KR100339019B1 - Method for forming wires for transmitting differential signal and an LCD having a PCB formed the same - Google Patents

Abstract

When a differential signal is transmitted, such as LVDS (Low Voltage Differential Signaling) or RSDS (Reduced Swing Differential Signaling), a pair of wires that transmit differential signals The present invention relates to a liquid crystal display device in which a differential signal wiring structure formed so as to be coupled to a circuit board and a printed circuit board having a pair of wirings for transmitting a differential signal up and down are mounted. A printed circuit board for processing a signal is mounted, a portion of the signal is transmitted through the differential signal wiring on the printed circuit board, and a pair of the first wiring and the second wiring for transmitting the differential signal on a predetermined substrate are provided. It is configured to be symmetrical up and down about the first insulating film.

Therefore, the area of the printed circuit board can be reduced to 50 percent or less, making it easy to slim, lighten, or reduce the size of products such as liquid crystal display devices, and have excellent electric field canceling effect due to the coupling effect between the differential signal wires and signal distortion. This has no effect.

Description

Liquid crystal display device having a printed circuit board having a differential signal wiring method and a differential signal wiring {Method for forming wires for transmitting differential signal and an LCD having a PCB formed the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having a differential signal wiring method and a printed circuit board having a differential signal wiring. In the case of transmitting a signal, a differential signal wiring method of forming a pair of wirings for transmitting a differential signal so as to be coupled up and down, and a pair of wirings are formed up and down in this manner to mount a printed circuit board for transmitting a differential signal. It relates to a liquid crystal display device.

Typically, a plurality of components are mounted on a printed circuit board and wiring is formed for signal transmission between the components. With the development of electronic technology, signal transmission of data is performed at high speed through wiring, and components to be mounted are also developed to respond at high speed.

Each wire through which data is transmitted forms an electric field that is induced by the flow of current, and radiation of such an electric field causes an EMI phenomenon that interferes with the normal operation of the component by adding noise to signals transmitted to adjacent wires. EMI is further amplified when high frequency signals for high speed operation are transmitted through the wiring.

On the other hand, in the case of a liquid crystal display device, a signal that transmits data or a control signal tends to increase its frequency in order to drive a high quality and large screen, and in the related art, these data and control signals are transmitted as TTL signals. Due to the large swing voltage, EMI is severely generated, and a liquid crystal display device for driving a high-definition and large screen should solve the above-mentioned EMI problem, but a proper solution has not been proposed. When transmitting data or control signals of a display device, a considerable number of wires must be formed on the printed circuit board, and as a result, an increase in the surface area and volume of the printed circuit board is required. Considering the trend of slimming, the increase in the surface area and volume of the printed circuit board can achieve lighter weight and slimmerness. This is a serious adverse effect.

Accordingly, an object of the present invention is to reduce the area occupied on the printed circuit board by the differential signal transmission wiring by forming the wiring for transmitting the differential signal up and down on different layers.

Another object of the present invention is to improve the coupling effect between wirings for transmitting differential signals to reduce the radiation amount of the electric field and to prevent the differential signal from being affected by other signals.

Another object of the present invention is to form wirings for transmitting differential signals formed on a printed circuit board up and down, and their vertical arrangement is uniformly crossed so that the influence on the ground is equal to the two wirings.

Other objects of the present invention will become more apparent from the following detailed description and the accompanying drawings.

1 is a plan view illustrating a schematic structure of a liquid crystal display device having a printed circuit board having a differential signal wiring according to the present invention. FIG. 2 is an enlarged perspective view of portion A of FIG.

3 is a partial cross-sectional view of VI-VI of FIG.

FIG. 4 is a waveform diagram illustrating a differential signal. FIG. 5 is a plan view schematically showing a part of a liquid crystal module for explaining another embodiment according to the present invention.

FIG. 6 is a diagram illustrating an electrical connection structure of a source drive integrated circuit and wirings connected to the source drive integrated circuit of FIG. 5. FIG.

7 is a waveform diagram illustrating input of data to a source drive integrated circuit;

FIG. 8 is a diagram illustrating a method of forming a differential relationship wiring configured in FIG. 6. FIG.

9 is a cross-sectional view taken along line X-X of FIG.

10 is a partial cross-sectional view taken along line Y-Y of FIG.

FIG. 11 is a cross-sectional view taken along the line Z-Z of FIG. 8.

In order to achieve the above object, the differential signal wiring structure according to the present invention configures a pair of first and second wirings for transmitting a differential signal on a predetermined substrate so as to be symmetrical with respect to the first insulating film.

When the ground wiring is formed on a predetermined substrate, a second insulating film may be formed over the second substrate, and the first wiring, the first insulating film, and the second wiring may be stacked over the second insulating film.

In addition, the differential signal wiring structure is configured such that a pair of first and second wirings for transmitting a differential signal on a predetermined substrate are vertically symmetric with respect to the first insulating film, and are equal in length to the first and second wirings. The third and fourth wirings having positions are configured to be vertically symmetrical with respect to the first insulating film, and the ends of the first and fourth wirings formed at different positions in the vertical direction are connected through a first contact hole, and a second And an end portion of the third wire is connected through the second contact hole to have a twisted shape in the length direction of the pair of wires for transmitting the differential signal.

In addition, the pair of wires for transmitting the differential signal is preferably twisted periodically in predetermined length units.

In addition, a liquid crystal display device having a printed circuit board having a differential signal wiring according to the present invention is mounted with a printed circuit board for processing a driving signal for displaying a desired screen in a liquid crystal panel having a predetermined area, and is partially mounted on the printed circuit board. And a pair of first wirings and second wirings for transmitting differential signals on the printed circuit board of the liquid crystal display device in which the transmission of the signals is performed through the differential signal wirings.

The differential signal may be an LVDS signal or an RSDS signal.

In addition, the differential signal transmission line consisting of the first wiring line and the second wiring line is preferably configured to be at least twice the thickness of the insulating film and the other signal transmission line.

In addition, a liquid crystal display device in which a printed circuit board is mounted is mounted with a printed circuit board for processing a driving signal for displaying a desired screen in a liquid crystal panel having a predetermined area, and transmission of a part of signals on the printed circuit board is differential signal wiring. The phase of each of the wires formed through the wires and transmitting the differential relationship signal on the printed circuit board is configured such that the first wires and the second wires are symmetrically moved up and down about the first insulating film. Third and fourth wirings having the same position in the longitudinal direction are configured to be vertically symmetrical with respect to the first insulating film, and end portions of the first and fourth wirings formed at different positions in the vertical direction are disposed through the first contact hole. Connected and end portions of the second and third wires are connected through the second contact hole so that a pair of wires for transmitting differential signals are twisted in the longitudinal direction It may have.

Hereinafter, a preferred embodiment of a liquid crystal display device having a printed circuit board having a differential signal wiring structure and a differential signal wiring according to the present invention will be described with reference to the accompanying drawings.

First, differential signal transmission is to transmit signals having the same amplitude and opposite phase through two adjacent wirings, and simultaneously transmitting the positive signal S + and the negative signal S- as shown in FIG. In this case, the electric field generated between adjacent wirings can be eliminated by interaction. Specifically, when the signal S + is converted from the high level to the low level, the signal S- is converted from the low level to the high level. At this time, the directions of the currents flowing in the two wirings are opposite to each other, and the electric fields are canceled due to the Fleming law. The present invention applies the above-described functions and effects of the differential signal connection to the liquid crystal display device. Referring to FIG. 1, a planar configuration of a general liquid crystal display device will be described. A liquid crystal panel 42 having an active region 40 is source printed with a tape carrier package 44 mounted with a drive integrated circuit (not shown). A cable 54 connected to the circuit board 46 and the gate printed circuit board 48, and the source printed circuit board 46 and the gate printed circuit board 48 are connected to the connectors 50 and 52 formed on the respective circuit boards 46. The electrical printed circuit board 48 is configured to receive data and control signals necessary to drive a predetermined screen via a cable 58 connected to another connector 56.

In the above-described source printed circuit board 48 and the gate printed circuit board 50, a plurality of components 59 including a timing controller, a gray voltage generator, and a power supply unit are distributed and mounted, and wirings connected to the components 59 are provided. Is formed.

Among the wires formed on the source printed circuit board 48 and the gate printed circuit board 50, the wires for transmitting data are configured in pairs for transmitting differential signals. The differential signal is formed by a manufacturer such as an LVDS method or an RSDS method. It can be determined according to the intention.

A partially enlarged perspective view of a portion A in which wires for transmitting differential signals of the source printed circuit board 48 are formed is shown in FIG. 2. Referring to this, each wire 60 and 62 are wires for transmitting different signals. Under the wirings 60 and 62, wirings for transmitting differential signals of the wirings are formed.

Specifically, referring to the cross-sectional structure of the VI-VI part of FIG. 2, the ground layer 72 is formed on the substrate 70 of the source printed circuit board 48, and the upper portion of the ground layer 72 is illustrated in FIG. 3. An insulating film 74 for interlayer insulation is formed thereon, and wirings 76 and 78 for transmitting the S-signal, that is, the negative signal of FIG. 1, of the differential signals are formed on the insulating film 74. The insulating film 80 for interlayer insulation is formed on the upper portion of the insulating film 80, and the wirings 82 and 84 for transmitting the S + signal, that is, the positive signal of FIG. 4, are formed on the insulating film 80. The wirings 60 and 62 shown in FIG. 2 are the wirings 82 and 84 of FIG. 6 that transmit a positive signal.

That is, pairs 76, 82, and 78 and 84 of wires for transmitting the positive and negative signals among the differential signals are vertically formed with the insulating film 80 interposed therebetween. Here, the pairs of wires 76 and 82 are preferably configured to be at least twice the thickness of the insulating film from the other signal transmission wires 78 and 84.

As described above, the positive signal and the negative signal transmitted through the wires 76 and 82 which transmit one pair of differential signals are reversed in phase. Accordingly, a signal swinging with the same potential difference while the voltage polling and rising time coincide is transmitted through the wirings 76 and 82, and thus the strength of the electric field induced by the flowing current is the same and the direction is reversed. Therefore, the electric field of the same size formed in the opposite direction is canceled. And, since the pair of signal lines 76 and 82 of FIG. 3 are overlapped in the vertical direction, the area occupied by the plane is small, and these wirings ( The capacitance is high between 76 and 82 by forming an insulator having a higher dielectric constant than air (dielectric constant is 1). In addition, these wirings 76 and 82 have a separation distance as small as the thickness of the insulator.

That is, since the capacitance is determined according to the dielectric constant × area / spacing distance, in the embodiment according to the present invention, the capacitance formed between the two wires 76 and 82 becomes large because the distance between the dielectric constants and the area becomes smaller and the distance becomes smaller. .

Therefore, the differential signal transmitted through the wirings 76 and 82 is not affected by the high frequency noise component generated from the wiring for transmitting other signals.

Therefore, the spacing of the paired wiring lines for transmitting the differential signal can be narrowed by the present invention, so that a lot of space for design is formed on the printed circuit board.

In addition, in consideration of the influence of the capacitance formed by the lower ground layer, the present invention may be configured such that the differential relationship wiring has a braided form at regular intervals, as shown in the embodiments of FIGS. 5 to 11. Another embodiment thereof will be described with reference to FIGS. 5 through 11.

As shown in FIG. 5, the LCD includes a flexible printed circuit (FPC) 100 in which components such as a timing controller 102 and a gray voltage generator 104 are mounted, and a source printed circuit. The substrate 110, the gate printed circuit board 140, the liquid crystal panel 130, and the tape carrier packages 120 may include a source drive integrated circuit or a gate drive integrated circuit.

The liquid crystal panel 130 is connected to the gate printed circuit board 140 or the source printed circuit board 110 by a predetermined number of tape carrier packages 120, and a tape carrier package connected to the gate printed circuit board 140. The gate drive integrated circuit is mounted on the gate 120, and the source drive integrated circuit is mounted on the tape carrier packages 120 connected to the source printed circuit board 110. In addition, connectors 112 and 142 are installed on the source printed circuit board 110 and the gate printed circuit board 140, respectively, and the cables 150 are connected therebetween to transmit signals.

The source printed circuit board 110 and the FPC 100 are physically and electrically coupled to each other by a connection member such as the anisotropic conductive film 108, and the FPC 100 is further provided with a connector 106 to supply a predetermined image source. It can be connected with.

In the liquid crystal display having the configuration described above, a data signal and a clock signal having a differential relationship may be transmitted on the source printed circuit board.

In this case, it is assumed that 6-bit R, G, and B data are transmitted through the RSDS scheme. As shown in FIG. 6, three pairs of data wires electrically connected to the source drive integrated circuit 122 are R, G, and B data, respectively. And a pair of wires for clock signal transmission, and a line for STL signal transmission of a TTL level. Then, a bus 124 for applying the gray scale voltage is formed. The number of wirings forming the bus 124 may vary depending on the number of gray levels.

In this case, the wiring of the differential relationship may have a twisted shape in any one of positions B, C, and D of FIG. 6, and R, G, and B data may be transmitted to the source drive integrated circuit through various methods by various methods. As illustrated in FIG. 7, two bits of data may be divided into even data and odd data and then alternately transmitted serially through each pair of wires. That is, the first even data and the second even data can be transmitted after the first odd data and the second odd data are transmitted through the first wire, and the second and third wires can be transmitted in the same manner. Is synchronized with the clock signal CLK.

Referring to Figures 8 to 11 will be described with respect to the twisted shape of the differential relationship wiring, the twisted shape of Figure 8 can be formed in any desired position of B, C and D of Figure 5, preferably tape By constructing between the carrier packages 120, the twist can be repeated periodically so that the capacitance can be averaged.

First, referring to FIG. 8 and FIG. 9, the differential relationship wirings in the X-X position are spaced apart from the top and the bottom in a planar overlapping area.

That is, the ground layer 222 is formed on the substrate 220, the insulating layer 224 is formed on the ground layer 222, and the wirings 206a and 202a are formed on the insulating layer 224 and the upper portion thereof. An insulating film 226 is formed thereon, and wirings 204 and 200 are formed thereon.

Among these wirings, the wiring 202a and the wiring 200 have a differential relationship, and the wiring 204 and the wiring 206a have a differential relationship.

The wirings 200 and 204 disposed at the upper portion in the XX position are connected through contact with the wirings 200a and 204a extending in the lower portion thereof while being bent in one direction at the YY position and at the lower portion in the XX position. Arranged wires 206a and 202a are connected through contacts with wires 206 and 202 which are bent at the upper end thereof in the YY position while being bent in the other direction. That is, the differential wirings are twisted at the Y-Y position.

That is, the wiring 200 and the wiring 200a, the wiring 202 and the wiring 202a, the wiring 204 and the wiring 204a, the wiring 206 and the wiring 206a transmit the same signal, and the wiring ( 200 and the wiring 202a, the wiring 200a and the wiring 202, the wiring 204 and the wiring 206a, and the wiring 204a and the wiring 206 are pairs of wirings for transmitting a differential relationship signal up and down. .

In the Y-Y position, the wire 200 and the wire 200a are electrically connected through the contact 210, and other wires are also electrically connected through the corresponding contacts 212, 214, and 216.

In the Y-Y position, the wires twisted as shown in FIG. 10 are spaced apart in parallel to the upper and lower portions again as shown in FIG. 11 in the Z-Z position.

The above-described configuration of FIG. 10 may be formed between each tape carrier package, may be formed for each position where a signal is connected to the tape carrier package, and may also be formed for each tape carrier package of a predetermined unit quantity.

As the wirings that periodically transmit signals having a relationship with the differential scene are twisted, the influence of the lower ground layer 222 is affected by each wiring, and thus the difference in signal delay between the wirings can be eliminated.

As a result, when the wiring for transmitting signals having a differential relationship is vertically configured, the area of the printed circuit board devoted to data or control signal wiring is actually reduced by 50% or more.

As described above, the signal canceling effect of the signals generated in the differential signal wires is excellent, and the signal distortion is not generated because it is not affected by other signals transmitted.

In particular, the signal delay difference can be eliminated by forming a wiring for transmitting signals having a differential relationship in a twisted shape at regular intervals.

As described in detail above, the present invention has been described in detail with respect to preferred embodiments, but those skilled in the art to which the present invention belongs, various modifications or changes without departing from the spirit of the present invention It is obvious that can be carried out by.

Therefore, according to the present invention, the area of the printed circuit board can be reduced to 50 percent or less, thereby making it easy to slim, lighten or reduce the size of a product such as a liquid crystal display device.

In addition, due to the coupling effect between the differential signal wires, the electric field canceling effect is excellent, and the distortion of the signal does not occur.

Claims (15)

In a differential signal wiring method of a liquid crystal display device, a printed circuit board is mounted to process driving signals for displaying a desired screen in a liquid crystal panel having a predetermined area, and transmission of a part of signals on the printed circuit board is via differential signal wiring. In And a pair of first and second wirings for transmitting a differential signal on a predetermined substrate so as to be symmetrical with respect to the first insulating film. The method of claim 1, A second insulating film is formed after the ground wiring is formed on the predetermined substrate, and the first wiring, the first insulating film and the second wiring are stacked on the second insulating film. Way. In a differential signal wiring method of a liquid crystal display device, a printed circuit board is mounted to process driving signals for displaying a desired screen in a liquid crystal panel having a predetermined area, and transmission of a part of signals on the printed circuit board is via differential signal wiring. In A pair of first and second wirings for transmitting differential signals on a predetermined substrate so as to be vertically symmetric with respect to the first insulating film, and having a third position having the same position in the longitudinal direction as the first and second wirings; A fourth wiring is formed to be vertically symmetric about the first insulating film, and ends of the first and fourth wirings formed at different positions in the vertical direction are connected through a first contact hole, and the second and third wirings And connecting the end portion through the second contact hole so as to have a twisted shape in the longitudinal direction of a pair of wires for transmitting the differential signal. The method of claim 3, wherein And a pair of wires for transmitting the differential signal are periodically twisted in predetermined length units. The method of claim 3, wherein Ends of the first wiring and the fourth wiring are bent in the first direction, and end portions of the second wiring and the third wiring are bent in the second direction so that the wirings formed at the top and the bottom thereof are alternately overlapped with each other. Forming the first and second contact holes in the recessed area to electrically connect the first wiring, the fourth wiring, and the second wiring and the third wiring. . In a liquid crystal display device in which a printed circuit board for processing a drive signal for displaying a desired screen in a liquid crystal panel having a predetermined area is mounted, and transmission of a part of signals on the printed circuit board is via differential signal wiring. And a pair of first and second wirings for transmitting a differential signal on a predetermined substrate so as to be symmetrical up and down around the first insulating film. The method of claim 6, And a differential signal is an LVDS signal. A liquid crystal display device having a printed circuit board having a differential signal line. The method of claim 6, And a differential signal is an RSDS signal. The method of claim 6, And a differential signal transmission line consisting of the first wiring line and the second wiring line is configured to be separated from other signal transmission lines by more than twice the thickness of the insulating layer. In a liquid crystal display device in which a printed circuit board for processing a drive signal for displaying a desired screen in a liquid crystal panel having a predetermined area is mounted, and transmission of a part of signals on the printed circuit board is via differential signal wiring. The phase of each wire that transmits a differential relationship signal on the printed circuit board is configured such that the first wire and the second wire are symmetrically up and down with respect to the first insulating film, and are positioned in the same length direction as the first and second wires. And third and fourth wirings having upper and lower symmetry around the first insulating film, and end portions of the first and fourth wirings formed at different positions in the vertical direction are connected through a first contact hole, and And a pair of wirings for transmitting differential signals having a shape in which the ends of the third wirings are connected through the second contact holes to have a twisted shape in the longitudinal direction. The method of claim 10, 2. A liquid crystal display mounted with a printed circuit board, characterized in that a pair of wires for transmitting differential signals are periodically twisted in predetermined length units. The method of claim 10, End portions of the first wiring line and the fourth wiring line are bent in a first direction, and end portions of the second wiring line and the third line line are bent in a second direction so that wirings formed at an upper side and a lower side are alternately overlapped with each other. The first and second contact holes are formed in the overlapped region to electrically connect the first wiring, the fourth wiring, the second wiring and the third wiring. Display. The method of claim 10, And a differential signal is an LVDS signal. A liquid crystal display device having a printed circuit board having a differential signal line. The method of claim 10, And a differential signal is an RSDS signal. The method of claim 10, And a differential signal transmission line consisting of the first wiring line and the second wiring line is configured to be separated from other signal transmission lines by more than twice the thickness of the insulating layer.