JPH06181556A - Liquid crystal multi-screen display method and its device - Google Patents

Abstract

PURPOSE:To simply attain a multi-screen simultaneous display system at at low cost without using picture memory technology. CONSTITUTION:When a multi-screen display mode is specified by a key input means 21, a microcomputer 13 controls a tuner 12 by tuning data for n channels, receives a selected channel like a step and writes the received channel in a liquid crystal module 16. A picture for one field (or frame) at the time of selecting a channel is thinned to 1/(the number of pictures)<1/2> in both the horizontal and vertical directions and thinned picture data are successively written in a position allocated in each channel. The operation is repeated by defining the writing of n pictures as one cycle so that multiscreen simultaneous display for frame feeding dynamic pictures can be attained. A display position control signal is prepared based upon a vertical synchronizing signal in a tuning stabilized area obtained by passing a vertical synchronizing signal for channel selection through a gate circuit 18 based upon a selected channel picture writing specification signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal multi-screen display method and a device for simultaneously displaying the images of receivable channels in one screen in a liquid crystal television device.

[0002]

2. Description of the Related Art FIG. 7 shows a block diagram of a conventional general liquid crystal television receiver. In the figure, 1 is an antenna, 2 is a tuner for tuning, 3 is a microcomputer for tuning and system control (hereinafter referred to as microcomputer), 4 is a video detection circuit, 5 is a color demodulation circuit, 6 is a liquid crystal module, 7
Is a sync separation circuit, 8 is a voice detection circuit, 9 is a speaker, 1
Reference numeral 0 is a key input means for giving an instruction such as a channel number to the microcomputer 3 for channel selection and system control.

The RF television signal input to the antenna 1 is selected by the tuner 2 controlled by the microcomputer 3,
Amplified and detected by video detection circuit 4, and composite video signal and 4.5MHz
The audio intercarrier signal of is extracted. The composite video signal is amplified and color demodulated by the color demodulation circuit 5, extracted as RGB primary color video signals and supplied to the liquid crystal module 6, while being synchronously separated by the sync separation circuit 7 to drive the liquid crystal module 6. Horizontal and vertical sync signal H for
D and VD are generated. Further, the audio intercarrier signal is amplified and detected by the audio detection circuit 8 to be an audio signal and supplied to the speaker 9.

FIG. 8 shows the structure of the liquid crystal module 6. The liquid crystal module 6 includes a controller 61 that generates signals for controlling the X driver 62 and the Y driver 63 based on the horizontal synchronizing signal HD and the vertical synchronizing signal VD, and RGB.
An X driver 62 that samples the primary color video signal to generate image data corresponding to the number of pixels in the horizontal direction, a Y driver 63 that controls a thin film transistor (TFT) for writing image data of one horizontal line in a liquid crystal cell, It is composed of a common driver 64 that generates a voltage Vcom applied to the common electrode of the liquid crystal cell, and a liquid crystal panel 65 including a liquid crystal cell, a TFT, a color filter, and the like.

In such a liquid crystal television receiver, in order to confirm the content of the receivable broadcast channel at the place where it is used, it goes without saying that the signal channel can be manually or automatically tuned and swept. It was necessary to repeat the method of receiving the images one after another and checking the images.
This has a problem that the operation is troublesome and it is difficult to compare the broadcast contents of each channel and select the receiving channel based on the comparison. As one means for solving this, a multi-screen display in which a screen is divided by an image memory and a plurality of channel images are simultaneously displayed is also performed, but it has a drawback that the system is complicated, the shape is large, and the cost is high.

[0006]

As described above, in the conventional device, the multi-screen simultaneous display system using the image memory technology is complicated, tends to have a large shape, and is expensive, so that it is a popular liquid crystal for consumer use. There is a problem that it is difficult to apply to a television receiver.

Therefore, the present invention has been made in view of the above problems.
An object of the present invention is to provide a liquid crystal multi-screen display method and a device thereof which can realize a multi-screen simultaneous display system with a relatively simple structure and at low cost without using an image memory technology. .

[0008]

A liquid crystal multi-screen display method according to the present invention according to claim 1 utilizes the voltage holding characteristic of a liquid crystal cell to simultaneously display a plurality of inputtable video signals in a single screen. A liquid crystal multi-screen display method, in which switching means for inputting a plurality of video signals, sequentially switching at a fixed cycle and outputting, and to which position on the multi-screen split display screen is synchronized with the switching cycle of this switching means. Means for outputting a display position control signal for designating whether to write the selected video signal, and liquid crystal display means for sequentially writing and displaying the selected video signal at a designated position on the liquid crystal screen by using the display position control signal. It is equipped with and.

According to another aspect of the liquid crystal multi-screen display device of the present invention, a switching means for inputting a plurality of video signals and sequentially switching and outputting the video signals at a constant cycle, and a switching means for switching in synchronization with the switching cycle of the switching means. Screen division display means for outputting a display position control signal for designating at which position on the screen the selected video signal is to be written, and the display position control signal is used to output the selected video signal to a designated position on the liquid crystal screen. And a liquid crystal display means for sequentially writing and displaying.

A liquid crystal multi-screen display device according to a third aspect of the present invention includes a video signal switching means for selectively switching and outputting a plurality of composite video signals supplied as inputs, and a composite video signal switching means. A sync separating means for separating horizontal and vertical sync signals from a video signal, and switching control data for outputting to the video signal switching means, and a predetermined number of switches corresponding to the number of selected screens to be displayed on a multi-screen. A means for sequentially outputting control data at a constant cycle and a vertical synchronization signal from the sync separation means are input, and in synchronization with the transmission of the switching control data at the constant cycle, the vertical synchronization of the stable area for each screen is performed. Means for extracting a signal and outputting a display position control signal for designating at which position on the multi-screen split display screen the image being selected is written based on the vertical synchronization signal; Using the horizontal and vertical synchronization signals from the above and the display position control signal, the image data for one field obtained from each selected video signal is reduced to 1/2 the screen number in the horizontal and vertical directions. Liquid crystal display means for sequentially writing and displaying thinned-out image data at designated positions on the liquid crystal screen assigned for each thinned-out and selected video signal is provided.

A liquid crystal multi-screen display device according to the present invention according to claim 4 is a video signal switching means for selectively switching and outputting a plurality of composite video signals supplied as inputs, and a composite video signal switching means. Color demodulation means for color demodulating a video signal to output a video signal of three primary colors, sync separation means for separating horizontal and vertical sync signals from a composite video signal from the video signal switching means, and designation of a multi-screen display mode Switching means for outputting switching control data to the input means for carrying out the video signal switching means, and when a multi-screen display mode is designated by the input means, for the video signal switching means, A means for sequentially outputting a predetermined number of switching control data corresponding to the number of selected screens to be displayed on a multi-screen and a multi-screen display mode is specified by the input means, The vertical sync signal from the sync separation means is input, the vertical sync signal of the stable area for each screen is extracted in synchronization with the switching control data transmission of the constant cycle, and multi-screen split display is performed based on this vertical sync signal. A means for outputting a display position control signal for designating at which position on the screen the selected image is to be written, and driven by the horizontal and vertical sync signals from the sync separation means, the three primary colors from the color demodulation means A video signal is displayed. When the multi-screen display mode is designated by the input means, the horizontal and vertical sync signals from the sync separation means and the display position control signal are used to select each Image data for one field obtained from the video signal is half the number of screens in both horizontal and vertical directions.
Liquid crystal display means is provided for thinning out to a power of 1 and sequentially writing and displaying thinned-out image data at a designated position on the liquid crystal screen assigned for each selected video signal.

A liquid crystal multi-screen display device according to a fifth aspect of the present invention is a tuner for selecting a signal of a desired channel by changing a local oscillation frequency based on tuning data, and a tuner selected by this tuner. Detecting means for video-detecting the signal, color demodulation means for color-demodulating the composite video signal detected by this detection means to output video signals of the three primary colors, and horizontal output from the composite video signal detected by the detecting means. A sync separation means for separating a vertical sync signal, an input means for designating a multi-screen display mode, and a means for outputting tuning data to the tuner,
When the multi-screen display mode is designated by the input means, a predetermined number of tuning data corresponding to the number of channel selection channels to be displayed on the multi-screen are sequentially output to the tuner at a constant cycle. Means and the key input means when a multi-screen display mode is designated, a vertical synchronizing signal is input from the sync separating means, and each screen is synchronized with the sending of the tuning data of the constant cycle. A means for extracting the vertical synchronization signal in the tuning stable region and outputting a display position control signal that specifies at which position on the multi-screen split display screen the image of the channel being selected is written based on this vertical synchronization signal, It is driven by the horizontal and vertical sync signals from the sync separation means, and displays the video signals of the three primary colors from the color demodulation means. Multi-screen display by the input means. Mode is specified, the horizontal and vertical sync signals from the sync separation means and the display position control signal are used to obtain one field of image data obtained in the tuning stable region of each channel. Liquid crystal display means is provided for thinning out to 1/2 power of the number of screens in both the horizontal and vertical directions, and sequentially writing and displaying thinned-out image data at designated positions on the liquid crystal screen assigned to each channel.

In a liquid crystal multi-screen display device according to a sixth aspect of the present invention, the liquid crystal display means according to the fourth or fifth aspect is a liquid crystal cell and a switch element for writing image data for one horizontal line into the liquid crystal cell. A liquid crystal panel for writing image data into a liquid crystal cell for color display; and image signals corresponding to the number of pixels in the horizontal direction by sampling the video signals of the three primary colors from the color demodulation means, and supplying them to the liquid crystal panel. For controlling the X driver and the Y driver by using an X driver for controlling the switch element, a Y driver for controlling the switch element, and horizontal and vertical synchronizing signals and the display position control signal from the sync separating means. When the multi-screen display mode is designated by the key input means, one field worth obtained from the video signals of the three primary colors being selected is selected. The image data is thinned out to 1/1/2 of the number of screens in both the horizontal and vertical directions, and a controller is provided to control so that the thinned-out image data is sequentially written to the designated position of the liquid crystal panel allocated for each selected video signal. It is characterized by having done.

[0014]

According to the structure of the present invention, the liquid crystal cell of the type in which the image data is written by using the switch element can hold and display the image data for several seconds once the image data is written. The video signal input is switched in steps, at the same time, the images at that time are sequentially written to the designated area of the liquid crystal panel, the writing of the screen for n channels completes within a few seconds, and the images at the next timing are sequentially written again. As a result, the image of the second cycle can be displayed before the display of the first cycle remains. Therefore, as in the fifth aspect of the invention, n channels are selected and received stepwise in a short time, and an image for one field (or frame) obtained at the time of selecting each channel is displayed in the horizontal and vertical directions. In both cases, the number of screens is thinned to the 1/2 power, and the thinned image data is sequentially written to the position assigned to each channel on the liquid crystal panel, and this operation is repeated by writing n screens as one cycle. It is possible to realize multi-screen simultaneous display of feed video. (However, n = 2 ² , 3 ² , 4 ² , ...)

[0015]

EXAMPLES Examples will be described with reference to the drawings. An example of the present invention will be described below by taking a four-screen display as an example. However, in this example, once image data is written as a characteristic of a TFT type liquid crystal panel, it is practically used for several seconds due to the voltage holding characteristic of the liquid crystal cell. This is because it is possible to display a typical image.

FIG. 1 shows a block diagram of a multi-screen liquid crystal display method and apparatus according to an embodiment of the present invention.

In FIG. 1, 11 is an antenna, 12 is a tuner for channel selection, 13 is a microcomputer for channel selection and system control, 14 is a video detection circuit, 15 is a color demodulation circuit, 16 is a liquid crystal module, and 17 is a sync separation circuit. , 18 are gate circuits for extracting the vertical synchronization signal in the tuning stable region from the vertical synchronization signal obtained from the synchronization separation circuit 17 in synchronization with the switching cycle of the tuning data by the microcomputer 13 in the multi-screen display mode. Is a voice detection circuit, 20 is a speaker, and 21 is a key input means for giving instructions such as a channel number and a multi-screen display mode to the microcomputer 13 for channel selection and system control.

In the normal reception mode, the RF television signal input to the antenna 11 is selected by the tuner 12 controlled by the microcomputer 13 based on the channel designation of the key input means 21, and amplified by the video detection circuit 14. The signal is detected and the composite video signal and the 4.5 MHz audio intercarrier signal are extracted. The voice inter-carrier signal is amplified and detected by the voice detection circuit 19 to become a voice signal and the speaker 2
Supplied to zero. The composite video signal is amplified and color demodulated by the color demodulation circuit 15, extracted as RGB primary color video signals and supplied to the liquid crystal module 16, while being synchronously separated by the synchronous separation circuit 17 to drive the liquid crystal module 16. The horizontal and vertical synchronizing signals HD and VD for generating are generated and supplied to the liquid crystal module 16. The microcomputer 13
In the normal reception mode, tuning data (a) corresponding to the channel designation by the key input means 21 is created and supplied to the tuner 12. In the normal reception mode, the liquid crystal module 16 uses the horizontal and vertical sync signals HD and VD from the sync separation circuit 17 to generate the RG signal from the color demodulation circuit 15.
The video signal of B is displayed on the screen.

On the other hand, when the multi-screen display mode is designated by the key input means 21, the microcomputer 13 supplies the tuning data (a) of a plurality of channels to the tuner 12 at a constant cycle and the tuning data.
The gate signal (e) synchronized with the transmission of (a) is supplied to the gate circuit 18
And a display position control signal (CA to CD) for designating the position of the channel selection channel image to be displayed on the liquid crystal screen based on the gate output (f) thereof, and then supplied to the liquid crystal module 16. . In the multi-screen display mode, the gate circuit 18 uses the gate signal (e) synchronized with the sending cycle of the tuning data (a) by the microcomputer 13 from the vertical synchronization signal (c) obtained from the sync separation circuit 17. The vertical synchronizing signal in the tuning stable area is extracted and supplied to the microcomputer 13 as a gate output (f). In the multi-screen display mode, the liquid crystal module 16 uses the horizontal and vertical sync signals HD and VD from the sync separation circuit 17 and the display position control signals (CA to CD) to display a color at a specified position on the screen for each channel. The RGB video signals from the demodulation circuit 15 are displayed on multiple screens.

FIG. 2 shows the structure of the tuner 12. Here, a channel selection system based on the PLL frequency synthesizer system will be described. In the tuner 12, the antenna 1
The RF television signal from the high frequency amplifier circuit 121
Is supplied to one input end of the mixer 122, the other input end of the mixer 122 is supplied with the local oscillation signal from the VCO 123, and an intermediate frequency signal (IF signal) is obtained as an output of the mixer 122. To be The VCO 123 includes a prescaler (fixed frequency divider) 124 and a programmable frequency divider 1
25, the phase comparator 126, the reference oscillator 127, and the low pass filter (LPF) 128 together with the PLL (Phase
Locked Loop). V
The local oscillation signal from the CO 123 is input to the mixer 122 and is also supplied to the prescaler 124, where the local oscillation frequency is divided into a predetermined number, and further divided into 1 / N by the programmable frequency divider 125 to obtain a phase. It is supplied to one input terminal of the comparator 126. Programmable frequency divider 12
The frequency division ratio (N) of 5 is changed by PLL data (frequency division ratio data) from the microcomputer 13. The PLL data from the microcomputer 15 is code data corresponding to the channel number designated by the key input means 16. In the phase comparator 126, the frequency from the frequency divider 125 and the reference oscillation frequency from the reference oscillator 127 are compared in phase,
The comparison output is converted into a direct current by the LPF 128 and then converted to the VCO.
It is adapted to be supplied to the oscillation control terminal 123.
As a result, the local oscillation frequency of the tuner can be properly set to the frequency of the channel designated by the key input means 21.

FIG. 3 shows the structure of the liquid crystal module 16. The liquid crystal module 16 has an X driver 162 and a Y driver 16 based on the horizontal synchronizing signal HD and the vertical synchronizing signal VD and the display position control signals CA to CD from the microcomputer 13.
A controller 161 that produces a signal for controlling
An X driver 162 for sampling RGB primary color video signals to generate image data corresponding to the number of pixels in the horizontal direction, and a Y driver 16 for controlling a thin film transistor (TFT) for writing image data for one horizontal line in a liquid crystal cell.
3, a common driver 164 that generates a voltage Vcom applied to the common electrode of the liquid crystal cell, and a liquid crystal panel 165 including a liquid crystal cell, a TFT, a color filter, and the like.

FIG. 4 shows an example of a screen when one screen is displayed in four divisions. Write the A screen at time T1, write the B screen at T2, the C screen at T3, the D screen at T4, and so on.
By writing repeatedly as a cycle, four-frame display is performed with frame-by-frame moving images. Not limited to the embodiment of FIG. 4, even if the A screen is written at the time T1, the C screen is displayed at T2, the B screen is displayed at T3, and the D screen is displayed at T4, the image of the receiving channel is written in the vertical direction of the liquid crystal screen. Well, and
Write A screen at time T1, D screen at T2, C at T3
Images of the receiving channels may be sequentially written in the diagonal direction of the liquid crystal screen, such as the screen, screen B at T4.

The operation of FIG. 1 will now be described in more detail with reference to the timing diagram of FIG. In this device, when the multi-screen display mode is selected, the PLL data (see FIG. 5 (a)) corresponding to the selected channel is selected from the channel selection and system control microcomputer 13 at a cycle of tens to hundreds of milliseconds. Sent to the tuner 12. As a result, the tuning voltage of the tuning tuner 12 changes stepwise as shown in FIG. 5 (b). And video detection output is obtained in the stable region of tuning voltage,
When this is synchronously separated, a vertical synchronous separation output as shown in FIG. 5 (c) is obtained. The timing of the vertical synchronization signal obtained at this time is different for each selected channel and is asynchronous.
A gate signal as shown in FIG. 5 (e) synchronized with the L data transmission ensures that the vertical synchronization signal in the stable area is extracted for each divided screen. FIG. 5 (f) shows the gate output extracted from the vertical synchronizing signal of FIG. 5 (c). The microcomputer 13 takes in this gate output as a trigger signal and outputs display position control signals CA to CD which specify at which position on the 4-division display screen the image of the selected channel is to be written and supplied to the liquid crystal module 16. To do. Fig. 5 (g), (i), (k), (m)
Display position control signals CA, CB, CC and CD respectively.
Indicates. The liquid crystal module 16 uses the control signals CA to C
In response to the D, the controller 161 controls the X driver 162 and the Y driver 163 so that an image decimated in both the vertical and horizontal directions can be written in the designated position, and the image data VA to VD for one field obtained in the stable area T1 ~ T4
Write to the specified position one after another at the timing of. Figure 5 (h)
, (J), (l), and (n) each have four screen write signals V
A, VB, VC and VD are shown. At timings after T5, the same operations as T1 to T4 are repeated. By thus writing the four screens within a few seconds, it is possible to simultaneously display the four screens A, B, C, and D simultaneously. The shorter the screen writing repetition cycle, the faster the frame feed speed of the split display screen becomes, resulting in a more natural moving image.However, the responsiveness of the channel selection system and the video detection circuit imposes a limit on shortening. is there. Therefore, since the image quality is degraded in principle in the split display screen, it is possible to prioritize the responsiveness by reducing the time constant of the AGC in the range where the video detection output is not impaired in the multi-screen display mode.

According to the above-described embodiment, the multi-screen split simultaneous display is performed on the liquid crystal display device without using the A / D, D / A converter and the field memory used in the conventional multi-screen display. Can be realized with a relatively simple structure and at low cost. Therefore, it is useful for a popular type liquid crystal television receiver.

In the above embodiment, the video displayed on the multi-screen is the video of a plurality of channels of the television broadcasting, but the present invention is not limited to the video signal of the television broadcasting, but a video tape recorder (VTR) or an optical system. It is also possible to input a video signal from an external video source such as a digital video recording / reproducing device (LD) and sequentially switch the plurality of video signals at a constant cycle for multi-screen display.

FIG. 6 is a block diagram showing another embodiment of the present invention. 6 is different from the embodiment of FIG. 1 in that
A composite video signal S1 to S4 from a plurality of video sources is input to the video signal switching circuit 22 having a switch function.
Are supplied to the input terminals a to d, and the input terminals a to d are connected to the microcomputer 1.
The point is that the switching control signal from 3 sequentially switches at a fixed cycle, and a plurality of composite video signals are sequentially output from the output end e. The switching control signal is shown in FIG.
Is supplied to the video signal switching circuit 22 at the same cycle as the sending cycle of the PLL data (see FIG. 5 (a)) in FIG. 5, and the circuit 22 receives the video signals S1 to S4 by this switching control signal.
Are sequentially selected. Other points are shown in Figure 1.
Is the same as. With the above configuration, a plurality of composite video signals S1 to S of the composite video signal from the means for selecting and detecting the television broadcast and the composite video signal from the external video source.
4 (or a plurality of composite video signals S1 to S4 from only an external video source may be sequentially and selectively input), and these video signals can be multi-screen displayed on one liquid crystal screen. .

In the above embodiment, the split display of four screens has been described, but the present invention is not limited to this, and it is not limited to this. It is also possible to display a screen or a multi-screen split display of more than that.

[0028]

As described above, according to the present invention, it is possible to realize multi-screen split simultaneous display on a liquid crystal display device with a relatively simple structure and at low cost, without using the image memory technology. it can. Therefore, it has a great effect when applied to a popular type liquid crystal television receiver.

[Brief description of drawings]

FIG. 1 is a block diagram showing a liquid crystal multi-screen display method and apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a tuner in FIG.

FIG. 3 is a block diagram showing a configuration of a liquid crystal module in FIG.

FIG. 4 is a diagram showing a four-division display screen.

FIG. 5 is a timing diagram for explaining the operation of the present invention.

FIG. 6 is a block diagram showing a liquid crystal multi-screen display method and apparatus according to another embodiment of the present invention.

FIG. 7 is a block diagram showing a conventional liquid crystal display device.

8 is a block diagram showing a configuration of a liquid crystal module in FIG.

[Explanation of symbols]

 12 ... Tuner for channel selection 13 ... Microcomputer for channel selection and system control 14 ... Video detection circuit 15 ... Color demodulation circuit 16 ... Liquid crystal module 17 ... Sync separation circuit 18 ... Gate circuit 21 ... Key input means 22 ... Video signal switching circuit

Claims (6)

[Claims] 1. A liquid crystal multi-screen display method for simultaneously displaying a plurality of inputtable video signals in one screen by utilizing a voltage holding characteristic of a liquid crystal cell. Switching means for sequentially switching and outputting by means of, and means for outputting a display position control signal for designating at which position on the multi-screen split display screen the video signal being selected is written in synchronization with the switching cycle of the switching means. And a liquid crystal display means for sequentially writing and displaying the selected video signal at a designated position on the liquid crystal screen by using the display position control signal. 2. A switching means for inputting a plurality of video signals, sequentially switching them at a fixed cycle and outputting the same, and an image being selected at any position on the multi-screen split display screen in synchronization with the switching cycle of the switching means. A means for outputting a display position control signal for designating whether to write a signal, and a liquid crystal display means for sequentially writing and displaying a selected video signal at a designated position on a liquid crystal screen by using the display position control signal are provided. A liquid crystal multi-screen display device characterized in that 3. A video signal switching means for selectively switching and outputting a plurality of composite video signals supplied as inputs, and a sync separation for separating horizontal and vertical sync signals from the composite video signal from the video signal switching means. Means for outputting switching control data to the video signal switching means, and means for sequentially outputting a predetermined number of switching control data corresponding to the number of selection screens to be displayed on a multi-screen at a constant cycle. The vertical sync signal from the sync separation means is input, and the vertical sync signal in the stable area for each screen is extracted in synchronization with the transmission of the switching control data of the constant cycle. Means for outputting a display position control signal for designating at which position on the split display screen the selected image is to be written, and horizontal and vertical sync signals from the sync separation means and the display position control signal. , The image data for one field obtained from each selected video signal is decimated to 1/2 of the number of screens in the horizontal and vertical directions, and the liquid crystal screen is assigned to each selected video signal. 2. A liquid crystal multi-screen display device comprising: liquid crystal display means for sequentially writing and displaying thinned-out image data at designated positions. 4. A video signal switching means for selectively switching and outputting a plurality of composite video signals supplied as inputs, and a composite video signal from the video signal switching means is subjected to color demodulation to generate video signals of three primary colors. A color demodulation means for outputting, a sync separation means for separating horizontal and vertical sync signals from a composite video signal from the video signal switching means, an input means for designating a multi-screen display mode, and a video signal switching means. Switching control data is output by the input means, and when the multi-screen display mode is designated by the input means, a predetermined number corresponding to the number of selection screens to be multi-screen displayed for the video signal switching means. Means for sequentially outputting the switching control data of a constant cycle, and when a multi-screen display mode is designated by the input means, the vertical sync signal from the sync separation means is input, The vertical sync signal in the stable area for each screen is extracted in synchronization with the transmission of switching control data at a fixed cycle, and based on this vertical sync signal, at which position on the multi-screen split display screen the selected image should be written. Means for outputting a display position control signal for designating the display position control signal, and means for displaying the video signals of the three primary colors from the color demodulation means, driven by the horizontal and vertical synchronization signals from the sync separation means, and by the input means. When the multi-screen display mode is designated, the image data for one field obtained from each selected video signal by using the horizontal and vertical sync signals from the sync separation means and the display position control signal, Horizontal,
Liquid crystal display means is provided for thinning out to 1/2 power of the number of screens both in the vertical direction and sequentially writing and displaying thinned-out image data at designated positions on the liquid crystal screen allocated for each selected video signal. LCD multi-screen display device. 5. A tuner for selecting a signal of a desired channel by changing a local oscillation frequency based on tuning data, a detecting means for detecting an image of the signal selected by the tuner, and the detecting means. Color demodulate the composite video signal detected in
A color demodulation means for outputting video signals of three primary colors; a sync separation means for separating horizontal and vertical sync signals from the composite video signal detected by the detection means; an input means for designating a multi-screen display mode; and the tuner. Tuning data is output to the tuner when a multi-screen display mode is designated by the input means, a predetermined number corresponding to the number of channel selection channels to be displayed on the multi-screen for the tuner. Means for sequentially outputting the tuning data in a constant cycle, and when the multi-screen display mode is specified by the key input means, the vertical sync signal from the sync separation means is input to the constant cycle. The vertical sync signal of the tuning stable area for each screen is extracted in synchronization with the sending of the tuning data of, and the multi-screen split display image is displayed based on this vertical sync signal. Means for outputting a display position control signal for designating at which position on the surface the image of the selected channel is to be written, and driven by the horizontal and vertical sync signals from the sync separation means, When the multi-screen display mode is specified by the input means, the horizontal and vertical sync signals from the sync separation means and the display position control signal are used to display each of the three primary color video signals. The image data for one field obtained in the tuning stable area of the selected channel is divided by 1/2 the number of screens in the horizontal and vertical directions.
And a liquid crystal display means for sequentially writing and displaying thinned-out image data at a designated position on the liquid crystal screen assigned to each channel. 6. The liquid crystal display means includes a liquid crystal cell and a switch element for writing image data of one horizontal line into the liquid crystal cell, the liquid crystal panel for writing image data in the liquid crystal cell for color display, An X driver for sampling the video signals of the three primary colors from the color demodulation means to create image data corresponding to the number of pixels in the horizontal direction and supplying the image data to the liquid crystal panel, a Y driver for controlling the switch element, and the sync separation means. For controlling the X driver and the Y driver by using the horizontal and vertical synchronization signals from the above and the display position control signal. When the multi-screen display mode is designated by the key input means, The image data for one field obtained from the video signals of the three primary colors being selected is decimated to 1/2 of the number of screens in both the horizontal and vertical directions, and each selected image is displayed. 6. A liquid crystal multi-screen display device according to claim 4, further comprising a controller for controlling to write the thinned-out image data in order to a designated position of the liquid crystal panel assigned for each image signal.