KR20030058138A - Flat panel display device and method for operating the same - Google Patents

Abstract

PURPOSE: A flat panel display and a driving method thereof are provided to disperse the energy of signals to drive a liquid crystal panel and reduce the electromagnetic interference by using a spread spectrum method. CONSTITUTION: A flat panel display includes an LVDS transmission portion(100), an LVDS reception portion(200), a frequency conversion portion(300), a timing control portion(400), and a drive IC(500). The LVDS transmission portion converts a TTL signal including an image data signal and a control signal to an LVDS signal and transmits the LVDS signal. The LVDS reception portion receives the LVDS signal and converts the LVDS signal to the TTL signal. The frequency conversion portion spreads a clock frequency of the LVDS transmission portion. The timing control portion performs a timing format operation for the signal of the LVDS reception portion by using the spread clock frequency. The drive IC drives a liquid crystal panel according to an output signal of the timing control portion.

Description

Flat panel display device and driving method {FLAT PANEL DISPLAY DEVICE AND METHOD FOR OPERATING THE SAME}

The present invention relates to a flat panel display device and a driving method, and more particularly to a flat panel display device and a driving method that can reduce electromagnetic interference (hereinafter EMI) by using a clock frequency from the outside.

Recently, flat panel display devices have been developed to have high frequency and high resolution in order to realize a more satisfactory screen of a product.

As a flat panel display device, a liquid crystal module may be described as a typical case, and a liquid crystal module has problems in implementation of high resolution due to an EMI problem, a noise problem through a transmission medium, and a limitation of the number of data transmissions in an XGA or higher module. have.

In the conventional flat panel display device, data is transmitted at a TTL level, and in such an environment, an EMI problem occurs because an image signal has a high frequency and a voltage level is changed at a corresponding frequency.

In addition, a method of transmitting data or clock signals at the TTL level requires a large number of transmission lines, and the greater the number of cables or connectors, the greater the probability of exposure to an external noise source. Therefore, when a transmission medium such as a cable or a connector is exposed to a noise source, noise affects normal data and a clock signal, thereby adversely affecting an abnormally formed screen.

In addition, the number of data transmission bits supported by a graphics controller commonly used to implement full color high resolution is limited. Therefore, it is not easy to implement a high resolution having more than 260,000 colors using a bi-division driving method that actually uses two channels.

In order to solve this problem, the introduction of LVDS technology has been attempted at the interface between the computer main body and the liquid crystal module. LVDS technology was defined in IEEE 'IEEE P 1596.3' in 1996, and LVDS technology is designed to realize data transmission at low voltage, and has a high transmission speed.

1 and 2 are block diagrams of a flat panel display device using LVDS technology as the first and second conventional examples.

As shown in FIG. 1, the LVDS transmitter 10 converts image data and control signals into LVDS signals and transmits them to the LVDS receiver 12. As described above, the LVDS signal transmitted from the LVDS transmitter 10 is converted into a TTL signal by the LVDS receiver 12, and the TTL signal output from the LVDS receiver 12 is controlled by the timing controller 14 and then the timing format is changed. It is converted and applied to the drive IC 16.

Meanwhile, referring to FIG. 2 as a second conventional example, the LVDS transmitter 20 converts image data and control signals into LVDS signals and transmits them to the one-chip IC 22. Here, the one-chip IC 22 is configured to perform a combination of the LVDS receiving function and the timing control function of FIG. 1, and thus the one-chip IC 22 converts the timing format while converting the input LVDS signal to the TTL level. The TTL signal whose timing format is converted is applied to the drive IC 24.

However, the image signal interface device of the conventional flat panel display device having the configuration as described above with reference to FIGS. 1 and 2 requires the configuration of a plurality of component blocks and peripheral passive elements in the liquid crystal module, and particularly, a configuration for timing format, that is, timing Since the controller 14 and the one chip 22 interface with the drive ICs 16 and 24 through a high frequency TTL signal, the controller 14 and the one chip 22 are easily generated by EMI and are susceptible to noise. In addition, since a large number of data transmission lines are formed, an EMI problem is caused, so that an additional component for preventing EMI is generated.

Therefore, conventionally, a simple wiring formation and a printed circuit board having a two-layer structure can be used, and a technology for reducing the manufacturing cost since the number of components required for configuration has been introduced.

That is, as shown in FIG. 3, the image signal interface of the liquid crystal display device includes a first LVDS transmitter 30 for converting and transmitting an image signal, which is a TTL signal including image data and a control signal, into an LVDS signal, and Converts the LVDS signal transmitted from the first LVDS transmitter 30 into a TTL signal, converts the signal corresponding to the image data into an LVDS signal, and transmits the converted signal; and converts a signal corresponding to the control signal into a timing format The one-chip IC 40 transmitting the TTL signal, the LVDS signal and the TTL signal of the one-chip IC 40 are input, and among the input signals, the LVDS signal is converted into a TTL signal, and the input and converted image data and control A composite drive IC 50 for outputting a signal for driving a liquid crystal panel as a TTL signal including a signal is provided.

Specifically, the LVDS signal output from the first LVDS transmitter 30 is transmitted to a liquid crystal module (not shown), which is a flat panel display device, and the one chip IC 40 and the complex drive IC 50 are connected to the liquid crystal module. And a liquid crystal panel on which a screen is formed.

The one-chip IC 40 has an LVDS receiver 42, a timing controller 44, and a second LVDS transmitter 46, and outputs image data as LVDS signals and control signals as TTL signals. The composite drive IC 50 is configured to have an LVDS receiving function for converting the LVDS signal into a TTL signal and a driving function for driving the liquid crystal panel.

The LVDS receiver 42 first converts the LVDS signal transmitted from the first LVDS transmitter 30 into a TTL signal, which is formatted by the timing controller 44 for display. Then, the image data among the timing-formatted TTL signals is converted into an LVDS signal by the second LVDS transfer unit 46 and transmitted to the composite drive IC 50, and the control signal is the TTL signal as it is. Is sent to.

The complex drive IC 50 converts the transmitted LVDS signal including the image data into a TTL signal. The driving signal is applied to the liquid crystal panel by the control signal inputted as the converted image data and the TTL signal. Displays a predetermined screen according to the input data.

However, since the data output of the liquid crystal display is a differential pair, the EMI filter cannot be applied, and the part capable of controlling the EMI can be made in the PCB pattern, but this is the EMI debugging. City is time consuming and expensive.

Accordingly, an object of the present invention is to provide a flat panel display device and a driving method capable of lowering an EMI level by dispersing an energy spectrum by applying a spread spectrum.

1 and 3 are block diagrams illustrating a conventional flat panel display device.

Figure 4 is a block diagram for explaining a flat panel display device and a driving method according to an embodiment of the present invention.

5 and 6 are circuit diagrams for explaining FIG.

7 is a block diagram for explaining another embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100: LVDS transmitter 200: LVDS receiver

300: frequency converter 400: timing controller

410: first memory unit 420: second memory unit

500, 900: drive IC 600: first LVDS transmitter

700: second LVDS transmission unit 800: one-chip IC

In the flat panel display device and the driving method of the present invention for achieving the above object, the flat panel display device driving method comprising a drive integrated circuit for outputting a display signal for forming a predetermined screen from a predetermined image signal transmission source, When converting signals from an image signal source into TTL signals for driving a liquid crystal panel, spread the clock frequency at the image signal source and use the spread clock frequency to convert the converted TTL. The timing format of the signal as a signal for driving the liquid crystal panel is characterized in that for transmitting to the drive integrated circuit.

In addition, according to the flat panel display apparatus of the present invention, an LVDS transmitter for converting and transmitting an image signal, which is a TTL signal including an image data signal and a control signal, into an LVDS signal, and inputting a signal from the LVDS transmitter to a TTL signal. An LVDS receiver for converting and outputting, a frequency converter for spreading the clock frequency of the LVDS transmitter, a timing controller for timing-formatting the signal of the LVDS receiver using the spread clock frequency, and a signal from the timing controller. It characterized in that it comprises a drive integrated circuit for driving the liquid crystal panel receives the input.

In addition, according to the display device of the present invention, a first LVDS transmitter for converting and transmitting an image signal, which is a TTL signal including an image data signal and a control signal, into an LVDS signal, and inputs a signal from the first LVDS transmitter. An LVDS receiver for converting and outputting a TTL signal, a frequency converter for spreading the clock frequency of the LVDS transmitter, a timing controller for timing-formatting the signal of the LVDS receiver using the spread clock frequency, and the timing controller A second LVDS transmitter converting a TTL signal into a low voltage differential signal, and a drive integrated circuit converting a signal from the second LVDS transmitter into a TTL signal and outputting a signal for driving a liquid crystal panel as the TTL signal. Characterized in that.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

4 is a block diagram of a flat panel display device according to an embodiment of the present invention, Figure 5 is a block diagram according to another embodiment of the present invention.

The flat panel display device according to the present invention is to provide a liquid crystal display device that can lower the EMI level by applying the spread spectrum (spread spectrum) to distribute the energy spectrum.

In addition, embodiments according to the present invention are for an image signal interface of a flat panel display system, and the interface is configured to transmit an LVDS signal including 6 bits of image data of each of R, G, and B.

To this end, as shown in FIG. 4, the flat panel display device of the present invention includes an LVDS transmitter 100 for converting and transmitting an image signal, which is a TTL signal including an image data signal and a control signal, into an LVDS signal, and the LVDS transmission. An LVDS receiver 200 for inputting a signal from the unit 100, converting the signal into a TTL signal, and outputting the signal, a frequency converter 300 for spreading the clock frequency of the LVDS transmitter, and an LVDS receiver using the spread clock frequency. And a drive integrated circuit 500 that receives the signal from the timing controller 400 and drives the liquid crystal panel.

Here, the frequency converter 300 applies a spread spectrum method, and spreads the clock frequency from the LVDS transmitter 100 to the TTL input from the timing controller 400 to the drive integrated circuit 500. By spreading the signal's frequency band to distribute the frequency, it ultimately concentrates energy in a specific frequency band, preventing the EMI from exceeding the threshold.

The timing controller 400 is configured as follows to output the timing-formatted TTL signal, that is, the image data signal and the control signal, to the drive integrated circuit 500 using the frequency converter 300.

That is, the signal stored in the first memory unit 410 using the first memory unit 410 for inputting the signal from the LVDS receiver 200 and the spread clock frequency from the frequency converter 300. And a second memory unit 420 for timing formatting and restoring.

Operation of the flat panel display device having the above configuration will be described in detail as follows.

First, a process of converting a TTL signal into an LVDS signal will be described with reference to FIG. 5.

The image signal output for display of a predetermined screen by the liquid crystal module may be divided into image data and control signals thereof, and the image data may be divided into three colors, i.e., six bits for red (R), green (G), and blue (B). These data are supplied to the TTL-TO-LVDS converter 110 constituting the LVDS transmitter 100 through 18 TTL signal transmission lines.

The control signal consists of a horizontal synchronization signal Hsync, a vertical synchronization signal Vsync, a data enable signal DE, and a clock signal CLK, which are applied to the TTL-TO-LVDS converter through the corresponding TTL signal transmission lines of four lines. The clock signal CLK is applied to a phase locked loop 120 (hereinafter referred to as a 'PLL').

The PLL 120 is configured to provide a reference clock for operation with the TTL-TO-LVDS converter 110, and the reference clock is synchronized with the input clock signal CLK. The TTL-TO-LVDS converter 110 converts the TTL signal into an LVDS signal using a reference clock, and the TTL-TO-LVDS converter 110 is transmitted for each transmission line through the buffers 130a, 130b, and 130c. Outputs LVDS signals IN0, IN1, and IN2. The PLL 120 also converts the clock signal CLK into an LVDS signal and outputs the clock signal CKIN through the buffer 130d.

Meanwhile, with reference to FIG. 6, the LVDS signal is converted into a TTL signal.

The LVDS signal including the image data transmitted through IN0, IN1, and IN2 is input to the LVDS-TO-TTL converter 220 through the buffers 210a, 210b, and 210c, and the LVDS signal transmitted to the CKIN is buffered 210d. Through PLL 230). Then, the reference signal is provided to the LVDS-TO-TTL converter 220 as a TTL signal from the PLL 230, and the LVDS-TO-TTL converter 220 converts the input LVDS signal into a TTL signal and outputs the TTL signal to the corresponding transmission line. do. Then, 18 bits of data corresponding to image data R, G, and B and each control signal are transmitted to the TTL transmission line as the TTL signal, and the clock signal CLK is also output from the PLL 230 and transmitted through the corresponding TTL transmission line. .

As such, the LVDS signal transmitted from the LVDS transmitter 100 is converted into a TTL signal by the LVDS receiver 200, and in this state, timing control for driving the liquid crystal panel (not shown) is performed by the timing controller 400. .

In this case, the TTL signals converted by the LVDS receiver 200 are stored in the first memory unit 410 of the timing controller 400, and the clock signal CKIN converted by the TTL-TO-LVDS converter 110 is converted into a frequency converter. The signals stored in the first memory unit 410 are timing-formatted in synchronization with the spread clock signal SCKIN and rearranged into signals for driving a liquid crystal panel (not shown).

As described above, EMI can be achieved by spreading energy of signals for driving the liquid crystal panel by applying a spread spectrum method from the outside.

Further, as described above in the prior art, the embodiment of the present invention can be applied with reference to FIG.

That is, as shown in FIG. 7, the flat panel display apparatus of the present invention includes a first LVDS transmitter 600 for converting and transmitting an image signal, which is a TTL signal including an image data signal and a control signal, into an LVDS signal, An LVDS receiver 200 for inputting a signal from the first LVDS transmitter 600 and converting the signal into a TTL signal and outputting the signal; a frequency converter 300 for spreading the clock frequency of the first LVDS transmitter 600; A timing controller 400 for timing-formatting the signal of the LVDS receiver 200 using the spread clock frequency, and a second LVDS transmitter 700 for converting the TTL signal of the timing controller 400 into a low voltage differential signal; And a drive integrated circuit 900 converting the signal from the second LVDS transmitter 700 into a TTL signal and outputting a signal for driving the liquid crystal panel as the TTL signal. In this case, the LVDS receiver 200, the timing controller 400, and the second LVDS transmitter 700 are integrated into the one-chip IC 800. In addition, the timing controller 400 includes a first memory unit and a second memory unit described with reference to FIG. 4. A detailed description of the operation is as described above.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

The flat panel display device and driving method of the present invention described above have the following effects.

The present invention can achieve EMI by dispersing energy of signals for driving the liquid crystal panel by applying a spread spectrum method from the outside.

In addition, the number of components and the number of wirings for transmitting image signals of the display apparatus can be minimized, thereby reducing manufacturing costs and improving the wiring structure.

Claims (6)

A driving method of a flat panel display device having a drive integrated circuit for outputting a display signal for forming a predetermined screen from a predetermined image signal transmission source, When converting signals from the image signal source into TTL signals for driving a liquid crystal panel, spread the clock frequency at the image signal source and convert the converted clock frequency using the spread clock frequency. And timing-formatting a TTL signal into a signal for driving a liquid crystal panel, and transmitting the TTL signal to the drive integrated circuit. An LVDS transmitter for converting and transmitting an image signal, which is a TTL signal including an image data signal and a control signal, into an LVDS signal; An LVDS receiver for inputting a signal from the LVDS transmitter and converting the signal into a TTL signal; A frequency converter for spreading the clock frequency of the LVDS transmitter; A timing controller for timing-formatting the signal of the LVDS receiver by using the spread clock frequency; And a drive integrated circuit configured to receive a signal from the timing controller and drive a liquid crystal panel. The method of claim 2, The timing controller comprises a first memory unit for inputting a signal from the LVDS receiver; And a second memory unit for timing-formatting and restoring a signal stored in the first memory unit using the clock frequency from the frequency converter. A first LVDS transmitter for converting and transmitting an image signal, which is a TTL signal including an image data signal and a control signal, into an LVDS signal; An LVDS receiver for inputting a signal from the first LVDS transmitter and converting the signal into a TTL signal; A frequency converter for spreading the clock frequency of the LVDS transmitter; A timing controller for timing-formatting the signal of the LVDS receiver by using the spread clock frequency; A second LVDS transmitter converting the TTL signal of the timing controller into a low voltage differential signal; And a drive integrated circuit converting a signal from the second LVDS transmitter into a TTL signal and outputting a signal for driving a liquid crystal panel as the TTL signal. The method of claim 4, wherein The timing controller comprises a first memory unit for inputting a signal from the LVDS receiver; And a second memory unit for timing-formatting and restoring a signal stored in the first memory unit using the clock frequency from the frequency converter. The method of claim 4, wherein And the LVDS receiver, the timing controller, and the second LVDS transmitter are integrated with a one-chip IC.