Middle frame forming method, manufacturing method of folding display device and printing device

Abstract

The invention relates to the technical field of folding display, in particular to a middle frame forming method, a manufacturing method of a folding display device and the display device. The middle frame forming method of the folding display device comprises the steps that a printing base body is provided; the printing substrate comprises a back plate, a display module and a cover plate; the printing base body comprises an edge area; the edge area comprises a folding area and a non-folding area, the folding area is in a bent state when the display device is in a folded state, and the non-folding area is the part, except the folding area, in the edge area; printing the middle frame: printing a middle frame non-folding part in a non-folding area by using a 3D printing mode; a middle frame folding part is printed in the folding area in a 3D printing mode; the problems that after a folding display device is used for a long time, a screen is loosened, and waterproof and dustproof effects are not ideal can be effectively solved.

Description

Technical Field

[0001] The present invention relates to the field of folding display technology, and in particular to a middle frame forming method, a manufacturing method of a folding display device, and a printing device. Background Art

[0002] With the development of display technology, the shapes of display screens are becoming more and more diverse. In particular, folding screens have become a widely used product in the field of smartphones. Display devices with folding screens, especially smartphones with folding screens, have two usage states when in use: folded state and unfolded state. After long-term use, problems such as loose screens and unsatisfactory waterproof and dustproof properties are prone to occur. This is because, for folding display devices, the mainstream middle frame is a metal middle frame, which is connected to the screen by adhesive. There is a certain degree of process error in the production of the metal middle frame, so it is difficult to achieve complete fit with the screen, which leads to loose screens and poor waterproof and dustproof effects after long-term use. In addition, the metal middle frame is prone to irreversible deformation after physical impact, which further causes the above problems. The metal middle frame has sharp edges, which can easily damage the screen during assembly with the screen. In addition, the metal middle frame also has the problems of complex process, low production efficiency and high cost.

[0003] Therefore, a solution is needed to solve the problems of loose screen after long-term use caused by the metal middle frame of the folding display device, poor waterproof and dustproof performance, easy damage to the screen during assembly, low production efficiency and high cost. Summary of the invention

[0004] Therefore, in order to solve the problems of the metal middle frame of the folding display device, such as the loosening of the screen after long-term use, unsatisfactory waterproof and dustproof properties, easy damage to the screen during assembly, low production efficiency and high cost, the present invention provides a method for forming a middle frame of a folding display device and a method for manufacturing a folding display device.

[0005] The present invention provides a method for forming a middle frame of a foldable display device, comprising the following steps: providing a printing substrate; the printing substrate comprising a back plate, a display module and a cover plate; the printing substrate comprising an edge area, the edge area being an area including an edge of the back plate, an edge of the display module and an edge of the cover plate, and a width of the back plate, the display module layer and the cover plate from the edge to the center of the printing substrate; the edge area comprising a folding area and a non-folding area, the folding area being in a bent state when the display device is in a folded state, and the non-folding area being a portion of the edge area excluding the folding area; printing the middle frame, comprising: using a 3D printing method to print a non-folding portion of the middle frame in the non-folding area; using a 3D printing method to print a folding portion of the middle frame in the folding area.

[0006] Optionally, the middle frame folding portion includes a plurality of parallel and spaced prismatic structures to form a middle frame folding portion having a tooth-like structure; the length extension direction of the prismatic structure is perpendicular to the edge of the display device where the prismatic structure is located.

[0007] Optionally, the step of printing the middle frame folding portion in the folding area using 3D printing includes: using the print head of a 3D printer to print a plurality of the prismatic structures in sequence and in parallel on one side surface of the folding area, until the distance between the currently printed prismatic structure and the nearest non-folding area is less than the width of one of the prismatic structures.

[0008] Optionally, the spacing between the prismatic structures is greater than half the width of the prismatic structure and less than the width of one prismatic structure.

[0009] Optionally, the method for forming a middle frame of a display device further includes: printing a folding area frame bottom on a side surface of the folding area; the folding area frame bottom completely covers the folding area; and the prismatic structure is printed and formed on the folding area frame bottom.

[0010] Optionally, the sum of the thickness of the bottom of the folding area frame and the height of the prismatic structure is equal to the thickness of the non-folding part of the middle frame; the longitudinal cross-sectional shape of the prismatic structure includes a rectangle or a triangle; and each vertex of the longitudinal cross-sectional shape of the prismatic structure is a sharp corner or a rounded corner.

[0011] Optionally, the step of printing the middle frame folding portion in the folding area using a 3D printing method includes: using the print head of a 3D printer to print a plurality of front rib-like structures in sequence and in parallel on the surface of one side of the cover plate of the folding area, wherein the spacing between the currently printed front rib-like structure and the nearest non-folding area is less than the width of one of the rib-like structures; using the print head of a 3D printer to print a plurality of back rib-like structures in sequence and in parallel on the surface of one side of the back plate of the folding area, until the spacing between the currently printed back rib-like structure and the nearest non-folding area is less than the width of one of the rib-like structures; the midline of the spacing area between the rib-like structures on one side of the cover plate corresponds one-to-one to the midline of the rib-like structures on one side of the back plate; the midline of the spacing area between the rib-like structures on one side of the back plate corresponds one-to-one to the midline of the rib-like structures on one side of the cover plate.

[0012] Optionally, the method for forming a middle frame of a display device also includes: printing a front folding area frame bottom on a surface of one side of a cover plate of the folding area; the front folding area frame bottom completely covers the folding area; various prismatic structures formed by printing on one side of the cover plate are printed on the front folding area frame bottom; printing a back folding area frame bottom on a surface of one side of a back plate of the folding area; the back folding area frame bottom completely covers the folding area; various prismatic structures formed by printing on one side of the cover plate are printed on the back folding area frame bottom.

[0013] Optionally, the step of printing the middle frame also includes: the 3D printing method includes using a 3D printer for 3D printing; the 3D printer includes a first print head and a second print head; the first print head and the second print head use different printing glues respectively; the 3D printer also includes a scanning unit and a path calculation unit; the scanning unit scans the shape of the printing substrate to obtain shape data; the path calculation unit calculates the printing paths of the first print head and the second print head according to the shape data; using the first print head to print along the inner edge of the edge area according to the calculated printing path to form an inner retaining wall; using the first print head to print along the outer edge of the edge area to form an outer retaining wall; printing along the boundary line between the non-folding area and the folding area to form a dividing retaining wall; using the second print head to print in the non-folding area according to the calculated printing path to form a filling layer, the filling layer fills the space in the non-folding area jointly defined by the inner retaining wall, the outer retaining wall and the dividing retaining wall; using the second print head to print in the folding area according to the calculated printing path to form the folding portion of the middle frame.

[0014] Optionally, the first print head prints a first glue, and the second print head prints a second glue; the viscosity of the first glue is greater than the viscosity of the second glue; the first glue is conformal, and the second glue is fluid.

[0015] Optionally, the 3D printing method includes one or more of direct writing printing, piezoelectric valve printing, needle valve printing and inkjet printing.

[0016] The present invention further provides a method for manufacturing a foldable display device, wherein a middle frame of the foldable display device is formed by the method for forming a middle frame of a foldable display device provided by the present invention.

[0017] The present invention also provides a printing device, which is suitable for 3D printing a printing substrate to form a middle frame; the printing device includes: a carrier, suitable for carrying the printing substrate; a printing unit, suitable for printing the middle frame material in the edge area of ​​the printing substrate; the printing unit includes at least two print heads, suitable for printing different materials respectively, one of which is suitable for forming an anti-overflow wall in the non-folding area and a prismatic structure in the folding area of ​​the middle frame; and the other is suitable for forming a filling layer filling the space surrounded by the anti-overflow wall; a bracket, suitable for installing the printing unit; a scanning unit, suitable for scanning the shape of the printing substrate and obtaining shape data; a path calculation unit, suitable for receiving the data obtained by the scanning unit and calculating the printing route; a driving unit, suitable for driving the bracket to move according to the printing route provided by the path calculation unit, so as to drive the scanning unit and the printing unit to move.

[0018] The beneficial effects of the technical solution of the present invention are:

[0019] The method for forming the middle frame of the folding display device provided by the present invention forms a middle frame folding part and a middle frame non-folding part of different shapes in the folding area and the non-folding area of ​​the edge area respectively by 3D printing; the folding display middle frame formed in this way, the middle frame formed by 3D printing and the back plate or cover plate are more tightly combined than the metal middle frame by adhesive bonding, and the bonding strength is higher, so the degree of loosening of the screen after long-term use can be reduced, and the waterproof and dustproof performance is better, and the degree of decline in waterproof and dustproof performance after long-term use can also be reduced, and a high waterproof and dustproof performance is maintained. Further overcome the problem of loose screen and unsatisfactory waterproof and dustproof after long-term use of the folding display device caused by the metal middle frame. At the same time, because the middle frame is formed by 3D printing, there is no need to use a metal middle frame, so the screen is easily damaged during assembly, and the problems of low production efficiency and high cost can be avoided. In addition, the present invention also correspondingly proposes a folding display device forming method including the middle frame forming method of the present invention and a printing device used therefor, so as to achieve the above-mentioned corresponding beneficial effects.

[0020] Furthermore, the method for forming the middle frame of the folding display device provided by the present invention forms a middle frame folding portion including a plurality of parallel and spaced prismatic structures, forming a middle frame folding portion having a tooth-like structure. Such a middle frame folding portion has a space between the prismatic structures, and when folded, this portion acts as a buffer when the physical structure is tightened, so that the mutual squeezing force on the physical structure during the folding process is reduced, the structural strain is reduced, and the loss of the physical structure after long-term use can be reduced. This further overcomes the problem of the screen becoming loose after long-term use and the unsatisfactory waterproof and dustproof caused by the metal middle frame of the folding display device.

[0021] Furthermore, in the method for forming the middle frame of the foldable display device provided by the present invention, the spacing between the prismatic structures is greater than the width of half of the prismatic structure and less than the width of one prismatic structure. If the spacing is too small, the prismatic structures will be obviously squeezed against each other when the display device is in the folded state, which is easy to increase the strain caused by use. If the spacing is too large, the prismatic structures cannot be perfectly fitted together when the display device is in the folded state, and the supporting and protective functions are not good.

[0022] Furthermore, in the method for forming a middle frame of a foldable display device provided by the present invention, the sum of the thickness of the frame bottom in the folding area and the height of the prismatic structure is equal to the thickness of the non-folding portion of the middle frame, so that the overall height of the middle frame in the folding area and the non-folding area is the same, the shape is beautiful, and the overall height consistency of the middle frame is ensured, thereby preventing the middle frame from warping in some positions due to inconsistent heights at various locations in the subsequent process.

[0023] Furthermore, in the method for forming the middle frame of the foldable display device provided by the present invention, when the design of the middle frame needs to cover the display device on both sides, it can be set so that the center line of the spacing area between the prismatic structures on one side of the cover plate corresponds to the center line of the prismatic structures on one side of the back plate; the center line of the spacing area between the prismatic structures on one side of the back plate corresponds to the center line of the prismatic structures on one side of the cover plate. In this way, the stress points can be more dispersed when bending, the stress is more uniform, and the loss caused by long-term use and the corresponding defects mentioned above can be avoided, which can effectively extend the service life of the middle frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A schematic top view of a middle frame formed by a method for forming a middle frame of a foldable display device;

[0026] Figure 2 A schematic top view of a middle frame formed by a method for forming a middle frame of a foldable display device according to an embodiment of the present invention;

[0027] Figure 3 A schematic top view of a folding area after a folding portion of a middle frame is formed in a method for forming a middle frame of a foldable display device according to an embodiment of the present invention;

[0028] Figure 4-Figure 7 A schematic longitudinal section diagram of a folding area after a folding portion of a middle frame is formed in a method for forming a middle frame of a folding display device according to different embodiments of the present invention;

[0029] Figure 8 It is a schematic flow chart of a method for forming a middle frame of a foldable display device according to an embodiment of the present invention;

[0030] Fig. 9 It is a flow chart of a step of printing a middle frame in a method for forming a middle frame of a foldable display device according to an embodiment of the present invention;

[0031] Fig.10 It is a flow chart of a step of printing a middle frame in a method for forming a middle frame of a foldable display device according to another embodiment of the present invention;

[0032] Fig.11 FIG. 4 is a schematic diagram of the structure of a printing device according to an embodiment of the present invention.

[0033] 100-printing substrate; 200-middle frame; 211-inner retaining wall; 212-outer retaining wall; 213-dividing retaining wall; 220-filling layer; 230-middle frame folding part; 231-folding area frame bottom; 232-prismatic structure; 2311-front folding area frame bottom; 2321-front prismatic structure; 2312-back folding area frame bottom; 2322-back prismatic structure; 310-carrier; 320-bracket; 331-first print head; 332-second print head; A-printing substrate. DETAILED DESCRIPTION

[0034] refer to Figure 1 A method for forming a middle frame of a foldable display device. The state after the middle frame is formed is as follows Figure 1 As shown. It includes a printed substrate 100 and a middle frame 200. The printed substrate includes a back plate, a display module and a cover plate which are stacked. The middle frame formed in this way is usually a metal middle frame. After long-term use, the screen becomes loose, the waterproof and dustproof are not ideal, and the screen is easily damaged during assembly. The metal middle frame itself also has the problems of low production efficiency and high cost.

[0035] Therefore, the present invention provides a method for forming a middle frame of a folding display device and a method for manufacturing the folding display device, so as to overcome the problems of the folding display device caused by the metal middle frame, such as the loosening of the screen after long-term use, unsatisfactory waterproof and dustproof, easy damage of the screen during assembly, low production efficiency and high cost.

[0036] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] Example 1

[0041] refer to Figure 8 and Figure 2 , Figure 3 , Figure 4 This embodiment provides a method for forming a middle frame of a foldable display device, comprising the following steps:

[0042] S100: providing a printing substrate 100; the printing substrate 100 comprises a back plate, a display module and a cover plate which are stacked; the printing substrate comprises an edge region, the edge region is a region including an edge of the back plate, an edge of the display module and an edge of the cover plate, and a width of the back plate, the display module layer and the cover plate from the edge to the center of the printing substrate; the edge region comprises a folding region and a non-folding region, the folding region is in a bent state when the display device is in a folded state, and the non-folding region is a portion of the edge region other than the folding region;

[0043] S200: Printing middle frame 200, including:

[0044] S210: Printing a non-folding portion of a middle frame in the non-folding area by 3D printing;

[0045] S220: Printing the middle frame folding portion 230 in the folding area by 3D printing.

[0046] The method for forming the middle frame of the folding display device provided in this embodiment forms the middle frame folding portion 230 and the middle frame non-folding portion of different shapes in the folding area and the non-folding area of ​​the edge area respectively by 3D printing. The folding display middle frame formed in this way, the middle frame formed by 3D printing and the back plate or cover plate are more tightly combined than the metal middle frame by adhesive bonding, and the bonding strength is higher, so the degree of looseness of the screen after long-term use can be reduced, and the waterproof and dustproof performance is better, and the degree of decline in waterproof and dustproof performance after long-term use can also be reduced. While maintaining a high waterproof and dustproof performance, because the middle frame is formed by 3D printing, there is no need to use a metal middle frame, so the screen can be easily damaged during assembly, and the problems of low production efficiency and high cost can be avoided.

[0047] The middle frame folding portion 230 includes a plurality of parallel and spaced prismatic structures 232, forming a middle frame folding portion 230 with a tooth-like structure; the length extension direction of the prismatic structure 232 is perpendicular to the side of the display device where the prismatic structure is located. In this way, when the display device is folded, the length direction of the prismatic structure is perpendicular to the folding direction of the display device and parallel to the crease direction, and will not hinder the folding of the display device. In addition, such a middle frame folding portion 230 has intervals between the prismatic structures. When folded, this part serves as a buffer when the physical structure part (such as the prismatic structure 232) is tightened, so that the mutual squeezing force on the physical structure part during the folding process is reduced, the structural strain is reduced, and the loss of the physical structure part after long-term use can be reduced. It further overcomes the problem of loose screen and unsatisfactory waterproof and dustproof after long-term use caused by the metal middle frame of the folding display device.

[0048] Specifically, as shown in the figure, the middle frame folding portion 230 is located at the long side of the display device, so the prismatic structure 232 is also located at the long side of the display device, and the length extension direction of the prismatic structure 232 is perpendicular to the long side of the display device where it is located. In some other embodiments, the folding area is located at the short side of the display device, and accordingly, the middle frame folding portion 230 is also located at the short side of the display device, and in this case, the length extension direction of the prismatic structure 232 is perpendicular to the short side of the display device where it is located.

[0049] In addition, the folding area and the corresponding middle frame folding portion 230 shown in the figure are located near the center line of the display device. In some other embodiments, they can also be located at other positions, which are determined by the specific setting position of the folding line of the folding display device, and the present invention is not limited to this.

[0050] Specifically, refer to Fig. 9 The step S220 of printing the middle frame folding portion in the folding area by 3D printing includes:

[0051] S222: Using the print head of the 3D printer, a plurality of prismatic structures 232 are sequentially and parallelly printed on one side surface of the folding area until the distance between the currently printed prismatic structure 232 and the nearest non-folding area is less than the width of one of the prismatic structures. By means of the print head, prismatic structures 232 spaced apart and arranged in parallel with each other are formed according to a pre-set printing path, so that the structural accuracy of the folding area of ​​the middle frame can be ensured.

[0052] More specifically, the spacing between the prismatic structures 232 is greater than half the width of the prismatic structure 232 and less than the width of one prismatic structure 232. If the spacing is too small, the prismatic structures 232 will be significantly squeezed against each other when the display device is in the folded state, which may easily increase the strain caused by use. If the spacing is too large, the prismatic structures 232 will not fit perfectly together when the display device is in the folded state, and the supporting and protective functions will be poor.

[0053] Further, also refer to Fig. 9 ,as well as Figure 4 The method for forming a middle frame of the display device of this embodiment further includes:

[0054] S221: Printing a folding area frame bottom 231 on one side surface of the folding area; the folding area frame bottom 231 completely covers the folding area; the prismatic structure 232 is printed and formed on the folding area frame bottom. By setting the folding area frame bottom 231, since it completely covers the folding area and is formed by printing, it is closely combined with the printed substrate of the folding area, so the waterproof and dustproof performance of the middle frame folding part 230 in the folding area can be guaranteed, and the problem of reduced waterproof and dustproof performance due to the presence of gaps due to the prismatic structure 232 set as an interval will not occur.

[0055] Furthermore, the sum of the thickness of the frame bottom 231 in the folding area and the height of the prismatic structure 232 is equal to the thickness of the non-folding portion of the middle frame; in this way, the overall height of the middle frame in the folding area and the non-folding area is the same, the shape is beautiful, and the overall height consistency of the middle frame is ensured, preventing the middle frame from warping in some places due to inconsistent heights in subsequent processes.

[0056] In addition, reference Figure 4 and Figure 5 The longitudinal section of the prismatic structure 232 includes a rectangular or triangular shape; different longitudinal section conditions can be selected according to the shape of the middle frame folding portion required when the folding display device is in the folded state. In addition, each vertex of the longitudinal section of the prismatic structure 232 can be a sharp corner or a rounded corner, that is, the corner is a special shape of a rectangle or triangle.

[0057] For further reference, Fig.10 as well as Figure 6 and Figure 7In some other embodiments, the step S220 of printing the middle frame folding portion in the folding area by 3D printing includes:

[0058] S2221: Using the print head of a 3D printer, a plurality of front prismatic structures 2321 are sequentially and parallelly printed on the surface of one side of the cover plate of the folding area, until the distance between the currently printed front prismatic structure 2321 and the nearest non-folding area is less than the width of one of the prismatic structures;

[0059] S2222: Using the print head of a 3D printer, a plurality of back prismatic structures 2322 are sequentially and parallelly printed on the surface of the back plate side of the folding area, until the distance between the currently printed back prismatic structure 2322 and the nearest non-folding area is less than the width of one of the prismatic structures;

[0060] The midline of the spacing area between the prismatic structures on one side of the cover plate (i.e., the front prismatic structure 2321) corresponds one-to-one to the midline of the prismatic structures on one side of the back plate (i.e., the back prismatic structure 2322); the midline of the spacing area between the prismatic structures on one side of the back plate corresponds one-to-one to the midline of the prismatic structures on one side of the cover plate.

[0061] In this way, when the design of the middle frame needs to cover the display device on both sides, a middle frame folding portion 230 can be formed on both sides of the display device to meet the folding requirements. The force points can be more dispersed and the force can be more evenly distributed during bending, and the wear and tear caused by long-term use and the corresponding defects mentioned above can be avoided, thereby effectively extending the service life of the middle frame.

[0062] For further information, please refer to Fig.10 as well as Figure 6 and Figure 7 In some other embodiments, in the method for forming a middle frame of a display device, the step S221 of printing a frame bottom of the folding area on a side surface of the folding area further includes:

[0063] S2211: Printing a front folding area frame bottom 2311 on one side of the cover plate of the folding area; the front folding area frame bottom 2311 completely covers the folding area; and each prismatic structure (i.e., the front prismatic structure 2321) formed by printing on one side of the cover plate is printed on the front folding area frame bottom 2311;

[0064] S2212: Print a back folding area frame bottom 2312 on one side of the back panel of the folding area; the back folding area frame bottom 2312 completely covers the folding area; and each prismatic structure (i.e., back prismatic structure 2322) formed by printing on one side of the cover plate is printed on the back folding area frame bottom 2312.

[0065] In this way, a folding area frame bottom is formed on the front and back sides of the display device, which can ensure that the folding areas on both sides are provided with tightly combined middle frames, thereby ensuring the waterproof and dustproof effect of this area from both sides.

[0066] Furthermore, in this embodiment, the 3D printer includes a first print head and a second print head; the first print head and the second print head use different printing glues respectively; the 3D printer also includes a scanning unit and a path calculation unit;

[0067] The scanning unit scans the shape of the printing substrate to obtain shape data;

[0068] The path calculation unit calculates the printing paths of the first print head and the second print head according to the shape data;

[0069] Using the first print head to print along the inner edge of the edge area according to the calculated printing path to form an inner retaining wall 211; using the first print head to print along the outer edge of the edge area to form an outer retaining wall 212; and printing along the boundary line between the non-folding area and the folding area to form a boundary retaining wall 213;

[0070] Using the second print head to print and form a filling layer 220 in the non-folding area according to the calculated printing path, the filling layer 220 fills the space defined by the inner retaining wall 211, the outer retaining wall 212 and the boundary retaining wall 213 in the non-folding area;

[0071] The second print head is used to print and form the middle frame folding portion in the folding area according to the calculated printing path.

[0072] Through the cooperation of the scanning unit, the path calculation unit and the print head, the non-folding part and the folding part of the middle frame are formed, so that the structure of each part of the middle frame can accurately meet the design, highly meet the design requirements, and provide precise performance guarantee.

[0073] Furthermore, the first print head prints the first glue, and the second print head prints the second glue; the viscosity of the first glue is greater than the viscosity of the second glue; the first glue is conformal, and the second glue is fluid; according to the different viscosity properties of the glue, the anti-overflow wall and the filling layer 220 are printed separately, and different print heads are selected to print different glues, which can make the final molding effect better and the printing smoother.

[0074] Preferably, the viscosity of the first glue is 1000000cps-2000000cps; the viscosity of the second glue is 50cps-500cps.

[0075] In addition, the middle frame forming method of this embodiment can adapt to different 3D printing methods. In different embodiments, in the step of printing the middle frame, the 3D printing method includes one or more of direct writing printing, piezoelectric valve printing, needle valve printing and inkjet printing.

[0076] Example 2

[0077] This embodiment provides a method for manufacturing a foldable display device, wherein the middle frame of the foldable display device is formed by the method for forming the middle frame of the foldable display device provided in the first embodiment.

[0078] The manufacturing method of the folding display device provided in this embodiment, the middle frame is formed by the middle frame forming method of the folding display device provided by the present invention. The folding area and the non-folding area of ​​the edge area are respectively formed by 3D printing to form a middle frame folding part and a middle frame non-folding part of different shapes; wherein the middle frame folding part includes a plurality of parallel and spaced prismatic structures to form a middle frame folding part with a toothed structure. The folding display middle frame formed in this way, the middle frame formed by 3D printing and the back plate or cover plate are more tightly combined than the metal middle frame through adhesive bonding, and the bonding strength is higher, so the degree of loosening of the screen after long-term use can be reduced, and the waterproof and dustproof performance is better, and the degree of decline of the waterproof and dustproof performance after long-term use can also be reduced, and a high waterproof and dustproof performance can be maintained. In addition, such a middle frame folding part has a gap between the prismatic structures. When folding, this part serves as a buffer when the physical structure part (such as the prismatic structure) is tightened, so that the mutual squeezing force of the physical structure part during the folding process is reduced, the structural strain is reduced, and the loss of the physical structure part after long-term use can be reduced. This further overcomes the problem of loose screen after long-term use and poor waterproof and dustproof performance caused by the metal middle frame of the folding display device. At the same time, because the middle frame is formed by 3D printing, there is no need to use a metal middle frame, so the screen can be easily damaged during assembly, and the problems of low production efficiency and high cost can be avoided.

[0079] Example 3

[0080] This embodiment provides a printing device suitable for performing 3D printing on a printing substrate to form a middle frame; Fig.11 , the printing device comprises:

[0081] The carrier 310 is suitable for carrying the printing substrate A;

[0082] A printing unit, adapted to print the middle frame material in the edge area of ​​the printing substrate; the printing unit comprises at least two printing heads, adapted to print different materials respectively, one of which is adapted to form the anti-overflow wall in the non-folding area and the prismatic structure in the folding area of ​​the middle frame; and the other is adapted to form a filling layer to fill the space enclosed by the anti-overflow wall;

[0083] Specifically, the two print heads include: Fig.11 The first print head 331 and the second print head 332 shown are suitable for printing different materials (such as different printing glues) respectively. The first print head 331 prints to form the anti-overflow wall in the non-folding area and the prismatic structure in the folding area of ​​the middle frame, and the second print head 332 prints to form a filling layer that fills the space enclosed by the anti-overflow wall.

[0084] A bracket 320, suitable for mounting the printing unit;

[0085] A scanning unit (not shown in the figure), adapted to scan the shape of the printing substrate A and obtain shape data;

[0086] A path calculation unit (not shown in the figure), adapted to receive the data acquired by the scanning unit and calculate a printing route;

[0087] The driving unit (not shown in the figure) is adapted to drive the support to move according to the printing route provided by the path calculation unit, so as to drive the scanning unit and the printing unit to move.

[0088] Through the printing device provided in this embodiment, the middle frame forming method of the folding display device of the above-mentioned embodiment 1, or the manufacturing method of the folding display device of the above-mentioned embodiment 2 can be applied to manufacture the corresponding middle frame or folding display device to achieve corresponding beneficial effects.

[0089] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for forming a middle frame of a foldable display device, characterized in that: The following steps are involved: A printing substrate is provided; the printing substrate comprises a back plate, a display module and a cover plate; the printing substrate comprises an edge area, the edge area is an area including the edge of the back plate, the edge of the display module and the edge of the cover plate, and the width of the back plate, the display module and the cover plate from the edge to the center of the printing substrate; the edge area comprises a folding area and a non-folding area, the folding area is in a bent state when the display device is in a folded state, and the non-folding area is a portion of the edge area other than the folding area; Printing a non-folding portion of the middle frame in the non-folding area by 3D printing; The middle frame folding portion is printed in the folding area by using a 3D printing method.

2. The method for forming a middle frame of a foldable display device according to claim 1, characterized in that: The middle frame folding portion includes a plurality of parallel and spaced prismatic structures to form a middle frame folding portion with a tooth-like structure; the length extension direction of the prismatic structure is perpendicular to the side of the display device where the prismatic structure is located.

3. The method for forming a middle frame of a foldable display device according to claim 2, characterized in that: The step of printing the middle frame folding portion in the folding area by 3D printing includes: Using the print head of a 3D printer, a plurality of the prismatic structures are sequentially and parallely printed on a surface of one side of the folding area, until the distance between the currently printed prismatic structure and the nearest non-folding area is less than the width of one of the prismatic structures.

4. The method for forming a middle frame of a foldable display device according to claim 3, characterized in that: The spacing between the prismatic structures is greater than half the width of the prismatic structure and less than the width of one prismatic structure.

5. The method for forming a middle frame of a foldable display device according to claim 3, characterized in that: Also includes: A folding area frame bottom is printed on one side surface of the folding area; the folding area frame bottom completely covers the folding area; and the prismatic structure is printed and formed on the folding area frame bottom.

6. The method for forming a middle frame of a foldable display device according to claim 5, characterized in that: The sum of the thickness of the bottom of the folding area frame and the height of the prismatic structure is equal to the thickness of the non-folding portion of the middle frame; The longitudinal section shape of the prismatic structure includes a rectangle or a triangle; each vertex of the longitudinal section shape of the prismatic structure is a sharp corner or a rounded corner.

7. The method for forming a middle frame of a foldable display device according to claim 1, characterized in that: The step of printing the middle frame folding portion in the folding area by 3D printing includes: Using the print head of a 3D printer, a plurality of front prismatic structures are sequentially and parallelly printed on a surface of one side of the cover plate of the folding area, until a distance between a currently printed front prismatic structure and a nearest non-folding area is less than a width of one of the prismatic structures; Using the print head of a 3D printer, a plurality of back prismatic structures are sequentially and parallelly printed on the surface of one side of the back plate of the folding area, until the distance between the currently printed back prismatic structure and the nearest non-folding area is less than the width of one of the prismatic structures; The midline of the spacing area between the prismatic structures on one side of the cover plate corresponds one-to-one with the midline of the prismatic structures on one side of the back plate; the midline of the spacing area between the prismatic structures on one side of the back plate corresponds one-to-one with the midline of the prismatic structures on one side of the cover plate.

8. The method for forming a middle frame of a foldable display device according to claim 7, characterized in that: Also includes: The front folding area frame bottom is printed on one side of the cover plate of the folding area; the front folding area frame bottom completely covers the folding area; each prismatic structure printed on one side of the cover plate is printed on the front folding area frame bottom; A back folding area frame bottom is printed on one side of the back plate of the folding area; the back folding area frame bottom completely covers the folding area; and each prismatic structure formed by printing on one side of the cover plate is printed on the back folding area frame bottom.

9. The method for forming a middle frame of a foldable display device according to any one of claims 2 to 8, characterized in that: The step of printing the middle frame also includes: The 3D printing method includes using a 3D printer to perform 3D printing; the 3D printer includes a first print head and a second print head; the first print head and the second print head use different printing glues respectively; the 3D printer also includes a scanning unit and a path calculation unit; The scanning unit scans the shape of the printing substrate to obtain shape data; The path calculation unit calculates the printing paths of the first print head and the second print head according to the shape data; Using the first print head to print along the inner edge of the edge area according to the calculated printing path to form an inner retaining wall; using the first print head to print along the outer edge of the edge area to form an outer retaining wall; and printing along the boundary line between the non-folding area and the folding area to form a boundary retaining wall; Using the second print head to print and form a filling layer in the non-folding area according to the calculated printing path, the filling layer fills the space defined by the inner retaining wall, the outer retaining wall and the boundary retaining wall in the non-folding area; The second print head is used to print and form the middle frame folding portion in the folding area according to the calculated printing path.

10. The method for forming a middle frame of a foldable display device according to claim 9, characterized in that: The first print head prints a first glue, and the second print head prints a second glue; The viscosity of the first glue is greater than that of the second glue; the first glue is shape-preserving, and the second glue is fluid.

11. The method for forming a middle frame of a display device according to claim 1, wherein: The 3D printing method includes one or more of direct writing printing, piezoelectric valve printing, needle valve printing and inkjet printing.

12. A method for manufacturing a foldable display device, characterized in that: The middle frame of the folding display device is formed by the method for forming the middle frame of a folding display device according to any one of claims 1 to 11.

13. A printing device, suitable for performing 3D printing on a printing substrate to form a middle frame, characterized in that: The printing device comprises: A carrier, suitable for carrying the printing substrate; A printing unit, adapted to print the middle frame material in the edge area of ​​the printing substrate; the printing unit comprises at least two printing heads, adapted to print different materials respectively, one of which is adapted to form the anti-overflow wall in the non-folding area and the prismatic structure in the folding area of ​​the middle frame; and the other is adapted to form a filling layer to fill the space enclosed by the anti-overflow wall; A bracket, suitable for mounting the printing unit; A scanning unit, adapted to scan the shape of the printing substrate and obtain shape data; A path calculation unit, adapted to receive the data acquired by the scanning unit and calculate a printing route; The driving unit is adapted to drive the support to move according to the printing route provided by the path calculation unit, so as to drive the scanning unit and the printing unit to move.

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