to support the display panel. In addition, since the groove is formed in the lower surface of the support substrate to overlap the foldable area, the display panel may be easily folded despite the thick thickness of the support substrate and the foreign substances may be collected and discharged when the foreign substances are introduced. Thus, defects due to denting or pressing may be prevented.

The above and other advantages of the present invention will become readily apparent by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:.

In the present disclosure, it will be understood that when an element or layer is referred to as being "on", "connected to" or "coupled to" another element or layer, it can be directly on, connected or coupled to the other element or layer or intervening elements or layers may be present.

In the drawings, the thickness, ratio, and dimension of components are exaggerated for effective description of the technical content. "Or" means "and/or.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention. As used herein, the singular forms, "a", "an" and "the" are intended to include the plural forms as well, including "at least one," unless the context clearly indicates otherwise.

Spatially relative terms, such as "beneath", "below", "lower", "above", "upper" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as shown in the figures.

It will be further understood that the terms "includes" and/or "including", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Hereinafter, exemplary embodiments of the present invention will be described with reference to accompanying drawings.

<FIG> are perspective views showing a display device <NUM> according to an exemplary embodiment of the present invention.

<FIG> is a perspective view showing an unfolded state of the display device <NUM> according to an exemplary embodiment of the present invention. <FIG> is a perspective view showing a folded state of the display device <NUM> shown in <FIG>.

Referring to <FIG>, the display device <NUM> is a foldable display device. The display device <NUM> according to the exemplary embodiment of the present invention may be applied to a large-sized electronic item, such as a television set or a monitor, or a small and medium-sized item, such as a mobile phone, a tablet computer, a car navigation unit, a game unit, or a smart watch.

An upper surface of the display device <NUM> may be defined as a display surface DS, and the display surface DS may have a plane surface defined by a first direction DR1 and a second direction DR2.

The display surface DS may include a display area DA and a non-display area NDA around the display area DA. The display area DA may be an active area through which an image IM is displayed, and the non-display area NDA may be a non-active area through which the image IM is not displayed. <FIG> shows application icons as a representative example of the image IM.

The display area DA may have a quadrangular shape. The non-display area NDA may surround the display area DA. However, the shapes of the display area DA and non-display area NDA of the present invention should not be limited thereto or thereby. The shape of the display area DA and the shape of the non-display area NDA may be designed relative to each other.

The display device <NUM> includes a first non-foldable area NFA1, a foldable area FA, and a second non-foldable area NFA2, which are sequentially defined in the display device <NUM> along the second direction DR2. That is, the foldable area FA may be defined between the first non-foldable area NFA1 and the second non-foldable area NFA2. <FIG> show one foldable area FA and two non-foldable areas, e.g., the first and second non-foldable areas NFA1 and NFA2. However, the number of the foldable areas and the non-foldable areas of the present invention should not be limited thereto or thereby. For example, the display device <NUM> may include three or more non-foldable areas and foldable areas disposed between the non-foldable areas in another embodiment.

The display device <NUM> may be folded around a folding axis FX. That is, the foldable area FA may be folded around the folding axis FX. The folding axis FX may extend in the first direction DR1. The folding axis FX may be defined as a short folding axis substantially parallel to short sides of the display device DD.

When the display device <NUM> is folded, the display surface corresponding to the first non-foldable area NFA1 and the display surface corresponding to the second non-foldable area NFA2 may face each other. Accordingly, the display surface DS may not be exposed to the outside in the folded state. However, this is merely exemplary. According to another exemplary embodiment of the present invention, when the display device <NUM> is folded, the display surface corresponding to the first non-foldable area NFA1 and the display surface corresponding to the second non-foldable area NFA2 may face in opposite directions. Accordingly, the display surface DS may be exposed to the outside in the folded state.

<FIG> is a perspective view showing a display device <NUM>-<NUM> according to an exemplary embodiment of the present invention. <FIG> is a perspective view showing a folded state of the display device <NUM>-<NUM> shown in <FIG>.

Referring to <FIG>, the display device <NUM>-<NUM> includes a first non-foldable area NFA1-<NUM>, a foldable area FA-<NUM>, and a second non-foldable area NFA2-<NUM>, which are sequentially defined in the display device <NUM>-<NUM> along the first direction DR1. That is, the foldable area FA-<NUM> may be defined between the first non-foldable area NFA1-<NUM> and the second non-foldable area NFA2-<NUM>.

The display device <NUM>-<NUM> may be folded around a folding axis FX-<NUM>. That is, the folding area FA-<NUM> may be folded around the folding axis FX-<NUM>. The folding axis FX-<NUM> may extend in the second direction DR2. The folding axis FX-<NUM> may be defined as a long folding axis substantially parallel to long sides of the display device <NUM>-<NUM>.

Hereinafter, a structure of the display device <NUM> folded around the short folding axis will be described in detail. However, structures described below may be applied to the display device <NUM>-<NUM> that is folded around the long folding axis.

<FIG> is a cross-sectional view schematically showing the display device <NUM> according to an exemplary embodiment of the present invention.

Referring to <FIG>, the display device <NUM> includes a display module <NUM>, a support substrate <NUM>, a support plate <NUM>, and may include a cushion member <NUM>.

The display module <NUM> may display the image IM (refer to <FIG>) and may sense an external input TC (refer to <FIG>). The external input TC may be a user input. The user input may include various types of external inputs, such as a part of the user's body, light, heat, or pressure. In <FIG>, the external input TC is shown as a user's hand being applied to the display surface DS. However, this is merely exemplary. As described above, the external input TC may be provided in various forms. In addition, the display device <NUM> may sense the external input TC applied to a side or rear surface of the display device <NUM> depending on its structure, however, it should not be limited to a specific embodiment. This will be described in more detail with reference to <FIG>.

A cover panel and members (hereinafter, referred to as "lower members") may be disposed under the display module <NUM>. The cover panel may include the support substrate <NUM> and a heat dissipation plate (not shown). The lower members may include the support plate <NUM>, the cushion member <NUM>, and an auxiliary plate <NUM> (refer to <FIG>). In this application, "under" is measured in the figures where the arrow of the third direction DR3 points upward.

The support substrate <NUM> supports the display module <NUM>. The support substrate <NUM> may include a sponge, a foam, or a urethane resin. The support substrate <NUM> may protect the display module <NUM> from external impacts.

The support plate <NUM> may be disposed under the support substrate <NUM>. The support plate <NUM> may include a stainless steel, aluminum, or an alloy thereof. The support plate <NUM> may have a strength greater than a strength of the display module <NUM>. The support plate <NUM> may support the display module <NUM> and the support substrate <NUM> and may protect the display module <NUM> from the external impacts. The support plate <NUM> may prevent a foreign substance from entering the display module <NUM>. The support plate <NUM> may have a thickness from about <NUM> micrometers to about <NUM> micrometers.

The cushion member <NUM> may be disposed under the support plate <NUM>. The cushion member <NUM> may include a thermoplastic polyurethane material. The cushion member <NUM> may be a thin material and may protect the support plate <NUM> from external impacts. The cushion member <NUM> may have a thickness from about <NUM> micrometers to about <NUM> micrometers.

<FIG> schematically shows the cross-section of the stack structure of the display device <NUM> according to an exemplary embodiment, and hereinafter, this will be described in more detail with reference to <FIG>.

<FIG> is a cross-sectional view showing the display module <NUM> according to an exemplary embodiment of the present invention.

Referring to <FIG>, the display module <NUM> includes a display panel <NUM>, may include an anti-reflection layer <NUM>, a window <NUM>, an upper protection film <NUM>, and a lower protection film <NUM>. Although not shown in figures, the display module <NUM> may further include an input sensing layer that obtains coordinate information of the external input.

The display panel <NUM> according to an exemplary embodiment of the present invention may be a light-emitting type display panel. However, the type of the display panel <NUM> of the present invention should not be particularly limited. For instance, the display panel <NUM> may be an organic light-emitting display panel or a quantum dot light-emitting display panel. A light-emitting layer of the organic light-emitting display panel may include an organic light-emitting material. A light-emitting layer of the quantum dot light-emitting display panel may include a quantum dot or a quantum rod.

The input sensing layer may be disposed directly on the display panel <NUM>. For example, the input sensing layer may be formed right on the display panel <NUM> through successive manufacturing processes. The input sensing layer may include a plurality of insulating layers and a plurality of conductive layers. The conductive layers may form a sensing electrode sensing the external input, a sensing line connected to the sensing electrode, and a sensing pad connected to the sensing line. The input sensing layer may sense the external input by a mutual capacitance method and/or a self-capacitance method. However, the method of sensing the external input of the present invention should not be limited thereto or thereby.

The display panel <NUM> may include a first area <NUM>-<NUM>, a second area <NUM>-<NUM>, and a third area <NUM>-<NUM>, which are defined in the display panel <NUM> along the second direction DR2. The first area <NUM>-<NUM> may correspond to the first non-foldable area NFA1 of <FIG>, the second area <NUM>-<NUM> may correspond to the foldable area FA of <FIG>, and the third area <NUM>-<NUM> may correspond to the second non-foldable area NFA2 of <FIG>. That is, each of the first area <NUM>-<NUM> and the third area <NUM>-<NUM> may be a non-foldable area, and the second area <NUM>-<NUM> may be a foldable area.

The anti-reflection layer <NUM> may be disposed on the display panel <NUM>. The anti-reflection layer <NUM> may reduce a reflectance of an external light incident thereto from the outside of the anti-reflection layer <NUM>. The anti-reflection layer <NUM> according to the exemplary embodiment of the present invention may include a retarder and a polarizer. The retarder may be a film type or liquid crystal coating type and may include a λ/<NUM> retarder and/or a λ/<NUM> retarder. The polarizer may be a film type or liquid crystal coating type. The film type polarizer may include a stretching type synthetic resin film, and the liquid crystal coating type polarizer may include liquid crystals aligned in a predetermined alignment. The retarder and the polarizer may further include a protective film.

The anti-reflection layer <NUM> may include color filters. The color filters may have a predetermined alignment. The alignment of the color filters may be determined by taking into account the emission colors of pixels included in the display panel <NUM>. The anti-reflection layer <NUM> may further include a black matrix disposed adjacent to the color filters.

The anti-reflection layer <NUM> may include a destructive interference structure. For instance, the destructive interference structure may include a first reflection layer and a second reflection layer, which are disposed on different layers from each other. A first reflection light and a second reflection light, which are reflected by the first reflection layer and the second reflection layer, respectively, may interfere destructively with each other, and thus, the reflectance of the external light may be reduced.

An adhesive layer <NUM> may be disposed between the display panel <NUM> and the anti-reflection layer <NUM>. The display panel <NUM> and the anti-reflection layer <NUM> may be coupled to each other by the adhesive layer <NUM>. In another exemplary embodiment of the present invention, the adhesive layer <NUM> may be omitted. The adhesive layers described in the present invention may include a conventional adhesive. As an example, each adhesive layer may include a pressure sensitive adhesive ("PSA"), an optically clear adhesive ("OCA"), or an optically clear resin ("OCR").

The window <NUM> may be disposed on the anti-reflection layer <NUM>. The window <NUM> may include a base layer <NUM> and a functional coating layer <NUM>. The base layer <NUM> may include a glass substrate and/or a synthetic resin film. For example, the base layer <NUM> may include a polyimide film. The base layer <NUM> of the present invention should not be limited to a single-layer structure. The base layer <NUM> may include two or more films coupled to each other by an adhesive member in another embodiment. The functional coating layer <NUM> may include at least one of an anti-fingerprint layer, an anti-reflection layer, and a hard coating layer.

An adhesive layer <NUM> may be disposed between the window <NUM> and the anti-reflection layer <NUM>. However, the adhesive layer <NUM> may be omitted in another embodiment.

The upper protection film <NUM> may be disposed on the window <NUM>. As the upper protection film <NUM> is added, an impact resistance characteristic of the display device <NUM> may be improved. The upper protection film <NUM> may be a polymer film or a tempered glass film. An adhesive layer <NUM> may be disposed between the upper protection film <NUM> and the window <NUM>. However, the adhesive layer <NUM> may be omitted in another embodiment. In addition, the upper protection film <NUM> may be omitted in another exemplary embodiment of the present invention.

The lower protection film <NUM> may be disposed under the display panel <NUM>. The lower protection film <NUM> may protect a rear surface (i.e., lower surface) of the display panel <NUM>. The lower protection film <NUM> may include a synthetic resin film, e.g., a polyimide film or a polyethylene terephthalate film. However, this is merely exemplary, and the lower protection film <NUM> of the present invention should not be limited thereto or thereby. An adhesive layer <NUM> may be disposed between the lower protection film <NUM> and the display panel <NUM>.

In the exemplary embodiment of the present invention, the support substrate <NUM> (refer to <FIG>) may be disposed under the lower protection film <NUM> of the display module <NUM>. A first adhesive member AD1 (refer to <FIG>) may be disposed between the lower protection film <NUM> and the support substrate <NUM>.

<FIG> and <FIG> are cross-sectional views showing a display device according to an exemplary embodiment of the present invention. <FIG> is a view showing a folded state of the display device of <FIG> is a perspective view showing the support substrate <NUM> according to an exemplary embodiment of the present invention. <FIG> is a plan view showing the support substrate <NUM> according to an exemplary embodiment of the present invention.

Referring to <FIG>, the display device <NUM> includes the display module <NUM>, the support substrate <NUM>, first and second support plates <NUM> and <NUM>, and may include first and second cushion members <NUM> and <NUM>.

Referring to <FIG> and <FIG>, the display device <NUM> includes the first non-foldable area NFA1, the second non-foldable area NFA2, and the foldable area FA. The display module <NUM> may be in a first state that is a flat state (i.e., unfolded state) as shown in <FIG> or may be in a second state that is a folded state as shown in <FIG>. In the folded state of the display device <NUM>, the display module <NUM> and the support substrate <NUM> may be folded in the foldable area FA and may be maintained in the flat state in the first and second non-foldable areas NFA1 and NFA2. According to the exemplary embodiment, a portion of the display module <NUM> corresponding to the foldable area FA is folded in the second state, and thus, the first non-foldable area NFA1 and the second non-foldable area NFA2 may face each other in the second state.

The display module <NUM> includes the display panel <NUM>. Repetitive descriptions are omitted.

Referring to <FIG>, the support substrate <NUM> may be disposed under the display module <NUM> and supports the display module <NUM>. The support substrate <NUM> may act as a cushion to prevent the display module <NUM> from being damaged. In the present exemplary embodiment, the support substrate <NUM> may have a thickness TH1 that is two to two and a half times greater than a thickness of a conventional support substrate (not shown). For example, the thickness TH1 of the support substrate <NUM> in the thickness direction (i.e., the third direction DR3) may be within a range from about <NUM> micrometers (<NUM> millimeters) to about <NUM> micrometers (<NUM> millimeters). In the present exemplary embodiment, since the support substrate <NUM> may support the display module <NUM> and may act as the cushion to protect the display module <NUM> from the impacts, the support substrate <NUM> may have the thickness TH1 greater than the thickness of the conventional support substrate.

The support substrate <NUM> includes an upper surface facing the display module <NUM> and a lower surface opposite to the upper surface. The support substrate <NUM> is provided with at least one groove GR defined in the lower surface of the support substrate <NUM>. In figures (e.g., <FIG>), three grooves GR are defined, however, the number of the grooves GR of the present invention should not be limited to three. The support substrate <NUM> may have the thickness TH1 sufficient to define the groove GR. That is, the support substrate <NUM> may have the thickness TH1 that is sufficiently thick to act as the cushion even when the thickness is reduced in the foldable area FA due to the arrangement of the groove GR. The groove GR may overlap the foldable area FA in a plan view. In the exemplary embodiment, the groove GR may be defined to overlap the entire foldable area FA. As shown in figures, three grooves GR overlap the entire foldable area FA, however, they should not be limited thereto or thereby. Regardless of the number of grooves GR, the groove GR may overlap a portion of the foldable area FA in another embodiment. The groove GR may be provided in plural, and the grooves GR may be consecutively arranged and may have a plurality of curved-concaved shapes in a thickness direction of the support substrate <NUM>. In this application, "overlap" is interpreted to mean "overlap in the thickness direction in the unfolded state" unless the content clearly indicates otherwise.

When the groove GR is provided in plural, the grooves GR may be arranged continuously or discontinuously in the foldable area FA. That is, when the grooves GR are arranged discontinuously, a flat surface may exist between the grooves GR.

In the exemplary embodiment, a depth WT of the groove GR in a third direction DR3, may be equal to or smaller than a half of a thickness of the support substrate <NUM>. When the depth WT of the groove GR is too large, the support substrate <NUM> may not act as the cushion in the foldable area FA. For example, the width of the groove GR may be within a range from about <NUM> micrometers to about <NUM> micrometers.

Referring to <FIG>, the support substrate <NUM> further includes a protective coating layer CM. The protective coating layer CM is disposed along a surface of at least one groove GR. The protective coating layer CM may overlap the foldable area FA in a plan view. The protective coating layer CM may be disposed on a lower surface of the support substrate <NUM> that overlaps the entire foldable area FA and defines the groove GR. The protective coating layer CM may include a non-adhesive material. In a case where a foreign substance enters the groove GR, the protective coating layer CM may prevent the foreign substance from adhering to the surface of the groove GR. The protective coating layer CM may include an ultraviolet coating member. That is, the protective coating layer CM may be formed by coating an ultraviolet curable material on the surface of the groove GR and curing the coated ultraviolet curable material.

The protective coating layer CM may include an anti-static material. Static electricity may be generated on the surface of the groove GR while the display device <NUM> are repeatedly folded and unfolded. However, since the protective coating layer CM disposed on the surface of the groove GR may include the anti-static material, the static electricity may be prevented from occurring.

The support plate <NUM> may include the first support plate <NUM> and the second support plate <NUM>. The first support plate <NUM> and the second support plate <NUM> may be a metal plate. The first and second support plates <NUM> and <NUM> may be spaced apart from each other in the foldable area FA. In <FIG>, the first and second support plates <NUM> and <NUM> may face each other in the third direction DR3 when the display device <NUM> is in the folded state. The first and second support plates <NUM> and <NUM> may be disposed under the support substrate <NUM> in the unfolded state to support the support substrate <NUM> and the display module <NUM> and may prevent the support substrate <NUM> and the display module <NUM> from being pressed, dented, and the like. The support substrate <NUM> may prevent a foreign substance from entering the display device <NUM>. Each of the first and second support plates <NUM> and <NUM> may have a thickness of about <NUM> micrometers in the third direction DR3. Accordingly, the thickness of the support substrate <NUM> may be greater than the thickness of each of the first and second support plates <NUM> and <NUM>.

The cushion member <NUM> may include the first cushion member <NUM> and the second cushion member <NUM>. The first cushion member <NUM> may be disposed under the first support plate <NUM>, and the second cushion member <NUM> may be disposed under the second support plate <NUM> in the unfolded state. The first cushion member <NUM> may be disposed to overlap a portion of the foldable area FA and a portion of the first non-foldable area NFA1, and the second cushion member <NUM> may be disposed to overlap another portion of the foldable area FA and a portion of the second non-foldable area NFA2. The first and second cushion members <NUM> and <NUM> may support the first and second support plates <NUM> and <NUM>, respectively, and may prevent the first and second support plates <NUM> and <NUM> from being impacted, pressed, and deformed by external forces. The first and second cushion members <NUM> and <NUM> may have a thickness from about <NUM> micrometers to about <NUM> micrometers in the third direction DR3.

The first adhesive member AD1 may be disposed between the display module <NUM> and the support substrate <NUM>. A second adhesive member AD2 may be disposed between the support substrate <NUM> and each of the first and second support plates <NUM> and <NUM>, and a third adhesive member AD3 may be disposed between the first support plate <NUM> and the first cushion member <NUM> and between the second support plate <NUM> and the second cushion member <NUM>. The first, second, and third adhesive members AD1, AD2, and AD3 may be an adhesive tape. The first, second, and third adhesive members AD1, AD2, and AD3 may be a pressure sensitive adhesive (PSA), an optical clear adhesive (OCA), or an optical clear resin (OCR).

A step-difference compensation member SCM may be disposed under the first and second support plates <NUM> and <NUM> in an area in which the first cushion member <NUM> or the second cushion member <NUM> is not disposed. The step-difference compensation member SCM may be various types of adhesives including the pressure sensitive adhesive. Although not shown in figures, the step-difference compensation member SCM may combine the first and second support plates <NUM> and <NUM> with a lower set. The lower set may correspond to a housing that covers the display module <NUM>, the cover panel, and the lower members.

<FIG> are views showing a method of manufacturing a display device according to an exemplary embodiment of the present invention.

Referring to <FIG>, the manufacturing method of the display device includes providing the display module <NUM> including the first non-foldable area NFA1, the second non-foldable area NFA2, and the foldable area FA, providing the support substrate <NUM> under the display module <NUM>, and providing the first support plate <NUM> and the second support plate <NUM> disposed under the support substrate <NUM> and spaced apart from each other in the foldable area FA.

The providing of the support substrate <NUM> may include providing a preliminary support substrate <NUM>-<NUM> and forming at least one groove GR in the preliminary support substrate <NUM>-<NUM> using a jig ZG.

The preliminary support substrate <NUM>-<NUM> shown in <FIG> may include a foam resin, a polyurethane resin, or a sponge. According to the exemplary embodiment, the preliminary support substrate <NUM>-<NUM> may be formed by coating (spraying) the foam resin on a first release film CF1. The first release film CF1 may be a medium-thin release film. When the preliminary support substrate <NUM>-<NUM> is provided, a foam resin surface of the preliminary support substrate <NUM>-<NUM> is pressed by the jig ZG, and thus, at least one groove GR may be formed. The jig ZG may be a mold used to form the support substrate <NUM> by forming a variety of patterns on the preliminary support substrate <NUM>-<NUM>. The jig ZG may include at least one protrusion formed on a surface thereof which makes contact with the preliminary support substrate <NUM>-<NUM> to overlap the foldable area FA and to correspond to the at least one groove GR. The at least one protrusion may correspond to the at least one groove GR.

Referring to <FIG>, the forming of the at least one groove GR may include pressing the foam resin surface of the preliminary support substrate <NUM>-<NUM> with the jig ZG while drying the coated foam resin.

In the exemplary embodiment, the jig ZG may include a coating layer NAL formed on the surface thereof which makes contact with the preliminary support substrate <NUM>-<NUM>. The coating layer NAL may prevent the preliminary support substrate <NUM>-<NUM> from being adhered to the jig ZG when the preliminary support substrate <NUM>-<NUM> is in contact with the jig ZG. The coating layer NAL may include a primer having superior water repellency or low surface energy. However, the coating layer NAL of the present invention should not be limited thereto or thereby. The coating layer NAL may include a variety of materials that are non-adhesive.

Referring to <FIG>, the providing of the support substrate <NUM> includes coating the protective coating layer CM along the surface of at least one groove GR formed using the jig ZG. The protective coating layer CM may be formed through a UV-coating process or a primer coating process having the low surface energy. As another way, the protective coating layer CM may be formed using various non-adhesive materials not to be adhered to foreign substances. In the exemplary embodiment, the protective coating layer CM may further include the anti-static material, which prevents the static electricity from occurring in the folding or unfolding operation, with the non-adhesive materials. The protective coating layer CM may be coated to overlap the entire foldable area.

Referring to <FIG>, the manufacturing method of the display device includes disposing the display module <NUM> on the support substrate <NUM>, and the first support plate <NUM>, and the second support plate <NUM> under the support substrate <NUM>.

The support substrate <NUM> includes the upper surface facing the display module <NUM> and the lower surface opposite to the upper surface. The manufacturing method of the display device may include disposing the second adhesive member AD2 on the lower surface of the support substrate <NUM> to overlap the first non-foldable area NFA1 and the second non-foldable area NFA2. In addition, the manufacturing method of the display device may include disposing the first and second support plates <NUM> and <NUM> on the second adhesive member AD2. Referring to <FIG>, the disposing of the first and second support plates <NUM> and <NUM> may include coating the second adhesive member AD2 and attaching a second release film CF2 to the first and second support plates <NUM> and <NUM> through the second adhesive member AD2. Referring to <FIG>, the manufacturing method of the display device may include removing the first release film CF1, coating the first adhesive member AD1 on the support substrate <NUM>, and attaching a third release film CF3 on the first adhesive member AD1. In the exemplary embodiment, each of the second release film CF2 and the third release film CF3 may be a medium-thin release film or a thin release film.

Referring to <FIG>, the first and second support plates <NUM> and <NUM> may be attached to the second adhesive member AD2 after the second release film CF2 is removed. In the exemplary embodiment, in the case where the second release film CF2 is the medium-thin release film, the second release film CF2 may be removed after being replaced with the thin release film. This is to prevent the removal of the other release films that is not intended when removing the second release film CF2. Referring to <FIG>, the display module <NUM> may be attached to the first adhesive member AD1 after the third release film CF3 is removed. Similarly, in the case where the third release film CF3 is the medium-thin release film, the third release film CF3 may be removed after being replaced with the thin release film.

In <FIG>, the display module <NUM> is disposed after the first support plate <NUM> and the second support plate <NUM> are disposed. However, the sequence of disposing of the present invention should not be limited thereto or thereby. After the third release film CF3 is removed from the upper surface of the support substrate <NUM> and the display module <NUM> is disposed, the second release film CF2 is removed, and then the first and second support plates <NUM> and <NUM> may be disposed on the lower surface of the support substrate <NUM> in another embodiment.

<FIG> are cross-sectional views showing a display device according to other exemplary embodiments of the present invention.

Referring to <FIG>, at least one groove GR having a shape pointed in a thickness direction of the support substrate <NUM> may be provided, and the groove GR may be provided in plural. In the present exemplary embodiment, the grooves GR may be consecutively arranged. For example, a depth in the third direction DR3 of the grooves GR may be the greatest at a center of a foldable area FA and may become smaller in a direction from the center of the foldable area FA to the first non-foldable area NFA1 or to the second non-foldable area NFA2. The grooves GR may be arranged to overlap the entire foldable area FA. In the present exemplary embodiment, the grooves GR may overlap the entire foldable area FA. However, the grooves GR may be arranged to be slightly spaced apart from each of the first and second non-foldable areas NFA1 and NFA2 in another embodiment. This is to prevent defects of a folded portion of the support substrate <NUM> when the support substrate <NUM> is folded.

Referring to <FIG>, a groove GR may be provided in a curved shape that is concave in a thickness direction of a support substrate <NUM>. The groove GR may have a recessed oval shape.

Referring to <FIG>, a groove GR may be provided in plural, and the grooves GR may be arranged discontinuously. The grooves GR may overlap the entire foldable area FA. The grooves GR may be concave in a thickness direction of a support substrate <NUM>, and discontinuous surfaces having a convex curved shape in a direction (i.e., a direction opposite to the third direction DR3) opposite to the thickness direction of the support substrate <NUM> may be disposed between the grooves GR.

Referring to <FIG>, a groove GR may be provided in plural, and the grooves GR may be discontinuously arranged in a straight-line shape. In the present exemplary embodiment, the groove GR may be arranged to be spaced apart from the first and second non-foldable areas NFA1 and NFA2. That is, at least one groove GR may not overlap the entire foldable area FA. A portion of a lower surface of the support substrate <NUM>, which does not include the groove GR, may be disposed adjacent to the first non-foldable area NFA1 or the second foldable area NFA2.

<FIG> is a cross-sectional view showing a display device according to another exemplary embodiment of the present invention.

Referring to <FIG>, the display device may include a first auxiliary plate <NUM> and a second auxiliary plate <NUM>.

The first auxiliary plate <NUM> may be disposed to overlap a first cushion member <NUM> and may support the first cushion member <NUM>, and the second auxiliary plate <NUM> may be disposed to overlap a second cushion member <NUM> in a plan view and may support the second cushion member <NUM>. The first and second auxiliary plates <NUM> and <NUM> may include a metal plate. For example, the first and second auxiliary plates <NUM> and <NUM> may include a stainless steel, aluminum, or an alloy thereof. The first and second auxiliary plates <NUM> and <NUM> may prevent a foreign substance from entering the display device <NUM> and may prevent a display module <NUM> from being pressed or dented.

In the present exemplary embodiment, a fourth adhesive member AD4 may be disposed between the first cushion member <NUM> and the first auxiliary plate <NUM> and between the second cushion member <NUM> and the second auxiliary plate <NUM>. The fourth adhesive member AD4 may be a pressure-sensitive adhesive (PSA), an optically clear adhesive (OCA), or an optically clear resin (OCR).

Claim 1:
A display device (<NUM>) comprising a first non-foldable area (NFA1), a second non-foldable area (NFA2), and a foldable area (FA), the display device (<NUM>) comprising:
a display module (<NUM>) comprising a display panel (<NUM>);
a support substrate (<NUM>) supporting the display module (<NUM>), comprising an upper surface facing the display module (<NUM>) and a lower surface opposite to the upper surface, and provided with at least a groove (GR) defined in the lower surface to overlap the foldable area (FA) in a thickness direction of the support substrate (<NUM>);
a first support plate (<NUM>) disposed under the support substrate (<NUM>); and
a second support plate (<NUM>) disposed under the support substrate (<NUM>) and spaced apart from the first support plate (<NUM>) with a distance in the foldable area (FA);
characterized in that
the support substrate (<NUM>) further comprises a protective coating layer (CM) disposed along the surface of the groove (GR).