KR20220167816A - Flexible display and methdo of forming back plate of flexible display - Google Patents

Abstract

Disclosed is a flexible display. The flexible display includes: a display panel; an appearance improvement film disposed on a rear surface of the display panel; and a backplate disposed on the rear surface of the appearance improvement film. The backplate includes: a plurality of pattern bars spaced apart from each other by a predetermined interval in the longitudinal or transverse direction of the display panel; and an elastic connector connected to the pattern bars between the pattern bars. The plurality of pattern bars and the elastic connector are disposed within a range of a width corresponding to or smaller than a length of the display panel in a transverse direction or a longitudinal direction along a direction in which the display panel is folded or wound. Therefore, folding and rolling driving can be stably implemented, and the visibility of the linear pattern can be reduced.

Description

Flexible display and back plate forming method of flexible display {FLEXIBLE DISPLAY AND METHDO OF FORMING BACK PLATE OF FLEXIBLE DISPLAY}

The present invention relates to a flexible display and a method for forming a back plate of the flexible display, and more particularly, to a flexible display that stably implements folding and rolling driving and a method for forming the back plate of the flexible display.

Recently, flexible displays have been commercialized. A flexible display reproduces an input image on the screen of a display panel formed with plastic OLED. Plastic OLEDs are formed on flexible plastic substrates.

Flexible displays can implement various designs and have advantages in portability and durability. The flexible display may be implemented in various types of displays such as a foldable display and a rollable display. Such a flexible display can be applied not only to mobile devices such as smart phones and tablet PCs, but also to TVs (Television), automobile displays, and wearable devices, and its application fields are expanding.

Such a flexible display includes a flexible display panel and a back plate supporting the display panel and having a flexible driving area that is rolled or folded along with the display panel when the display panel is rolled or folded. The flexible driving area of the back plate is configured to be rolled or folded by forming a divided structure in a predetermined pattern.

After repeating the rolling or folding operation of the back plate, recovery of flatness and elasticity has a very important effect on maintaining the quality of the flexible display.

In addition, since the back plate has a structure in which the flexible driving area is divided into a predetermined pattern, the pattern can be viewed on a display panel, so that the pattern cannot be viewed.

Korean Patent Publication No. 10-2019-0064183

Accordingly, an object to be solved by the present invention is to provide a flexible display capable of stably implementing folding and rolling driving and reducing the visibility of a linear pattern and a method for forming a back plate of the flexible display.

A flexible display according to an embodiment of the present invention includes a display panel; an appearance improvement film disposed on a rear surface of the display panel; and a back plate disposed on a rear surface of the appearance improvement film, wherein the back plate includes: a plurality of pattern bars spaced apart from each other at predetermined intervals in a longitudinal or transverse direction of the display panel; and an elastic connecting body connected to the pattern bars between the pattern bars, wherein the plurality of pattern bars and the elastic connecting body extend in a direction in which the display panel is folded or wound in a transverse direction or a longitudinal direction of the display panel. It is arranged within a range of a width corresponding to the length of or a width smaller than that.

In one embodiment, the pattern bar may be a fiber composite plastic or alloy material.

In one embodiment, the elastic connector may be a thermosetting or thermoplastic resin.

In one embodiment, the elastic connecting body may be made of a material having an adhesive force of 1.0 kgf/inch or more with the pattern bar.

In one embodiment, the elastic connector may be formed by filling and curing a material having a modulus of 1000 Mpa or less at a low temperature or a material having a modulus of 50 Mpa or less at room temperature between the pattern bars.

In one embodiment, the pattern bars may be made of a material having a low coefficient of thermal expansion (CTE) in a wide temperature range.

In one embodiment, the appearance improvement film may be formed of a metal foil or a flexible film of synthetic resin material.

In one embodiment, the flexible film may be made of a black color.

In one embodiment, the elastic connector may be configured to cover the entire surface of the back plate between the appearance improvement film and the back plate while being connected between the pattern bars.

A method of forming a back plate of a flexible display according to an embodiment of the present invention is a method of forming a back plate disposed on a rear surface of a flexible display panel, comprising the steps of arranging pattern bars along one direction within a square forming space of a release jig; Release guide bars are inserted between the pattern bars arranged in the molding space, and the upper or lower surface of each of the release guide bars is inserted to have a step with the upper or lower surface of the pattern bar to provide a filling space between the pattern bars. doing; filling the filling space between the pattern bars with an elastic material in a liquid state; and curing the liquid elastic material filled in the filling space.

In one embodiment, the step of filling the filling space between the pattern bars with a liquid elastic material may include filling the filling space with a method of heat-sealing a film-type elastic material or screen-printing a liquid-type elastic material. .

In one embodiment, prior to the step of arranging the pattern bars along one direction in the rectangular molding space of the release jig, the step of seating an elastic material in the form of a heat-meltable film in the molding space, further comprising placing the pattern bars between the pattern bars. In the step of filling the filling space with the elastic material in a liquid state, the elastic material in the form of a film may be heat-sealed into the filling space.

In one embodiment, in the step of filling the filling space between the pattern bars with the elastic material in a liquid form, the elastic material may be screen-printed in a liquid form and filled in the filling space.

In one embodiment, the elastic material may be a polymer resin that melts at a temperature between 80 and 150 °C.

In one embodiment, the elastic material has a maximum elongation obtained based on a thickness from an upper surface of the flexible display panel to a lower surface of the pattern bar and a maximum radius of curvature in a state in which the flexible display panel is folded or wound one or more times. The type of material and filling rate can be set in consideration.

According to the flexible display and the method for forming the back plate of the flexible display according to the present invention, folding and rolling driving are stably implemented, and visibility of a linear pattern can be reduced.

1 is a cross-sectional view showing the configuration of a flexible display according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view illustrating a state in which the elastic connector shown in FIG. 1 is configured to cover the entire surface of the back plate.
3 is a flowchart illustrating a process of forming a back plate of a flexible display according to an embodiment of the present invention.
4 is a perspective view illustrating a first embodiment of a release jig used for a method of forming a back plate of a flexible display according to an embodiment of the present invention.
5 is a perspective view illustrating a second embodiment of a release jig used for a method of forming a back plate of a flexible display according to an embodiment of the present invention.
FIG. 6 is a cross-sectional view illustrating how a back plate is molded by a thermal fusion method using the release jig according to the first embodiment shown in FIG. 4 .
FIG. 7 is a cross-sectional view illustrating how a back plate is molded by a screen printing method using the release jig according to the second embodiment shown in FIG. 5 .
8 is a diagram showing a schematic diagram for calculating the maximum elongation of the elastic connector shown in FIG. 1;
9A and 9B are diagrams illustrating shapes of a rollable type flexible display that can be manufactured through a method of forming a back plate of a flexible display according to an embodiment of the present invention.
10A and 10B are diagrams illustrating the shape of a flexible display of a slider type that can be manufactured through a method of forming a back plate of a flexible display according to an embodiment of the present invention.
11A and 11B are diagrams illustrating the shape of a foldable flexible display that can be manufactured through a method of forming a back plate of a flexible display according to an embodiment of the present invention.

Hereinafter, a flexible display according to an embodiment of the present invention and a method of forming a back plate of the flexible display will be described in detail with reference to the accompanying drawings. Since the present invention can have various changes and various forms, specific embodiments will be illustrated in the drawings and described in detail in the text. However, it should be understood that this is not intended to limit the present invention to the specific disclosed form, and includes all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. Like reference numerals have been used for like elements throughout the description of each figure. In the accompanying drawings, the dimensions of the structures are shown enlarged than actual for clarity of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "comprise" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present application, they should not be interpreted in an ideal or excessively formal meaning. don't

1 is a cross-sectional view showing a structure of a flexible display according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing how the elastic connector shown in FIG. 1 is configured to cover the entire surface of the back plate.

Referring to FIGS. 1 and 2 , a flexible display according to an exemplary embodiment includes a display panel 110 , an appearance improvement film 120 and a back plate 130 .

The display panel 110 is made of a flexible material that can be folded or rolled one or more times. For example, the display panel 110 may include a plastic OLED device formed on a flexible plastic substrate.

The appearance improvement film 120 may be disposed on the rear surface of the display panel 110 and attached to the rear surface of the display panel 110 to cover the rear surface of the display panel 110 .

The appearance improvement film 120 may be made of a flexible material that can be folded or rolled together with the display panel 110 . For example, the appearance improvement film 120 may be formed of a flexible film made of metal foil or synthetic resin material.

The appearance improvement film 120 may have a color to reduce visibility of the back plate 130 supporting the display panel 110 and allowing the display panel 110 to be folded or wound in the direction of the display panel 110 . there is. Preferably, the appearance improvement film 120 may be provided to have a black color.

The back plate 130 is disposed on the rear surface of the appearance improvement film 120 to support the display panel 110 and the appearance improvement film 120, and the display panel 110 and the appearance improvement film 120 are unfolded on a flat surface. is maintained and supports the display panel 110 and the appearance improvement film 120 to be folded or rolled.

The back plate 130 includes a plurality of pattern bars 131 and elastic connectors 132 .

The plurality of pattern bars 131 are arranged spaced apart from each other by a predetermined interval in a longitudinal direction or a transverse direction of the display panel 110 , that is, in a direction in which the display panel 110 is folded or wound.

The plurality of pattern bars 131 may be made of a material having a low coefficient of thermal expansion (CTE) in a wide temperature range. For example, the pattern bar 131 may be a fiber composite plastic or alloy material having high specific stiffness. For example, it may be carbon fiber reinforced plastic (CFRP) or glass fiber reinforced plastic (GFRP) with high specific stiffness.

The elastic connecting body 132 is connected to the pattern bars 131 between the pattern bars 131, and the elastic connecting body 132 is tensioned when the display panel 110 is folded or rolled, and the display panel 110 is It has elasticity that can be restored when unfolded after folding or winding.

For example, the elastic connector 132 may be located only between pattern bars 131 as shown in FIG. 1 .

As another example, as shown in FIG. 2 , the elastic connector 132 is connected between the pattern bars 131 and is interposed between the appearance improvement film 120 and the back plate 130 . It may be configured to cover the entire surface with a certain thickness. In this case, the visibility of the pattern bars 131 on the display panel 110 is minimized by the area covering the entire surface of the back plate 130 and the appearance improvement film 120 so that the pattern bars 131 form a linear shape. Visibility of the pattern may be further improved.

The elastic connector 132 is made of a material having an adhesive force of 1.0 kgf/inch or more with the pattern bar 131 to be connected to the pattern bars 131 .

A material having a specific modulus range may be used for the elastic connector 132 according to the field of use of the flexible display. For example, a material having a modulus of 1000 Mpa or less at a low temperature may be used. For example, a material having a modulus of 50 Mpa or less at room temperature may be used.

The plurality of pattern bars 131 and the elastic connector 132 have a width corresponding to a length of the display panel 110 in the horizontal direction or the vertical direction along a direction in which the display panel 110 is folded or wound. It may be arranged within a range of a smaller width than that.

For example, when the display panel 110 is circularly wound one or more times, the plurality of pattern bars 131 and the elastic connector 132 correspond to the lengths of the direction in which the display panel 110 is wound. When the display panel 110 is folded one or more times, the display panel 110 may be disposed within a range of a width corresponding to the width of the folded portion.

Hereinafter, a method of forming the back plate 130 disposed on the rear surface of the flexible display will be described.

3 is a flowchart illustrating a process of forming a back plate of a flexible display according to an embodiment of the present invention.

Referring to FIG. 3 , a method of forming a back plate of a flexible display according to an embodiment of the present invention includes arranging pattern bars along one direction within a square forming space of a release jig (S110); Release guide bars are inserted between the pattern bars arranged in the molding space so that the upper or lower surfaces of each of the release guide bars are positioned lower than the height of the upper or lower surface of the pattern bars to fill the filling space between the pattern bars. Preparing a step (S120); filling the filling space between the pattern bars with an elastic material in liquid form (S130); and curing the liquid elastic material filled in the filling space (S140).

4 is a perspective view illustrating a first embodiment of a release jig used for a method of forming a back plate of a flexible display according to an embodiment of the present invention, and FIG. 5 is a back view of a flexible display according to an embodiment of the present invention. It is a perspective view illustrating the second embodiment of the release jig used for the plate forming method.

Here, the release jig 200 is a first embodiment, and as shown in FIG. 4 , a bar insertion guide is applied to each of the square forming space 210 and the two parallel sides of the forming space 210. Grooves 220 and the bar insertion guide jaws 230 each having a height higher than the bottom surface of the molding space 210 and lower than the upper end of the bar insertion guide groove 220 are alternately along the direction in which the two sides extend. It can be provided in an arranged structure.

As the second embodiment, the release jig 200 may have a structure in which the bar insertion guide jaw 230 is omitted, as shown in FIG. 5 .

On the other hand, in the step S130, in one embodiment, the elastic material may be filled in a thermal fusion method, and in another embodiment, the elastic material may be filled in a screen printing method.

FIG. 6 is a cross-sectional view illustrating how a back plate is molded by a thermal fusion method using the release jig according to the first embodiment shown in FIG. 4 .

When the thermal fusion method is used, a step of seating an elastic material in the form of a thermally meltable film in the molding space may be included before step S110, and the release jig 200 of the first embodiment may be used. .

Referring to FIG. 6 , in this case, first, the elastic material 132a in the form of a film is seated in the molding space 210 according to step S100, and then the pattern is inserted into the bar insertion guide groove 220 according to step S110. When the bar 131 is inserted to arrange the pattern bars 131, and then the release guide bars 300 are inserted on the bar insertion guide jaw 230 according to the step S120, each of the inserted release guide bars 300 is spaced apart from the bottom surface of the molding space 210 so that the mold release guide bar 300 has a step difference with the pattern bar 131, and accordingly, a filling space between the pattern bars 131 ( 240) may be provided. Then, in step S130, the elastic material 132a in the form of a film is thermally fused. That is, when heat is applied to the release jig 200 and pressure is applied to the pattern bar 131 and the release guide bar 300 with a press, the elastic material 132a in the form of a film is melted to form the filling space. It can be filled in 240 and heat-sealed. Subsequently, the elastic material 132a may be cured according to the step S140. For example, the elastic material 132a may be cured at room temperature.

FIG. 7 is a cross-sectional view illustrating how a back plate is molded by a screen printing method using the release jig according to the second embodiment shown in FIG. 5 .

Meanwhile, when the screen printing method is used, the release jig 200 of the second embodiment may be used.

Referring to FIG. 7 , in this case, the pattern bars 131 are first inserted into the bar insertion guide groove 220 according to step S110 to arrange the pattern bars 131, and then the pattern bars 131 are inserted between the pattern bars 131. When the release guide bar 300 having a lower height than the pattern bars 131 is inserted, the upper surface of each inserted release guide bar 300 is located lower than the upper surface of the pattern bar 131, so that the release guide bar 300 is disposed to have a step difference with the pattern bars 131, and accordingly, a filling space 240 may be provided between the pattern bars 131. Subsequently, the elastic material 132a may be filled in the filling space 240 by supplying and screen-printing the liquid elastic material 132a onto the pattern bar 131 and the release guide bar 300 . Subsequently, the elastic material 132a may be cured according to the step S140. For example, the elastic material 132a may be cured at room temperature.

The plurality of pattern bars 131 of the flexible display according to the present invention and the elastic connectors 132 connected therebetween can be manufactured through this method of forming the back plate of the flexible display.

Meanwhile, when performing the process of forming the back plate of the flexible display according to an embodiment of the present invention, the elastic material 132a may be a polymer resin that melts at a temperature between 80 and 150°C. The selection of such a polymer resin is to secure product reliability at a temperature of 60 to 100° C. when using the flexible display according to the present invention.

In addition, in order to perform the process of forming the back plate of the flexible display according to an embodiment of the present invention, the type and filling rate of the elastic material may be set in advance. The setting of the type of elastic material and the filling factor is determined based on the thickness from the upper surface of the flexible display panel to the lower surface of the pattern bar and the maximum elongation obtained based on the maximum radius of curvature in a state in which the flexible display panel is folded or wound one or more times. can be set in consideration of

According to the flexible display and the back plate molding method of the flexible display according to an embodiment of the present invention described above, a plurality of pattern bars 131 having high specific rigidity and a flexible material connected between the plurality of pattern bars 131 Since the elastic connector 132 supports the display panel 110 and constitutes a folding area of the display panel 110, the degree of freedom of the radius of curvature is improved when the display panel 110 is folded or rolled, thereby enabling folding and rolling of the flexible display. The flexible, free and stable support of the display panel 110 may be possible.

In addition, the appearance improvement film 120 is disposed between the display panel 110 and the back plate 130, and the appearance improvement film 120 has a specific color such as black so that the back plate 130 is the display panel ( 110), visibility of a linear pattern appearing according to the arrangement of the pattern bars 131 may be lowered by reducing the degree of visible to the naked eye in the direction.

8 is a diagram showing a schematic diagram for calculating the maximum elongation of the elastic connector shown in FIG. 1; In FIG. 8 , R represents the radius of curvature, T represents the thickness of the panel portion, and t represents the thickness of the pattern bar.

On the other hand, when performing the back plate molding method of the flexible display according to an embodiment of the present invention described above, the thicknesses (L1 to L4) from the upper surface of the flexible display panel to the lower surface of the pattern bar and the flexible display panel Since the type of material and the filling rate are set in consideration of the maximum elongation obtained based on the maximum radius of curvature in the state of being folded or rolled more than once, it is possible to produce a reliable flexible display that implements stable folding and rolling driving. .

9A and 9B are diagrams illustrating the shape of a flexible display in a rollable form that can be manufactured through a method of forming a back plate of a flexible display according to an embodiment of the present invention, and FIGS. 10A and 10B are views illustrating one embodiment of the present invention A view illustrating a shape of a flexible display of a slider type that can be manufactured through a method of forming a back plate of a flexible display according to an example, and FIGS. 11A and 11B show a method of forming a back plate of a flexible display according to an exemplary embodiment It is a diagram illustrating the shape of a foldable type flexible display that can be manufactured through

Through the method of forming the back plate of a flexible display according to an embodiment of the present invention described above, it is possible to manufacture a flexible display in a rollable shape as shown in FIGS. 9A and 9B.

In addition, a slideable display as shown in FIGS. 10A and 10B , that is, a flexible display that slides while being bent at a certain curvature may be manufactured through a method of forming a back plate of a flexible display according to an embodiment of the present invention.

In addition, a foldable flexible display as shown in FIGS. 11A and 11B may be manufactured through a method of forming a back plate of a flexible display according to an embodiment of the present invention.

The description of the presented embodiments is provided to enable any person skilled in the art to use or practice the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the scope of the present invention. Thus, the present invention is not to be limited to the embodiments presented herein, but is to be construed in the widest scope consistent with the principles and novel features presented herein.

Claims (15)

display panel;
an appearance improvement film disposed on a rear surface of the display panel; and
Including a back plate disposed on the rear surface of the appearance improvement film,
The back plate,
a plurality of pattern bars spaced apart from each other by a predetermined interval in the longitudinal or transverse direction of the display panel; and
Including an elastic connecting body connected to the pattern bars between the pattern bars,
The plurality of pattern bars and the elastic connector are disposed within a range of a width corresponding to or less than a length of the display panel in a transverse direction or a longitudinal direction along a direction in which the display panel is folded or wound.
flexible display. According to claim 1,
The pattern bar is a fiber composite plastic or alloy material,
flexible display. According to claim 1,
The elastic connector is a thermosetting or thermoplastic resin,
flexible display. According to claim 1,
The elastic connector is made of a material having an adhesive force of 1.0 kgf / inch or more with the pattern bar,
flexible display. According to claim 1,
The elastic connector,
A material having a modulus of 1000 Mpa or less at a low temperature or a material having a modulus of 50 Mpa or less at room temperature is filled and cured between the pattern bars,
flexible display. According to claim 5,
The pattern bars are made of a material having a low coefficient of thermal expansion (CTE) in a wide temperature range.
flexible display. According to claim 1,
The appearance improvement film is made of a flexible film of metal foil or synthetic resin material,
flexible display. According to claim 7,
The flexible film is made of black color,
flexible display. According to claim 1,
The elastic connector is configured to cover the entire surface of the back plate between the appearance improvement film and the back plate while being connected between the pattern bars.
flexible display. As a method of forming a back plate disposed on the rear surface of a flexible display panel,
arranging pattern bars along one direction within a square molding space of a release jig;
Release guide bars are inserted between the pattern bars arranged in the molding space, and the upper or lower surface of each of the release guide bars is inserted to have a step with the upper or lower surface of the pattern bar to provide a filling space between the pattern bars. doing;
filling the filling space between the pattern bars with an elastic material in a liquid state; and
Characterized in that it comprises the step of curing the liquid elastic material filled in the filling space,
A method for forming the back plate of a flexible display. According to claim 10,
The step of filling the filling space between the pattern bars with an elastic material in liquid form,
Filling the filling space by heat-sealing an elastic material in the form of a film or screen-printing a liquid elastic material,
A method for forming the back plate of a flexible display. According to claim 10,
Prior to the step of arranging the pattern bar along one direction in the rectangular molding space of the release jig,
Further comprising the step of seating an elastic material in the form of a thermally meltable film in the molding space,
In the step of filling the filling space between the pattern bars with an elastic material in a liquid state, the elastic material in the form of a film is thermally fused into the filling space.
A method for forming the back plate of a flexible display. According to claim 10,
In the step of filling the filling space between the pattern bars with an elastic material in a liquid state,
The elastic material is screen-printed in liquid form and filled in the filling space.
A method for forming the back plate of a flexible display. According to claim 12 or 13,
The elastic material is a polymer resin that melts at a temperature between 80 and 150 ° C.
A method for forming the back plate of a flexible display. According to claim 10,
The elastic material is a type of material in consideration of the maximum elongation obtained based on the thickness from the top surface of the flexible display panel to the bottom surface of the pattern bar and the maximum radius of curvature in a state in which the flexible display panel is folded or wound one or more times. And the filling rate is set,
A method for forming the back plate of a flexible display.

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