KR102478673B1 - Cable and rollable flexible display device - Google Patents

Abstract

The present invention provides a roll-type flexible display device including a display panel, a source substrate, a control substrate, and a cable. The display panel displays an image. A source substrate is attached to the display panel. The control substrate is spaced apart from the source substrate. The cable electrically connects the control board and the source board. The cable includes a first film, signal lines positioned on a first surface of the first film, a second film positioned on the signal lines, and a shielding layer positioned on a second surface of the first film.

Description

Cable and roll type flexible display device {CABLE AND ROLLABLE FLEXIBLE DISPLAY DEVICE}

The present invention relates to a cable and a roll type flexible display device.

As information technology develops, the market for display devices, which are communication media between users and information, is growing. Accordingly, Organic Light Emitting Display (OLED), Electrophoretic Display Device (ED), Liquid Crystal Display (LCD) and Plasma Display Panel (PDP) The use of display devices such as the like is increasing.

Among the display devices described above, an organic light emitting display device includes a display panel including a plurality of subpixels and a driver that drives the display panel. The driver includes a scan driver for supplying scan signals (or gate signals) to the display panel and a data driver for supplying data signals to the display panel.

Since the organic light emitting display device can impart ductility, the display panel can be bent or have a curved surface, and the display panel can be deformed by rolling and unfolding the display panel. For this reason, recently, attempts to design a mechanism structure accommodating the display panel of the organic light emitting display device in various forms have been increasing.

The present invention to solve the problems of the background art described above is to provide a roll-type flexible display device capable of maintaining normal and uniform display quality by solving the problem of deterioration in signal transmission quality. In addition, the present invention is to provide a cable capable of solving the signal distortion problem.

As a means for solving the above problems, the present invention provides a roll-type flexible display device including a display panel, a source substrate, a control substrate, and a cable. The display panel displays an image. A source substrate is attached to the display panel. The control substrate is spaced apart from the source substrate. The cable electrically connects the control board and the source board. The cable includes a first film, signal lines positioned on a first surface of the first film, a second film positioned on the signal lines, and a shielding layer positioned on a second surface of the first film.

The thickness of the shielding layer may be equal to or greater than the thickness of the first film.

The shielding layer may be disposed corresponding to the width and length of signal lines or the width and length of cables.

The shielding layer may be made of a conductive or non-conductive material.

The shielding layer may be formed in the form of a film or tape.

The shielding layer may be made of aluminum foil, polyethylene terephthalate (PET), and acrylic adhesive.

The shielding layer may be made of aluminum sheet, polypropylene, limestone, titanium, silica gel, polyethylene terephthalate (PET), and acrylic adhesive.

The shielding layer may be made of polypropylene and acrylic adhesive.

In another aspect, the present invention provides a cable including a first film, signal lines, a second film and a shielding layer. The signal lines are located on the first side of the first film, the second film is located on the signal lines, and the shielding layer is located on the second side of the first film.

The thickness of the shielding layer may be equal to or greater than the thickness of the first film.

The present invention has an effect of providing a roll-type flexible display device capable of maintaining a normal and uniform display quality by solving the problem of deterioration in signal transmission quality due to physical deformation and impedance deformation of a cable. In addition, the present invention has an effect of solving a signal distortion problem that may occur in a display device using a long cable.

1 is a schematic block diagram of an organic light emitting display device;
2 is a schematic circuit configuration diagram of a subpixel;
3 is a schematic diagram of a roll-type flexible display device;
4 is a cross-sectional view of some components of a roll-type flexible display device;
5 is a configuration diagram showing a front view of devices for modularizing a display panel;
6 is a rear view illustrating a state in which a modularized display panel is installed on a panel roller unit;
7 is a view illustrating a reinforcing member attached to a rear surface of a display panel;
8 is a cross-sectional view of the area A1-A2 of FIG. 7;
9 to 11 are views for explaining problems caused by close contact between a cable and an upper substrate according to an experimental example.
12 is a diagram showing a cable according to an embodiment of the present invention;
13 is a cross-sectional view showing a first cable and an upper substrate according to an embodiment of the present invention.
14 and 15 are diagrams showing an electrical connection structure according to the material of the shielding layer.
16 and 17 are cross-sectional views showing a hierarchical structure according to the material of the shielding layer.

Hereinafter, specific details for the implementation of the present invention will be described with reference to the accompanying drawings.

Hereinafter, an example of implementing a roll-type flexible display device using an organic light emitting display device as an example will be described as an embodiment. However, the roll-type flexible display device may be implemented with an electrophoretic display device (ED), a liquid crystal display (LCD), or the like, but is not limited thereto.

1 is a schematic block diagram of an organic light emitting display device, and FIG. 2 is a schematic circuit diagram of a sub-pixel.

As shown in FIG. 1 , the organic light emitting display device includes a power supply unit 100, an image processing unit 110, a timing controller 120, a data driver 140, a scan driver 130, and a display panel 150. included

The power supply unit 100 generates first power (high potential power) and second power (low potential power) to be supplied through the first power line (EVDD) and the second power line (EVSS) of the display panel 150 and print out The power supply 100 may generate and output power for driving the image processor 110 , the timing controller 120 , the data driver 140 , and the scan driver 130 .

The image processor 110 outputs a data enable signal DE along with the data signal DATA supplied from the outside. The image processor 110 may output one or more of a vertical sync signal, a horizontal sync signal, and a clock signal in addition to the data enable signal DE, but these signals are omitted for convenience of description.

The timing controller 120 receives a data signal DATA along with a data enable signal DE or driving signals including a vertical synchronization signal, a horizontal synchronization signal, and a clock signal from the image processing unit 110 . The timing controller 120 generates a gate timing control signal (GDC) for controlling the operation timing of the scan driver 130 and a data timing control signal (DDC) for controlling the operation timing of the data driver 140 based on the driving signal. outputs

The data driver 140 samples and latches the data signal DATA supplied from the timing controller 120 in response to the data timing control signal DDC supplied from the timing controller 120, converts it into a gamma reference voltage, and outputs the result. . The data driver 140 outputs the data signal DATA through the data lines DL1 to DLn. The data driver 140 may be formed in the form of an integrated circuit (IC). The mounting position and number of data drivers 140 may vary depending on the resolution or implementation method of the display panel 150 .

The scan driver 130 outputs a scan signal in response to the gate timing control signal GDC supplied from the timing controller 120 . The scan driver 130 outputs scan signals through scan lines GL1 to GLm. The scan driver 130 is formed in the form of an integrated circuit (IC) or formed in the display panel 150 in a gate-in-panel method. The mounting position and number of the scan driver 130 may vary depending on the resolution or implementation method of the display panel 150 .

The display panel 150 displays an image in response to the data signal DATA and the scan signal supplied from the data driver 140 and the scan driver 130 . The display panel 150 includes sub-pixels SP that operate to display an image.

The sub-pixels SP are formed on a flexible lower substrate that can be bent or bent by a deposition method. Since the subpixels SP formed on the lower substrate are vulnerable to moisture or oxygen, they are sealed by the upper substrate. While the lower substrate is made of a material such as glass or resin capable of transmitting light, the upper substrate may be made of a material such as metal that is thin enough to have rigidity and resilience.

The sub-pixels SP are formed in a top-emission method, a bottom-emission method, or a dual-emission method, depending on the structure. The subpixels SP include a red subpixel, a green subpixel, and a blue subpixel, or include a white subpixel, a red subpixel, a green subpixel, and a blue subpixel. The subpixels SP may have one or more different light emitting areas according to light emitting characteristics.

As shown in FIG. 2, one sub-pixel includes a switching transistor SW, a driving transistor DR, a capacitor Cst, a compensation circuit CC, and an organic light emitting diode OLED.

The switching transistor SW performs a switching operation to store the data signal supplied through the first data line DL1 as a data voltage in the capacitor Cst in response to the scan signal supplied through the first scan line GL1. The driving transistor DR operates to allow a driving current to flow between the first power line EVDD and the second power line EVSS according to the data voltage stored in the capacitor Cst. The organic light emitting diode OLED operates to emit light according to a driving current formed by the driving transistor DR.

The compensation circuit CC is a circuit added in the sub-pixel to compensate for the threshold voltage of the driving transistor DR. The compensation circuit (CC) is composed of one or more transistors. Since the configuration of the compensation circuit (CC) varies greatly depending on the compensation method, a detailed description thereof will be omitted.

The organic light emitting display device described above may be implemented as a roll-type flexible display device in which a display panel may be rolled and unfolded in the form of a roll, which is as follows.

FIG. 3 is a schematic diagram of a roll-type flexible display device, FIG. 4 is a cross-sectional view of some components of the roll-type flexible display device, and FIG. 5 is a block diagram showing the front of devices for modularizing a display panel. FIG. 6 is a rear view showing a modular display panel installed on the panel roller unit, FIG. 7 is a view showing a reinforcing member attached to the rear surface of the display panel, and FIG. 8 is a view showing areas A1-A2 of FIG. 7 . is a cross-section of

As shown in FIGS. 3 and 4 , the roll-type flexible display device includes a display panel 150 and a panel roller unit 160 . The panel roller unit 160 has a circular or elliptical shape. A control board 125 on which a timing controller 120 and the like are mounted is received inside the panel roller unit 160 . On the control board 125, not only the timing controller 120 but also other devices such as a power supply unit are mounted.

The panel roller unit 160 is accommodated in a storage unit (not shown). The panel roller unit 160 rolls and unfolds the display panel 150 on its outer circumferential surface based on the operation of a motor or the like installed inside the unit or inside the storage unit.

As shown in FIG. 5 , the display panel 150 and its peripheral devices are modularized. The scan driver 130 is formed on the non-display area of the display panel 150 in a gate-in-panel manner. The data driver 140 is formed in the form of an IC and mounted on the source substrate 145 . The timing controller 120 is formed in the form of an IC and mounted on the control board 125 .

It may be desirable to form the scan driver 130 in a gate-in-panel method on the left, right, or left and right sides of the display area AA to form the display panel 150 in a scroll form, but is not limited thereto. .

While the data driver 140 is mounted on the source board 145 made of a flexible circuit board, the timing controller 120 and the like may be mounted on the control board 125 made of a printed circuit board, but is not limited thereto. The source board 145 and the control board 125 may be electrically connected in a connector method using cables 127a and 127b, but are not limited thereto.

As shown in FIG. 6 , when the entire display panel 150 is unfolded from the outer circumferential surface of the panel roller unit 160 , the source substrate 145 on which the data driver 140 is mounted is located at the bottom of the display panel 150 . Unlike this, the control board 125 on which the timing controller 120 is mounted is positioned on the top of the display panel 150 .

Cables 127a and 127b are positioned between the control board 125 and the source board 145 . Since the cables 127a and 127b electrically connect the control board 125 and the source board 145, they are disposed as long as the length of the display panel 150 in the vertical direction.

The first cable 127a serves to transfer data signals output from the timing controller 120 of the control board 125 to the source board 145 . The second cable 127b serves to transfer the power output from the power supply 100 of the control board 125 to the source board 145 .

The first cable 127a may transmit a data signal or the like using an EPI (Embedded clock point to point interface) method for transmitting a signal from a timing controller to a data driver. In the drawing, the first cable 127a is disposed inside the second cable 127b and the second cable 127b is disposed outside the first cable 127a as an example. It may be changed.

As shown in FIGS. 6 , 7 and 8 , a reinforcing member 170 is disposed on the rear surface of the display panel 150 . The reinforcing member 170 serves to protect the display panel 150 from mechanical shock that may be received when the display panel 150 is rolled into a roll shape or the like.

In addition, the reinforcing member 170 serves to cover and protect the source substrates 145a and 145b, the first cable 127a, and the second cable 127b located on the rear surface of the display panel 150 from being exposed to the outside. do In addition, the reinforcing member 170 serves to smooth and flatten the rear surface of the display panel 150 so that an operation such as rolling the display panel 150 in a roll shape can be performed smoothly. In addition, the reinforcing member 170 serves to provide various advantages to the display panel 150 and the like when implementing a roll-type flexible display device.

On the other hand, as a result of manufacturing and testing the above-described roll-type flexible display device, a problem occurred due to adhesion between the cable and the upper substrate of the display panel, and this will be described.

9 to 11 are diagrams for explaining problems caused by adhesion between a cable and an upper substrate according to experimental examples.

As shown in FIGS. 9 and 10 , the display panel 150 is rolled or unfolded on the panel roller unit 160 in the form of a roll. At this time, the cable 127 located in a specific area (the area where the display panel is spread out) remains spaced apart from the upper substrate 155 located on the rear surface of the display panel 150 .

However, the cable 127 located in another specific area (the area where the display panel is rolled up) comes into close contact with the upper substrate 155 located on the rear surface of the display panel 150 (corresponding to the cable in FIG. 9). Refer to FSM contact part corresponding to FFC and upper board). Hereinafter, the problem of signal transmission quality deterioration will be described using the first cable as an example.

The first cable 127a is composed of a first film 127a1, signal lines 128 and a second film 127a2. The first cable 127a transfers data signals and the like to signal lines 128 made of metal.

The first cable 127a transfers data signals and the like in a differential manner. Therefore, when designing the differential impedance for the first cable 127a, the thickness (B) of the first film (127a1), the width (W) and thickness (T) of the signal lines (128, A) and these The separation distance (S) between the two layers and the thickness (D) of the second film 127a2 are taken into consideration.

However, the first cable 127a and the upper substrate 155 come into close contact with each other during the process of rolling the display panel into a roll shape. At this time, the reinforcing member 170 also contributes to adhesion between the first cable 127a and the upper substrate 155.

When the first cable 127a and the upper substrate 155 come into close contact with each other, the first film 127a1 is formed by the adhesive force between the signal line 128 (A) and the upper substrate 155 serving as a reference plane. The height H (or thickness) becomes lower than before. In addition, although the upper substrate 155 serves as a reference plane, since it is made of a metal material, it is found that the capacitance of the signal lines 128 increases as it comes into close contact with the first cable 127a.

For this reason, when the first cable 127a and the upper substrate 155 come into close contact with each other in the area where the display panel 150 is rolled up, the differential impedance value may deviate from the pre-designed value (set value) or Changes such as lower than this will occur.

As a result, signal transmission quality is degraded in the signal lines 128 (A) due to variations in impedance. The deterioration of the signal transmission quality leads to problems such as line defect (VLE) in which an image is not displayed (displayed in black) on a specific signal line of the display panel 150 .

In addition, it was found that problems caused by close contact between the cable and the upper substrate have a greater effect on the first cable 127a for transmitting data signals than the second cable for transmitting power.

12 is a view showing a cable according to an embodiment of the present invention, FIG. 13 is a cross-sectional view showing a first cable and an upper substrate according to an embodiment of the present invention, and FIGS. 14 and 15 are electrical according to the material of the shielding layer. These are drawings showing a connection structure, and FIGS. 16 and 17 are cross-sectional views showing a hierarchical structure according to the material of the shielding layer.

12 and 13, the first cable 127a includes a shielding layer 129, a first film 127a1, signal lines 128, and a second film 127a2. Signal lines 128 are positioned on the first surface of the first film 127a1, a second film 127a2 is positioned on the signal lines 128, and a shielding layer ( 129) is located. The first cable 127a (or may be the second cable 127b) further includes a shielding layer 129. However, the shielding layer 129 may be attached on the upper substrate 155 instead of on the first cable 127a.

The shielding layer 129 is attached to the first film 127a1 so as to be positioned between the first film 127a1 and the upper substrate 155 . The shielding layer 129 serves to secure a separation distance (or space) between the first film 127a1 and the upper substrate 155.

Unlike the experimental example, in the first cable 127a according to the embodiment, even if the first cable 127a and the upper substrate 155 come into close contact with each other, the separation distance between the first film 127a1 and the upper substrate 155 (or space) can maintain the pre-designed value (setting value).

The reason is that even if the height (H) (or thickness) of the first film 127a1 changes, the shielding layer 129 maintains the separation distance between the first film 127a1 and the upper substrate 155 as well as the predesigned differential impedance value. because it can maintain and compensate for In addition, this is because the shielding layer 129 can maintain a pre-designed differential impedance value by minimizing an increase in capacitance of the signal lines 128 .

As such, the shielding layer 129 provides a structure capable of maintaining and compensating for a pre-designed differential impedance value even if physical deformation occurs in the first cable 127a. As a result, it is possible to prevent a problem of deterioration of signal transmission quality in the signal lines 128 .

When designing the differential impedance for the first cable 127a, the thickness (B) of the first film (127a1), the width (W) and thickness (T) of the signal lines (128, A), and the The separation distance (S) and the thickness (D) of the second film 127a2 may be considered. And it is designed in consideration of all the above elements of the shielding layer 129 .

The thickness (E) of the shielding layer 129 may be equal to or greater than the thickness (B) of the first film 127a1. The thickness E of the shielding layer 129 is preferably designed based on the thickness B of the first film 127a1 among the above factors. For example, the thickness E of the shielding layer 129 may be designed to have a thickness of 0.05 mm to 0.5 mm when the thickness B of the first film 127a1 is 0.06 mm.

According to the experiment, when the thickness (E) of the shielding layer 129 is less than 0.05 mm, it is difficult to sufficiently secure the separation distance between the first film 127a1 and the upper substrate 155, so the pre-designed differential impedance value is maintained. and could not be compensated. The closer the thickness E of the shielding layer 129 is to 0.05 mm, the more difficult it is to secure a gap, so the effect of maintaining the differential impedance at the design value is reduced.

In contrast, when the thickness (E) of the shielding layer 129 is 0.5 mm or more, a sufficient separation distance between the first film 127a1 and the upper substrate 155 can be secured, and a pre-designed differential impedance value can be maintained and compensated. Could. However, as the thickness E of the shielding layer 129 increases, the thickness of the cross section of the display panel increases, as well as an increase in weight and cost.

The shielding layer 129 may be disposed in a line shape corresponding to the width W and length of the signal lines 128 disposed on the first cable 127a. In addition, the shielding layer 129 may be disposed in the form of a film or tape corresponding to the width and length of the first cable 127a. In addition, the shielding layer 129 may be disposed only in a portion of the cable where problems due to mechanical deformation occur.

The shielding layer 129 is made of a conductive (metal) or non-conductive (non-metal) material. For example, the shielding layer 129 is formed in the form of a film made of aluminum foil, polyethylene terephthalate (PET), and acrylic adhesive (adhesive layer). As another example, the shielding layer 129 may be formed of aluminum sheet, polypropylene, limestone, titanium, silica gel, polyethylene terephthalate (PET), acrylic adhesive, or the like. It is made in the form of a film consisting of As another example, the shielding layer 129 is formed in the form of a film made of polypropylene, acrylic adhesive, or the like.

14 and 15, when the shielding layer 129 has a structure including conductivity, the shielding layer 129 is a ground line (located on the control substrate 125 or the source substrate 145b) GND) can be connected. This is because when the shielding layer 129 has conductivity, parasitic capacitance is not generated as long as an electrically stable state is maintained.

As shown in FIGS. 16 and 17 , the shielding layer 129 may have a two-layer structure 129a and 129b, a three-layer structure 129a to 129c, or a four or more layer structure (not shown). For example, a film made of polypropylene and acrylic adhesive has a two-layer structure 129a and 129b. As another example, a film made of aluminum foil, polyethylene terephthalate (PET), and acrylic adhesive has a three-layer structure 129a to 129c.

As described above, the present invention has an effect of providing a roll-type flexible display device capable of maintaining a normal and uniform display quality by solving the problem of deterioration in signal transmission quality due to physical deformation and impedance deformation of a cable. In addition, the present invention has an effect of solving a signal distortion problem that may occur in a display device using a long cable.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, the above-described technical configuration of the present invention can be changed into other specific forms by those skilled in the art without changing the technical spirit or essential features of the present invention. It will be appreciated that this can be implemented. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. In addition, the scope of the present invention is indicated by the claims to be described later rather than the above detailed description. In addition, all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

100: power supply unit 110: image processing unit
120: timing controller 140: data driver
130: scan drive unit 150: display panel
125: control board 145, 145a, 145b: source board
129: shielding layer 127, 127a, 127b: cable
127a1: first film 128: signal lines

Claims (12)

a display panel displaying an image;
a source substrate attached to one end of the display panel;
a panel roller unit disposed on the other end of the source substrate;
a control board spaced apart from the source substrate and disposed on the panel roller unit; and
a cable electrically connecting the control board and the source board;
the cable
A first film, signal lines positioned on the first surface of the first film, a second film positioned on the signal lines, and a shielding layer positioned on the second surface of the first film Roll type flexible display device. According to claim 1,
The thickness of the shielding layer is
A roll-type flexible display device having a thickness equal to or thicker than the thickness of the first film. According to claim 1,
The shielding layer is
A roll-type flexible display device disposed corresponding to the width and length of the signal lines or the width and length of the cable. According to claim 1,
The shielding layer is
A roll-type flexible display device made of conductive or non-conductive material. According to claim 1,
The shielding layer is
A roll-type flexible display device in the form of a film or tape. According to claim 1,
The shielding layer is
A roll-type flexible display device made of aluminum foil, polyethylene terephthalate (PET), and acrylic adhesive. According to claim 1,
The shielding layer is
A roll-type flexible display made of aluminum sheet, polypropylene, limestone, titanium, silica gel, polyethylene terephthalate (PET), and acrylic adhesive. According to claim 1,
The shielding layer is
A roll-type flexible display made of polypropylene and acrylic adhesive. delete delete According to claim 1,
The shielding layer is
A roll-type flexible display device positioned between the upper substrate of the display panel and the first film of the cable. a display panel displaying an image;
a source substrate attached to one end of the display panel;
a panel roller unit disposed on the other end of the source substrate;
a control board spaced apart from the source substrate and disposed on the panel roller unit; and
a cable electrically connecting the control board and the source board;
the cable
A first film, signal lines positioned on the first surface of the first film, a second film positioned on the signal lines, and a second film positioned on the second surface of the first film, wherein the signal lines A shielding layer that maintains and compensates for a pre-designed differential impedance by minimizing an increase in capacitance,
The signal lines transmit signals in a differential manner,
When the thickness of the first film is 0.06 mm, the thickness of the shielding layer has a thickness of 0.05 mm to 0.5 mm,
The shielding layer is disposed in a line shape corresponding to the width and length of the signal lines.

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