KR102641893B1 - Flexible display device - Google Patents

Abstract

This application relates to a flexible display device that can prevent transfer phenomenon by eliminating the step between the bending area and the height of the adhesive member in the area excluding the bending area, while also being flexible in the bending area. The flexible display device according to the present application includes a display panel that displays an image and a support plate disposed below the display panel, wherein the support plate includes a first support plate and a second support plate disposed below the first support plate. Included, the ductility of the second support plate is greater than the ductility of the first support plate.

Description

Flexible display device {FLEXIBLE DISPLAY DEVICE}

This application relates to a flexible display device.

Recently, the importance of display devices has increased along with the development of multimedia. In response to this, various types of flat panel displays, such as liquid crystal displays, plasma displays, and organic light emitting displays, are being commercialized.

Among flat panel displays, organic light emitting displays are widely used as display devices for laptop computers, televisions, tablet computers, monitors, smartphones, portable display devices, and portable information devices due to their excellent characteristics such as thinness, weight reduction, and low power consumption. .

Additionally, flexible display devices are being developed recently. A flexible display device can bend, fold, or bend a display panel for user convenience. In a flexible display device, both the display area that displays an image and the non-display area surrounding the display area can be bent or curved, allowing various types of images to be implemented.

The flexible display device places a rigid support plate (back plate) under the display panel to ensure impact resistance and flatness of the display panel. A pattern was formed through cutting or etching on the bending area that is bent or folded on the support plate to ensure flexibility and flatness of the area excluding the bending area.

However, when forming a pattern on a support plate, when pressure is applied in the process of bonding the support plate and the display panel with an adhesive member, the adhesive member penetrates between the patterns. When the adhesive member penetrates between the patterns, the height of the adhesive member in the bending area where the pattern is provided becomes lower than the height of the adhesive member in areas excluding the bending area. When a step occurs between the height of the adhesive member in the bending area and the area excluding the bending area, a transfer phenomenon occurs in which the boundary line between the bending area and the area excluding the bending area is visible.

Accordingly, the inventors of the present specification recognized the above-mentioned problem and invented a flexible display device in which the boundary line of the bending area is not visible.

The present application seeks to provide a flexible display device that can prevent transfer phenomenon by eliminating the step between the bending area and the height of the adhesive member in the area excluding the bending area, while also being flexible in the bending area.

The flexible display device according to the present application includes a display panel that displays an image and a support plate disposed below the display panel, wherein the support plate includes a first support plate and a second support plate disposed below the first support plate. Included, the ductility of the second support plate is greater than the ductility of the first support plate.

The flexible display device according to the present application does not form a pattern on the support plate, but applies a structure that combines a rigid support plate and a flexible support plate to fundamentally prevent the first adhesive member from seeping between the patterns, thereby forming a bending area and a bending area. By removing the step between the heights of the adhesive members in areas other than , transfer phenomenon can be prevented and flexibility can be achieved in the bending area.

1 is a perspective view of a flexible display device according to an example of the present application.
Figure 2 is a block diagram of a flexible display device according to an example of the present application.
Figure 3 is a block diagram of a flexible display device according to an example of the present application.
Figure 4 is a cross-sectional view of a support plate according to one example.
Figure 5 is a cross-sectional view of a support plate according to an example when bent.
Figure 6 is a cross-sectional view of a support plate according to another example.
Figure 7 is a cross-sectional view of a support plate according to another example when bent.
8 is a cross-sectional view of a support plate according to another example.
Figure 9 is a cross-sectional view of a support plate according to another example when bent.

The advantages and features of the present application and methods for achieving them will become clear by referring to examples described in detail below along with the accompanying drawings. However, the present application is not limited to the examples disclosed below and will be implemented in various different forms, and only the examples of the present application are intended to ensure that the disclosure of the present application is complete and are within the scope of common knowledge in the technical field to which this application pertains. It is provided to fully inform those who have the scope of the invention, and this application is only defined by the scope of the claims.

The shape, size, ratio, angle, number, etc. disclosed in the drawings for explaining an example of the present application are illustrative, and the present application is not limited to the matters shown. Like reference numerals refer to like elements throughout the specification. Additionally, in describing the present application, if it is determined that a detailed description of related known technology may unnecessarily obscure the gist of the present application, the detailed description will be omitted.

When 'includes', 'has', 'consists of', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the plural is included unless specifically stated otherwise.

When interpreting a component, it is interpreted to include the margin of error even if there is no separate explicit description.

In the case of a description of a positional relationship, for example, if the positional relationship of two parts is described as 'on top', 'on the top', 'on the bottom', 'next to', etc., 'immediately' Alternatively, there may be one or more other parts placed between the two parts, unless 'directly' is used.

In the case of a description of a temporal relationship, for example, if a temporal relationship is described as 'after', 'successfully after', 'after', 'before', etc., 'immediately' or 'directly' Unless used, non-consecutive cases may also be included.

Although first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are merely used to distinguish one component from another. Accordingly, the first component mentioned below may also be the second component within the technical spirit of the present application.

The “first horizontal axis direction”, “second horizontal axis direction”, and “vertical axis direction” should not be interpreted as only geometric relationships in which the relationship between each other is vertical, and the scope within which the configuration of the present application can function functionally It can mean having a broader direction than within.

The term “at least one” should be understood to include all possible combinations from one or more related items. For example, “at least one of the first, second, and third items” means each of the first, second, or third items, as well as two of the first, second, and third items. It can mean a combination of all items that can be presented from more than one.

Each feature of the various examples of the present application can be combined or combined with each other partially or entirely, and various technological interconnections and operations are possible, and each example can be implemented independently of each other or together in a related relationship. .

Hereinafter, a preferred example of a flexible display device according to the present application will be described in detail with reference to the attached drawings. In adding reference numerals to components in each drawing, identical components may have the same reference numerals as much as possible even if they are shown in different drawings.

Figure 1 is a perspective view of a flexible display device 100 according to an example of the present application. The flexible display device 100 according to an example of the present application includes a display area (DA), a non-display area (NDA), and a bending area (FDA).

The flexible display device 100 according to the present application may be implemented as an organic light emitting display. However, it is not limited to this, and the flexible display device 100 according to the present application can be applied to a quantum dot display device, a micro light emitting diode (μ-LED) display device, etc.

The display area DA is provided on the front of the flexible display device 100. The display area DA is an area that displays an image. Pixels are provided in the display area DA to display an image.

The non-display area NDA is arranged outside the display area DA to surround the display area DA. Circuits for supplying driving signals and driving voltages that enable image display in the display area DA are provided in the non-display area NDA.

The bending area (FDA) is defined in the display area (DA) and the non-display area (NDA). The bending area FDA defines an area where the flexible display device 100 is bent or curved. The bending area FDA is an area where the flexible display device 100 can be folded or bent. The bending area FDA may be formed across the display area DA and the non-display area NDA. The bending area FDA may be formed from one edge of the flexible display device 100 to the other edge of the flexible display device 100 when the flexible display device 100 is folded or bent. In this case, the bending area FDA extends from the outer boundary of the non-display area NDA and is formed to cross from one side of the display area DA to the other side.

For example, when bending the central portion of the flexible display device 100, the bending area FDA may be formed to cross the central portion of the display area DA and the non-display area NDA.

In the bending area FDA, the flexible display device 100 may be bent in the Z-axis direction, which is the height direction, folded to have a predetermined curvature, or folded to have a predetermined inclination angle. When the flexible display device 100 is bent in the Z-axis direction in the bending area (FDA), an image can be displayed with the display area (DA) protruding in the height direction. When the flexible display device 100 is folded to have a predetermined curvature in the bending area (FDA), the display area (DA) may remain folded on its inner surface. When the flexible display device 100 is folded to have a predetermined inclination angle in the bending area (FDA), the display area (DA) can display an image while maintaining the predetermined inclination. Accordingly, the flexible display device 100 according to an example can implement various types of images and three-dimensional images compared to a flat display device.

FIG. 2 is a block diagram of a flexible display device 100 according to an example of the present application. The flexible display device 100 according to an example of the present application includes a display area DA, a timing controller 10, a data driving circuit 20, and a gate driving circuit 30. Although a block diagram according to function is shown in FIG. 2, the timing controller 10, the data driving circuit unit 20, and the gate driving circuit unit 30 are a single unit mounted outside the display area (DA) of the organic light emitting display device. It can be implemented with a driver integrated circuit (Driver IC), which is a driver chip.

The display area DA includes scan lines that supply scan signals (SL1 to SLp, p is a positive integer of 2 or more), data lines that supply data voltages (DL1 to DLq, q is a positive integer of 2 or more), and driving power lines (RL1 to RLq) that supply driving power. The data lines DL1 to DLq and the driving power lines RL1 to RLq may intersect the scan lines SL1 to SLp. The data lines DL1 to DLq and the driving power lines RL1 to RLq may be parallel to each other. The display area DA may include a lower substrate on which pixels P are provided and an upper substrate that performs an encapsulation function.

Each of the pixels P may be connected to any one of the scan lines (SL1 to SLp), any one of the data lines (DL) (DL1 to DLq), and any one of the driving power lines (RL1 to RLq). there is. Each of the pixels P may include an organic light emitting diode (OLED) and a pixel circuit that supplies current to the organic light emitting diode (OLED).

The timing controller 10 generates digital video data (DATA) for implementing images on the organic light emitting display device and timing signals for controlling the timing of driving the organic light emitting display device. The timing signal includes a vertical sync signal, a horizontal sync signal, a data enable signal, and a dot clock.

The timing controller 10 uses timing signals to provide a data control signal (DCS) for controlling the operation timing of the data driving circuit unit 20 and a scan control signal (SCS) for controlling the operation timing of the gate driving circuit unit 30. creates . The timing controller 10 outputs digital video data (DATA) and a data control signal (DCS) to the data driving circuit unit 20. The timing controller 10 outputs a scan control signal (SCS) to the gate driving circuit unit 30.

The data driving circuit unit 20 receives a data control signal (DCS) from the timing controller 10. The data driving circuit unit 20 generates data voltages based on the data control signal DCS. The data driving circuit unit 20 supplies data voltages to the data lines DL (DL1 to DLq).

The gate driving circuit unit 30 receives a scan control signal (SCS) from the timing controller 10. The gate driving circuit unit 30 generates scan signals based on the scan control signal (SCS). The gate driving circuit unit 30 supplies scan signals to the scan lines SL1 to SLp.

As described above, the timing controller 10, the data driving circuit unit 20, and the gate driving circuit unit 30 are mounted outside the display area DA of the organic light emitting display device. At this time, the timing controller 10, the data driving circuit unit 20, and the gate driving circuit unit 30 are the external area surrounding the display area DA using the gate drive in panel (GIP) method. It can be mounted in the display area (NDA).

The driver IC mounting the data driving circuit unit 20 and the gate driving circuit unit 30 may be connected to a printed circuit board (FPCB). The printed circuit board may be attached to the front edge and back edge areas of the interior of the organic light emitting display device.

In this case, the timing controller 10 can be mounted on the printed circuit board, and the data control signal (DCS) and scan control signal (SCS) can be transmitted to the driver integrated circuit (Driver IC) on the control printed circuit board. The printed circuit board is arranged in a folded state at the edge area inside the organic light emitting display device. Accordingly, the printed circuit board can be mounted without providing a separate space inside the organic light emitting display device. Additionally, when the timing controller 10 is mounted on a printed circuit board, functions performed by circuits within the driving integrated circuit can be reduced, thereby reducing the size of the driving integrated circuit.

Figure 3 is a block diagram of a flexible display device according to an example of the present application. The flexible display device according to an example of the present application includes a support plate 110, a first adhesive member 120, a display panel 130, a second adhesive member 140, and a cover window 150.

The support plate 110 is disposed at the bottom of the flexible display device 100. The support plate 110 forms the lower surface of the flexible display device 100. The support plate 110 protects the flexible display device 100 from impact from the bottom. The support plate 110 ensures impact resistance, which is the ability of the display panel 130 to withstand impacts. The support plate 110 ensures flatness that maintains a flat state when the display panel 130 is not bent due to external force.

The first adhesive member 120 is disposed on the protection member 110. The first adhesive member 120 may be disposed on the entire upper surface of the protection member 110. For example, the first adhesive member 120 may be made of a transparent adhesive member such as OCR (Optical Clear Resin) or OCA (Optical Clear Adhesive), but is not limited thereto. The first adhesive member 120 attaches the support plate 110 and the display panel 130.

The display panel 130 is disposed on the first adhesive member 120 . The display panel 130 includes a display area DA in which pixels P for displaying an image are provided, and a non-display area NDA arranged to surround the display area DA. The display panel 130 according to one example may be an organic light emitting display panel that displays an image by emitting light from an organic light emitting diode implemented by an organic light emitting layer, but is not limited thereto. The display panel 130 may be a quantum dot (Quantum-Dot) display panel or a micro light emitting diode (μ-LED) display panel. Each of the pixels P provided in the display panel 130 is turned on by a gate signal and emits light at a predetermined brightness according to the data voltage to display an image. The display panel 130 applied to the flexible display device 100 has flexibility. The display panel 130 may be implemented with a polymer material such as polyimide, which has excellent bending ability, or a plastic thin film or film.

The second adhesive member 140 is disposed on the upper part of the display panel 130 . The second adhesive member 140 may be disposed on the entire upper surface of the display panel 130 . For example, the second adhesive member 140 may be made of a transparent adhesive member such as OCR (Optical Clear Resin) or OCA (Optical Clear Adhesive), but is not limited thereto. The second adhesive member 140 attaches the display panel 130 and the cover window 150.

The cover window 150 is disposed on the second adhesive member 140. The cover window 150 forms the upper surface of the flexible display device 100. The cover window 150 protects the flexible display device 100 from impacts from the top surface. The cover window 150 applied to the flexible display device 100 has flexibility. The cover window 150 may be implemented as transparent plastic or transparent film with excellent bending ability.

As such, the flexible display device 100 according to an example of the present application includes a display panel 130 that displays an image and a support plate 110 disposed below the display panel 130. Accordingly, the impact resistance and flatness of the display panel 130 can be secured.

Figure 4 is a cross-sectional view of the support plate 110 according to one example. The support plate 110 according to one example includes a first support plate 111 and a second support plate 112.

The first support plate 111 forms the upper layer of the support plate 110. The upper surface of the first support plate 111 is in contact with the first adhesive member 120. The first support plate 111 may be formed in the same shape as the flexible display device 100. For example, when the flexible display device 100 is square, the first support plate 111 is formed into a square shape, and when the flexible display device 100 is a heterogeneous display with an atypical shape, the first support plate ( 111) may also have an atypical shape corresponding to the shape of the flexible display device 100.

The first support plate 111 may have an area corresponding to that of the display panel 130 . The first support plate 111 may be made of a material with excellent rigidity. The first support plate 111 ensures impact resistance and flatness of the display panel 130. The first support plate 111 has a first thickness T1. The first thickness T1 is 30 ㎛ or more and 50 ㎛ or less.

The second support plate 112 is disposed below the first support plate 111. The upper surface of the second support plate 112 is in contact with the first support plate 111. The second support plate 112 may be formed in the same shape as the first support plate 111. The second support plate 111 may have an area corresponding to the first support plate 111. The second support plate 111 may be formed of a material with excellent ductility. Ductility can be defined as the property of a material being stretched and plastically deformed without being broken or destroyed by tensile force, which is a pulling force that exceeds the elastic limit. Ductility of a target metal material can be measured by calculating elongation through a tensile test. The ductility of the second support plate 112 is greater than that of the first support plate 111. The second support plate 112 secures the flexibility and bending ability of the display panel 130. The second support plate 112 has a second thickness T2. The second thickness (T2) is 15 ㎛ or more and 45 ㎛ or less.

The ductility of the second support plate 112 according to one example is greater than that of the first support plate 111. The flexible display device 100 according to an example of the present application can secure flexibility without forming a separate pattern in the bending area (FDA) of the support plate 110. If a separate pattern is not formed in the bending area (FDA), the first adhesive member 120 seeps between the patterns, causing the first adhesive member ( 120) height difference phenomenon can be prevented. Accordingly, the flexible display device 100 according to an example of the present application prevents a problem in which the bending area (FDA) is viewed differently from the area excluding the bending area (FDA) depending on the height difference of the first adhesive member 120. can do.

The first adhesive member 120 according to one example is disposed between the display panel 130 and the support plate 110. The first adhesive member 120 according to one example is uniformly provided on the upper surface of the first support plate 111. Since the upper surface of the first support plate 111 is a flat surface without a pattern, the first adhesive member 120 can be provided with a uniform thickness. Accordingly, the flexible display device 100 according to an example of the present application attaches the first support plate 111 using the first adhesive member 120 in both the bending area FDA and the area excluding the bending area FDA. The upper surface of and the display panel 130 can be uniformly attached. In this case, the flexible display device 100 according to an example can stably bond the top surface of the first support plate 111 and the display panel 130, so that the top surface of the first support plate 111 and the display panel 130 can be stably bonded to each other. (130) It is possible to increase the adhesion between

According to one example, the areas of the first support plate 111 and the second support plate 112 may be the same. In this case, flexibility and bending ability can be improved in the entire area of the support plate 110, not limited to the bending area (FDA).

Figure 5 is a cross-sectional view of the support plate 110 according to an example when bent. The support plate 110 according to one example has a stacked structure of first and second support plates 111 and 112. Since the ductility of the second support plate 112 is greater than that of the first support plate 111, the second support plate 112 is stretched more.

The second support plate 112 according to an example places within it a tensile central axis (TCA) that receives a tensile force when bent. Tensile force is a force that pulls an object from the outside and acts in both directions of the Y-axis, which is the first direction. At the tensile central axis (TCA), the tensile force for pulling and bending the support plate 110 from the outside in the first direction is maximized. The greatest physical strain occurs at the tensile center axis (TCA).

The second support plate 112 prevents the tensile central axis (TCA) from deviating from the inside. The tensile central axis (TCA) may change its position within the second support plate 112 depending on the degree of bending of the support plate 110. Accordingly, the second support plate 112 can receive as much tensile force as possible, thereby preventing the first support plate 111, which has rigidity but insufficient ductility, from being damaged by the tensile force.

For example, when the second support plate 112 is bent to the maximum, that is, when the radius of curvature has a minimum value, the tensile central axis (TCA) is based on the height of the inside of the second support plate 112. It can be placed in the center. When the tensile central axis (TCA) passes through the central part of the second support plate 112, the force capable of withstanding the tensile force is maximum. Accordingly, even when tensile force is applied to the flexible display device 100, bending can be repeatedly performed without damage.

Figure 6 is a cross-sectional view of the support plate 110 according to another example. The support plate 110 according to another example also includes first and second support plates 111 and 112.

The second support plate 112 according to another example is disposed in a partial area of the lower part of the first support plate 111. When the second support plate 112 is disposed, ductility in the area increases, but rigidity decreases compared to when only the first support plate 111 is disposed. Accordingly, a structure in which the first and second support plates 111 and 112 are stacked is applied to areas of the flexible display device 100 where bending ability is important, and where relative rigidity is important to prevent damage to the border area, etc. Only the first support plate 111 can be placed in the area.

For example, the second support plate 112 may be disposed only in the bending area FDA. The second support plate 112 is not disposed in the first and second rigid areas RA1 and RA2, which are areas excluding the bending area FDA. Since repetitive bending and folding of the support plate 110 occurs in the bending area (FDA), the second support plate 112 must be disposed in the bending area (FDA). However, since the support plate 110 is less likely to be bent or folded in the first and second rigid regions RA1 and RA2, it is more important to have rigidity to protect the display panel 130.

According to another example, the height of the lower surface of the first support plate 111 in the rigid areas RA1 and RA2 is the same as the height of the lower surface of the second support plate 112 in the bending area FDA. In the bending area FDA, the first support plate 111 has a first thickness T1, and the second support plate 112 has a second thickness T2. In the rigid regions RA1 and RA2, the first support plate 111 has a thickness that is the sum of the first thickness T1 and the second thickness T2. The upper surface of the first support plate 111 is formed uniformly. The second support plate 112 is formed between grooves formed in the bending area FDA on the lower surface of the first support plate 111.

When the height of the lower surface of the first support plate 111 in the rigid areas RA1 and RA2 is the same as the height of the lower surface of the second support plate 112 in the bending area FDA, the lower surface of the support plate 110 is It can be formed uniformly without irregularities in all areas. Accordingly, it is possible to prevent a phenomenon in which the bending area (FDA) and the rigid areas (RA1, RA2) are viewed as distinct depending on the difference in height of the lower surface of the support plate 110.

Figure 7 is a cross-sectional view of the support plate 110 according to another example when bent. When bending the support plate 110, the bending area (FDA) receives a relatively large amount of tensile force and has a large degree of deformation relative to the plane based on the degree of bending or radius of curvature. When bending the support plate 110, the rigid regions RA1 and RA2 receive a relatively small tensile force, and the degree of deformation relative to the plane is small based on the degree of bending or radius of curvature. On the other hand, the rigid areas (RA1, RA2) can easily receive shock from the outside.

The flexible display device 100 according to another example forms a second support plate 112 with excellent flexibility only in the bending area (FDA), and the first support plate 111 is formed on the top and side surfaces of the second support plate 112. It was formed to surround. The support plate 110 according to another example maintains a constant thickness in all areas, and selectively applies a core structure and a cladding structure in some areas.

Figure 8 is a cross-sectional view of the support plate 110 according to another example. The support plate 110 according to another example also includes first and second support plates 111 and 112.

The second support plate 112 according to another example has inclination angles θ1 and θ2 on the boundary lines of the bending area FDA and the rigid areas RA1 and RA2. The second support plate 112 is disposed only in the bending area FDA. The second support plate 112 may have a thinner thickness as it approaches the boundary between the bending area FDA and the rigid areas RA1 and RA2.

The first support plate 111 has a first thickness T1 at the center of the bending area FDA where the second support plate 112 is disposed. As the first support plate 111 approaches the boundary between the bending area FDA and the rigid areas RA1 and RA2, its thickness increases up to the sum of the first thickness T1 and the second thickness T2. The first support plate 111 has a thickness equal to the sum of the first thickness T1 and the second thickness T2 in the rigid regions RA1 and RA2.

Figure 9 is a cross-sectional view of the support plate 111 according to another example when bent. When the support plate 110 is bent, boundary areas EDG1 and EDG2 may be formed between the bending area FDA and the rigid areas RA1 and RA2. In another example, in the boundary areas (EDG1, EDG2), the boundary areas (EDG1, EDG2) between the first support plate 111 and the second support plate 112 are the first support plate 111 and the second support plate ( 112) includes the boundary line.

When forming the first support plate 111 and the second support plate 112 into a core and cladding structure, it is important to prevent the second support plate 112 from being separated from the first support plate 111. When the second support plate 112 is formed vertically on the boundary areas (EDG1, EDG2), when bending, the force to separate outward from the boundary areas (EDG1, EDG2) of the second support plate 112 is concentrated, causing the second support plate 112 to be separated from the boundary areas (EDG1, EDG2). The support plate 112 may be separated.

In another example, one side of the second support plate 112 is inclined at the boundary between the bending area FDA and the rigid areas RA1 and RA2. The second support plate 112 according to another example is formed to have inclination angles (θ1, θ2) on the boundary areas (EDG1, EDG2), so that it resists the force to separate outward from the boundary areas (EDG1, EDG2) when bending. It can be dispersed. Accordingly, the second support plate 112 according to another example may be stably coupled to the first support plate 111 without being separated from the first support plate 111 even when bending.

For example, the angle formed by one side of the second support plate 112 has an inclination angle of 30° to 60°. When the inclination angles θ1 and θ2 are 30° or more and 60° or less, the effect of preventing force from being concentrated in the direction in which the second support plate 112 deviates from the boundary areas EDG1 and EDG2 is greatest.

The support plate 110 according to examples of the present application consists of a first support plate 111 having excellent rigidity and a second support plate 112 having excellent ductility.

The tensile modulus of the first support plate 111 according to examples of the present application is 150 GPa or more and 250 GPa or less, and the tensile modulus of the second support plate 112 is 40 GPa or more and 140 GPa or less. When the tensile coefficients of the first and second support plates 111 and 112 satisfy the above-mentioned range, an impact resistance test was performed by dropping a reference object on the support plate 110, and as a result, 150% of the reference height It was confirmed that it can withstand impact even when dropped from a height of 300% or less. As an example, it was confirmed that a steel ball weighing 22g was not damaged even when dropped from a height of 1.5 m or more and 3.0 m or less.

The thickness of the first support plate 111 according to examples of the present application is 30 ㎛ or more and 50 ㎛ or less, and the thickness of the second support plate 112 is 15 ㎛ or more and 45 ㎛ or less. If the thickness of the first support plate 111 exceeds 50 μm, the display panel 130 cannot be bent in the bending area FDA. Additionally, even when the thickness of the first support plate 111 and the second support plate 112 exceeds 100 ㎛, the display panel 130 cannot be bent in the bending area FDA. Therefore, the thickness of the first and second support plates 111 and 112 should be set to ensure minimum impact resistance within a range in which the display panel 130 can be bent in the bending area FDA.

According to examples of the present application, the thickness of the first support plate 111 may be defined as the first thickness T1, and the thickness of the second support plate 112 may be defined as the second thickness T2. In this case, it was confirmed that both impact resistance and bending ability can be maintained when the first thickness (T1) is 1 to 2 times the second thickness (T2).

When the first thickness (T1) is smaller than the second thickness (T2), an impact resistance test showed that the impact resistance performance was inefficiently reduced. In addition, when the first thickness (T1) exceeds twice the second thickness (T2), repeated bending experiments confirmed that defects occurred when bending was performed less than 10,000 times and the bending ability was not maintained.

Accordingly, it was confirmed that the support plate 110 capable of maintaining both impact resistance and bending ability can be provided when the first thickness (T1) is 1 to 2 times the second thickness (T2). In particular, it was confirmed that when the first thickness (T1) was 1.6 times the second thickness (T2), the ability to withstand impact was maximized while maintaining the bending ability. For example, when the first thickness (T1) is 48 ㎛ and the second thickness (T2) is 30 ㎛, the impact resistance of the support plate 110 that has a total thickness of 78 ㎛ and maintains bending ability is compared to the standard impact. 2. It was confirmed to be the best as it could withstand up to 67 times the impact.

The first support plate 111 according to examples of the present application is made of high-rigidity stainless steel (Stainless Steel) or iron (Fe), and the second support plate 112 is made of soft stainless steel, copper (Cu), or aluminum ( Al), or nickel (Ni).

Examples of high-rigidity stainless steel include SUS301 and SUS304. SUS301 and SUS304 have high rigidity, do not break or break easily, and are relatively easy to process thin plates. SUS301 and SUS304 are made by mixing iron (Fe) with carbon (C), silicon (Si), manganese (Mn), phosphorus (P), sulfur (S), nickel (Ni), and chromium (Cr) in a predetermined ratio. It can be formed by doing so.

Ductile stainless steel can be formed by lowering the proportion of carbon (C) compared to high-strength stainless steel. Alternatively, ductile stainless steel can be formed from an alloy of iron (Fe), copper (Cu), aluminum (Al), or nickel (Ni). In order for the second support plate 112 to have high ductility, the iron (Fe) content is set to 30% or more and 50% or less, and copper (Cu), aluminum (Al), nickel (Ni), and copper-aluminum (Cu) are added. -Al) alloy or copper-nickel (Cu-Ni, cupronickel) alloy is preferably used.

The flexible display device according to the present application does not form a pattern on the support plate, but applies a structure that combines a rigid support plate and a flexible support plate to fundamentally prevent the first adhesive member from seeping between the patterns, thereby forming a bending area and a bending area. By removing the step between the heights of the adhesive members in areas other than , transfer phenomenon can be prevented and flexibility can be achieved in the bending area.

Through the above-described content, those skilled in the art will be able to see that various changes and modifications can be made without departing from the technical idea of the present invention. Therefore, the technical scope of the present invention should not be limited to what is described in the detailed description of the specification, but should be defined by the scope of the patent claims.

100: Flexible display device DA: Display area
NDA: Non-display area FDA: Bending area
10: Timing controller 20: Data driving circuit unit
30: Gate driving circuit P: Pixel
110: support plate 111: first support plate
112: second support plate 120: first adhesive member
130: display panel 140: second adhesive member
150: cover window

Claims (24)

A flexible display panel including a display area and a folding area;
a support plate disposed below the flexible display panel; and
It includes an adhesive member formed between the flexible display panel and the support plate,
The support plate includes a first support plate and a second support plate disposed below the first support plate,
The upper surface of the first support plate is a continuous plane, and the lower surface of the first support plate is in contact with the entire upper surface of the second support plate,
The first support plate has a flat top surface, and the thickness of the first support plate is greater than the thickness of the second support plate. According to claim 1,
A foldable display device wherein the first and second support plates have the same shape. According to claim 1,
The thickness of the first support plate is 30 ㎛ or more and 50 ㎛ or less, and the thickness of the second support plate is 15 ㎛ or more and 45 ㎛ or less. According to claim 1,
A foldable display device wherein the ductility of the second support plate is greater than that of the first support plate. According to claim 1,
The tensile coefficient of the first support plate is 150 GPa or more and 250 GPa or less, and the tensile coefficient of the second support plate is 40 GPa or more and 140 GPa or less. According to claim 1,
The second support plate is a foldable display device that positions a central axis of tension within the second support plate, which receives a tensile force when bent. According to claim 1,
The second support plate is disposed only in the folding area. According to claim 1,
The thickness of the second support plate decreases as it approaches the boundary between the folding area and the rigid area excluding the folding area. According to claim 1,
A foldable display device wherein an angle formed by one side of the second support plate has an inclination angle of 30° to 60°. According to claim 1,
A foldable display device in which materials forming the first and second support plates are different. According to claim 10,
The first support plate is made of high-rigidity stainless steel or iron,
The second support plate is made of soft stainless steel, copper, aluminum, nickel, copper-aluminum alloy, or copper-nickel alloy with an iron content of 30% to 50%. According to claim 1,
The second support plate has an area corresponding to the first support plate. According to claim 1,
The second support plate is disposed in a portion of a lower portion of the first support plate. A flexible display panel including a display area and a folding area; and
It includes a support plate disposed below the flexible display panel,
The support plate includes a first support plate and a second support plate disposed below the first support plate,
The upper surface of the first support plate is a continuous plane, and the lower surface of the first support plate is in contact with the entire upper surface of the second support plate,
The first support plate has a flat upper surface,
The thickness of the first support plate is greater than the thickness of the second support plate,
A foldable display device wherein the first and second support plates have different areas. delete According to claim 14,
The thickness of the first support plate is 30 ㎛ or more and 50 ㎛ or less, and the thickness of the second support plate is 15 ㎛ or more and 45 ㎛ or less. According to claim 14,
A foldable display device wherein the ductility of the second support plate is greater than that of the first support plate. According to claim 14,
The tensile coefficient of the first support plate is 150 GPa or more and 250 GPa or less, and the tensile coefficient of the second support plate is 40 GPa or more and 140 GPa or less. According to claim 14,
The second support plate is a foldable display device that positions a central axis of tension within the second support plate, which receives a tensile force when bent. According to claim 14,
The second support plate is disposed only in the folding area. According to claim 14,
The thickness of the second support plate decreases as it approaches the boundary between the folding area and the rigid area excluding the folding area. According to claim 14,
A foldable display device wherein an angle formed by one side of the second support plate has an inclination angle of 30° to 60°. According to claim 14,
A foldable display device in which materials forming the first and second support plates are different. According to clause 23,
The first support plate is made of high-rigidity stainless steel or iron,
The second support plate is made of soft stainless steel, copper, aluminum, nickel, copper-aluminum alloy, or copper-nickel alloy with an iron content of 30% to 50%.