Liquid crystal display device

Disclosed is a liquid crystal display device in which printed circuit board (PCB) modules are suitably arranged to form a large screen with high resolution. The liquid crystal display device includes first and second main PCBs for driving a dual bank type liquid crystal panel, the first main PCB having a timing controller for processing external odd input signals to generate driving signals, and sending part of the driving signals to a corresponding source driver PCB, so as to generate video signals to be supplied to the odd pixels of the liquid crystal panel; and the second main PCB having a timing controller for processing external even input signals to generate driving signals, and sending part of the driving signals to a corresponding source driver PCB, so as to generate video signals to be supplied to the even pixels of the liquid crystal panel. According to the present invention, two source driver PCBs are used to supply video data to the upper part and the lower part of the liquid crystal panel, respectively, and thereby to reduce signal delay and distortion in driving the dual bank type liquid crystal display device for a large screen with high resolution, thus solving the problems of coupling between signals more deviating from the tolerance range with an increased frequency, noise, and EMI.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a liquid crystal display device and, more particularly, to a liquid crystal display device in which printed circuit board (PCB) modules are suitably arranged to form a large screen with a high resolution.

(b) Description of the Related Art

In general, the liquid crystal display device includes a liquid crystal display module composed of a liquid crystal panel having a plurality of liquid crystal cells arranged in a matrix form between two glass substrates, and a back light unit disposed on the backside of the liquid crystal panel opposite to the display side; a PCB module disposed on the backside of the back light unit opposite to the display side; and a case for protecting and integrating those modules. Particularly, the PCB module is a driving circuit for processing externally applied red (R), green (G) and blue (B) video data and sync signals to supply video data, scanning signals and timing control signals to the liquid crystal panel, so as to allow the liquid crystal panel to successfully display application images such as computer images, television (TV) images, etc. The PCB module comprises a plurality of PCB's, and a plurality of flexible printed cables (FPC's) for signal transmission between the PCB's.

As is apparent from the schematic circuit diagram of a conventional liquid crystal display device as shown inFIG. 1, the PCB module, which is disposed on the backside of the display of the liquid crystal panel50to drive the liquid crystal panel50and has a relatively low resolution in the order of SVGA (600*800), comprises a main PCB10for processing externally applied RGB video data and sync signals by means of a timing-controller (T-con) which is a custom integrated circuit (IC) in the form of a flat pin grid array (FPGA), to generate video data and various control signals suitable to the structure of the liquid crystal panel; a gate driver PCB20equipped with a gate driver IC tape automated bond (TAB) for supplying a scanning signal based on the gate driver control signal received from the main PCB10; and source driver PCB's30and40equipped with a source driver IC TAB for supplying video data based on the video data processed from the main PCB10and the control signals. The FPC, which is flexible cable for connecting the PCB's for signal transmission, includes an FPC that is to transmit various gate driver control signals60and61generated from the main PCB10to the gate driver PCB20; a second FPC that is to transmit various source driver control signals70and71generated from the main PCB10to the source driver PCB's30and40; and a third FPC that is to interconnect at least two main PCB's10which are separated from each other.

However, as the display device has a larger screen with higher resolutions such as XGA (768*1024), SXGA (1024*1280) and UXGA (1200*1600), some problems occur in regard to the width of data lines provided on the lower plate of the liquid crystal panel50, the space for installing the source driver PCB's70and71and the driver IC TAB's provided on the lower plate of the liquid crystal panel50, a rise of the data processing rate that requires a separate drive, etc. As such, the mostly used liquid crystal display device is of a dual bank type, which uses two separate source driver PCB's70and71that are respectively provided on the upper and lower part of the backside of the liquid crystal panel50to supply video data to the upper and lower parts of the liquid crystal panel50.

FIG. 2shows a PCB module of the conventional dual bank type liquid crystal display device for a large screen with a high resolution.

The dual bank type liquid crystal display device as shown inFIG. 2has a liquid crystal display module100; source drivers110and120provided on the backside of the display and connected to the upper and lower parts of the display by a main PCB140and FPC's150and170; and a gate driver PCB130laterally connected to the main PCB140via FPC160. The main PCB140has a timing controller for processing video data received via an external video data input signal line180, and for supplying various data and control signals to the source driver110and120and the gate driver130via the FPC's150,160and170.

The above-described dual bank type PCB module as shown inFIG. 2processes video data to form a large screen with high resolution in a bipartite drive manner, as follows. First, the main PCB140has a timing controller for processing video data from the external video data input signal line180to generate video data and various control signals, and sending them to the corresponding source driver PCB's110and120. Here, the video data, i.e., R2n-1, B2n-1and G2nare sent to the source driver PCB110on the upper side of the display via the FPC150, and the video data, i.e., G2n-1, R2nand B2nare sent to the source driver PCB120on the lower side of the display via the FPC170, so that the video data are displayed on the pixels of the liquid crystal panel in the order as shown inFIG. 3as viewed from the front side of the display of the liquid crystal panel. Besides, the signals sent via the FPC's150and170include various control signal to be supplied to the source driver IC TAB as well as video data.

However, such a method in which various control signals in addition to video data are sent via the FPC's150and170to drive the liquid crystal panel on a large screen with high resolution incurs many problems in regard to coupling between signals more deviating from a tolerance range at an increased frequency, noises, and electromagnetic interference (EMI). Besides, when connecting PCB's with FPC's150and170, the resistance capacitance (RC) intrinsic delay component caused by the coupling resistance between the PCB and FPC connectors and the other parasitic capacitance component results in both signal delay and signal distortion. Hence, an inadequate timing control between signals supplied to the source driver PCB's110and120provided on the upper and lower parts of the liquid crystal display module100makes setting and holding of video data inadequate to display. This causes noises or line defect on the liquid crystal display and, for the worse, provides a display that cannot be recognized. In particular, this problem becomes worse due to the longer FPC170shown inFIG. 2rather than the shorter FPC150.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a configuration of the PCB module to reduce signal delay and distortion in driving a liquid crystal panel for a large screen with a high resolution.

In one aspect of the present invention to achieve the above object, there is provided a liquid crystal display device including a main printed circuit board (PCB) for driving a dual bank type liquid crystal panel, wherein the main PCB includes: a first main PCB having a timing controller for processing external odd input signals to generate driving signals, and sending part of the driving signals to a corresponding source driver PCB, so as to generate video signals to be supplied to the odd pixels of the liquid crystal panel; and a second main PCB having a timing controller for processing external even input signals to generate driving signals, and sending part of the driving signals to a corresponding source driver PCB, so as to generate video signals to be supplied to the even pixels of the liquid crystal panel.

In another aspect of the present invention, there is provided a liquid crystal display device including a main PCB for driving a dual bank type liquid crystal panel, wherein the main PCB includes: a first main PCB having a timing controller for processing odd input signals among externally input signals to generate driving signals, and sending part of the driving signals to a corresponding source driver PCB, so as to generate video signals to be supplied to the odd pixels of the liquid crystal panel; and a second main PCB having a timing controller for processing even input signals received from the first main PCB via a cable to generate driving signals, and sending part of the driving signals to a corresponding source driver PCB, so as to generate video signals to be supplied to the even pixels of the liquid crystal panel.

In still another aspect of the present invention, there is provided a liquid crystal display device including a main PCB for driving a dual bank type liquid crystal panel, wherein the main PCB includes: a first main PCB having a timing controller for processing even input signals among externally input signals to generate driving signals, and sending part of the driving signals to a corresponding source driver PCB, so as to generate video signals to be supplied to the even pixels of the liquid crystal panel; and a second main PCB having a timing controller for processing odd input signals received from the first main PCB via a cable to generate driving signals, and sending part of the driving signals to a corresponding source driver PCB, so as to generate video signals to be supplied to the odd pixels of the liquid crystal panel.

Preferably, the externally input signals include low-voltage data signals (LVDS).

Preferably, either the first main PCB or the second main PCB is connected to a gate driver PCB via a cable so as to send part of the generated driving signals to a corresponding gate driver PCB.

Consequently, the present invention uses the above-described PCB module arrangement to reduce signal delay and distortion in driving a dual bank type liquid crystal display device in which two source driver PCBs are respectively provided on the upper and lower backsides of the display of the liquid crystal panel to supply video data to the upper part and the lower part of the liquid crystal panel, thereby successfully driving a liquid crystal display panel for a large screen and a high resolution.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 4shows a liquid crystal display device according to a first embodiment of the present invention.

As shown inFIG. 4, the liquid crystal display device according to the first embodiment of the present invention comprises a liquid crystal display module200, a first source driver PCB210a second source driver PCB220, a gate driver PCB230, a first main PCB240, a second main PCB250, a first source FPC260, a second source FPC280, a gate FPC270, and an external input signal line290.

The liquid crystal display module200comprises, as in the usual cases, a liquid crystal panel having liquid crystal cells arranged in the matrix form between two glass substrates, and a back light unit provided on the backside of the liquid crystal panel opposite to the display side.

The first source driver PCB210is provided with a source driver IC TAB for supplying odd video data, i.e., R2n-1, G2n-1and B2n-1(inFIG. 6) via a source line pad on the upper side of the liquid crystal panel based on a driving signal received from the first main PCB240.

The second source driver PCB220is provided with a source driver IC TAB for supplying even video data, i.e., R2n, G2nand B2n(inFIG. 6) via a source line pad on the lower side of the liquid crystal panel based on a driving signal received from the second main PCB250.

The gate driver PCB230is provided with a gate driver IC TAB for supplying a scanning signal based on a gate driver control signal received from the first main PCB240.

The first main PCB240has a timing controller for processing odd input signals such as odd video signals Ro, Go and Bo, and sync signals received from the external input signal line290to generate driving signals, in order to generate video signals to be supplied to odd pixels of the liquid crystal panel, and thereby sends the corresponding driving signals to the first source driver PCB210. The first main PCB240also sends power and various control signals for driving the gate driver IC TAB of the gate driver PCB230to the gate driver PCB230via the gate FPC270.

The second main PCB250has a timing controller for processing even input signals such as even video signals Re, Ge and Be, and sync signals received from the external input signal line290to generate driving signals, in order to generate video signals to be supplied to even pixels of the liquid crystal panel, and sends the corresponding driving signals to the second source driver PCB220.

The first source FPC260is a flexible cable for transmitting odd video data and various control signals generated from the first main PCB240to the first source driver PCB210in order to drive the source driver IC TAB of the first source driver PCB210.

The second source FPC280is a flexible cable for transmitting even video data and various control signals generated from the second main PCB250to the second source driver PCB220in order to drive the source driver IC TAB of the second source driver PCB220.

The gate FPC270is a flexible cable for transmitting power and various control signals generated from the first main PCB240to the gate driver PCB230in order to drive the gate driver IC TAB of the gate driver PCB230. Here, the gate FPC270for driving the gate driver IC TAB of the gate driver PCB230may be provided between the second main PCB250and the gate driver PCB230in order to make power and various control signals generated at the second main PCB250and applied to the gate driver PCB230.

The external input signal line290, which is a cable for receiving various external signals in order to drive the liquid crystal panel, sends the corresponding signals to the first main PCB240and the second main PCB250. Examples of the input signals include, as shown inFIG. 1, RGB video data signals, sync signals, system clock CLK, enable signals, and power. The RGB video data signals are divided into odd video data applied to the first main PCB240and even video data applied to the second main PCB250. The other signals are input to both the first main PCB240and the second main PCB250.

Now, a detailed description will be given on how the liquid crystal display device operates according to the first embodiment of the present invention as constructed above.

The dual bank type liquid crystal display device according to the first embodiment of the present invention as shown inFIG. 4has the liquid crystal display module200. The first and second source driver PCBs210and220are provided on the backside of the display and connected to the upper part and the lower part of the display by the first and second source FPCs260and280corresponding to the first and second main PCB's240and250, respectively. The gate driver PCB230is laterally connected to the first main PCB240by the gate FPC270. The first and second main PCBs240and250process external video data received via the input signal line290by way of their timing controller to supply various data and control signals to the source drivers PCBs210and220and the gate driver PCB230via the FPCs260,270and280, respectively.

The above-described dual bank type PCB module according to the first embodiment of the present invention processes video data to form a large screen with high resolution in a bipartite drive manner as follows. First, the first main PCB240has its timing controller that processes odd video data such as odd input signals received from the external input signal line290to generate video data and various control signals and sends them to the first source driver PCB210via the first source FPC260. The second main PCB250has its timing controller that processes even video data such as even input signals received from the external input signal line290to generate video data and various control signals and sends them to the second source driver PCB220via the second source FPC280. The first main PCB240also generates power and various control signals for driving the gate driver IC TAB provided on the gate driver PCB230and sends them to the gate driver PCB230via the gate FPC270. The gate FPC270for driving the gate driver IC TAB of the gate driver PCB230may be interposed between the second main PCB250and the gate driver PCB230in order to have the power and various control signals generated at the second main PCB250and applied to the gate driver PCB230. Here, the odd video data, i.e., R2n-1, G2n-1and B2n-1generated from the first main PCB240are sent to the first source driver PCB210on the upper side of the display via the first source FPC260, and the even video data, i.e., R2n, G2nand B2ngenerated from the second main PCB250are sent to the second source driver PCB220on the lower side of the display via the second source FPC280, so that the video data are displayed on the pixels of the liquid crystal panel in the order as shown inFIG. 6as viewed from the front side of the display of the liquid crystal panel.

FIG. 5shows a liquid crystal display device according to a second embodiment of the present invention.

As shown inFIG. 5, the liquid crystal display device according to the second embodiment of the present invention comprises a liquid crystal display module300, a first source driver PCB310, a second source driver PCB320, a gate driver PCB330, a first main PCB340, a second main PCB350, a first source FPC360, a second source FPC380, a third source FPC390, a gate FPC370, and an external input signal line400.

The liquid crystal display module300comprises, as the liquid crystal display module200ofFIG. 4, a liquid crystal panel having liquid crystal cells arranged in the matrix form between two glass substrates, and a back light unit provided on the backside of the liquid crystal panel opposite to the display side.

The first source driver PCB310is provided with a source driver IC TAB for supplying odd video data, i.e., R2n-1, G2n-1and B2n-1(inFIG. 6) via a source line pad on the upper side of the liquid crystal panel based on a driving signal received from the first main PCB340.

The second source driver PCB320is provided with a source driver IC TAB for supplying even video data, i.e., R2n, G2nand B2n(inFIG. 6) via a source line pad on the lower side of the liquid crystal panel based on a driving signal received from the second main PCB350.

The gate driver PCB330is provided with a gate driver IC TAB for supplying a scanning signal based on a gate driver control signal received from the first main PCB340.

The first main PCB340has a timing controller for processing odd input signals such as odd video signals Ro, Go and Bo, and sync signals received from the external input signal line400to generate driving signals, so as to generate video signals to be supplied to odd pixels of the liquid crystal panel, and thereby sends the corresponding driving signals to the first source driver PCB310. The first main PCB340also sends power and various control signals for driving the gate driver IC TAB of the gate driver PCB330to the gate driver PCB330via the gate FPC370.

The second main PCB350has a timing controller for processing even input signals such as even video signals Re, Ge and Be, and sync signals received from the external input signal line400to generate driving signals, so as to generate video signals to be supplied to even pixels of the liquid crystal panel, and sends the corresponding driving signals to the second source driver PCB320.

The first source FPC360is a flexible cable for transmitting odd video data and various control signals generated from the first main PCB340to the first source driver PCB310in order to drive the source driver IC TAB of the first source driver PCB310.

The second source FPC380is a flexible cable for transmitting only even input signals among the various input signals, such as low-voltage video signals, as received via the external input signal line400, from the first main PCB340to the second main PCB350.

The third source FPC390is a flexible cable for transmitting even video data and various control signals generated from the second main PCB350to the second source driver PCB320in order to drive the source driver IC TAB of the second source driver PCB320.

The gate FPC370is a flexible cable for transmitting power and various control signals generated from the first main PCB340to the gate driver PCB330in order to drive the gate driver IC TAB of the gate driver PCB330. Here, the gate FPC370for driving the gate driver IC TAB of the gate driver PCB330may be provided between the second main PCB350and the gate driver PCB330in order to make power and various control signals generated at the second main PCB350and applied to the gate driver PCB330.

The external input signal line400is a cable for receiving various external signals including low-voltage video signals for driving the liquid crystal panel to transmit the various input signals to the first main PCB340and the even signals among the externally input signals received via the external input signal line400from the first main PCB340to the second main PCB350. Examples of the externally input signals include, as shown inFIG. 1, RGB video data signals, sync signals, system clock CLK, enable signals, and power. The RGB video data signals are divided into low-voltage odd video data applied to the first main PCB340and low-voltage even video data applied to the second main PCB350. The other signals are input to both the first main PCB340and the second main PCB350.

The dual bank type liquid crystal display device according to the second embodiment of the present invention as shown inFIG. 5has the liquid crystal display module300. The first and second source driver PCBs310and320are provided on the backside of the display and connected to the upper part and the lower part of the display by the first and second source FPCs360and390corresponding to the first and second main PCBs340and350, respectively. The gate driver PCB330is laterally connected to the first main PCB340by the gate FPC370. The first and second main PCBs340and350process external video data received via the input signal line400by means of their timing controller to supply various data and control signals to the source drivers PCB's310and320and the gate driver PCB330via the FPC's360to390, respectively.

The above-described dual bank type PCB module according to the second embodiment of the present invention processes video data to form a large screen with high resolution in a bipartite drive manner as follows. First, the first main PCB340has its timing controller that processes odd input signals such as low-voltage odd video data received from the external input signal line400to generate video data and various control signals and sends them to the first source driver PCB310via the first source FPC360. The second main PCB350has its timing controller that processes even input signals such as low-voltage even video data received from the external input signal line400to generate video data and various control signals and sends them to the second source driver PCB320via the third source FPC390. The first main PCB340also generates power and various control signals for driving the gate driver IC TAB provided on the gate driver PCB330and sends them to the gate driver PCB330via the gate FPC370. The gate FPC370for driving the gate driver IC TAB of the gate driver PCB330may be interposed between the second main PCB350and the gate driver PCB330so as to have the power and various control signals generated at the second main PCB350and applied to the gate driver PCB330. Here, the odd video data, i.e., R2n-1, G2n-1and B2n-1generated from the first main PCB340are sent to the first source driver PCB310on the upper side of the display via the first source FPC360, and the even video data, i.e., R2n, G2nand B2ngenerated from the second main PCB350are sent to the second source driver PCB320on the lower side of the display via the third source FPC390, so that the video data are displayed on the pixels of the liquid crystal panel in the order as shown inFIG. 6as viewed from the front side of the display of the liquid crystal panel.

The functions of the first and second main PCB's340and350may be inverted. That is, the first main PCB340has its timing controller process even input signals such as low-voltage even video data received from the external input signal line400to generate video data and various control signals and send them to the first source driver PCB310via the first source FPC360; and the second main PCB350has its timing controller process odd input signals such as low-voltage odd video data received from the external input signal line400to generate video data and various control signals and send them to the second source driver PCB320via the third source FPC390. Here, the even video data, i.e., R2n, G2nand B2ngenerated from the first main PCB340are sent to the first source driver PCB310on the upper side of the display via the first source FPC360, and the odd video data, i.e., R2n-1, G2n-1and B2n-1generated from the second main PCB350are sent to the second source driver PCB320on the lower side of the display via the third source FPC390, so that the video data are displayed on the pixels of the liquid crystal panel in the order as shown inFIG. 6as viewed from the front side of the display of the liquid crystal panel.

The liquid crystal display device according to the embodiments of the present invention uses the above-described PCB module arrangement to reduce signal delay and distortion in driving a dual bank type liquid crystal display device in which two source driver PCBs are respectively provided on the upper and lower backsides of the display of the liquid crystal panel to supply video data to the upper part and the lower part of the liquid crystal panel, thereby successfully driving a liquid crystal display panel for a large screen with a high resolution.

As described above, the present invention has two main PCBs, i.e., a first main PCB to process odd video data and a second main PCB to process even video data, each of which includes a timing controller for generating various data and control signals to the corresponding source driver PCB via the FPC, so that each main PCB supplies the nearer source driver PCB with various data and control signals necessary to the corresponding source driver IC TAB via the FPC, thereby solving the problems of RC intrinsic delay, coupling between signals, noise and EMI, and reducing signal distortion.