Display device

Abstract

A display device is disclosed, wherein air bubbles generated during the bonding process of a display module can be eliminated. The display device includes a foldable display device, comprising a system frame foldable relative to a folding axis, and a foldable display module. The foldable display module has a folding region that is fused with the system frame and foldable relative to the folding axis, and a plurality of flat regions connected through the folding region. The foldable display module includes a display panel including the plurality of flat regions and the folding region, and includes a base plate engaged between the display panel and the system frame. The base plate includes a plurality of folding patterns disposed in the folding region and a plurality of opening patterns disposed in the plurality of flat regions.

Description

A display device This invention relates to a display device. Electroluminescence display (ESD) devices offer advantages such as high brightness, low driving voltage, ultra-thin design, and flexible shape due to the use of light-emitting elements. Electroluminescent display devices can be used in display devices in which the display area can be folded or unfolded as required by the application. In display devices, air bubbles generated during the lamination process can cause screen defects, thus requiring methods to remove these air bubbles. Display devices may exhibit image retention due to heat generated by their circuit components, thus requiring a heat dissipation plan. Therefore, this disclosure aims to provide a display device that substantially solves one or more problems caused by the limitations or disadvantages of prior art. One aspect of this disclosure provides a display device in which air bubbles generated during the bonding process of display modules can be eliminated, thereby improving screen defects. One aspect of this disclosure is to provide a display device that can improve the heat dissipation characteristics of a display module. Other advantages and features of this disclosure will be set forth in the description which follows, and in part will be obvious to those skilled in the art upon review of the narration or may be learned from practice of this disclosure. The objects and other advantages of this disclosure may be realized and achieved through the structures particularly pointed out in the written description and the accompanying drawings. According to one aspect of this disclosure, a foldable display device may include a system frame capable of folding relative to a folding axis; and a foldable display module having a folding region and a plurality of flat regions, wherein the folding region is engaged with the system frame and capable of folding relative to the folding axis, and the plurality of flat regions are connected through the folding region, wherein the foldable display module includes a display panel and a base plate, wherein the display panel includes a plurality of flat regions and a folding region, and the base plate is engaged between the display panel and the system frame and includes a plurality of folding patterns disposed in the folding region and a plurality of opening patterns disposed in the plurality of flat regions, wherein each of the plurality of opening patterns includes an outer hole pattern and an inner hole pattern associated with the outer hole pattern. According to one aspect of this disclosure, a foldable display device may include a display panel comprising a plurality of flat regions and folding regions disposed between the plurality of flat regions and foldable relative to a folding axis; a base plate, joined to the back surface of the display panel, and including a plurality of folding patterns corresponding to the plurality of folding regions and a plurality of opening patterns corresponding to the plurality of flat regions, the plurality of opening patterns including an outer hole pattern and an inner hole pattern having a size different from the outer hole pattern; and a system frame, joined to the base plate by a plurality of adhesives respectively disposed on the back surface of the base plate corresponding to the plurality of flat regions, and foldable relative to a folding axis. It should be understood that both the foregoing general description and the following specific description are exemplary and explanatory, and are intended to provide further explanation of the scope of the claims for protection sought in this disclosure. The advantages and features of this disclosure, and its implementation methods, will be illustrated by the following aspects described with reference to the accompanying drawings. However, this disclosure may be implemented in various forms and should not be construed as limited to the aspects described herein. Rather, these aspects are intended to make this disclosure complete and thorough and to fully convey the scope of this disclosure to those skilled in the art. Furthermore, this disclosure is defined only by the scope of the patent application. The shapes, dimensions, scales, angles, and quantities disclosed in the accompanying drawings are merely examples to illustrate various aspects of this disclosure; therefore, this disclosure is not limited to the details shown. The same symbols denote the same elements throughout the specification. In the following description, detailed descriptions of known functions or constructions are omitted where such description would unnecessarily obscure the gist of the disclosure. The terms "comprising," "having," and "including" are used in this specification, unless "limited" is used, in addition to other terms. Singular terms may include plural forms unless the contrary is stated. When interpreting components, even if not explicitly described, the components should be interpreted as including a range of error. When describing positional relationships, for example, when the position between two parts is described as "above", "over", "below", and "next to", one or more other parts may be placed between the two parts, unless more restrictive terms such as "only" or "directly" are used. When describing temporal relationships, such as when using time sequence terms like "after," "following," "next," and "before," discontinuous situations may be included unless more restrictive terms such as "immediately," "immediately," or "directly" are used. It should be understood that although terms such as "first" and "second" may be used herein to describe different elements, these elements should not be limited by these terms. These terms are used only to distinguish different elements. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of this disclosure. In describing the elements of this disclosure, terms such as "first," "second," "A," "B," "(a)," and "(b)" may be used. These terms are intended to distinguish the corresponding element from other elements, and the basis, order, sequence, or number of the corresponding elements shall not be defined or limited by these terms. As to the description of an element or layer being "connected," "coupled," or "attached" to another element or layer, the element or layer may not only be directly connected or attached to another element or layer, but may also be indirectly connected or attached between elements or layers through one or more intermediary elements or layers "set" between elements or layers, unless otherwise stated. The term "at least one" should be understood to include any and all related combinations of one or more of the listed elements. For example, "at least one or more first elements, second elements and third elements" means all combinations of two or more of the first element, second element and third element, as well as the first element, second element or third element. The features of this disclosure may be combined or integrated with each other in whole or in part, and may operate and be driven in various ways internally and technically, so as to be fully understood by one of ordinary skill in the art. The various aspects of this disclosure may be carried out independently or together and may be interdependent. The aspects of this disclosure will now be described with reference to the accompanying drawings. Since the scale of each element shown in the drawings differs from the actual scale for ease of explanation, this disclosure is not limited to the scale shown. Furthermore, all components of each display device according to all aspects of this disclosure are operatively coupled and configured. Figures 1 and 2 are perspective views schematically illustrating examples of the configuration of a foldable display device before and after joining according to an embodiment of the present disclosure. Figures 3 and 4 are cross-sectional views schematically illustrating examples of the configuration of a foldable display device before and after joining according to an embodiment of the present disclosure. Figure 5 is a diagram illustrating an example of the cross-sectional structure of a foldable display device and the back structure of the base plate according to an embodiment of the present disclosure. Figure 6 is a plan view illustrating an example of the back side structure of the base plate according to an embodiment of the present disclosure. Figures 7A and 7B are perspective views illustrating example base plate structures from the top and back views, respectively, according to an embodiment of the present disclosure. Referring to Figures 1 to 8, a foldable display device 1000 according to one embodiment may include a foldable display module 500 and a system frame 700, wherein the foldable display module 500 includes a display panel 100, and the system frame 700 is attached to the foldable display module 500 by an adhesive 600 and is foldable relative to the folding axis FCL. In Figures 1 to 8, the first direction X and the second direction Y may be the horizontal and vertical directions in the plane of the display device 1000, respectively, while the third direction Z may be the thickness direction of the display device 1000. According to one embodiment, the foldable display module 500 may include a display panel 100, a base plate 300 disposed on the back surface of the display panel 100, and a driving circuit unit 200 connected to the frame area BZ of the display panel 100, the driving circuit unit 200 being used to drive the display panel 100. The foldable display module 500 can be bonded to the system frame 700 via an adhesive 600 disposed on the top surface of the system frame 700, and the circuit film 210 of the drive circuit unit 200 can be bent so that the printed circuit board (PCB) 230 is disposed on the back surface of the system frame 700 for assembly. A foldable display device 1000 according to one embodiment may include a plurality of flat regions FA and a folding region FPA disposed and connected between the plurality of flat regions FA. The folding region FPA of the foldable display device 1000 may be disposed along the folding axis FCL of the system frame 700. A foldable display device 1000 according to one embodiment may include, but is not limited to, a folding region FPA disposed between two flat regions FA. A foldable display device 1000 according to one embodiment may include three or more flat regions FA and two or more folding regions FPA, wherein the folding regions FPA are disposed between adjacent flat regions FA. The foldable display device 1000 can be in a folded state and an unfolded state. In the folded state, the folding area FPA is folded relative to the folding axis FCL of the system frame 700, and in the unfolded state, the folding area FPA is unfolded relative to the folding axis FCL of the system frame 700. According to one embodiment, the foldable display device 1000 can be folded inward so that the display area DA of the display panel 100 faces inward. According to another embodiment, the foldable display device 1000 can be folded outward with the back side facing inward. According to one embodiment, the foldable display device 1000 can be folded along a second direction Y, wherein the second direction Y is relative to the folding axis FCL along the first direction X, but is not limited thereto. When the direction of the folding axis FCL is along the second direction Y, the foldable display device 1000 can be folded along the first direction X. According to one embodiment, the display panel 100 can be a flexible display panel. The flexible display panel can be an electroluminescent display panel, a micro-light-emitting diode display panel, or a liquid crystal display panel. The electroluminescent display panel can be an organic light-emitting diode (OLED) display panel, a quantum dot light-emitting diode display panel, or an inorganic light-emitting diode display panel. According to one embodiment, the display panel 100 may include a display area DA for displaying an image and a border area BZ surrounding the display area DA. According to one embodiment, the display panel 100 may further include a touch sensor array disposed on and overlapping the display area DA. According to one embodiment, the display panel 100 may provide touch sensing functionality for sensing the presence and coordinates of a user touch, and display functionality for displaying an image. According to one embodiment, the display panel 100 may include a display unit 110 disposed on a back plate 140, a polarizer 120 disposed on the display unit 110, and a cover film 130 disposed on the polarizer 120. According to one embodiment, the display panel 100 may also include other top layers disposed on the display unit 110, these top layers having optical performance enhancement or protection functions. According to one embodiment, the display panel 100 may also include a support plate 150 disposed behind the back plate 140, and may further include another lower layer with enhancement or protection functions. The support plate 150 may be referred to as a top plate. According to one embodiment, the display unit 110 of the display panel 100 may include a pixel array comprising a plurality of sub-pixels disposed on a back panel 140, an encapsulation layer sealing the pixel array, and a touch sensor array comprising sensing electrodes disposed on the encapsulation layer. The pixel array may include a circuit element layer and a light-emitting element layer. The circuit element layer includes a plurality of thin-film transistors and a plurality of signal lines, and the light-emitting element layer includes a plurality of light-emitting elements disposed on the circuit element layer, each light-emitting element embodying a plurality of sub-pixels. The circuit element layer may include a gate driver for driving the gate lines of the plurality of signal lines. The gate driver may be disposed in the bezel area BZ, or may be distributed in the display area DA and the bezel area BZ. The plurality of thin-film transistors disposed in the display unit 110 of the display panel 100 may include at least one of low-temperature polysilicon (LTPS) transistors and oxide transistors using metal-oxide semiconductors. According to one embodiment, the display panel 100 may be configured to simultaneously contain both LTPS transistors and oxide transistors to reduce power consumption. According to one embodiment, the base plate 300 can be attached to the back of the display panel 100 via an adhesive 610 and provides the display panel 100 with folding characteristics. The base plate 300 can provide additional rigidity to the foldable display module 500 and facilitate heat dissipation. For example, the base plate 300 can be represented by a metal plate or sheet. The base plate 300 can have a laminated structure with multiple metal layers 310, 320, 330. According to one embodiment, the base plate 300 may include a folded area FPA with a folding pattern 340, and a bubble venting pattern 350 is provided in a flat area FA located on both sides of the folded area FPA. The bubble venting pattern 350 may be represented as an opening pattern or an internal pattern. The back of the base plate 300 corresponding to the back of the foldable display module 500 can be bonded to the top surface of the system frame 700 through an adhesive 600 corresponding to each of the multiple flat areas FA. The adhesive 600 can be disposed on the top surface of the frame 700 in the system, overlapping each of the multiple flat areas FA of the foldable display module 500, and not overlapping with the folding area FPA. The foldable display module 500 may have multiple flat areas FA bonded to the top surface of the system frame 700 by multiple adhesives 600, thereby increasing the adhesion between the foldable display module 500 and the system frame 700. The system frame 700 can support the foldable display module 500 to provide additional rigidity and can have a foldable structure relative to the folding axis FCL. According to one embodiment, the system frame 700 may include a plurality of plates connected by hinges disposed in the folding region FPA, thereby having a foldable structure relative to the folding axis FCL. The driving circuit unit 200 may include a plurality of circuit films 210 connected to the bezel area BZ of the display panel 100. Each of the plurality of circuit films 210 has a plurality of driving integrated circuits 220 mounted thereon, and a printed circuit board 230 connected to the plurality of circuit films 210. A plurality of driving integrated circuits 240 and 250 are mounted on the printed circuit board 230. The circuit films 210 may be flexible circuits, such as chip-on-film (COF) or flexible printed circuits (FPC). The driving integrated circuits 220 mounted on the circuit films 210 may be data drivers that drive the data lines of the display panel 100. The plurality of driving integrated circuits 240 and 250 mounted on the printed circuit board 230 may include timing controllers, power management circuits, touch driving circuits, touch controllers, etc. The printed circuit board 230 disposed on and overlapping the rear surface of the system frame 700 can be attached and fixed to the back of the system frame 700 through the adhesive 620. According to one embodiment, adhesives 600, 610, and 620 may include at least one optically clear adhesive (OCA), pressure-sensitive adhesive (PSA), heat-sensitive adhesive, conventional adhesive, and double-sided tape. According to one embodiment, the base plate 300 may have a stacked structure of multiple metal layers 310, 320, and 330. According to one embodiment, the base plate 300 may have a composite metal structure of stacked first to third metal layers 310, 320, and 330, but is not limited thereto. The base plate 300 may include a first metal layer 310 and a third metal layer 330 made of a non-ferrous metal or metal with a rigid reinforcing material, and a second metal layer 320 made of a non-ferrous metal located between the first metal layer 310 and the third metal layer 330, the second metal layer 320 being made of a material with better heat dissipation properties. For example, the first metal layer 310 and the third metal layer 330 may include at least one stainless steel (SUS), magnesium (Mg), titanium (Ti), and other metallic materials. The second metal layer 320 may include at least one metallic material such as aluminum (Al), copper (Cu), etc. The embodiments described herein are not limited thereto. According to one embodiment, the plurality of folding patterns 340 disposed in the folding area FPA of the base plate 300 may have the form of multiple gaps penetrating multiple metal layers 310, 320, 330. Taking into account the folding characteristics and elastic resilience of the folding display device 1000, the size, spacing and number of the plurality of folding patterns 340 may be changed according to their position. According to one embodiment, a plurality of folding patterns 340 in the base plate 300 may include a plurality of slit patterns extending along a first direction X (i.e., the direction of the folding axis FCL of the folding region FPA) and configured to be arranged side by side along a second direction Y perpendicular to the folding axis FCL. The folding characteristics of the plurality of folding patterns 340 can be improved by reducing the spacing between the folding patterns 340 from the folding region FPA along the second direction Y toward the center of the folding axis FCL. Multiple perforation patterns (hereinafter also referred to as bubble venting patterns 350) provided in the flat area FA of the base plate 300 may have the form of double holes provided in some of the multiple metal layers 310, 320, 330. Multiple bubble venting patterns 350 may be connected in a matrix in the flat area FA to serve as venting channels and may perform heat dissipation function to dissipate heat. According to one embodiment, each bubble venting pattern 350 in the base plate 300 may include an outer hole pattern 352 disposed in a first metal layer 310 on the outer side of the back surface of the base plate 300, and an inner hole pattern 354 disposed in an inner second metal layer 320 and corresponding to the outer hole pattern 352. For example, the outer hole pattern 352 may be different from the inner hole pattern 354. The outer hole pattern 352 may have a smaller width than the inner hole pattern 354. After the base plate 300 is bonded to the system frame 700 by the adhesive 600, the flat area FA of the base plate 300 may include a bonding area and a non-bonding area, the bonding area being the area where the adhesive 600 is bonded, and the non-bonding area where the adhesive 600 is not bonded by the outer hole pattern 352. In the flat area FA of the base plate 300, the bonding area area of ​​the adhesive 600 may be larger than the non-bonding area area of ​​the outer hole pattern 352, and the width of the outer hole pattern 352 may be smaller than the width of the inner hole pattern 354 to minimize the non-bonding area area of ​​the adhesive 600. In one embodiment, a material with a greater etching rate for the second metal layer 320 of the base plate 300 than that for the first metal layer 310 can be used, and by over-etching the second metal layer 320 compared to the first metal layer 310, the inner hole pattern 354 can be formed to have a wider width than the outer hole pattern 352. Therefore, according to one embodiment, the base plate 300 can further improve the exhaust and heat dissipation functions by making the inner hole pattern 354 wider than the outer hole pattern 352. Furthermore, according to one embodiment, the base plate 300 can minimize the increase in the non-bonding area of ​​the adhesive 600 to the base plate 300 by having an outer hole pattern 352 with a smaller width than the inner hole pattern 354. Therefore, according to one embodiment, the base plate 300 can minimize the reduction in the bonding area of ​​the adhesive 600 disposed between the foldable display module 500 and the system frame 700 to prevent a decrease in adhesion, thereby preventing the foldable display module 500 from moving due to vibration or impact, and thus preventing screen crease defects. According to one embodiment, the folding pattern 340 disposed in the folding area FPA of the base plate 300 can be formed by using a double-sided etching method, while the bubble venting pattern 350 disposed in the flat area FA can be formed in the same process by using a single-sided etching method. Figures 9 to 12 are perspective views illustrating examples of the back structure of a base plate according to various embodiments of the present disclosure. Referring to FIG9, according to one embodiment, the base plate 300A may include a plurality of bubble venting patterns 350A arranged in a diagonal stripe pattern in a plurality of flat regions FA. Referring to FIG10, the base plate 300B, according to one embodiment, may include a plurality of bubble exhaust patterns 350B disposed in a plurality of flat regions FA in the form of stripes along a first direction X. Referring to FIG11, the base plate 300C, according to one embodiment, may include a plurality of bubble exhaust patterns 350C arranged in a matrix staggered manner in a plurality of flat regions FA. Referring to FIG12, the base plate 300D, according to one embodiment, may include a plurality of bubble venting patterns 350D disposed in a plurality of flat regions FA in the form of stripes along a second direction Y. Figure 13 is a schematic diagram illustrating an example of a bubble removal process during the base plate bonding process according to an embodiment of the present disclosure. Referring to FIG13, according to one embodiment, even if bubble B is generated on the back side of the flat area FA of the base plate 300 during the bonding process of the adhesive 600 and the system frame (system frame 700 as shown in FIG4), bubble B can be removed by the bubble venting pattern 350 of the base plate 300 under the action of bonding pressure, thereby preventing screen defects caused by bubbles and improving product yield. Figure 14 is a cross-sectional view illustrating an example of the overlapping area of ​​the base plate and the drive circuit unit in a foldable display device according to an embodiment of the present disclosure. Referring to FIG14, according to one embodiment, the flat area FA of the base plate 300E may overlap the printed circuit board 230 in the adhesive 600 and system frame 700 therebetween. According to one embodiment, the base plate 300E may include a first bubble venting pattern (first opening pattern) 350A disposed in the region 360 where the flat area FA overlaps with the printed circuit board 230, and a second bubble venting pattern (second hole pattern) 350B disposed in the remaining regions where the flat area FA does not overlap with the printed circuit board 230. The outer hole pattern 352A of the first bubble discharge pattern 350A may have the same or similar width as the outer hole pattern 352B of the second bubble discharge pattern 350B. The inner hole pattern 354A of the first bubble discharge pattern 350A may have a width greater than that of the inner hole pattern 354B of the second bubble discharge pattern 350B. Therefore, according to one embodiment, the first bubble emission pattern 350A of the base plate 300B can further improve the heat dissipation characteristics of the circuit components 240 on the printed circuit board 230, and thus reduce the degradation of the display panel and increase the lifespan of the display panel to achieve a low power consumption effect. Figures 15A to 17B are top and bottom views of examples of the structure of a foldable display device before and after assembly, according to different embodiments of the present invention. The foldable display modules 500A, 500B, and 500C of the foldable display devices 1000A, 1000B, and 1000C shown in Figures 15A to 17B may include a base plate 300E having a first bubble venting pattern 350A and a second bubble venting pattern 350B as shown in Figure 14. Referring to Figures 15A and 15B, according to one embodiment, the foldable display module 500A of the foldable display device 1000A may include a plurality of driving circuit units 200A connected to the bezel regions on both sides of the display panel 100A facing the second direction Y. The first driving circuit unit connected to the first bezel region of the display panel 100A may include a plurality of flexible printed circuit boards 210A and a plurality of printed circuit boards 230A, while the second driving circuit unit connected to the second bezel region of the display panel 100A may include a plurality of flexible printed circuit boards 212A, 214A, 216A and a plurality of printed circuit boards 232A, 234A. After the base plate of the flexible display module 500A (base plate 300E as shown in Figure 14) is joined and assembled with the system frame 700A, the flexible printed circuit board 210A and printed circuit board 230A of the first driving circuit unit and the flexible printed circuit boards 212A, 214A, 216A and printed circuit boards 232A, 234A of the second driving circuit unit can be disposed on the back of the system frame 700A to overlap with the display panel 100A. According to one embodiment, the base plate of the foldable display module 500A (base plate 300E as shown in FIG. 14) may include a first bubble venting pattern (first bubble venting pattern 350A as shown in FIG. 14) and a second bubble venting pattern (second bubble venting pattern 350B as shown in FIG. 14). The first bubble venting pattern is disposed in regions 360A and 362A (corresponding to region 360 in FIG. 14) of the flat region FA that overlaps with the first and second driving circuit units of the driving circuit unit 200A, respectively. The second bubble venting pattern is disposed in the remaining regions of the flat region FA. For example, the inner hole pattern of the first bubble venting pattern may have a larger width than the inner hole pattern of the second bubble venting pattern to further improve the heat dissipation characteristics for heat generated in the driving circuit unit. Referring to Figures 16A and 16B, according to one embodiment, the foldable display module 500B of the foldable display device 1000B may include a driving circuit unit 200B connected to a side bezel area of ​​the display panel 100B. The driving circuit unit 200B connected to the side bezel area of ​​the display panel 100B may include a plurality of flexible printed circuit boards 212B, 214B, 216B and a plurality of printed circuit boards 230B, 232B. After the base plate of the foldable display module 500B (base plate 300E as shown in Figure 14) is joined and assembled with the system frame 700B, the drive circuit unit 200B can overlap the display panel 100B with multiple flexible printed circuit boards 212B, 214B, 216B and multiple printed circuit boards 230B, 232B disposed on the back of the system frame 700B. According to one embodiment, the base plate of the foldable display module 500B (base plate 300E as shown in FIG. 14) includes a first bubble exhaust pattern (first bubble exhaust pattern 350A as shown in FIG. 14), which is disposed in region 360B (corresponding to 360 in FIG. 14) of the flat region FA overlapping with the driving circuit unit, and a second bubble exhaust pattern (second bubble exhaust pattern 350B as shown in FIG. 14) disposed in the remaining regions of the flat region FA. The inner hole pattern of the first bubble exhaust pattern may have a larger width than the inner hole pattern of the second bubble exhaust pattern to further improve the heat dissipation characteristics of heat generated in the driving circuit unit. Referring to Figures 17A and 17B, according to one embodiment, the foldable display module 500C of the foldable display device 1000C may include a plurality of driving circuit units 200C connected to the side bezel regions of the display panel 100C facing the second direction Y. A first driving circuit unit connected to the first bezel region of the display panel 100C may include a plurality of flexible printed circuit boards 210C and printed circuit boards 230C, while a second driving circuit unit connected to the second bezel region of the display panel 100C may include a plurality of flexible printed circuit boards 212C and printed circuit boards 232C. After the base plate of the flexible display module 500C (base plate 300E as shown in Figure 14) is joined and assembled with the system frame 700C, the flexible printed circuit board 210C and printed circuit board 230C of the first driving circuit unit and the flexible printed circuit board 212C and printed circuit board 232C of the second driving circuit unit can be disposed on the back of the system frame 700C to overlap with the display panel 100C. According to one embodiment, the base plate of the foldable display module 500C (base plate 300E as shown in FIG. 14) may include a first bubble venting pattern (first bubble venting pattern 350A as shown in FIG. 14), which is disposed in regions 360C and 362C (corresponding to region 360 in FIG. 14) of the flat region FA that overlaps with the first and second driving circuit units of the driving circuit unit 200C, respectively, and a second bubble venting pattern (second bubble venting pattern 350B as shown in FIG. 14) disposed in the remaining regions of the flat region FA. The inner hole pattern of the first bubble venting pattern may have a larger width than the inner hole pattern of the second bubble venting pattern to further improve the heat dissipation characteristics for heat generated in the driving circuit unit. Figure 18 is a cross-sectional view illustrating an example of the area where a printed circuit board is disposed in a foldable display device according to an embodiment of the present disclosure. Referring to FIG18, in a foldable display device according to one embodiment, a foldable display module including a display panel 100 and a base plate 300E is engaged with a system frame 700. A circuit film 210 connected to the frame area of ​​the display panel 100 can be bent toward the back of the system frame 700 and overlapped with the reinforcing pad 630 between the back of the system frame 700. The printed circuit board 230, which is connected to the display panel 100 through the circuit film 210 and has multiple drive circuits 240, 250 mounted on it, can be attached and fixed to the back of the system frame 700 through the adhesive 620. As shown in Figure 14, in the base plate 300E according to one embodiment, the inner hole pattern 354A of the first bubble venting pattern 350A disposed in the region 360 where the flat region FA overlaps with the printed circuit board 230 has a larger width than the inner hole pattern 354B of the second bubble venting pattern 350B disposed in the remaining regions of the flat region FA where it does not overlap with the printed circuit board 230. Therefore, the heat dissipation characteristics of the circuit components 240, 250 on the printed circuit board 230 can be further improved, thereby reducing the degradation of the display panel and extending its lifespan, achieving a low power consumption effect. As described above, according to one embodiment, even if bubbles are generated during the joining process between the foldable display module and the system frame, the foldable display device can prevent screen defects caused by bubbles by removing the bubbles through an opening pattern (bubble venting pattern) provided in a flat area of ​​the bottom plate of the foldable display module, thereby improving product yield and achieving the effect of reducing production energy and reducing greenhouse gas emissions. According to one embodiment, the foldable display device has an opening pattern (bubble discharge pattern) on the base plate, the opening pattern having an outer width smaller than the inner width, which can minimize the degradation of the bonding area of ​​the adhesive disposed between the foldable display module and the frame of the system to prevent degradation of the adhesive, thereby preventing the foldable display module from moving due to vibration or impact, and thus avoiding the occurrence of screen wrinkles. According to one embodiment, the foldable display device can improve the heat dissipation characteristics of the foldable display module by utilizing a base plate with an opening pattern (bubble venting pattern). Furthermore, according to one embodiment, the foldable display device can further improve the heat dissipation characteristics of the circuit components by providing that the inner width of the opening pattern (bubble venting pattern) in the area overlapping the printed circuit board is larger than the inner width of other portions. Therefore, the foldable display device according to one embodiment can improve heat dissipation characteristics, thereby reducing display panel degradation and extending the display panel's lifespan, and thus achieving low power consumption. According to some aspects, the foldable display device may include a system frame capable of folding relative to a folding axis; and a foldable display module having a folding region engaged with the system frame and capable of folding relative to the folding axis, and a plurality of flat regions connected through the folding region, wherein the foldable display module includes a display panel containing the plurality of flat regions and the folding region, and a base plate engaged between the display panel and the system frame, the base plate including a plurality of folding patterns disposed in the folding region and a plurality of opening patterns disposed in the plurality of flat regions, wherein each of the plurality of opening patterns includes an outer hole pattern and an inner hole pattern associated with the outer hole pattern. In some aspects of foldable display devices, the inner hole pattern among multiple opening patterns may have a width greater than that of the outer hole pattern. In some aspects of the foldable display device, the base plate may include multiple stacked metal layers, and the outer hole pattern may be set in the outer metal layer among the multiple metal layers closest to the system frame, and the inner hole pattern may be set in the inner metal layer located inside the outer metal layer. In some aspects of the foldable display device, the base plate may include stacked first, second and third metal layers, and an outer hole pattern may be provided in the first metal layer closest to the system frame, while an inner hole pattern may be provided in the second metal layer located inside the first metal layer. In some aspects of foldable display devices, the base plate can overlap with multiple flat areas and can be joined to the top surface of the system frame through multiple adhesives in the folded areas. In some aspects of the foldable display device, the multiple flat areas of the base plate may include bonding areas where the adhesive is joined and non-bonding areas where the adhesive is not joined by an external hole pattern, and the area of ​​the bonding areas may be larger than the area of ​​the non-bonding areas. In some aspects of the foldable display device, multiple opening patterns can be arranged in the form of stripes extending in at least one of a first direction parallel to the folding axis, a second direction perpendicular to the first direction, and a diagonal direction between the first and second directions, or connected in a matrix form. In some aspects of the foldable display device, the multiple folding patterns of the base plate may have multiple slits that penetrate multiple metal layers and extend in the same direction as the folding axis, and the spacing between the multiple folding patterns may be reduced as the folding axis approaches the folding area from multiple flat areas. In some aspects of foldable display devices, the foldable display module may further include a drive circuit unit associated with the display panel and disposed on the back of the system frame. In a foldable display device according to some aspects, the plurality of opening patterns in the base plate may include a plurality of first opening patterns disposed in a plurality of flat regions overlapping a first region of a driving circuit unit, and a plurality of second opening patterns disposed in a plurality of flat regions not overlapping a second region of a driving circuit unit and having a different size from the plurality of first opening patterns. In a foldable display device according to some aspects, the first inner hole pattern among a plurality of first opening patterns may have a wider width than the second inner hole pattern among a plurality of second opening patterns. In a foldable display device according to some aspects, the first outer hole pattern among a plurality of first opening patterns may have the same or similar width as the second outer hole pattern among a plurality of second opening patterns. In some aspects of the foldable display device, the driving circuit unit may include a printed circuit board that is connected to the display panel through a circuit film and on which a plurality of driving circuits are mounted, and a plurality of first opening patterns may be set in an area overlapping with the printed circuit board. According to some aspects, a foldable display device may include a display panel comprising a plurality of flat areas and a folding area disposed between the plurality of flat areas and foldable relative to a folding axis; a base plate attached to the back of the display panel, the base plate including a plurality of folding patterns corresponding to the folding areas and a plurality of opening patterns corresponding to the plurality of flat areas, the plurality of opening patterns including an outer hole pattern and an inner hole pattern having a size different from the outer hole pattern; and a system frame attached to the base plate by a plurality of adhesives respectively disposed on the back of the base plate corresponding to the plurality of flat areas, and the system frame being foldable relative to a folding axis. In some aspects of foldable display devices, the inner hole pattern can have a width greater than that of the outer hole pattern. In some aspects of the foldable display device, the base plate may include stacked first, second and third metal layers, and an outer hole pattern may be provided in the first metal layer bonded to the system frame through a plurality of adhesives, while an inner hole pattern may be provided in the second metal layer located inside the first metal layer. In some aspects of the foldable display device, multiple opening patterns can be arranged in the form of stripes extending in at least one of a first direction parallel to the folding axis, a second direction perpendicular to the first direction, and a diagonal direction between the first and second directions, or connected in a matrix form. In a foldable display device according to some aspects, the multiple folding patterns of the base plate may have the form of multiple slits penetrating the base plate and extending in a first direction, and the spacing between the multiple folding patterns may be reduced as the folding axis approaches the folding area from multiple flat areas. The foldable display device may further include a drive circuit unit associated with the display panel and disposed on the back of the system frame. The plurality of opening patterns in the base plate may include a plurality of first opening patterns disposed in a plurality of flat areas overlapping a first area of ​​the drive circuit unit, and a plurality of second opening patterns disposed in a plurality of flat areas not overlapping a second area of ​​the drive circuit unit and having a different size from the plurality of first opening patterns. In a foldable display device according to some aspects, the first inner hole pattern of a plurality of first opening patterns may have a wider width than the second inner hole pattern of a plurality of second opening patterns. In a foldable display device according to some aspects, the first outer hole pattern of a plurality of first opening patterns may have the same or similar width as the second outer hole pattern of a plurality of second opening patterns. In some aspects of the foldable display device, the driving circuit unit may include a printed circuit board that is connected to the display panel through a circuit film and on which a plurality of driving circuits are mounted, and a plurality of first opening patterns may be disposed in an area overlapping the printed circuit board. The features, structures, and effects described above are included in at least one embodiment of the present invention, but are not limited to only one embodiment. Furthermore, the features, structures, and effects described in at least one embodiment of the present invention can be implemented by those skilled in the art through combination or modification of other embodiments. Therefore, content related to combination and modification should be considered to fall within the scope of the present invention. Various substitutions, modifications, and alterations are readily apparent to those skilled in the art without departing from the spirit and scope of this invention. Therefore, the scope of this invention is defined by the following claims, and all alterations or modifications derived from the meaning, scope, and equivalent concepts of the claims should be interpreted as being included within the scope of this invention. 1000, 1000A, 1000B, 1000C: Foldable display device; 100, 100A, 100B, 100C: Display panel; 110: Display unit; 120: Polarizing film; 130: Cover film; 140: Back plate; 150: Support plate; 200, 200A, 200B, 200C: Drive circuit unit; 210: Circuit film; 210A: Flexible printed circuit board; 210C: Flexible printed circuit board; 21 2A: Flexible Printed Circuit Board 212B: Flexible Printed Circuit Board 212C: Flexible Printed Circuit Board 214A: Flexible Printed Circuit Board 214B: Flexible Printed Circuit Board 216A: Flexible Printed Circuit Board 216B: Flexible Printed Circuit Board 220: Driver Integrated Circuit 230, 230A, 230B, 230C: Printed Circuit Board 232A, 232B, 232C: Printed Circuit Board 234A: Printed Circuit Board 240: Drive integrated circuit board; 250: Drive integrated circuit board; 300, 300A, 300B, 300C, 300D, 300E: Base plate; 310: Metal layer; 320: Metal layer; 330: Metal layer; 340: Folding pattern; 350, 350A, 350B, 350C, 350D: Exhaust pattern; 352, 352A, 352B: External hole pattern; 354, 354A, 354B: Internal hole pattern. 60, 360A, 360B, 360C: Areas; 362A, 362C: Areas; 500, 500A, 500B, 500C: Foldable display module; 600: Adhesive; 610: Adhesive; 620: Adhesive; 630: Reinforcing pad; 700, 700A, 700B, 700C: System frame; B: Bubble; BZ: Border area; DA: Display area; FA: Flat area; FCL: Folding axis; FPA: Folding area. The accompanying drawings, which are included in this disclosure and form part of this invention, illustrate embodiments of the disclosure and, together with the description, explain the principles of the disclosure. In the drawings: Figures 1 and 2 are perspective views schematically illustrating an example of the front and rear configuration of a foldable display device according to an embodiment of the present disclosure. Figures 3 and 4 are schematic cross-sectional views illustrating an example of a foldable display device configured before and after engagement according to an embodiment of the present disclosure. Figure 5 is a cross-sectional view of a foldable display device and an example of the back structure of the base plate according to an embodiment of the present disclosure. Figure 6 is a plan view of an example of the back side structure of a base plate according to an embodiment of the present disclosure. Figures 7A and 7B are perspective views of an example base plate structure, respectively, showing views from the top and rear sides according to an embodiment of the present disclosure. Figure 8 is a cross-sectional view of an example base plate portion according to an embodiment of the present disclosure. Figures 9 to 12 are perspective views of the back side structure of an example base plate according to several embodiments of the present disclosure. Figure 13 is a schematic diagram illustrating an example of a bubble removal process during the base plate bonding process according to an embodiment of the present disclosure. Figure 14 is a cross-sectional view illustrating an example of the overlapping area of ​​the base plate and the drive circuit unit in a foldable display device according to an embodiment of the present disclosure. Figures 15A and 15B are top and bottom views of an example of the structure of a foldable display device before and after assembly, according to an embodiment of the present disclosure. Figures 16A and 16B are top and bottom views illustrating a structural example of a foldable display device before and after assembly, according to another embodiment of the present disclosure. Figures 17A and 17B are top and bottom views of an example of a foldable display device according to an embodiment of the present disclosure. Figure 18 is a cross-sectional view illustrating an example of the area where a printed circuit board is disposed in a foldable display device according to an embodiment of the present disclosure. 1000: Foldable display device 100: Display panel 110: Display Unit 120: Polarizing film 130: Covering film 140: Backplate 150: Support plate 200: Drive circuit unit 210: Circuit Thin Film 230: Printed Circuit Board 240: Driver integrated circuit 250: Driver integrated circuit 300: Base Plate 310: Metal layer 320: Metal layer 330: Metal layer 340: Folded Pattern 350: Exhaust pattern 352: External Hole Pattern 354: Inner Hole Pattern 500: Foldable display module 600: Adhesive 610: Adhesive 620: Adhesive 700: System frame FA: Flat area FPA: Folded Area

Claims

1. A display device, comprising: A system frame that can be folded relative to a folding axis; The system also includes a foldable display module having a folding area and a plurality of flat areas. The folding area is engaged with the system frame and is foldable relative to the folding axis. The flat areas are connected through the folding area. The foldable display module includes: a display panel including the flat areas and the folding area; and a base plate engaged between the display panel and the system frame, including a plurality of folding patterns disposed in the folding area and a plurality of opening patterns disposed in the flat areas. Each of the opening patterns includes an outer hole pattern and an inner hole pattern associated with the outer hole pattern. The opening patterns are arranged in a stripe pattern and extend along at least one of a first direction parallel to the folding axis, a second direction perpendicular to the first direction, and a diagonal direction between the first and second directions, or are connected in a matrix.

2. The display device as claimed in claim 1, wherein the inner hole pattern of the aperture pattern has a width greater than that of the outer hole pattern.

3. The display device as claimed in claim 1, wherein the base plate comprises a plurality of stacked metal layers, and wherein the outer hole pattern is provided in an outer metal layer among the metal layers closest to the system frame, and the inner hole pattern is provided in an inner metal layer among the metal layers located inside the outer metal layer.

4. The display device as claimed in claim 1, wherein the base plate includes a stacked first metal layer, a second metal layer and a third metal layer, and wherein the outer hole pattern is provided in the first metal layer closest to the system frame, and the inner hole pattern is provided in the second metal layer located inside the first metal layer.

5. The display device as claimed in claim 1, wherein the base plate overlaps the flat areas and is joined to a top surface of a frame in the system via a plurality of adhesives in the folded areas.

6. The display device as claimed in claim 5, wherein the flat areas of the base plate include a bonding area and a non-bonding area, the adhesives are bonded in the bonding area and the adhesives are not bonded by the external hole pattern in the non-bonding area, and wherein the area of ​​the bonding area is larger than the area of ​​the non-bonding area.

7. The display device as claimed in claim 3, wherein the folded patterns of the base plate have a plurality of slits penetrating the metal layers and extending in the same direction as the folding axis, and wherein a spacing between the folded patterns decreases as the folding axis approaches the folding region from the flat areas.

8. The display device as claimed in claim 1, wherein the foldable display module further includes a driving circuit unit, wherein the driving circuit unit is associated with the display panel and disposed on a back surface of the frame of the system.

9. The display device as claimed in claim 8, wherein the opening pattern in the substrate includes: Multiple first aperture patterns are disposed in a first region overlapping the flat regions of the drive circuit unit; And a plurality of second opening patterns, disposed in a second region that does not overlap with the flat regions of the drive circuit unit, and having a size different from the first opening patterns.

10. The display device as claimed in claim 9, wherein a first inner hole pattern of the first opening patterns has a width greater than a second inner hole pattern of the second opening patterns.

11. The display device as claimed in claim 9, wherein a first outer hole pattern of the first opening patterns has a width identical to a second outer hole pattern of the second opening patterns.

12. The display device as claimed in claim 9, wherein the driving circuit unit includes a printed circuit board connected to the display panel through a circuit film and having a plurality of driving circuits disposed thereon, and wherein the first aperture pattern is disposed in a region overlapping the printed circuit board.

13. A display device, comprising: A display panel includes multiple flat areas and a folding area disposed between the flat areas and foldable relative to a folding axis. A base plate, joined to a back surface of the display panel, and including a plurality of folding patterns corresponding to the folding areas and a plurality of opening patterns corresponding to the flat areas, the opening patterns including an outer hole pattern and an inner hole pattern having a size different from the outer hole pattern; and a system frame, joined to the base plate by a plurality of adhesives respectively disposed on a back surface of the base plate corresponding to the flat areas, and foldable relative to the folding axis, wherein the opening patterns are arranged in a stripe pattern and extend along at least one of a first direction parallel to the folding axis, a second direction perpendicular to the first direction, and a diagonal direction between the first direction and the second direction, or connected in a matrix form.

14. The display device as claimed in claim 13, wherein the inner hole pattern has a width greater than that of the outer hole pattern.

15. The display device as claimed in claim 14, wherein the base plate includes a stacked first metal layer, a second metal layer and a third metal layer, and wherein the outer hole pattern is provided in the first metal layer bonded to the system frame through the adhesives, and the inner hole pattern is provided in the second metal layer located inside the first metal layer.

16. The display device as claimed in claim 13, wherein the folded patterns of the base plate have a form in which a plurality of slits penetrate the base plate and extend along the first direction, and wherein a spacing between the folded patterns decreases as the folding axis approaches the folded regions from the flat regions.

17. The display device as claimed in claim 13 further includes a drive circuit unit associated with the display panel and disposed on a back surface of a frame in the system, wherein the opening pattern in the base plate includes: Multiple first aperture patterns are disposed in a first region overlapping the flat regions of the drive circuit unit; And a plurality of second opening patterns, disposed in a second region that does not overlap with the flat regions of the drive circuit unit, and having a size different from the first opening patterns.

18. The display device as claimed in claim 17, wherein a first inner hole pattern of the first opening patterns has a width greater than a second inner hole pattern of the second opening patterns.

19. The display device as claimed in claim 17, wherein a first inner hole pattern of the first opening patterns has a width identical to a second inner hole pattern of the second opening patterns.

20. The display device as claimed in claim 18, wherein the driving circuit unit includes a printed circuit board connected to the display panel through a circuit film and having a plurality of driving circuits disposed thereon, and wherein the first aperture pattern is disposed in a region overlapping the printed circuit board.

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