KR20220070653A - Flexible flat cable and display device - Google Patents

Abstract

Embodiments of the present invention relate to a flexible flat cable and a display device. More specifically, provided are the flexible flat cable and the display device which form an opening in an impedance matching unit of the flexible flat cable to receive a voltage from the outside so as to form a reference voltage, thereby reducing EMI noise.

Description

FLEXIBLE FLAT CABLE AND DISPLAY DEVICE

Embodiments of the present invention relate to a flexible flat cable and a display device.

In general, a display device such as an organic light emitting diode (OLED) and a liquid crystal display (LCD) has a display panel disposed inside a case, and a main printed circuit board (PCB: Printed Circuit Board) outside the case. Circuit Board) and sub-PCB are arranged.

The display panel is electrically connected to the main PCB or sub-PCBs, and may be connected to, for example, a cable such as LVDS (Low Voltage Differential Signaling).

However, since the LVDS cable connecting the display panel and the main PCB or sub-PCB is expensive to manufacture, a flexible cable such as a cheaper flexible flat cable (FFC) is widely used in recent years.

A plurality of signal lines are positioned in the flexible cable as described above, and each of them may include one terminal (eg, a terminal connected to a display device) and the other terminal (eg, a terminal connected to a PCB). That is, the terminals of the flexible cable are connected to the terminals of the device to be connected in a 1:1 manner.

Accordingly, the flexible cable includes a plurality of signal lines corresponding to terminals for connection, which are spaced apart from each other in the insulating film. As described above, the conventional flexible cable has a disadvantage in that it is vulnerable to noise caused by an external electric field, etc. because a plurality of signal lines made of an insulating film are disposed.

Also, if the flexible cable connecting the display panel and the PCB is vulnerable to noise, as a result, a signal supplied to the display device is distorted, which may cause image quality deterioration.

Embodiments of the present invention may provide a flexible flat cable and a display device in which an opening is formed by removing a portion of the impedance matching unit.

Embodiments of the present invention may provide a flexible flat cable and a display device in which a reference voltage is formed in an impedance matching unit.

In addition, embodiments of the present invention may provide a flexible flat cable and a display device in which a sub-cable applies a voltage to an impedance matching unit by removing a portion of the sub-cable.

In addition, embodiments of the present invention may provide a flexible flat cable and a display device in which an impedance matching unit is connected to a substrate to receive a voltage applied thereto to form a reference voltage.

In addition, embodiments of the present invention may provide a flexible flat cable and a display device in which the influence of external noise is reduced by forming a reference voltage in the impedance matching unit.

In one aspect, embodiments of the present invention may provide a flexible flat cable including a sub-cable formed of a first conductor insulated from each other and a first insulating part covering the first conductor, and an impedance matching part formed outside the sub-cable. have.

The impedance matching unit of the above-described flexible flat cable may include a first opening from which a part of the surface is removed.

In another aspect, embodiments of the present invention provide a display panel in which a plurality of data lines and a plurality of gate lines are disposed, a data driving circuit driving the data lines, and a source printed circuit supplying voltages to the gate driving circuit driving the gate lines. Substrate, a control printed circuit board electrically connected to the source printed circuit board, and supplying a signal for driving the data driving circuit and the gate driving circuit and a common voltage for driving the display panel, and the source printed circuit board and the control printed circuit It is possible to provide a display device including a flexible flat cable connecting a substrate, wherein the flexible flat cable is disposed outside the cable and includes an impedance matching unit having an opening on at least one surface thereof.

In addition, the above-described impedance matching unit of the display device may include a second conductor and a second insulating unit covering the second conductor, and a part of the second insulating unit may be removed to provide an opening formed therein.

According to embodiments of the present invention, it is possible to provide a flexible flat cable and a display device capable of receiving a voltage from the outside by removing a part of the impedance matching unit.

In addition, according to embodiments of the present invention, it is possible to provide a flexible flat cable and a display device in which a reference voltage is formed in an impedance matching unit.

In addition, according to embodiments of the present invention, it is possible to provide a flexible flat cable and a display device in which a sub-cable applies a voltage to an impedance matching unit by removing a part of the sub-cable.

In addition, according to embodiments of the present invention, it is possible to provide a flexible flat cable and a display device in which an impedance matching unit is connected to a substrate and receives a voltage to form a reference voltage.

In addition, according to embodiments of the present invention, it is possible to provide a flexible flat cable and a display device having improved signal quality and reducing the influence of external noise by forming a reference voltage in the impedance matching unit.

1 is a system configuration diagram of a display device according to embodiments of the present invention and an equivalent circuit of sub-pixels.
2A and 2B are an example of a flexible flat cable.
3 is a view showing a flexible flat cable according to an embodiment of the present invention.
4 is a cross-sectional view taken along line YY' of FIG. 3 of the impedance matching part of the flexible flat cable according to an embodiment of the present invention.
5 is a cross-sectional view of the flexible flat cable taken along line XX' of FIG. 3 before bonding the sub-cable and the impedance matching unit.
6 is a view showing a sub-cable of a flexible flat cable according to an embodiment of the present invention.
7 is a view showing a state in which a flexible flat cable is coupled to a connector and mounted on a printed circuit board according to another embodiment of the present invention.
8 is a cross-sectional view taken along line XX' of FIG. 7 in which a flexible flat cable according to another embodiment of the present invention is coupled to a connector and mounted on a printed circuit.
9 is a view showing a state in which a flexible flat cable is coupled to a connector and mounted on a printed circuit according to another embodiment of the present invention.
10 is a cross-sectional view of a flexible flat cable according to another embodiment of the present invention cut along the line ZZ' of FIG.
11 is a view showing the effect of a flexible flat cable including an impedance matching unit.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted. When "includes", "having", "consisting 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, it may include a case in which the plural is included unless otherwise explicitly stated.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, order, or number of the elements are not limited by the terms.

In the description of the positional relationship of the components, when it is described that two or more components are "connected", "coupled" or "connected", two or more components are directly "connected", "coupled" or "connected" ", but it will be understood that two or more components and other components may be further "interposed" and "connected," "coupled," or "connected." Here, other components may be included in one or more of two or more components that are “connected”, “coupled” or “connected” to each other.

In the description of the temporal flow relationship related to the components, the operation method or the production method, for example, the temporal precedence relationship such as "after", "after", "after", "before", etc. Alternatively, when a flow precedence relationship is described, it may include a case where it is not continuous unless "immediately" or "directly" is used.

On the other hand, when numerical values or corresponding information (eg, level, etc.) for a component are mentioned, even if there is no separate explicit description, the numerical value or the corresponding information is based on various factors (eg, process factors, internal or external shock, Noise, etc.) may be interpreted as including an error range that may occur.

1 is a system configuration diagram of a display device according to embodiments of the present invention and an equivalent circuit of sub-pixels.

Referring to FIG. 1 , a display device 100 according to embodiments of the present invention may include a display panel 110 and a driving circuit for driving the display panel 110 .

The driving circuit may include the data driving circuit 120 and the gate driving circuit 130 , and may further include a controller 140 controlling the data driving circuit 120 and the gate driving circuit 130 .

The display panel 110 may include a substrate SUB and signal lines such as a plurality of data lines DL and a plurality of gate lines GL disposed on the substrate SUB. The display panel 110 may include a plurality of sub-pixels SP connected to a plurality of data lines DL and a plurality of gate lines GL.

Referring to FIG. 1 , the display panel 110 may include a display area DA in which an image is displayed and a non-display area NDA in which an image is not displayed. In the display panel 110 , a plurality of sub-pixels SP for displaying an image are disposed in the display area DA, and the driving circuits 120 , 130 , and 140 are electrically connected to the non-display area NDA. The connected or driving circuits 120 , 130 , 140 may be mounted, and a pad unit to which an integrated circuit or a printed circuit is connected may be disposed.

The data driving circuit 120 is a circuit for driving the plurality of data lines DL, and may supply data signals to the plurality of data lines DL. The gate driving circuit 130 is a circuit for driving the plurality of gate lines GL, and may supply gate signals to the plurality of gate lines GL. The controller 140 may supply the data driving timing control signal DCS to the data driving circuit 120 to control the operation timing of the data driving circuit 120 . The controller 140 may supply the gate driving timing control signal GCS for controlling the operation timing of the gate driving circuit 130 to the gate driving circuit 130 .

The controller 140 starts scanning according to the timing implemented in each frame, and converts the input image data input from the outside to match the data signal format used by the data driving circuit 120 to convert the converted image data (Data) may be supplied to the data driving circuit 120 and data driving may be controlled at an appropriate time according to the scan.

The controller 140 includes various timing signals including a vertical synchronization signal VSYNC, a horizontal synchronization signal HSYNC, an input data enable signal DE, and a clock signal CLK, along with input image data. are received from the outside (eg host system).

The controller 140 controls the data driving circuit 120 and the gate driving circuit 130 , a vertical synchronization signal VSYNC, a horizontal synchronization signal HSYNC, an input data enable signal DE, and a clock signal ( CLK), and the like, generate various control signals DCS and GCS, and output them to the data driving circuit 120 and the gate driving circuit 130 .

For example, in order to control the gate driving circuit 130 , the controller 140 may include a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable signal (GOE). : Outputs various gate driving timing control signals (GCS) including Gate Output Enable and the like.

In addition, in order to control the data driving circuit 120 , the controller 140 includes various data driving timing control signals including a source start pulse (SSP), a source sampling clock (SSC), and the like. (DCS: Data Driving Timing Control Signal) is output.

The data driving circuit 120 drives the plurality of data lines DL by receiving image data Data from the controller 140 and supplying data signals to the plurality of data lines DL. Here, the data driving circuit 120 is also referred to as a source driving circuit.

The data driving circuit 120 may include one or more source driver integrated circuits (SDICs).

For example, each source driver integrated circuit (SDIC) is connected to the display panel 110 by a tape automated bonding (TAB) method, or is connected to a chip on glass (COG) or a chip on panel (COG). It may be connected to a bonding pad of the display panel 110 in a Chip On Panel (COP) method, or may be implemented in a Chip On Film (COF) method to be connected to the display panel 110 .

Referring to FIG. 1 , the data driving circuit 120 and one or more source driver integrated circuits SDIC may be mounted on the circuit film SF connected to the non-display area NDA of the display panel 110 .

The gate driving circuit 130 may output a gate signal of a turn-on level voltage or a gate signal of a turn-off level according to the control of the controller 140 . The gate driving circuit 130 may sequentially drive the plurality of gate lines GL by sequentially supplying a gate signal of a turn-on level voltage to the plurality of gate lines GL.

Referring to FIG. 1 , the gate driving circuit 130 may be disposed on or connected to the substrate SUB. That is, the gate driving circuit 130 may be implemented as a gate in panel (GIP) type. In this case, the gate driving circuit 130 may be disposed in the non-display area NDA of the display panel 110 . Unlike FIG. 1 , the gate driving circuit 130 may be implemented as a chip-on-glass (COG) type or a chip-on-film (COF) type.

When a specific gate line GL is opened by the gate driving circuit 130 , the data driving circuit 120 converts the image data received from the controller 140 into an analog data signal to form a plurality of data lines ( DL) can be supplied.

The display device 100 includes at least one source printed circuit board (SPCB), control components, and various electric It may include a control printed circuit board (CPCB: Control Printed Circuit Board) for mounting the devices.

The circuit film SF on which the source driver integrated circuit SDIC is mounted may be connected to at least one source printed circuit board SPCB. That is, one side of the circuit film SF on which the source driver integrated circuit SDIC is mounted may be electrically connected to the display panel 110 and the other side may be electrically connected to the source printed circuit board SPCB.

A controller 140 and a power management circuit (PMIC: Power Management IC, 150) may be mounted on the control printed circuit board (CPCB). The controller 140 may perform overall control functions related to driving of the display panel 110 , and may control operations of the data driving circuit 120 and the gate driving circuit 130 . The power management circuit 150 may supply various voltages or currents to the data driving circuit 120 and the gate driving circuit 130 or control various voltages or currents to be supplied.

The at least one source printed circuit board (SPCB) and the control printed circuit board (CPCB) may be circuitly connected through at least one connection cable. Here, the connection cable may be a flexible flat cable 160 (FFC: Flexible Flat Cable).

The display device 100 according to embodiments of the present invention may further include a level shifter for adjusting a voltage level. For example, the level shifter may be disposed on a control printed circuit board (CPCB) or a source printed circuit board (SPCB). In the display device 100 according to embodiments of the present invention, the level shifter may supply signals necessary for gate driving to the gate driving circuit 130 . For example, the level shifter may supply a plurality of clock signals to the gate driving circuit 130 . Accordingly, the gate driving circuit 130 may output the plurality of gate signals to the plurality of gate lines GL based on the plurality of clock signals input from the level shifter. Here, the plurality of gate lines GL may transmit a plurality of gate signals to the plurality of subpixels SP disposed in the display area DA of the display panel 110 .

1 is a circuit diagram illustrating an equivalent circuit of a sub-pixel SP of the display device 100 according to embodiments of the present invention.

Referring to FIG. 1 , each of a plurality of sub-pixels SP disposed on a display panel 110 of a display device 100 according to embodiments of the present invention includes a light emitting device ED, a driving transistor DRT, and a scan pattern. It may include a transistor SCT and a storage capacitor Cst.

For example, the light emitting device ED may be an organic light emitting diode (OLED), a light emitting diode (LED), or a quantum dot light emitting device.

The driving transistor DRT is a transistor for driving the light emitting device ED, and may include a first node N1 , a second node N2 , and a third node N3 .

The first node N1 of the driving transistor DRT may be a gate node of the driving transistor DRT, and may be electrically connected to a source node or a drain node of the scan transistor SCT. The second node N2 of the driving transistor DRT may be a source node or a drain node of the driving transistor DRT, and may also be electrically connected to the pixel electrode PE of the light emitting device ED. The third node N3 of the driving transistor DRT may be electrically connected to the driving voltage line DVL supplying the driving voltage EVDD.

The scan transistor SCT is controlled by a scan pulse SCAN, which is a type of a gate signal, and may be connected between the first node N1 of the driving transistor DRT and the data line DL. In other words, the scan transistor SCT is turned on or turned off according to the scan pulse SCAN supplied from the scan line SCL, which is a type of the gate line GL, to be turned on or off, so that the data line DL and the driving transistor SCT are turned on or off. It is possible to control the connection between the first node N1 of the DRT.

Referring to FIG. 1 , the storage capacitor Cst may be connected between the first node N1 and the second node N2 of the driving transistor DRT. The storage capacitor Cst is charged with an amount of charge corresponding to the voltage difference between both ends, and serves to maintain the voltage difference between both ends for a predetermined frame time. Accordingly, during a predetermined frame time, the corresponding sub-pixel SP may emit light.

The structure of the sub-pixel SP shown in FIG. 1 is merely an example, and may be variously modified by further including one or more transistors or further including one or more capacitors.

In FIG. 1 , the sub-pixel structure is described assuming that the display device 100 is a self-luminous display device. However, when the display device 100 is a liquid crystal display device, each sub-pixel SP includes a transistor and a pixel electrode. and the like.

2A and 2B are an example of a flexible flat cable.

Referring to FIGS. 2A and 2B , the flexible flat cable 160 may include a sub-cable 200 capable of supplying signals and power. In addition, the sub-cable 200 may include a first conductor 210 insulated from each other and a first insulating part 220 capable of insulating the first conductor 210 from each other.

Referring to FIG. 1 , the sub-cable 200 of the flexible flat cable 160 may electrically connect the circuits of the control printed circuit board (CPCB) and the source printed circuit board (SPCB).

The controller 140 of the control printed circuit board (CPCB) generates various control signals (DCS, GCS) in order to control the data driving circuit 120 and the gate driving circuit 130 to form a sub-cable ( 200) may be output to the first conductor 210 .

In addition, the power management circuit 150 of the control printed circuit board (CPCB) may output various voltages applied to the data driving circuit 120 and the gate driving circuit 130 to the first conductor 210 .

Meanwhile, the first conductors 210 insulated from each other may form a plurality of conductive wires having different widths.

In this case, the voltage applied to the small-width conductive line is the voltage of the data signal, or the voltage of various control signals (DCS, GCS, etc.) for controlling the data driving circuit 120 and the gate driving circuit 130 . can be

In addition, the voltage applied to the wide conductive wire may be a driving power supply voltage VDD and a low potential power supply voltage VSS for driving the display panel 110 and various circuits.

Accordingly, when the display device 100 is turned on, the voltage applied to the wide wire may be constant compared to the voltage applied to the narrow wire.

And, since various signals are output from the control printed circuit board (CPCB) to the source printed circuit board (SPCB) through the sub-cable 200 of the flexible flat cable 160, the control printed circuit board (CPCB) and the source printed circuit board (SPCB) and the impedance of the flexible flat cable 160 should be designed to match the same value.

Accordingly, in the design process, the control printed circuit board (CPCB), the source printed circuit board (SPCB), and the sub-cable 200 are designed such that the impedance value is matched to 100Ω in design.

However, in the process in which the sub cable 200 is connected to the control printed circuit board (CPCB) or the source printed circuit board (SPCB), due to problems such as poor contact or misalignment of the connection, the sub cable ( The impedance of one end of 200 ) may greatly deviate from 100Ω, and the impedance may change rapidly in the first conductor 210 . Accordingly, there is a problem in that the signal transmitted through the first conductor 210 is reflected in the first conductor 210 due to a sharply increased impedance, and thus the signal transmission efficiency is greatly reduced.

Accordingly, in order to gently change the impedance from one end to the other end in the first conductor 210 even when the impedance value at one end of the sub-cable 200 increases, the sub-cable 200 and the impedance matching unit 300 are used. may be bonded to provide a flexible flat cable 160 .

Although the impedance matching unit 300 is thermally bonded to the sub-cable 200 , the impedance matching unit 300 is electrically insulated by the first insulating unit 220 and the second insulating unit 320 . Accordingly, the impedance matching unit 300 may be floating.

However, the impedance matching unit 300 is not electrically connected to the sub-cable 200 or the printed circuit board at both ends of the sub-cable 200, so that a reference voltage is not formed. Accordingly, the impedance matching unit 300 may be affected by an external electromagnetic wave or the like.

Accordingly, the transmission efficiency of various signals applied to the sub-cable 200 may be deteriorated.

Accordingly, it is required to form a voltage reference in the impedance matching unit 300 to reduce the influence of external noise.

3 is a view showing a flexible flat cable according to an embodiment of the present invention.

The flexible flat cable 160 according to an embodiment of the present invention may include a sub-cable 200 and an impedance matching unit 300 positioned outside the sub-cable 200 .

In addition, the impedance matching unit 300 according to the embodiment of the present invention may include one or more first openings H1.

4 is a cross-sectional view taken along the line Y-Y' of FIG. 3 of the impedance matching part of the flexible flat cable according to the embodiment of the present invention.

The impedance matching unit 300 may include an internal second conductor 310 and a second insulating part 320 covering the internal second conductor 310 from the outside.

Meanwhile, in the impedance matching unit 300 according to the embodiment of the present invention, one or more first openings H1 formed by removing a portion of the second insulating unit 320 may be formed.

The first opening H1 may be formed by removing a portion of the second insulating portion 320 , and a portion of the second conductor 310 may be exposed to the outside by the first opening H1 .

The shape of the first opening H1 may be a rectangular parallelepiped, a cylinder, a truncated cone shape having an inclined side surface, or a wedge shape, but the present invention is not limited thereto. Hereinafter, for convenience, it is assumed that the shape of the first opening H1 is a rectangular parallelepiped shape.

5 is a cross-sectional view of a flexible flat cable according to an embodiment of the present invention cut along the line X-X' of FIG.

The flexible flat cable 160 according to the embodiment of the present invention may be formed by bonding the sub-cable 200 and the impedance matching unit 300 to each other.

In the manufacturing process of the flexible flat cable 160 , the sub-cable 200 is thermally bonded to the impedance matching unit 300 , so that an empty space between the two components can be removed.

In the sub-cable 200 according to the embodiment of the present invention, a region in which a portion of the first conductor 210 is exposed may be formed in a region corresponding to the first opening H1 formed in the impedance matching unit 300 . . In addition, this region is formed as an opening, so that the second opening H2 may be included in the sub-cable 200 .

The second opening H2 may be a rectangular parallelepiped, a cylinder, a truncated cone shape having an inclined side surface, or a wedge shape, but the present invention is not limited thereto. Hereinafter, it is assumed that the second opening H2 has a rectangular parallelepiped shape.

Referring to FIG. 5 , the first opening H1 of the impedance matching unit 300 is positioned to correspond to the second opening H2 , so that the same voltage as the voltage applied to the sub-cable 200 is applied to the impedance matching unit 300 . ) can be approved.

For example, in a state in which a conductive ball (not shown) is inserted between the first opening H1 of the impedance matching unit 300 and the second opening of the sub cable 200 , impedance matching with the sub cable 200 . As the part 300 is thermally bonded, a conductive material may be positioned between the first conductor 210 and the second conductor 310 . Accordingly, the first conductor 210 and the second conductor 310 may be electrically connected.

Alternatively, according to the area of the first opening H1 and the second opening H2, by thermal bonding the sub-cable 200 and the impedance matching unit 300 without using a conductive ball, the first conductor 210 and The second conductors 310 may abut and be electrically connected.

Accordingly, a voltage may be applied to the impedance matching unit 300 from the sub-cable 200 , and the impedance matching unit 300 may have a voltage reference.

In other words, the impedance matching unit 300 receives a voltage applied to the second conductor 310 by the voltage applied to the first conductor 210 exposed by removing a portion of the first insulating unit 220 to thereby increase the impedance. The matching unit 300 may have a voltage reference.

Accordingly, it is possible to select a voltage that can be used as a reference voltage (Voltage reference) of the impedance matching unit 300 from among the voltages applied to the sub-cable 200 constituting the flexible flat cable 160 .

Accordingly, by selecting the first conductor 210 to which the voltage can be applied in the display device 100 , it is possible to form the second opening H2 in the region from which the first insulating part 220 is partially removed. do.

For example, when the low potential power voltage VSS is used as the voltage reference of the impedance matching unit 300 , the second opening is so that the first conductor 210 connected to the low potential power voltage VSS is exposed. (H2) can be formed.

The flexible flat cable 160 according to an embodiment of the present invention forms a voltage reference in the impedance matching unit 300, thereby alleviating the problem that the voltage of the impedance matching unit 300 is shaken by external noise. can In addition, by forming a voltage reference by receiving a low potential power voltage VSS rather than a high voltage such as the driving voltage VDD, the influence on other electronic components in the display device 100 may be minimized. .

Meanwhile, referring to FIG. 5 , the size of the first opening H1 formed in the impedance matching unit 300 may be larger than the size of the second opening H2 .

Since the size of the first opening H1 formed in the impedance matching unit 300 is larger than the size of H2 formed in the sub cable 200 , the first opening H1 and the second opening H1 of the impedance matching unit 300 are formed ( It may be easier to align H2) to face each other.

Also, since the first opening H1 and the second opening H2 face each other, the same voltage as the voltage applied to the partially exposed first conductor 210 may be applied to the impedance matching unit 300 .

Accordingly, it is possible to form a voltage reference in the impedance matching unit 300 .

6 is a view showing a sub-cable of a flexible flat cable according to an embodiment of the present invention.

The sub-cable 200 according to the embodiment of the present invention electrically connects the control printed circuit board (CPCB) and the source printed circuit board (SPCB).

In addition, the sub-cable 200 according to the embodiment of the present invention includes a signal for controlling various circuits such as the data driving circuit 120 or the gate driving circuit 130 from the control printed circuit board (CPCB), and various circuits. A common voltage for driving is applied.

The sub-cable 200 may include a first conductor 210 and a second conductor 220, and in this case, the first conductor 210 may be formed of a plurality of conductors having different widths.

At this time, the narrow wire may be a wire that transmits signals (eg, DCS, GCS, etc.) applied to various circuits to control the various circuits, and the wide wire is a common voltage ( For example: VDD, VSS, etc.).

The second opening H2 of the sub-cable 200 according to the embodiment of the present invention may be formed in a conductive wire to which the low potential power voltage VSS is applied, among the wide conductive wires.

The second opening H2 may be formed to correspond to one of the first conductors 210 insulated from each other constituting the sub-cable 200 , and two or more first conductors 210 . It may be formed corresponding to . In addition, both of the two or more first conductors 210 may be conductors that apply the low potential power voltage VSS.

Also, the second opening H2 may be formed as one area, or two or more areas may be formed to be spaced apart from each other.

When the second openings H2 are formed to be spaced apart from each other in two or more regions, each of the second openings H2 may be formed around both ends of the sub-cable 200 .

When the same voltage is applied to both ends of the sub-cable 200 , the same voltage is applied to the impedance matching unit 300 as a whole to form a voltage reference.

Accordingly, a voltage reference is formed in the impedance matching unit 300 so that the voltage is not shaken by external noise, thereby reducing EMI noise.

Meanwhile, in the display device 100 , the two substrates 710 connected by the flexible flat cable 160 may have different low-potential power voltages VSS. Also, due to a difference in voltage applied to both ends of the impedance matching unit 300 , there may be a voltage difference at both ends of the impedance matching unit 300 .

Even in this case, since a constant voltage is applied to the impedance matching unit 300 , the fluctuation of the voltage from external noise may be relatively small compared to the floating state. Accordingly, compared to the impedance matching unit 300 in which the first opening H1 is not formed, the effect of reducing EMI noise may be excellent.

7 is a view showing a state in which a flexible flat cable is coupled to a connector and mounted on a printed circuit board according to another embodiment of the present invention.

The flexible flat cable 160 according to another embodiment of the present invention includes a sub-cable 200 and an impedance matching unit 300 , and a first opening H1 may be formed in the impedance matching unit 300 .

The first opening H1 may be formed on both the control printed circuit board CPCB and the source printed circuit board SPCB, or may be formed on only one side. Hereinafter, for convenience, a case in which the first opening H1 is formed in both sides will be described as an example.

In addition, a connector 720 is connected to one end of the flexible flat cable 160 , so that the flexible flat cable 160 may receive a signal or voltage from the substrate 710 .

The board 710 is a component capable of supplying a signal or voltage to the flexible flat cable 160, and may be a printed circuit board (PCB), and in some cases, a flexible flexible printed circuit board (FPCB) or It may be a glass substrate, but the present invention is not limited thereto. Hereinafter, it is assumed that a printed circuit board (PCB) is used for convenience of description.

A voltage supply unit 730 for supplying a signal or voltage to the flexible flat cable 160 coupled to the connector 720 may be formed on the substrate 710 .

The voltage supply unit 730 may supply a signal or voltage to the sub-cable 200 constituting the flexible flat cable 160 .

The signal may be various signals for controlling an image display or driving timing of the display device 100 . Also, the voltage may include a low potential power supply voltage VSS or a ground voltage GND for supplying a reference voltage.

The connector 720 may be connected to the voltage supply unit 730 of the board 710 to apply various signals or voltages to the sub-cable 200 .

Meanwhile, in the impedance matching unit 300 according to the embodiment of the present invention, a first opening H1 extending in the horizontal direction may be formed.

The impedance matching unit 300 may receive a voltage from the outside through the formed first opening H1 , and the voltage may be any one of voltages applied to the flexible flat cable 160 .

For example, any one wire of the sub-cable 200 constituting the flexible flat cable 160 may receive a low potential power voltage VSS from the substrate 710 .

In addition, the impedance matching unit 300 may receive a low potential power supply voltage VSS from the substrate 710 , and the low potential power supply voltage VSS passes through the first opening H1 to the second conductor 310 . may be authorized for

In this case, the reference voltage formed in the impedance matching unit 300 may be the same voltage as the low potential power voltage VSS applied through the flexible flat cable 160 .

The impedance matching unit 300 receives a voltage from the substrate 710 and forms a voltage reference, thereby reducing the problem of voltage fluctuation of the impedance matching unit 300 due to external noise.

In addition, as the low potential power voltage VSS is used as a voltage reference, the voltage applied to the impedance matching unit 300 may be maintained at a constant value.

8 is a cross-sectional view taken along line X-X' of FIG. 7 showing a flexible flat cable coupled to a connector and mounted on a printed circuit according to an embodiment of the present invention.

One end of the flexible flat cable 160 according to the embodiment of the present invention is connected to the connector 720 and may be mounted on the substrate 710 .

A reference voltage supply unit 740 for forming a voltage reference in the impedance matching unit 300 may be positioned on the substrate 710 .

The reference voltage supply unit 740 may be located in a region corresponding to the first opening H1 of the impedance matching unit 300 , but may be located apart from the first opening H1 .

For example, referring to FIG. 8 , the first opening H1 may be positioned to correspond to the reference voltage supply 740 . Also, if the first opening H1 located in the X direction is described as an example, the first opening H1 located in the X direction may be located more inclined in the X′ direction than the reference voltage supply unit 740 . In this case, the conductive member 800 may electrically connect the reference voltage supply unit 740 and the second conductor 320 while forming an acute angle with the substrate 710 . The conductive member 800 electrically connects the reference voltage supply unit 740 and the second conductor 320 so that the impedance matching unit 300 uses the same voltage as the voltage applied from the reference voltage supply unit 740 to the reference voltage ( Voltage reference) can be formed.

Meanwhile, the reference voltage supply unit 740 may be located in a narrow area on the substrate 710 , but may be located in a wide area in proportion to the width of the impedance matching unit 300 .

That is, when the first opening H1 is widely located in the width direction of the impedance matching unit 300 , the positions where the reference voltage supply unit 740 can be located on the substrate 710 may be varied.

For example, the reference voltage supply unit 740 is located on the substrate 710 , overlaps the flexible flat cable 160 , and a low potential power voltage VSS is applied from the substrate 710 to the sub-cable 200 . It may be located in an area adjacent to the area. This region may be a region adjacent to a region to which the low potential power voltage VSS is applied to the connector 720 .

As the reference voltage supply unit 740 is positioned adjacent to a region to which the low potential power voltage VSS is applied to the connector 720 , the substrate 710 so that the low potential power voltage VSS is applied to the reference voltage supply unit 740 . ) is easy to design, and the distance between the reference voltage supply unit 740 and the impedance matching unit 300 is close, so that the conductive member 800 can be used less.

In addition, in some cases, the reference voltage supply unit 740 may be formed to be wide in the widthwise direction of the impedance matching unit 300 . Accordingly, even if the product type of the flexible flat cable 160 is different, it may be possible to apply the same substrate 710 .

In other words, the position of the reference voltage supply unit 740 on the substrate 710 may be changed according to the purpose, so that the design freedom of the substrate 710 may be increased.

Meanwhile, the reference voltage supply unit 740 may supply a voltage to the impedance matching unit 300 through the conductive member 800 . One end of the conductive member 800 is electrically connected to the reference voltage supply unit 740 , and the other end is attached to and electrically connected to the second conductor 310 of the impedance matching unit 300 , or through the first opening H1 . It may be disposed to be attached to the surrounding second insulating part 320 .

The conductive member 800 may be an adhesive conductive tape. The length of the conductive member 800 may be appropriately selected by those skilled in the art in consideration of the distance between the reference voltage supply unit 740 and the first opening H1 , and the reference voltage supply unit 740 in consideration of the shaking of the flexible flat cable 160 . ) and the first opening (H1) may be formed longer than the length.

9 is a view showing a state in which a flexible flat cable is coupled to a connector and mounted on a printed circuit according to another embodiment of the present invention.

Referring to FIG. 9 , in the flexible flat cable 160 according to the present invention, a first opening H1 may be formed on one surface of the impedance matching unit 300 located on the upper surface of the sub-cable 200 .

There may be one or a plurality of first openings H1, and in the case of a plurality of first openings H1, the first openings H1 may be spaced apart from each other in the width direction as well as being spaced apart from each other in the longitudinal direction. Hereinafter, it is assumed that the two first openings H1 are formed to be spaced apart in the longitudinal direction for convenience.

In addition, the second conductor 320 may be exposed through the first opening H1 formed in the impedance matching unit 300 . In addition, the second conductor 310 may be connected to the conductive member 800 through the first opening H1 , and the conductive member 800 may receive a voltage from the reference voltage supply unit 740 .

For example, one end of the conductive member 800 may be connected to the reference voltage supply unit 740 , and the other end may be connected to the second conductor 310 through the first opening H1 .

Accordingly, the second conductor 310 may receive a voltage from the reference voltage supply unit 740 of the substrate 710 to form a voltage reference.

Meanwhile, the first openings H1 may be formed to be spaced apart from each other in the length direction of the impedance matching unit 300 .

In this case, each of the first openings H1 may receive a voltage from the adjacent substrate 710 .

When only one first opening H1 is formed, voltage may be supplied only to one substrate 710 adjacent to the first opening H1 .

10 is a cross-sectional view taken along the line Z-Z' of FIG. 9 of a flexible flat cable according to another embodiment of the present invention.

Referring to FIG. 10 , the reference voltage supply unit 740 is formed in a region where the substrate 710 and the flexible flat cable 160 do not overlap, and applies a voltage to the second conductor 310 through the conductive member 800 . can give

Even in this case, the voltage applied by the reference voltage supply unit 740 to the second conductor 310 may be the same voltage as the low potential power voltage VSS.

As the reference voltage supply unit 740 is located in a region that does not overlap the flexible flat cable, it is possible to supply a voltage to the second conductor 310 avoiding the central portion of the substrate 710 having a relatively complicated design. For example, the reference voltage supply unit 740 may be located in an edge region of the substrate 710 .

In this case, as shown in FIG. 10 , the conductive member 800 may be bent to supply a voltage from the reference voltage supply unit 740 to the second conductor 310 .

The display device 100 according to the embodiment of the present invention may be an organic light emitting display device in which a light emitting element ED is disposed on a sub-pixel SP. In this case, the flexible flat cable 160 according to the present invention controls the Signals for controlling the emission timing and luminance of the light emitting device ED and common power for driving various circuits may be applied from the printed circuit board CPCB.

Referring to FIG. 10 , the first openings H1 are formed to be spaced apart in the longitudinal direction, so that only one first opening H1 is expressed. However, it is also possible that the first openings H1 are spaced apart in the horizontal direction. . In this case, a reference voltage may be formed by receiving voltages from both sides of the substrate 710 through each of the first openings H1 .

Meanwhile, the display device 100 according to the embodiment of the present invention may be a liquid crystal display (LCD) including a backlight unit. In this case, signals for controlling the luminance of light output from the control printed circuit board (CPCB) to the upper surface of the display panel 110 in accordance with timing and common power for driving various circuits are applied to the flexible flat cable 160 . can be

The display device 100 according to the present invention can stably transmit and receive a signal through the sub-cable 200 by forming a voltage reference in the impedance matching unit 300 .

In addition, by forming a voltage reference in the impedance matching unit 300 , the influence of external noise may be reduced compared to that of the floating impedance matching unit 300 . Accordingly, the display device 100 according to the present invention can reduce EMI noise.

In addition, by forming a voltage reference in the impedance matching unit 300 , the length of the flexible flat cable 160 can be variously designed by reducing signal transmission loss, and the design of the substrate 710 . The degree of freedom can be increased.

Meanwhile, by forming a voltage reference in the impedance matching unit 300 , the signal quality can be improved and the swing level of the signal can be diversified.

11 is a view showing the effect of a flexible flat cable including an impedance matching unit.

Specifically, FIG. 11 is a view showing the results of observing an embodiment in which the impedance value formed in the flexible flat cable is subjected to different conditions by dividing it into a predetermined unit.

11, the floating (Floating) item represents an impedance value formed in the flexible flat cable 160 in which the impedance matching unit 300 is not formed, and the reference (Reference) item is flexible according to an embodiment of the present invention It represents an impedance value formed in the flat cable 160 .

The impedance of the flexible flat cable 160 in which the impedance matching unit 300 is not formed may change rapidly at one end of the flexible flat cable 160 . Accordingly, a signal may be reflected inside the first conductor 210 of the sub-cable 200 , and a problem in which signal transmission/reception performance is deteriorated may occur.

On the other hand, when the impedance matching unit 300 according to the embodiment of the present invention is formed, even if the impedance is changed at one end of the flexible flat cable 160, the impedance of the sub cable 200 by the impedance matching unit 300 is It can alleviate sudden changes.

In addition, as a voltage is applied to the impedance matching unit 300 to form a voltage reference, a problem in which the voltage of the impedance matching unit 300 is shaken due to external noise can be prevented.

Therefore, the flexible flat cable 160 according to the embodiment of the present invention can function to gradually change the impedance of the sub cable 200, and at the same time, the signal transmitted through the sub cable 200 is affected by external noise. It can reduce what you receive. Accordingly, the display device 100 to which the flexible flat cable 160 according to the present invention is applied may have improved signal quality.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. In addition, since the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: display device 110: display panel
120: data driving circuit 130: gate driving circuit
140: controller 150: power management circuit
200: sub cable 210: first conductor
220: first insulating unit 300: impedance matching unit
310: second conductor 320: second insulating part
710: board 720: connector
730: voltage supply 740: reference voltage supply
800: conductive member H1: first opening

Claims (18)

a sub-cable formed of a first conductor insulated from each other and a first insulating portion covering the first conductor;
A flexible flat cable disposed outside the sub-cable and including an impedance matching unit including a first opening from which a part of the surface is removed.
According to claim 1,
The impedance matching unit includes a second conductor therein, and a second insulating unit surrounding the second conductor,
The sub-cable includes a second opening in which a portion of the first conductor is exposed by removing a portion of the first insulation,
The second opening and the first opening are positioned to face each other.
3. The method of claim 2,
The impedance matching unit has two or more first openings,
The two or more first openings are positioned to be spaced apart in the longitudinal direction of the sub-cable flexible flat cable.
3. The method of claim 2,
The size of the first opening is larger than the size of the second opening flexible flat cable.
3. The method of claim 2,
The sub-cable includes a plurality of conductors formed of first conductors insulated from each other and having different widths,
The width of the first conductor of the conducting wire positioned in the region corresponding to the first opening is greater than the width of at least one first conductor among the first conductors of the conducting wire positioned in the region not corresponding to the first opening Large flexible flat cable.
According to claim 1,
The impedance matching unit includes a second conductor therein, and a second insulating unit surrounding the second conductor,
The first opening is formed by removing a portion of the second insulating part outside the impedance matching part, the flexible flat cable formed on a surface opposite to the surface on which the sub-cable is located.
7. The method of claim 6,
The flexible flat cable further comprising a conductive member attached to the second conductor through the first opening.
7. The method of claim 6,
The first opening is a flexible flat cable extending in the width direction of the sub-cable.
7. The method of claim 6,
A flexible flat cable with a connector attached to one end of the sub-cable.
a display panel on which a plurality of data lines and a plurality of gate lines are disposed;
a source printed circuit board for supplying a voltage to a data driving circuit for driving the data line and a gate driving circuit for driving the gate line;
a control printed circuit board electrically connected to the source printed circuit board to supply a signal for driving the data driving circuit and the gate driving circuit and a common voltage for driving the display panel; and
A flexible flat cable connecting the source printed circuit board and the control printed circuit board,
The flexible flat cable is
a sub-cable formed of a first conductor insulated from each other and a first insulating portion covering the first conductor;
and an impedance matching unit disposed outside the sub-cable and having an opening on at least one surface thereof.
11. The method of claim 10,
The impedance matching unit includes a second conductor therein, and a second insulating unit surrounding the second conductor,
The sub-cable includes a second opening in which a part of the first insulation part is removed and a part of the first conductor is exposed,
The second opening and the first opening are positioned to face each other.
12. The method of claim 11,
The sub-cable includes a plurality of conductors formed of first conductors insulated from each other and having different widths,
The first opening is positioned adjacent to a conductive line to which a low potential power voltage VSS or a ground voltage GND is applied.
13. The method of claim 12,
A width of the first conductor of the conducting wire to which the low potential power voltage or the ground voltage is applied is greater than a width of the first conductor of at least one of the conducting wires other than the conducting line.
11. The method of claim 10,
The first opening is formed by removing a portion of the second insulating part of the impedance matching part, and is formed on a surface opposite to a surface on which the sub-cable is located.
15. The method of claim 14,
The opening is formed on a lower surface of the impedance matching unit and is positioned on a surface facing the source printed circuit board or the control printed circuit board.
16. The method of claim 15,
The display device further includes a conductive member connecting the impedance matching unit and the printed circuit,
The conductive member has one end electrically connected to the second conductor through the first opening, and the other end electrically connected to the reference voltage supply unit on the printed circuit.
17. The method of claim 16,
The reference voltage supply unit to which the conductive member is connected supplies a low potential power voltage or a ground voltage,
The reference voltage supply unit is formed to extend in a width direction of the impedance matching unit.
15. The method of claim 14,
The reference voltage supply unit is located on the printed circuit in an area where the printed circuit and the flexible flat cable do not overlap,
The first opening is formed on the upper surface of the impedance matching unit and exposed to the outside;
The conductive member has one side electrically connected to the reference voltage supply unit, and is bent to be electrically connected to the second conductor through the first opening.

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