KR20210087605A - Manufacturing method of display panel supporting device for foldable display apparatus - Google Patents

Abstract

The present invention relates to a method for manufacturing a panel support member of a foldable display device. Provided is the method for manufacturing the panel support member of the display device which supports the flexible display panel to guide a folding operation, which includes the steps of: (a) forming a porous hole pattern in a folding area of a support plate; (b) disposing a filler on at least one surface of the support plate on which the hole pattern is formed; (c) maintaining a vacuum state by removing air inside a jig device in which an assembly in which a filler and a support plate are combined; and (d) filling the hole pattern by reacting the filler in a vacuum state. Accordingly, there is no defect in which bubbles are generated, or foreign substances are introduced during a filling process.

Description

Manufacturing method of a panel supporting member of a foldable display device TECHNICAL FIELD

The present invention relates to a method for manufacturing a panel support member of a foldable display device.

In general, display devices such as smartphones and tablet PCs used by many people are small and medium-sized electronic devices, and are very convenient to carry. However, in recent years, as the demand for a large screen in portable display devices increases, a foldable display device that can be bent or folded has been spotlighted as a next-generation technology in the display field.

The foldable display device includes a display device that is bent, bent, folded, or rolled like paper while maintaining the display characteristics of the existing flat panel display device. Such a foldable display device may be implemented in the form of connecting flat panel display panels, or may be implemented using a flexible display panel in which the display panel itself has flexibility.

The foldable display device includes a flexible display panel and a support member for supporting the display panel from the rear surface, and the support member provides a folding area folded with a predetermined curvature in the center portion. The support member should be made of a rigid material in order to stably support the display panel, and at the same time, a flexible material should be applied to facilitate folding and unfolding operations in the folding area. As such, the support member should have both rigidity and ductility, but a single material having these opposite properties at the same time has not been developed until now.

As a method of implementing a folding operation in a foldable display device, as an example, as introduced in Korean Patent Application Laid-Open No. 10-2018-0062271, a porous hole pattern is formed in a folding area of a metal plate constituting a support member and a hole pattern is formed. A technique for filling the inside of a soft resin is generally applied. A foldable display device using a hole pattern has the advantage of stably supporting the display panel using a rigid metal plate and at the same time filling the porous hole pattern with a flexible resin to easily implement a folding operation. In this way, the support member is composed of two or more different materials such as a metal having a rigidity and a resin having a ductility.

On the other hand, as a method of filling the hole pattern of the metal plate with resin, processes such as dispensing, insert injection, and silk screen are used. The dispensing method has a problem in that it is difficult to completely fill the resin inside the fine hole pattern, and the insert injection method has a problem that the boundary line is visually recognized to the outside at the interface of different materials and deteriorates the appearance. There is a problem that the hole pattern is not completely filled inside, and the process is complicated, and there are difficulties such as control of curl and filling rate for each process, and the inflow of foreign substances.

In general, in the method of manufacturing a panel support member according to the prior art, the filled resin is prepared by stirring an elastic body having an appropriate viscosity and elongation. Therefore, there is a disadvantage in that a difference in viscosity occurs between the resin used immediately after stirring and the resin after a certain period of time, resulting in a change in the coating thickness.

In addition, the conventional method of manufacturing a panel support member has a problem in that a defect such as a height difference occurs as the filled resin shrinks during curing (see FIG. 1 ).

In addition, in the conventional panel support member manufacturing method, the resin is cured after leveling the bubbles and the resin. The resin before curing has strong viscosity, which causes product defects due to adsorption of floating foreign substances in the chamber during the curing process. there is a problem with

In addition, the conventional panel support member manufacturing method removes the protective film for preventing leakage after curing, and the protective film increases adhesion during the resin curing process to reduce workability for removing the protective film or to prevent a defect in separation with the resin. cause

As described above, in the conventional panel support member manufacturing method, the rigid metal plate pattern is filled with a flexible resin, and serious problems such as incomplete filling or product defects frequently occur.

The object of the present invention has been proposed to solve the above problems, and the resin can be completely filled in the hole pattern, and it is possible to remove factors that may cause product defects such as foreign substances inflow and bubble generation during the filling process. An object of the present invention is to provide a method for manufacturing a support member of a foldable display panel that can be used.

An embodiment of the present task for achieving the above object is a method for manufacturing a panel support member of a display device for guiding a folding operation by supporting a flexible display panel, (a) a porous area in the folding area of the support plate Forming a hole pattern, (b) disposing a filler on at least one surface of the support plate on which the hole pattern is formed, (c) removing air inside the jig device in which the assembly in which the filler and the support plate are combined to maintain a vacuum state, and (d) filling the hole pattern by reacting the filler in a vacuum state.

In addition, in the method for manufacturing a panel support member of this embodiment, the filler in step (b) is composed of a first filler disposed on one surface of the support plate and a second filler disposed on the other surface of the support plate, and the The vacuum state of step (c) may be achieved after the second filler is spaced apart from the hole pattern of the support plate.

In addition, in the method for manufacturing the panel support member of the present embodiment, in step (c), a guide member connected to the jig device via an elastic member may support the support plate to be spaced apart from the second filler.

In addition, in the method of manufacturing the panel support member of the present embodiment, the jig device may be shrunk as the inside changes to a vacuum state to bring the second filler into close contact with the support plate.

In addition, in the panel support member manufacturing method of this embodiment, the first filler is composed of a crosslinkable first resin having a relatively low reaction temperature compared to the second filler, and the second filler is compared to the first filler. It may be composed of a non-crosslinkable second resin having a relatively high reaction temperature.

In addition, in the method for manufacturing the panel support member of this embodiment, step (d) comprises a process of blocking the hole pattern by crosslinking the first resin, then melting the second resin to fill the hole pattern inside. can

In the present invention, the inside of the hole pattern can be completely filled by disposing heterogeneous resins having different reaction temperatures and curing characteristics on both sides of the metal plate to fill the inside of the hole pattern.

In addition, in the present invention, since the resin is filled in a vacuum state after the metal plate is spaced apart from the resin on one side, there is no defect in which bubbles or foreign substances are introduced during the filling process.

1 is an enlarged view showing in detail a pattern portion of a panel support member filled with resin according to the prior art;
2 is an exploded view showing the main configuration of the foldable display device according to the present embodiment;
3 is a process diagram showing the resin filling process of the panel support member according to the present embodiment;
Figure 4 is a process diagram showing the main part of the hot press process of Figure 3;

The present invention and the technical problems achieved by the practice of the present invention will be made clear by the preferred embodiments described below. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

It should be understood that the differences between the embodiments described below are not mutually exclusive. That is, without departing from the spirit and scope of the present invention, the specific shapes, structures, and characteristics described may be implemented in other embodiments in relation to one embodiment, and the location of individual components within each disclosed embodiment. Or it should be understood that the arrangement may be changed, and similar reference numerals in the drawings refer to the same or similar functions over several aspects, and the length, area, thickness, etc., may be exaggerated for convenience. In the description of this embodiment, expressions such as before, after, left, right, top, bottom, etc. indicate positions or directions relative to each other, and their technical meanings are not limited by dictionary meanings.

2 is an exploded view showing the main configuration of the foldable display device according to the present embodiment, FIG. 3 is a process diagram showing the resin filling process of the panel support member according to the present embodiment, and FIG. 4 is a hot press which is the main part of FIG. It is a process diagram showing the process.

First, referring to FIG. 2 , the foldable display device of the present embodiment includes the display panel 100 and the panel support member 200 , and a case for protecting them may be further coupled to the edge and the rear surface. Here, one surface of the panel support member 200 to which the display panel 100 is coupled is referred to as a front surface, and the opposite surface is referred to as a rear surface.

Specifically, the display panel 100 may be a flexible display panel using a flexible substrate. As an example, the display panel 100 includes an organic light emitting display panel having a flexible function, an electrophoretic display panel, a liquid crystal display panel, and an electrowetting display panel. (Electro-Wetting Display Panel), a plastic organic light emitting display panel (Plastic OLED), etc. may be used.

The display panel 100 includes a flexible substrate including a pixel array having a plurality of pixels for displaying an image, and a cover member formed on the flexible substrate to cover the pixel array.

The foldable display device according to the present embodiment may further include a touch screen (not shown) for a user interface using a user's touch, and the touch screen is attached to the display panel 100 or is formed by forming a pixel array. It may be embedded in the display panel 100 together with the process.

As described above, the display panel 100 includes a display unit DA formed of a plurality of pixels, and the display unit DA may be a display screen displaying a predetermined image according to driving of a panel driver (not shown). The display unit DA may be divided into a first display area DA1 , a second display area DA2 , and a bending display area DA3 . The first display area DA1 may be defined as a first area (eg, a left area) positioned at one side of the bending display area DA3 of the display unit DA, and the second display area DA2 is the display unit It may be defined as a second area (eg, a left area) positioned on the other side of the bending display area DA3 among (DA).

When the display panel 100 is unfolded in a flat state, the first display area DA1 , the second display area DA2 , and the bending display area DA3 constitute one display unit DA to provide a relatively wide screen. do.

The panel support member 200 is configured to guide the folding operation while coupling and supporting the display panel 100 to the front surface, and includes a first display area DA1, a second display area DA2, and bending of the display panel 100 . It includes a first support part GA1 , a second support part GA2 , and a bending guide part GA3 supporting the display area DB. The first support part GA1 and the second support part GA2 form a non-folding area, and the bending guide part GA3 forms a folding area.

The panel support member 200 is made of a rigid material to stably support the display panel 100 , and may be made of, for example, a metal plate 210 . In addition, the metal plate 210 in the bending guide portion GA3 region further includes a flexible material to be easily bent.

Specifically, the metal plate 210 of the bending guide part GA3 region has a porous hole pattern 220 , and the hole pattern 220 is filled with a flexible filler resin 230 . The porous hole pattern 220 may be formed by etching, punching, pressing, laser processing, or the like with respect to the metal plate 210 .

The resin 230 filled in the hole pattern 220 may be composed of an elastomer-based resin, for example, PE (Polyethylene), POE (Polyolefin Elastomer), TPU (Thermoplastic Polyurethane), EVA (Ethylene-) A resin such as vinyl acetate) may be used. The elastomeric resin used as a filler in this embodiment is composed of a first resin 231 of a crosslinking type and a second resin 232 of a non-crosslinking type. In addition, the first resin 231 and the second resin 232 have different curing temperatures, and it is preferable that the curing temperatures have a difference of about 20° C. or more.

When cured once, cross-linked resins are cross-linked between molecules and exhibit high reliability to withstand heat or external shocks after curing. Therefore, the cross-linked resin is difficult to deform after curing, and thus has a characteristic that control must be precise during curing. On the other hand, the non-crosslinked resin has a characteristic that it can be melted and shaped several times by heat. In this embodiment, the hole pattern 220 is filled using these characteristics of the crosslinkable resin and the non-crosslinkable resin.

Since the porous hole pattern 220 is formed through the metal plate 210, one side must be blocked when filling the resin. If both sides are drilled, filling is easy, but thickness control for soft resin becomes difficult. Therefore, as in the present embodiment, by filling the hole pattern 220 by mixing the cross-linked first resin 231 and the non-cross-linked second resin 232 , this problem can be solved.

Referring specifically to FIG. 3 , as shown in (a), a metal plate 210 on which a hole pattern 220 is formed is prepared, and the first surface in the form of a film or sheet is formed on one surface and the other surface of the metal plate 210 . A resin sheet 231' and a second resin sheet 232' are respectively disposed. The first resin sheet 231' is made of a cross-linkable resin, the second resin sheet 232' is made of a non-cross-linkable resin, and the first resin sheet 231' is attached to the second resin sheet 232'. It is composed of a resin having a lower reaction temperature than that.

Heat is applied to the first resin sheet 231 ′ and the second resin sheet 232 ′ on both sides of the metal plate 210 to crosslink the first resin sheet 231 ′ that reacts under a low temperature condition to form a hole pattern. One side of 220 is blocked, and the second resin sheet 232 ′ is reacted under a relatively higher temperature condition as shown in (b) to fill the inside of the hole pattern 220 . At this time, since the first resin 231 is a cross-linkable resin and its shape is not easily changed after curing, one side of the hole pattern 220 is continuously maintained, and the second resin 232 does not leak and the hole pattern is not changed. 220 can be easily filled.

In general, in order to fill a rigid plate with a hole in it, one side of the hole must be blocked. If both sides of the hole are drilled, filling is easy, but it is very difficult to control the thickness of the resin. However, as in this embodiment, when the cross-linked elastomer resin with a low reaction temperature is cross-linked first using the cross-linked and non-cross-linked elastomer properties to block one side of the hole and then fill the non-cross-linked elastomer resin, the resin can be easily filled Accurate thickness control is possible.

On the other hand, when the elastomer resin is melted to fill the hole pattern, there is a problem in that a thickness deviation occurs between the central portion and the edge portion, and bubbles are easily generated inside the hole pattern. In order to solve this problem, it is necessary to be able to press the filled resin with the same pressure while having a high level of smoothness, and all air inside the hole pattern must be removed before the resin sheets are in close contact with both sides of the metal plate.

To this end, in the resin filling method of this embodiment, crosslinked and non-crosslinked resin sheets are respectively disposed on both sides of the metal plate, and the filling process is performed while the non-crosslinked resin on one side is spaced apart from the metal plate.

Referring in detail with reference to FIG. 4 , the first resin sheet 231 ′ and the second resin sheet 232 ′ are respectively disposed on both sides of the metal plate 210 in the jig device 300 , and the ratio as shown in (a) is The bridge-shaped second resin sheet 232 ′ is spaced apart from the metal plate 210 by a predetermined distance. To this end, the jig device 300 includes a pair of upper jigs 310 and lower jigs 320 for accommodating the metal plate 210 , and includes a guide member 330 for guiding the position of the metal plate 210 . do. The guide member 330 supports and fixes the side of the metal plate 210 while being connected to the lower jig 320 via the elastic member 340 , and the second resin sheet 232 ′ is the lower jig 320 . ) and spaced apart from the metal plate 210 in a state of being mounted on the hole pattern 220 to open the lower portion. Here, the elastic member may be, for example, an elastic spring.

The jig device 230 maintains a vacuum state by discharging internal air in a state in which the lower part of the hole pattern 220 is opened, and cross-links the first resin sheet 231 ′ while the vacuum is maintained inside the jig device to form a hole. The upper part of the pattern 220 is blocked, the lower jig 320 is raised to attach the second resin sheet 232' to the lower part of the hole pattern 220, and then the second resin sheet 232' is melted to form the hole pattern 220. ) fill the inside. Here, the vacuum state includes a state of atmospheric pressure such that bubbles are not generated while the resin is discharged into the hole pattern. The lower jig 320 rises according to the pressure inside the jig device 230 , and at the same time the elastic member 340 is contracted, but the guide member 330 presses and supports the metal plate 210 to be maintained. can

At this time, the vacuum state of the jig device 230 is a process performed before the second resin 232 is filled in the hole pattern 220 , and the first resin sheet 231 ′ is first crosslinked to form an upper portion of the hole pattern 220 . It is natural that it may proceed after blocking. In addition, the jig device 230 may be preferably made of a material having high thermal conductivity and high surface smoothness in order to transfer uniform pressure and heat.

Since the filling process is performed while the inside of the hole pattern 220 is maintained in a vacuum state by using the jig device having the guide member 330 and the elastic member 340 as described above, the inside of the hole pattern 220 during the filling process. It is possible to solve the problem of air bubbles or foreign substances inflow. In addition, there is no need to remove the protective film (refer to 13 of FIG. 1 ) for blocking the hole pattern, so there is no defect problem due to the removal of the protective film.

Although exemplary embodiments of the present invention have been illustrated and described as described above, various modifications and other embodiments may be made by those skilled in the art. All such modifications and other embodiments are intended to be contemplated and included in the appended claims without departing from the true spirit and scope of the present invention.

100: display panel
200: panel support member
210: metal plate
220: hole pattern
230: resin
231: first resin 232: second resin

Claims (6)

A method of manufacturing a panel support member of a display device for guiding a folding operation by supporting a flexible display panel, the method comprising:
(a) forming a porous hole pattern in the folding area of the support plate;
(b) disposing a filler on at least one surface of the support plate on which the hole pattern is formed;
(c) maintaining a vacuum state by removing the air inside the jig device in which the assembly in which the filler and the support plate are coupled;
(d) filling the hole pattern by reacting the filler in a vacuum state; comprising, a method for manufacturing a panel support member of a display device. The method of claim 1,
The filler in step (b) is composed of a first filler disposed on one surface of the support plate and a second filler disposed on the other surface of the support plate,
The vacuum state of step (c) is made after the second filler is spaced apart from the hole pattern of the support plate, the panel support member manufacturing method of the display device. The method of claim 2, wherein the step (c) comprises:
A method of manufacturing a panel support member for a display device, wherein a guide member connected to the jig device via an elastic member supports the support plate to be spaced apart from the second filler. According to claim 3, wherein the jig device,
A method for manufacturing a panel support member of a display device, wherein the second filler is in close contact with the support plate while contracting as the inside changes to a vacuum state. 4. The method of claim 3,
The first filler is composed of a crosslinkable first resin having a relatively low reaction temperature compared to the second filler,
The second filler is composed of a non-crosslinkable second resin having a relatively higher reaction temperature than that of the first filler, the method for manufacturing a panel support member of a display device. The method of claim 5, wherein step (d) comprises:
After the first resin is crosslinked to block the hole pattern, the second resin is melted to fill the inside of the hole pattern.

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