JP2003333462A - Display device and television receiver set - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a technique for displaying a video having an aspect ratio of 16:9 on a liquid crystal monitor having an aspect ratio of 4:3, which can reduce a circuit scale and cost. <P>SOLUTION: The liquid crystal monitor 1 includes a liquid crystal module 9 having an aspect ratio of 4:3. When a video signal applied to a video circuit 2 is judged as a video having an aspect ratio of 16:9, a CPU 4 determines a vertical magnification ratio, a horizontal magnification ratio and a video display ratio for the input video signal. The input video signal contains a non-video signal unnecessary for displaying as a video in its upper and lower ends of the vertical direction, which is subjected to masking operation when the signal is displayed on the module 9. Part of the upper and lower ends of the video signal is also subjected to the masking operation. A ratio of the video signal to a signal used for displaying without being subjected to the masking is the video display ratio. Vertical and horizontal magnifications for displaying without any distortion of the video are processed with the same magnification ratio. The vertical magnifying operation is executed by arithmetically calculating a plurality of line signals stored in a line memory 3. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video display device, and even when a video signal having an aspect ratio different from that of the screen is received, most of the video is displayed in the center of the screen without distortion. Technology.

[0002]

2. Description of the Related Art In recent TV broadcasting, normal N
In addition to TSC (national television system committee) television images (aspect ratio 4: 3), horizontally long images (aspect ratio 16: 9) such as high-definition television are mixed and transmitted. In this specification,
The aspect ratio indicates the ratio of the horizontal length of the image or screen to the vertical length (aspect ratio).

Against this background, in the market, there are monitors having an image display area with an aspect ratio of 4: 3 and 16: 9. Further, a device for displaying an image having an aspect ratio of 16: 9 on a monitor having an image display area having an aspect ratio of 4: 3 has been devised.

[0004]

When a video having an aspect ratio of 16: 9 is input to a monitor having a video display area having an aspect ratio of 4: 3, the video is displayed in the center of the screen to display the video. Generally, a method of displaying a black mask on the upper and lower parts (letter box display) is used.
The reason why such a method is adopted is as follows.

When an image having an aspect ratio of 16: 9 is output to a liquid crystal monitor having an image having an aspect ratio of 4: 3, the displayed image becomes a horizontally compressed image. Therefore, in order to eliminate the distortion of the display image, it is necessary to compress and display the image in the vertical direction, but by compressing the image in the vertical direction, the image width in the vertical direction becomes smaller. When the vertical video width becomes smaller than the vertical width of the screen, the video starts from the top of the screen due to the characteristics of the liquid crystal module, and the same video is repeatedly displayed below the video section.

Therefore, in a liquid crystal monitor using a matrix type display panel for sequentially displaying images horizontally and vertically from the screen edge and a module having a driver for performing such sequential display control, a circuit in the preceding stage of the liquid crystal module is used. A frame memory is provided inside, and in the frame memory, image data is arranged in the center part and black image is arranged respectively at the upper and lower parts of the image to compose the image data, and this image data is displayed on the liquid crystal module. Was there.

Therefore, in order to display an image having an aspect ratio of 16: 9 without distortion in a liquid crystal display device having an aspect ratio of 4: 3, it is necessary to provide a frame memory, which causes a problem that the circuit scale becomes large. It was Also,
There was a problem of high cost.

Therefore, the present invention is a technique for displaying most of a video signal having an aspect ratio of 16: 9 in the central portion of a display screen having an aspect ratio of 4: 3 without distortion, while the circuit scale is small and the cost is reduced. The challenge is to provide.

[0009]

In order to solve the above-mentioned problems, the invention according to claim 1 is a display device provided with a matrix type display module having an image display region with an aspect ratio of 4: 3. The input video signal of one frame input by the display device is composed of a plurality of line signals in the horizontal direction which are scanned in the vertical direction. The predetermined number of video signals at the ends are non-video signals that do not need to be displayed, and signals other than the non-video signals in the input video signal are defined as video signals, and the display device Is a video judging means for judging the type of the input video signal, and the input video signal when the video judging means judges that the input video signal is a signal corresponding to a video with an aspect ratio of 16: 9. Scaling means for generating a similar video signal by scaling the input video signal at a specific scaling ratio while maintaining the aspect ratio of the vertical video signal, and a vertical upper end corresponding to the non-video signal of the similar video signal and A predetermined number of line signals at the lower end are masked with a predetermined color, and a certain proportion of line signals at the upper and lower ends in the vertical direction corresponding to the video signal among the similar video signals are masked with a predetermined color. Thus, the display means for displaying a video image having an aspect ratio of 16: 9 (hereinafter referred to as a real video image) in the video image display area and the maximum ratio of the real video area to the video area corresponding to the entire video signal are Therefore, a determining unit that determines the specific ratio and the specific scaling ratio is provided.

According to a second aspect of the present invention, in the display device according to the first aspect, a line memory for storing a line signal of the input video signal is further provided, and the enlarging / reducing means is a current scanning target. It is characterized in that it includes means for expanding / compressing the input video signal by processing the line signal and the previous line signal stored in the line memory.

According to a third aspect of the present invention, in the display device according to the first or second aspect, the enlarging / reducing means is further configured such that the input video signal is a signal corresponding to a video with an aspect ratio of 4: 3. When it is determined by the image determination unit that the image is present, a unit that enlarges or reduces the image while maintaining the aspect ratio of the image generated by the input image signal is included, and the determination unit further includes the input image signal. Of the above, a means for determining the enlargement / reduction ratio is provided so that an image having an aspect ratio of 4: 3 corresponding to the image signal is displayed in the entire image display area.

According to a fourth aspect of the present invention, there is provided a display device including a matrix type display module having an image display area having an aspect ratio of a: b, wherein the display device inputs 1
The input video signal of the frame is composed of a plurality of horizontal line signals scanned in the vertical direction, and has a predetermined number of line signals at the upper and lower ends in the vertical direction and a predetermined number of video signals at the left and right ends of each line signal. Is a non-video signal that does not need to be displayed, and the signal excluding the non-video signal from the input video signal is defined as a video signal. When the image determination unit determines the type and the image determination unit determines that the input image signal is a signal corresponding to an image having an aspect ratio c: d, the aspect ratio of the input image signal is maintained. A scaling means for generating a similar video signal by scaling the input video signal as it is at a specific scaling ratio, and masking a predetermined peripheral signal corresponding to the non-video signal of the similar video signal with a predetermined color. By masking a specific ratio of peripheral signals corresponding to the video signal among the similar video signals with a predetermined color, a video with an aspect ratio c: d in the video display area (hereinafter , Real image), and a determining unit that determines the specific ratio and the specific enlargement / reduction ratio so that the ratio of the real image region to the image region corresponding to the entire image signal becomes maximum. It is characterized by including.

According to a fifth aspect of the present invention, there is provided a display device including a matrix type display module having an image display area having an aspect ratio of 4: 3, wherein the display device inputs 1
The input video signal of the frame is composed of a plurality of line signals in the horizontal direction that are scanned in the vertical direction, and the predetermined number of line signals at the upper and lower ends in the vertical direction are non-video signals that need not be displayed. When the video signal input by the display device is a video with an aspect ratio of 16: 9, the non-video signal is displayed in the video display area in the same manner as the video signal that needs to be displayed, and The video signal is masked with a predetermined color.

According to a sixth aspect of the present invention, in the display device according to any of the first to fifth aspects, the display device including the matrix type display module is a liquid crystal display device. .

The invention according to claim 7 comprises a device for receiving a television image signal, and the display device according to any one of claims 1 to 6 for inputting and displaying the received television image signal. It is characterized by

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 is a diagram showing functional blocks of a liquid crystal monitor 1 which is an image display device according to a first embodiment of the present invention. In FIG. 1, the video circuit 2
Inputs a video signal supplied from a video supply means (not shown) and outputs a digital video signal and a synchronizing signal from the video signal. The sync signal includes a horizontal sync signal and a vertical sync signal used as timing information of the input video signal. In the following description, the digital video signal output from the video circuit 2 will also be simply referred to as the input video signal.

The line memory 3 is a memory for storing the input video signal output by the video circuit 2 for several lines. Here, the line of the input video signal indicates a set of video signals displayed in the horizontal direction on the monitor. That is, the input video signal forms a frame video as one screen by scanning a plurality of horizontal line signals in the vertical direction. In the present embodiment, the line memory 3 may have a capacity capable of storing the line signal of one line. The number of line signals that need to be stored in the line memory 3 is determined by the vertical expansion rate of the image, which will be described later.

The CPU 4 determines the vertical enlargement ratio and the horizontal enlargement ratio for the input video signal according to the type of the input video signal. The vertical enlargement ratio and the horizontal enlargement ratio are determined so that the actual image display area (A) is displayed at the maximum and without distortion. Further, the CPU 4 sets the position to mask the input video signal and the mask color. The type of the input video signal is determined by the interlace method (I), the progressive method (P), the number of scanning lines, the frequency, and the like.

The input video signal includes a synchronizing signal and signals such as a front porch and a back porch that are not required to be displayed on the monitor (these are collectively referred to as non-video signals). On the other hand, a signal that needs to be displayed on the monitor is called a video signal. The actual image display area (A) indicates an area of the image signal that is contained in the image display area of the liquid crystal module and is actually displayed without being masked (in FIG. 6, Areas not masked in black).

The above-mentioned definitions are summarized as follows: -Input video signal: a video signal input by the video circuit 2 and including a video signal and a non-video signal, a video signal: Signals corresponding to the image of the subject, etc. that need to be displayed as images on the monitor, non-image signals: signals that do not need to be displayed as images on the monitor, such as synchronization signals, front and back porch signals Real video signal: Of the video signals, a signal corresponding to the real video display area (A) that is not masked in the vertical direction and is within the video display area of the liquid crystal module 9 in the horizontal direction.

The vertical image conversion circuit 5 uses the current line signal or the previous line signal stored in the line memory in accordance with the vertical expansion rate determined by the CPU 4 to vertically expand the input image signal. Alternatively, reduction processing is performed.

The horizontal image conversion circuit 6 enlarges or reduces the horizontal image signal according to the horizontal enlargement ratio determined by the CPU 4.

Here, the video signal output from the horizontal video conversion circuit 6 is a video signal that has undergone vertical or horizontal enlargement or reduction processing. In the present embodiment,
Since the input image is scaled in the vertical direction and the horizontal direction while maintaining the aspect ratio, this image signal will be referred to as a similar image signal.

The image masking circuit 7 carries out a masking process with an arbitrary color on an arbitrary position of the similar image signal output from the horizontal image converting circuit 6. As described above, the colors for masking are
Although determined by the CPU 4, black mask processing is performed by default in the present embodiment.

The timing signal generating circuit 8 is the video circuit 2
Input the sync signal output from. Then, the type of the input video signal is determined from this synchronization signal, and the type of the input video signal is notified to the CPU 4. The timing signal generation circuit 8 also includes a timing signal for writing an input video signal in the line memory 3, a timing signal for reading a video signal from the line memory 3, and a vertical video conversion circuit 5 in the vertical video conversion circuit 5 according to the vertical and horizontal enlargement ratios determined by the CPU 4. Timing signals of start and end of enlargement or reduction processing, timing signals of start and end of enlargement or reduction processing in the horizontal video conversion circuit 6, video mask circuit 7
The timing signals of the start and end of the masking process, the timing signal for driving the liquid crystal module 9, and the like are transmitted.

The liquid crystal module 9 includes a liquid crystal display panel, a data driver and a gate driver, and displays an image on the panel according to the image signal output from the image masking circuit 7 and the timing signal output from the timing signal generating circuit 8. . The image display area of the liquid crystal display module 9 is defined as an area of pixels that can be displayed by the liquid crystal display panel, the driver, or the like.

The operation of image processing of the liquid crystal monitor 1 configured as above will be described. Here, a case where the input video signal is a 750P video (750 scanning lines, progressive video) will be described as an example. Further, the image display area of the liquid crystal module 9 has a horizontal dot width Ho = 1024.
dot, vertical dot width Vo = 768 dot, and panel clock PCLK = 75 MHz.

FIG. 2 shows a 750P video format and an input video image. 750P video is dot clock DCLK = 74.1758MHz, horizontal period Ht =
It is an image configured in a format of 1650 dots and vertical cycle Vt = 750 lines.

The horizontal cycle Ht = 1650 dot has a horizontal front porch Hfp = 70 dot and a horizontal synchronizing signal Hd = 8.
0 dot, horizontal back porch Hbp = 220 dot, and horizontal image area Hap = 1280 dot.

The vertical cycle Vt = 750 lines is composed of a vertical front porch Vfp = 5 lines, a vertical synchronizing signal Vd = 5 lines, a vertical back porch Vbp = 20 lines, and a vertical image area Vap = 720 lines.

The signal in the common area of the horizontal video area Hap and the vertical video area Vap is a video signal, and the other signals are non-video signals.

Conventionally, the liquid crystal monitor does not need to display vertical and horizontal synchronizing signals in the input video signal, non-video signals such as the front porch and back porch portions, and includes signals other than the image signal. Because sometimes
Only the video signal was processed and displayed. However, in the present invention, in order to display as many vertical image areas as possible, the vertical synchronizing signal Vd, the front porch Vfp,
The back porch Vbp portion is also processed and displayed (though the mask processing is finally performed).

7 supplied to the liquid crystal monitor 1 as shown in FIG.
The 50P video signal is input to the video circuit 2 and the sync signal is extracted. In response to the synchronization signal input to the timing signal generation circuit 8, the CPU 4 changes the supplied video signal to 750
Since it can be specified that the image is a P image, the vertical enlargement rate Vz and the horizontal enlargement rate Hz are set so that the actual image display area (A) is maximized and an image without distortion is displayed.
To calculate.

A processing procedure for calculating the vertical expansion rate Vz and the horizontal expansion rate Hz in the CPU 4 will be described. So in the following description indicates a video display rate. The image display rate So is the actual image display area (A) with respect to the image area when all the image signals are displayed.
The ratio is expressed by the ratio of the length in the vertical direction or the horizontal direction, not by the area ratio.

FIG. 3 shows a vertical input video signal (input I
It is a figure which shows the relationship between the display signal (output Out) of a vertical direction, and n).

As described above, in the present invention, Vd, Vbp, and V which are unnecessary for actual display in the input video signal are used.
The fp part is also displayed. Further, in the vertical direction of the liquid crystal module, when one vertical cycle ends before reaching the bottom of the screen, the same as the image from the first line displayed on the upper part of the screen is below that. The image is repeatedly displayed. Considering the input video signal in one frame including this repeated portion, the vertical input width of the input video signal is expressed by the equation (1).

[0038]

[Equation 1]

Here, the actual image display area (A) is uniformly selected vertically from the vertical center of the vertical image area Vap. Since the vertical display width displayed on the liquid crystal module 9 is Vo, the vertical enlargement ratio Vz
Is expressed by Equation 2.

[0040]

[Equation 2]

On the other hand, FIG. 4 is a diagram showing the relationship between the horizontal input video signal (input In) and the horizontal display signal (output Out). Horizontal display area is horizontal input Hap
Corresponds to × So. Since the horizontal display width displayed on the liquid crystal module 9 is Ho, the horizontal magnification rate Hz is
It is expressed by Equation 3.

[0042]

[Equation 3]

Here, the aspect ratio of the 750P image is 16: 9.
Therefore, the relation of Equation 4 is established.

[0044]

[Equation 4]

Here, Sq represents the square pixel ratio of the input image. For D4 video (750p video signal, etc.), the aspect ratio of the input video is 1280 dot: 72.
Since 0dot = 16: 9, which is the same as the output aspect ratio (the aspect ratio of the liquid crystal module 9), Sq = 1. D
For two images (525p image signal, etc.), the aspect ratio of the input image is 756dot: 483dot = 14.087:
Since it is 9, Sq = 16 / 14.087 = 1.136
Becomes Here, since the aspect ratio of the 750P image is 16: 9, Sq = 1 is calculated.

Therefore, from the equations 3 and 4, the equation 5 is established.

[0047]

[Equation 5]

Further, in order to prevent the image from being distorted in the display on the liquid crystal module 9, that is, to display the input image while maintaining the aspect ratio, Vz = Hz.
Therefore, the equation 6 is established from the equations 2 and 5.

[0049]

[Equation 6]

Then, substituting the actual value into the equation (6),
It is expressed by Equation 7.

[0051]

[Equation 7]

By calculating the equation (7), So = 0.8
6 is calculated. According to this, the actual video signal is 0.86 times the video signal, that is, 86% of the video signal can be displayed. Vertical expansion rate Vz at this time
Is obtained by the equation 8 by substituting each value into the equation 2.

[0053]

[Equation 8]

From this, it is understood that the reduction may be performed at the vertical enlargement ratio Vz = 0.931. Further, since the horizontal enlargement ratio Hz for displaying the image without distortion may be equal to Vz, it may be reduced to Hz = 0.931 times.

On the other hand, the input video signal digitized by the video circuit 2 is sequentially stored in the line memory 3 including the vertical synchronizing signal, the vertical back porch and the vertical front porch. Here, the required number of horizontal pixels of the line memory 3 is H
If m, Hm is expressed by the equation (9).

[0056]

[Equation 9]

From this, the required number of horizontal pixels Hm = 11
It is 01 dot. Then, the total of the non-display area of the sync signal Hd which is not displayed on the monitor, the back porch Hbp, and the video area signal is obtained by the expression (10).

[0058]

[Equation 10]

From the equations (9) and (10), the line memory 3 is 110 from the 390th dot from the start of the horizontal synchronizing signal Hd.
It can be seen that it is sufficient to control so that image data for 1 dot is sequentially stored.

The reason for performing such processing is as follows. In a later step, the video signal has its horizontal video width reduced by 0.931 times in the horizontal video conversion circuit 6, but among the video reduced by 0.931 times, the liquid crystal module is finally The image displayed in 9 is an image of 86% in the horizontal center. Therefore, when the line signal is stored in the line memory 3, the unnecessary video signal at the beginning is deleted.

In such an environment, that is, when a 750P image is displayed on the liquid crystal monitor 1 having the above-described specifications, the vertical expansion rate Vz = 0.931, so the line memory 3 stores one line of lines. It suffices if there is a capacity capable of storing signals. That is, the vertical image conversion circuit 5 outputs an image obtained by vertically reducing the input image signal by 0.931 times the current image signal (line signal) and the image signal (line signal) one line before.

Specifically, from the input specific line signal (this specific line signal is selected at predetermined intervals according to the reduction ratio) and the line signal one line before,
By outputting one line signal, vertical image reduction processing (thinning processing) is performed. The output line signal is generated by multiplying the pixel value of the specific line signal and the pixel value of the line signal one line before by a predetermined coefficient, so that no unnaturalness remains in the reduced image. I am trying.

In the vertical video conversion circuit 5, after vertical reduction processing is performed, in the horizontal video conversion circuit 6,
The horizontal video signal is also reduced by 0.931.

FIG. 5 is an output image of the horizontal image conversion circuit 6 when the 750P image as shown in FIG. 2 is input to the liquid crystal monitor 1. That is, the output image from the vertical image conversion circuit 5 is horizontally reduced in the horizontal image conversion circuit 6 to 0.931, and the output image is directly connected to the liquid crystal module 9 (without masking). It is an image of the display.

The output of the horizontal video conversion circuit 6 includes the vertical synchronizing signal Vd, the vertical back porch Vbp, and the vertical front porch Vfp. Therefore, if there is an unnecessary signal in these signals, the unnecessary signal is generated. Will also be displayed. Further, since one vertical cycle has only 698 lines, the same image as that from the 6th line on the liquid crystal panel is repeatedly displayed.

Therefore, the video mask circuit 7 performs mask processing on the video of these unnecessary signals and repetitive signals. The video mask circuit 7 masks the unnecessary portion with an arbitrary designated color.

Of the areas requiring the mask, the area Mu in the upper part of the display image is expressed by the equation (11).

[0068]

[Equation 11]

From this, it can be seen that it is necessary to carry out the mask processing from the first line to the 70th line. Further, the region Ml in the lower part of the display image is expressed by Expression 12.

[0070]

[Equation 12]

From this, it can be seen that it is necessary to carry out the mask processing from the 647th line to the 698th line.

FIG. 6 is an image of the image displayed on the liquid crystal module 9 after the mask processing is applied to the 750P image shown in FIG. Here, 70 lines above the actual image display area (A) are masked with black.
At the same time, 698 to 7 displayed repeatedly as images
Black is also displayed for 70 lines of 68. Also, the 51 line below the actual image display area (A) is masked in black. As a result, the actual video display area (A) displayed without being masked corresponds to 86% of the video area corresponding to the video signal.

At this time, the cycle Vs of the vertical timing signal output from the timing signal generating circuit 8 to the liquid crystal module 9 is expressed by the equation (13).

[0074]

[Equation 13]

That is, the cycle Vs of the vertical timing signal is 698 lines. Further, the cycle Hs of the horizontal timing signal is expressed by the equation (14).

[0076]

[Equation 14]

That is, the period Hs of the horizontal timing signal is 1792 dots.

7 and 8 are timing charts showing the flow of processing in the liquid crystal monitor 1 according to the first embodiment described above.

In FIG. 7, (a) is a diagram showing the vertical direction of the input video signal as the horizontal axis. A serial number is attached to each line signal. FIG. 7B is a diagram showing the horizontal direction of the input video signal as the horizontal axis. 1101 dots from the 390th dot are stored in the line memory 3 for each 1 line signal.

(C) is an output of the vertical image conversion circuit 5, and shows a reduced signal obtained by multiplying the input image signal by 0.931 in the vertical direction. (D) is a vertical image conversion circuit 5
1101d stored in the line memory 3
ot is output as it is, and (e) is the output of the horizontal direction conversion circuit 6, and 1024 dots reduced by 0.931 times in the horizontal direction are output.

In FIG. 8, (f) shows the horizontal conversion circuit 6
Is output, and (g) is an output of the video mask circuit 7. The areas of the non-video signal and the upper and lower areas of the video signal (about 7% each) are masked in black.
(H) is the drive signal Vs of the liquid crystal module 9, (i)
Is the drive signal Hs of the liquid crystal module 9, and (j) is the enable signal En transmitted to the liquid crystal module 9, and the video signal input to the module is displayed during the period when this signal is High.

As described above, the liquid crystal monitor 1 according to the present embodiment has the aspect ratio of 1 only by including the line memory.
Most of the video signal having 6: 9 can be displayed in the central portion of the display screen of 4: 3 without distortion. That is, since it is not necessary to provide a frame memory, the circuit scale is small and the cost can be reduced.

In the video display method of this embodiment, when the input video is 750P, the displayable video portion is 86% of the input video area. However, because the conventional television displays overscan,
Only 90 to 95% of the input image area is displayed. Therefore, it can be said that there is little discomfort as compared with the conventional television and it is excellent in practical use.

{Second Embodiment} In the first embodiment, a video signal with an aspect ratio of 16: 9 is displayed in the center of a video display area with an aspect ratio of 4: 3. The second embodiment has the following functions in addition to the functions described in the first embodiment. That is, the aspect ratio of the input video signal is 4: 3.
In this case, the display method is switched so that the input image is displayed on the entire surface of the 4: 3 image display area of the liquid crystal module 9.

Here, a 525i video signal as an input video signal (interlace system video with 525 scanning lines)
The case where is input will be described as an example.

The 525i image is a dot clock DCLK.
= 14.318 MHz, horizontal period Ht = 910 dots, vertical period Vt = 262.5 lines.

The horizontal cycle Ht = 910dot is equivalent to the horizontal front porch Hfp = 22dot and the horizontal synchronizing signal Hd = 68.
dot, horizontal back porch Hbp = 64 dot, and horizontal image area Hap = 756 dot.

The vertical cycle Vt = 262.5 lines is composed of a vertical front porch Vfp = 3 lines, a vertical synchronizing signal Vd = 3 lines, a vertical back porch Vbp = 15 lines, and a vertical image area Vap = 241.5 lines. .

When the input video signal is determined to be the 525i video signal based on the synchronization signal input to the timing signal generation circuit 8, the CPU 4 causes the real video display area (A) to be maximized and has no distortion. Vertical magnification and horizontal magnification are determined so that various images can be displayed.

At this time, since the input image is 4: 3, the image can be displayed at the image display rate So = 1, that is, 100%, and the vertical enlargement rate Vz at this time is expressed by the equation (15).
In this embodiment, the input video is actually 4.
Since it is 7: 3, a 100% display in a 4: 3 image display area results in a slightly elongated image. As described above, it is shown that the present invention can be applied to an aspect ratio similar to 4: 3 even if there is a practically allowable range even with some distortion. And if the input video is 4: 3,
It is possible to perform 100% display without causing distortion.

[0091]

[Equation 15]

From this, the vertical enlargement ratio Vz is enlarged to 3.18 times. The horizontal magnification rate Hz for displaying without distortion is expressed by the equation (16).

[0093]

[Equation 16]

From this, it can be seen that the horizontal enlargement ratio Hz = 1.35 times may be enlarged.

On the other hand, when the aspect ratio of the video signal digitized by the video circuit 2 is 4: 3, the video circuit 2 outputs only the video signal except the vertical synchronizing signal, the vertical back porch and the vertical front porch. Output to the line memory 3. Then, the line memory 3 sequentially stores only the video signal.

Here, the required number Hm of pixels in the horizontal direction of the line memory 3 is obtained from the equation (17).

[0097]

[Equation 17]

From this, the required number of horizontal pixels Hm is 75.
It can be seen that it is 6 dots. In addition, d of the unnecessary video signal
The ot number is calculated by the equation 18.

[0099]

[Equation 18]

Accordingly, the line memory 3 is controlled so as to sequentially store 756 dot image data from the 133th dot from the start of the horizontal synchronizing signal Hd.

When the input video signal is 525i, the vertical expansion rate is Vz = 3.18. Therefore, if the line memory 3 has a capacity for storing line signals for three lines. It will be good.

In the vertical video conversion circuit 5, from the current video signal and the video signal of one line before, or from the video signal of one line before and the video signal of two lines before, or 2
From the video signal before the line and the video signal three lines before,
The input video signal is vertically enlarged by 3.18 and output as an image. In this way, the line signal to be increased for the enlargement processing is output by calculating a plurality of line signals that are temporally preceding and succeeding, so that the enlarged image becomes a natural image. The horizontal image conversion circuit 6 enlarges the output signal of the vertical image conversion circuit 5 by 1.35 times in the horizontal direction and outputs it.

In the present embodiment, the video mask circuit 7 does not carry out mask processing. That is, when it is determined that the aspect ratio of the input video is 4: 3, the mask processing is not performed.

At this time, the period Hs of the horizontal timing signal output from the timing signal generation circuit 8 to the liquid crystal module 9 is expressed by the equation (19).

[0105]

[Formula 19]

Therefore, the horizontal timing signal Hs is 14
It becomes 95 dots. Also, the cycle V of the vertical timing signal
s is. It is calculated by the equation (20).

[0107]

[Equation 20]

From this, the cycle Vs of the vertical timing signal becomes 836 lines.

9 and 10 are timing charts showing the processing flow of the liquid crystal display device 1 according to the second embodiment described above.

In FIG. 9, (a) is a diagram showing the vertical direction of the input video signal as the horizontal axis. A serial number is attached to each line signal. FIG. 7B is a diagram showing the horizontal direction of the input video signal as the horizontal axis. For each 1-line signal, 756 dots from the 133th dot are stored in the line memory 3.

(C) shows an output of the vertical image conversion circuit 5, which is a signal obtained by expanding the input image signal by 3.18 times in the vertical direction. (D) is a vertical image conversion circuit 5
Of 756do stored in the line memory 3
t is output as it is, and (e) is the output of the horizontal direction conversion circuit 6, and 1024 dots enlarged by 1.35 times in the horizontal direction are output.

In FIG. 10, (f) is the output of the horizontal conversion circuit 6, and (g) is the output of the video mask circuit 7. In this embodiment, no mask processing is performed. (H) shows the drive signal Vs of the liquid crystal module 9,
(I) is a drive signal Hs of the liquid crystal module 9, (j)
Is an enable signal En transmitted to the liquid crystal module 9, and the video signal input to the module is displayed during the period when this signal is High.

As described above, the liquid crystal monitor 1 of the present embodiment
By including a line memory capable of storing line signals for three lines, it is possible to display most of an image having an aspect ratio of 16: 9 without distortion and to display all of an image having an aspect ratio of 4: 3 without distortion. It is possible. Further, since the frame memory for storing the video signal is not required to realize these functions, it is possible to reduce the circuit scale and cost.

{Third Embodiment} In the first and second embodiments,
An image having an aspect ratio of 16: 9 on a liquid crystal module 9 including a screen having an aspect ratio of 4: 3;
The case of displaying an image having an aspect ratio of 3 has been described as an example. However, an image having an arbitrary aspect ratio a: b is input, and this image signal is enlarged or reduced at a predetermined ratio to display on the liquid crystal module. It is possible to display the image in the center of the screen having an arbitrary aspect ratio c: d without distortion and arrange a mask region of a predetermined color around the center.

That is, the relationship between the aspect ratio a: b of the input video and the aspect ratio c: d of the display screen is a / b ≦ c / d
In the case of 2, the input image is vertically or horizontally enlarged or reduced according to the second embodiment, and the input image area 100% is displayed without distortion at the center of the screen of c: d. However, a /
When b <c / d, the left part and the right part of the central part are masked with an arbitrary designated color. As in the second embodiment, a / b = c
In case of / d, no mask is required.

On the other hand, when there is a relationship of a / b> c / d, the input image is vertically or horizontally enlarged or reduced according to the first embodiment, and the input image is displayed at the center of the c: d screen. The area 100 × So% is displayed without distortion. further,
The upper part and the lower part of the central part are masked with an arbitrary designated color.

As described above, according to the present invention, an input image having an arbitrary aspect ratio a: b is converted to an arbitrary aspect ratio c:
It is widely applicable to display on a display screen having d without distortion.

{Modification} In the liquid crystal monitor 1 according to the first to third embodiments, the horizontal image conversion circuit 6 is connected to the subsequent stage of the vertical image conversion circuit 5. The same effect can be obtained by connecting the circuit 6 to the subsequent stage of the video circuit 2.

In the second to third embodiments, 10 of the input video area is used.
Although the case where 0% is displayed on the screen has been described as an example, overscan display of about 90 to 95% of the input image area may be performed as in a conventional television.

The present invention is not limited to video signals of 525I and 750P, but can be widely applied to video signals of 525P, 1125I, NTSC and PAL systems.

Furthermore, in the above-described first to third embodiments, the present invention has been described by taking the case where the liquid crystal module is used as the display module, but the present invention is not limited to the matrix type display panel, data driver It is similarly applicable to a display module having a gate driver. Examples of this type of display module include a plasma module (PDP), an LED module, and an electroluminescence module (EL).

In the first embodiment, the ratio of displaying 86% of the input image area on the screen without distortion has been described as an example. , 86% or more of the area can be displayed on the screen.

[0123]

As described above, according to the first aspect of the invention, most of an image having an aspect ratio of 16: 9 is displayed in the center of the screen of a matrix type display device having a display area of 4: 3. It is possible to display without distortion.

According to the second aspect of the present invention, the line signal stored in the line memory is used to perform the expansion / contraction processing of the video signal. Therefore, the circuit scale can be reduced and the cost can be reduced.

According to the third aspect of the invention, even when an image having an aspect ratio of 4: 3 is received, it is possible to display the image without distortion at the maximum.

According to the fourth aspect of the present invention, it is possible to maximize the display of a distortion-free image in a combination of an image display area having various aspect ratios and an image having various aspect ratios.

According to the fifth aspect of the present invention, it is possible to secure a large display area by displaying the non-video signal in the same manner as the video signal and performing the mask process.

According to the sixth aspect of the invention, the liquid crystal display device is adopted as the matrix type display device, so that it can be used for various products.

The seventh aspect of the present invention relates to a television receiver, and is capable of maximally displaying an image without distortion according to the aspect ratio of the received image signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing a structure of a liquid crystal monitor according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an image of a video format and a video area for a 750P video signal input to a liquid crystal monitor.

FIG. 3 is a diagram showing a relationship between an input image and an output image in the horizontal direction.

FIG. 4 is a diagram showing a relationship between an input image and an output image in a vertical direction.

FIG. 5 is an output image diagram of a horizontal image conversion circuit.

FIG. 6 shows that after masking the 750P video signal,
It is a video display image figure output to the screen of a liquid crystal monitor.

FIG. 7 is a timing chart showing the operation in the first embodiment.

FIG. 8 is a timing chart showing the operation in the first embodiment.

FIG. 9 is a timing chart showing the structure of the liquid crystal monitor according to the second embodiment.

FIG. 10 is a timing chart showing the operation in the second embodiment.

FIG. 11 is a block diagram showing a structure of a liquid crystal monitor according to modified examples of the first to third embodiments.

[Explanation of symbols]

1 LCD monitor, 2 video circuit, 3 line memory,
4 CPU, 5 vertical image conversion circuit, 6 horizontal image conversion circuit, 7 image mask circuit, 8 timing generation circuit,
9 Liquid crystal module.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09G 3/20 660 G09G 3/20 660Q 5C080 3/36 3/36 H04N 5/46 H04N 5/46 7 / 01 7/01 J F term (reference) 2H093 NA16 NA31 NA43 NC09 NC11 NC29 NC50 ND42 ND54 5C006 AA01 AB01 AB03 AF23 AF36 AF42 AF45 BB11 BC16 BF05 BF28 FA05 FA44 FA52 5C025 BA02 BA11 BA25 BA27 DA04 DA05 DA06 5C058 BA14 BA01 BA14 CA01 CA09 DA07 EB04 EB35 5C080 AA10 BB05 DD22 DD27 EE21 FF09 GG08 GG12 JJ01 JJ02 JJ04 KK43

Claims (7)

[Claims] 1. A display device comprising a matrix type display module having a video display area with an aspect ratio of 4: 3, wherein an input video signal of one frame input by the display device is:
It is composed of a plurality of horizontal line signals scanned in the vertical direction, and a predetermined number of line signals at the upper and lower ends in the vertical direction and a predetermined number of video signals at the left and right ends of each line signal need not be displayed. A non-video signal, wherein a signal excluding the non-video signal from the input video signal is defined as a video signal, and the display device determines a type of the input video signal. And when the input image signal is determined by the image determination means to be a signal corresponding to an image having an aspect ratio of 16: 9,
Scaling means for generating a similar video signal by scaling the input video signal at a specific scaling ratio while maintaining the aspect ratio of the input video signal; and a vertical axis corresponding to the non-video signal of the similar video signals. A predetermined number of line signals at the upper and lower ends in the direction are masked with a predetermined color, and a predetermined ratio of the line signals at the upper and lower ends in the vertical direction corresponding to the video signal among the similar video signals is predetermined. By masking with a color, the aspect ratio within the image display area is 1
Display means for displaying an image of 6: 9 (hereinafter referred to as an actual image), and the specific ratio and the specific enlargement / reduction ratio so that the ratio of the area of the actual image to the image area corresponding to the entire image signal is maximized. And a determining means for determining. 2. The display device according to claim 1, further comprising a line memory that stores a line signal of the input video signal, wherein the expansion / contraction unit includes a line signal that is a current scan target and the line. A display device comprising: a unit that expands or contracts the input video signal by performing arithmetic processing on a previous line signal stored in a memory. 3. The display device according to claim 1, wherein the scaling unit further determines that the input video signal is a signal corresponding to a video having an aspect ratio of 4: 3. The image signal generated from the input image signal is maintained while maintaining the aspect ratio of the image, the determining unit further includes the image signal of the input image signal. And a means for determining the enlargement / reduction ratio so that an image having an aspect ratio of 4: 3 corresponding to is displayed in the entire image display area. 4. A display device comprising a matrix type display module having a video display area with an aspect ratio of a: b, wherein one frame of input video signal input by the display device is:
It is composed of a plurality of horizontal line signals scanned in the vertical direction, and a predetermined number of line signals at the upper and lower ends in the vertical direction and a predetermined number of video signals at the left and right ends of each line signal need not be displayed. A non-video signal, wherein a signal excluding the non-video signal from the input video signal is defined as a video signal, and the display device determines a type of the input video signal. And when the input image signal is determined to be a signal corresponding to an image having an aspect ratio of c: d by the image determination means, the input image signal is specified while maintaining the aspect ratio of the input image signal. A scaling unit for generating a similar video signal by scaling at a scaling ratio, a predetermined peripheral signal corresponding to the non-video signal among the similar video signals being masked with a predetermined color, and the similar video signal. Of the peripheral signals corresponding to the video signal, a specific ratio of peripheral signals are masked with a predetermined color to display a video with an aspect ratio of c: d (hereinafter, actual video) in the video display area. Display means and determining means for determining the specific ratio and the specific enlargement / reduction ratio so that the ratio of the area of the actual image to the image area corresponding to all the image signals is maximized. Display device. 5. A display device comprising a matrix type display module having a video display area having an aspect ratio of 4: 3, wherein an input video signal of one frame inputted by the display device is scanned in a vertical direction. A plurality of line signals in the horizontal direction, and a predetermined number of line signals at the upper and lower ends in the vertical direction are non-video signals that do not need to be displayed. : 9, the non-video signal is displayed in the video display area in the same manner as the video signal that needs to be displayed, and the non-video signal is masked with a predetermined color. Characteristic display device. 6. The display device according to claim 1, wherein the display device including the matrix type display module is a liquid crystal display device. 7. A television set comprising: a device for receiving a television video signal; and the display device according to claim 1 for inputting and displaying the received television video signal. Receiver.