KR19990066080A - Transmission Method of Video Parameter Using Blank Segment - Google Patents

Abstract

The present invention relates to a method for transmitting video parameters using a blank period. In the video parameter transmission method, after the vertical synchronization signal goes low, the video parameter is transmitted in the form of serial data to the horizontal synchronization signal in the blank period. It is characterized by.

Description

Transmission Method of Video Parameter Using Blank Segment

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of transmitting a video parameter using a blank period. More specifically, an unused blank between frames is used in a video signal input to a liquid crystal display. The present invention relates to a transmission method for carrying video parameters using an interval and a driving circuit of a liquid crystal display for converting and displaying a screen mode according to the transmitted parameters.

In general, a computer display device is a cathode ray tube (CRT) and a liquid crystal display device for a monitor.

Recently, as the size of the liquid crystal display device is enlarged and the price is much lowered, the liquid crystal display device for the monitor which can replace the existing cathode ray tube is continuously developed. In the meantime, the biggest problem in the popularization of monitor liquid crystal display devices, that is, narrow viewing angle problem and high price problem, has been almost solved by the recent rise in technology level. It is becoming.

Hereinafter, a method of determining a screen display position from characteristics of a video signal and a video signal used in the conventional liquid crystal display will be described with reference to the accompanying drawings.

1 is a timing diagram of a video signal input to a conventional liquid crystal display.

Most liquid crystal display devices for note book computers use digital video signals, and liquid crystal display devices for monitors use digital signals, but they are different from notebook computers. That is, in the liquid crystal display device for notebook computers, since the liquid crystal display device is fixed 1: 1 to the notebook computer, a digital video signal for the liquid crystal display device is generated from the beginning, but the liquid crystal display device used in the monitor is a cathode ray tube. It receives and processes the analog video signal output. However, since the liquid crystal display module receives and processes a digital video signal internally, the received analog video signal is converted into a digital video signal and used by a converter that converts the analog signal into a digital signal.

The format of the video signal of Fig. 1 is used in a cathode ray tube, in which there is a blank section between the previous frame and the next frame, in which the electron gun of the cathode ray tube returns from the last line of the previous frame to the first line of the next frame. It exists for the return time needed to come. Thus, the blank section is a period in which the electron gun of the cathode ray tube passes about 40-50 lines from the end of scanning of the last line of the previous frame to the scan of the first line of the next frame, so there is no valid data in the blank section and only synchronization. Only the signal is present, and the electron gun detects the blank section to achieve vertical synchronization.

However, the liquid crystal display device does not use a blank section for the blanking section because the method of displaying an image is fundamentally different from that of the cathode ray tube, and thus does not use an electron gun, so this vertical blanking period has little meaning.

2 is a timing diagram of a main signal for determining a position of a screen in a conventional liquid crystal display, where (a) is a vertical timing diagram and (b) is a horizontal timing diagram.

Referring to the vertical timing diagram of (a), the starting position of the screen display in the vertical direction on the screen is counted by the number of X horizontal periods 1H based on the vertical synchronization signal Vsync of the video signal. Display the next vertical start signal (STV). In response to the vertical start signal STV, a screen of a new frame is started by holding the start position of the screen display in the vertical direction.

In the horizontal timing diagram of (b), the starting position of the screen display in the horizontal direction on the screen is the same principle, and the X horizontal data shift clocks 1T are counted based on the horizontal synchronization signal Hsync, and then the horizontal start signal. Display (STH). In response to the horizontal start signal STH, a line of the screen starts to be displayed by holding the start position of the screen display in the horizontal direction.

Therefore, in positioning the vertical start signal STV and the horizontal start signal STH, the vertical start signal STV and the horizontal start signal at a position apart from the vertical sync signal Vsync and the horizontal sync signal Hsync. The position of the screen is determined by whether or not STH) is displayed.

On the other hand, a problem that is difficult to solve when using a liquid crystal display as a monitor is a method of adapting the liquid crystal display to various systems and resolutions. That is, in the case of the conventional liquid crystal display device for notebook computers, since the panel of the liquid crystal display device is fixed to the system by 1: 1, the screen of the liquid crystal display device according to one type of video signal suitable for the fixed liquid crystal display device is used. Design various timing control signals for display.

However, in the case of a liquid crystal display for a monitor, there is a high possibility that it is not limited to one system and connected to an unspecified number of systems. Since a conventional VGA card has different video parameters for each manufacturer, all systems and VGAs It is virtually impossible to output the timing control signal for the card.

Therefore, the conventional liquid crystal display device solves this problem by allowing the user to adjust the position of the screen, but this method is not the ultimate solution and is contrary to the basic concept of plug and play. Of course, all VGA card companies can standardize on a single video parameter, but this is also not easy.

In addition, a problem to be solved in a liquid crystal display monitor is a problem of a method of detecting a signal of various resolutions and a method of applying video parameters suitable for each detected resolution to a screen display of the liquid crystal display device.

In order to solve such a problem, a conventional liquid crystal display for a monitor finds a resolution using a synchronization signal of a video signal called multi sync used in a cathode ray tube, and magnifies the screen to the found resolution. The method of displaying on the panel of a display apparatus is used.

However, even in the above case, it is difficult to precisely fit the image on the screen, which is inconvenient for the user to make fine adjustments directly. As an alternative, one can think of storing various video parameters in a storage medium such as a ROM and selecting one suitable for the input video signal and using it as a video parameter, but this is also the video parameter of dozens of VGA cards. It is difficult to store all of them in a limited amount of ROM, and it is impossible to store all of them by resolution, and the overhead is large in terms of cost.

Accordingly, an object of the present invention is to solve the above-described problems, and to solve the above-mentioned problems, various positions of the current picture mode being used in the system using a blank section of the video signal input to the liquid crystal display, that is, an unused section. And transmitting the information about the resolution to the liquid crystal display device, wherein the liquid crystal display device receives the information and generates a timing control signal for displaying the screen of the liquid crystal display device. The present invention provides a liquid crystal display device using the same.

1 is a timing diagram of a video signal input to a conventional liquid crystal display.

2 is a timing diagram of main signals for determining the position of a screen in a conventional liquid crystal display.

(a) is a vertical timing diagram.

(b) is a horizontal timing diagram.

3 is a timing diagram carrying video parameters in a vertical blank section in a method for transmitting video parameters using a blank section according to an embodiment of the present invention.

4 is a block diagram of a liquid crystal display device to which a method of transmitting video parameters using a blank period according to an embodiment of the present invention is applied.

As a means for achieving the above object, the configuration of the present invention

In the video parameter transmission method,

After the vertical synchronizing signal goes low, the video parameter is transmitted in the form of serial data on the horizontal synchronizing signal in the blank period.

In addition, the video parameter,

Position of the first line in the vertical sync signal Vsync, time from the horizontal sync signal Hsync to the first pixel, resolution, polarity of the sync signal, front porch, back porch, and valid data It is characterized in that the number of clocks included in the interval and one line.

The structure which applied the said method to a liquid crystal display device,

A clock generator which receives a vertical synchronization signal Vsync and a horizontal synchronization signal Hsync and outputs a synchronization clock that maintains a constant phase relationship with the synchronization signals at all times;

A converter configured to receive the synchronous clock output from the clock generator as a reference clock, convert the input analog video signal into a digital video signal, and output the digital video signal;

Receiving the synchronization clock output from the clock generator, receiving the analog video signal and the vertical synchronization signal (Vsync) as an input to separate the video parameters from the input analog signal, and the separated video parameters A decoder for converting and outputting digital information;

In response to the use request signal, the synchronization clock output from the clock generation unit is received, the video parameter converted into digital information by the decoder is received and stored, and the use request signal for the stored video parameter is received. A storage unit which outputs the video parameter;

The digital video signal output from the converting unit is input to output video data, a use request signal for reading the video parameter stored in the storage unit, and is input from the storage unit by the use request signal. A liquid crystal display controller outputting a control signal for displaying an image on a screen according to the video parameter;

And a liquid crystal panel that receives video data and control signals from the liquid crystal display controller and actually outputs an image.

In addition, the storage unit,

A memory for receiving and storing the video parameter converted into digital information by the decoder, receiving a use request signal for the stored video parameter, and outputting the stored video parameter;

And a memory controller configured to receive the synchronous clock generated by the clock generator and generate a control signal used to store video parameters or output the video parameters in the memory.

By the above configuration, the configuration and operation of the most preferred embodiment that can easily implement the present invention will be described in detail with reference to the accompanying drawings.

3 is a timing diagram carrying video parameters in a vertical blank section in a method for transmitting video parameters using a blank section according to an embodiment of the present invention.

After the vertical sync signal Vsync goes low, the video signal has a blank section until the actual image data comes in. This blank section corresponds to the retrace time used by the cathode ray tube and is valid data as described above. There is only a sync signal without.

Each of the horizontal sync signals in the blank period is loaded with video parameters in the form of serial data. In this case, the video parameters include the position of the first line in the vertical sync signal Vsync and the first pixel in the horizontal sync signal Hsync. It refers to all kinds of video parameters such as time, resolution, sync signal polarity, front porch, back porch, valid data interval and the number of clocks included in a line.

4 is a block diagram of a method for transmitting video parameters using a blank period according to an embodiment of the present invention.

First, referring briefly to how the image is represented on the liquid crystal display, the input analog video signal is converted into a digital video signal by an A / D converter 20 and input to the LCD controller 50. Various control signals output from the LCD controller 50 are finally represented by the LCD panel 60 as an image.

Next, in order to accurately represent the image of the liquid crystal display according to the screen mode, a method of transmitting video parameters using the blank period using the blank period will be described in detail.

A video parameter transmission method using a blank section includes an A / D converter 20, an LCD controller 50, an LCD panel 60, a clock locked part (PLL, 10), a decoder 30, and a memory. 42 and a memory controller 44.

The clock generator 10 receives the vertical synchronizing signal Vsync and the horizontal synchronizing signal Hsync, generates a synchronizing clock in phase with the synchronizing signals Vsync and Hsync, and generates the generated synchronizing clock A /. Inputs are made to the D converter 20, the decoder 30, and the memory controller 44.

The A / D converter 20 converts an analog video signal into a digital video signal using the clock synchronized by the clock generator 10 as a reference clock.

The decoder 30 receives the vertical sync signal Vsync and the analog video signal input in the above process by using the clock synchronized by the clock generator 10 to separate the video parameters from the video signal. The video parameters are converted into digital data and stored in the memory 42.

The memory 42 operates only when the power is turned on, and when the power is turned off, a RAM or a volatile memory may be used to add a very useful function. That is, in most cases, when the liquid crystal display for the monitor is installed in the system, the user may receive the same video parameter continuously. Therefore, the video parameter suitable for the mode selected by the user is stored in the memory through the above process. Even when the system is changed, the video parameters already stored in the memory 42 are updated by separating the video parameters by the decoder 30 from the above process, that is, the newly input video signal.

The memory controller 44 uses the synchronous clock generated by the clock generator 10 so that the decoder 30 stores the video parameters in the memory 42 or the LCD controller 50 stores the video parameters stored in the memory 42. Generate control signals for use.

The LCD controller 50 reads video parameters such as screen resolution and screen position stored in the memory 42 to display an image by displaying a vertical start signal (STV), a horizontal start signal (STH), and a load signal (TP). Outputs a timing control signal such as) to represent the image on the LCD panel 60 that matches the video parameters stored in the memory 42.

On the other hand, the components of the above embodiments can be changed within the scope not departing from the gist of the present invention.

According to the present invention, since the input video signal includes a video parameter in its own blank section, the screen can be exactly matched to the image even when the user selects various modes or changes the mode of the screen during use. Can be imported.

Claims (4)

In the video parameter transmission method, After the vertical synchronization signal goes low, the video parameter transmission method using a blank period, characterized in that for transmitting the video parameters in the form of serial data to the horizontal synchronization signal of the blank period. The method of claim 1, The video parameter is, The position of the first line in the vertical sync signal, the time from the horizontal sync signal to the first pixel, the resolution, the polarity of the sync signal, the front porch, the back porch, the effective data section, and the number of clocks included in one line. And video parameter transmission method using a blank period. A clock generator which receives a vertical synchronization signal Vsync and a horizontal synchronization signal Hsync and outputs a synchronization clock that maintains a constant phase relationship with the synchronization signals at all times; A converter configured to receive the synchronous clock output from the clock generator as a reference clock, convert the input analog video signal into a digital video signal, and output the digital video signal; Receiving the synchronization clock output from the clock generator, receiving the analog video signal and the vertical synchronization signal (Vsync) as an input to separate the video parameters from the input analog signal, and the separated video parameters A decoder for converting and outputting digital information; In response to the use request signal, the synchronization clock output from the clock generation unit is received, the video parameter converted into digital information by the decoder is received and stored, and the use request signal for the stored video parameter is received. A storage unit which outputs the video parameter; The digital video signal output from the converting unit is input to output video data, a use request signal for reading the video parameter stored in the storage unit, and is input from the storage unit by the use request signal. A liquid crystal display controller outputting a control signal for displaying an image on a screen according to the video parameter; And a video parameter transmission method using a blank section including a liquid crystal panel receiving video data and a control signal from the liquid crystal display controller and actually outputting an image. The method of claim 3, The storage unit, A memory for receiving and storing the video parameter converted into digital information by the decoder, receiving a use request signal for the stored video parameter, and outputting the stored video parameter; And a memory controller configured to receive the synchronous clock generated by the clock generator and generate a control signal used to store video parameters or output the video parameters to the memory. Liquid crystal display device using the transmission method of the.