JPH10150614A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the disorder of right and left no-signal areas of a display screen and to make the screen easy to see by forming the no-signal areas on the right and left of the display screen and masking the right and left no-signal areas when an image whose lateral width is narrower than the lateral width of the display screen is displayed. SOLUTION: A wide controller 3 performs dot clock control in response to the display mode of an image and controls a source driver 4 and a gate driver 5 to display the image on a liquid crystal panel 6 with a display screen of 9:16 in aspect ratio. The wide controller 3 generates a free-run synchronizing signal as an output signal for a case wherein there is no external signal of an external signal trigger oscillation circuit. Then the wide controller 3 when displaying an image of 3:4 in aspect ratio on the display screen of 9:16 in aspect ratio generates timing pulses synchronized with the period of no-signal areas from the free-run synchronizing signal and a switching circuit 1 masks the no-signal areas with the timing pulses.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a display device having a display screen having a wide aspect ratio (screen aspect ratio).

[0002]

2. Description of the Related Art Hi-vision broadcasting (HDTV television broadcasting) and wide clear vision broadcasting (EDTV)
2. Description of the Related Art A display device having a display screen with a wide aspect ratio of 9:16 for receiving (II-type television broadcasting) is known. In this type of display device, an image having a conventional aspect ratio of 3: 4 can be displayed by an identification signal indicating a television broadcast system.

FIG. 3 shows a display screen when a high-vision broadcast or a wide clear vision broadcast is received by a display device having a display screen having an aspect ratio of 9:16. In this case, an image of the display period of 50.0 μsec excluding the overscan portion from the image of the effective video period of 52.6 μsec is expressed by 9:
16 are displayed on the entire display screen.

FIG. 4 shows a display screen when a conventional television broadcast having an aspect ratio of 3: 4 is received by a display device having a display screen having an aspect ratio of 9:16. In this case, the dot clock is lowered to switch to display an image with a display period of 60.5 μsec over the entire 9:16 display screen,
The image of 3: 4 is displayed as it is. Thus, 9: 1
6, a display screen of 3: 4 is apparently formed at the center of the wide display screen, and a non-signal area is left and right.

[0005]

However, 9: 1
In a conventional display device which displays a 3: 4 image by controlling a dot clock on the display screen of No. 6, the left and right non-signal areas have:
As shown in FIG. 5, there is a problem that a synchronization signal is seen, noise is mixed under a weak electric field, or fluctuations due to interlace scanning occur at a boundary between a display area and a no-signal area.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the disturbance of the left and right non-signal areas of a display screen when forming a non-signal area on the left and right sides of the display screen and displaying an image having a width smaller than the width of the display screen. It is an object of the present invention to provide a display device that makes it easier to see.

[0007]

[Means for Solving the Problems]

(1) The invention of claim 1 is applied to a display device which forms a non-signal area on the left and right sides of a display screen to display an image having a width smaller than the width of the display screen, and masks the left and right non-signal areas. A mask circuit is provided. (2) The display device according to claim 2, wherein a free-run synchronization signal generation circuit that outputs a free-run synchronization signal even when there is no video synchronization signal, and a pulse signal synchronized with a period of a no-signal area based on the free-run synchronization signal And a pulse signal generation circuit for generating a signal, and masking the non-signal area by the pulse signal by the mask circuit. (3) The display device according to claim 3, wherein the mask circuit
When a pulse signal is input, the video signal level is forcibly reduced to a common level. (4) The display device according to claim 4, wherein the mask circuit
When a pulse signal is input, the composite video signal is switched to an RGB signal. (5) The display device according to claim 5, wherein the mask circuit
When a pulse signal is input, the composite video signal is switched to an RGB signal to perform black drawing.

[0008]

FIG. 1 shows a configuration of an embodiment. The switching circuit 1 includes a composite color video signal (composite video signal) of television broadcast or video, an RGB signal from a personal computer or a navigation device, and an R signal.
It switches between the GB synchronization signal and the switching signal according to the switching signal and outputs the signal to the video interface circuit 2. The video interface circuit 2 processes the composite video signal and
The RGB signal and the synchronizing signal are separated into the GB signal and the synchronizing signal, or the video of the television or the video is synthesized with the image of the personal computer or the navigation device, and the RGB signal and the synchronizing signal are output to the wide controller 3.

The wide controller 3 performs dot clock control according to an image display mode (full screen mode, wide mode, normal mode, cinema mode, etc.), controls the source driver 4 and the gate driver 5, and controls the aspect ratio 9: An image is displayed on the liquid crystal panel 6 of the display screen 16.

[0010] The wide controller 3 also generates a free-run synchronization signal. The free-run synchronization signal is a PLL
(Phaseed Locked Loop) is an output signal when there is no external signal in an external signal trigger oscillation circuit. In this embodiment, when there is no video synchronization signal, a PLL synchronization signal generation circuit (not shown) in the wide controller 3 Means the signal output from When displaying an image having an aspect ratio of 3: 4 on a display screen having an aspect ratio of 9:16, the wide controller 3 generates a timing pulse synchronized with the period of the no-signal area from the free-run synchronization signal. The timing pulse is supplied to the switching circuit 1, and the switching circuit 1 masks the non-signal area by the timing pulse.

FIG. 2 shows a muting circuit built in the switching circuit 1. Video signals such as composite video signals and RGB signals are output to the video interface circuit 2 via the muting circuit 1a. In the muting circuit 1a, when a mask timing pulse is input from the wide controller 3, the transistor T1 is turned on and the video signal line from C1 to C2 is connected to common. That is, the video signal level is forcibly reduced to the common level during the period of the no-signal region by the mask timing pulse generated by the free-run synchronization signal, and the non-signal region is masked. Therefore, in the non-signal area on the left and right sides of the display screen, disturbances such as a synchronization signal being seen, noise being mixed, and fluctuations are eliminated, and the image is easily viewed. In addition, by using the free-run synchronization signal, it is possible to stably mask a no-signal area even when a video signal such as a VTR is interrupted.

Modification of Embodiment of the Invention In the above-described embodiment, an example has been described in which a video signal is forcibly dropped to common by a mask timing pulse to mask a non-signal area, but a mask timing pulse is used. May be switched from the composite video signal to the RGB signal to mask the non-signal area. Alternatively, black drawing may be performed by switching from a composite video signal to an RGB signal by a mask timing pulse. As a result, the disturbance in the left and right non-signal areas is eliminated as in the above embodiment.

In the configuration of the above embodiment, the switching circuit 1 constitutes a mask circuit, and the wide controller 3 constitutes a free-run synchronization signal generation circuit and a pulse signal generation circuit.

Note that the video signal muting method, R
Among the methods of masking by switching to the GB signal and the method of drawing black by switching to the RGB signal, the most appropriate method is adopted according to the isolation performance of the liquid crystal display device, cost, required specifications for the display device, and the like. Just choose.

In the above-described embodiment, an example in which a liquid crystal panel is used as a display has been described. However, the present invention can be applied to a case where another display such as a CRT or a plasma display is used.

In the above-described embodiment, the aspect ratio is 9:
The case where a 4: 4 television broadcast image is displayed on the 16 display screens has been described as an example. However, the aspect ratio between the display screen and the image is not limited to the above embodiment, and the present invention is applied to the left and right sides of the display screen. The present invention can be applied to a general display device that forms a no-signal area in order to display an image having a width smaller than the width of the display screen.

[0017]

【The invention's effect】

(1) As described above, according to the invention of claim 1,
When a non-signal area is formed on the left and right sides of the display screen to display an image with a width smaller than the width of the display screen, the left and right non-signal areas are masked. This eliminates disturbances such as a visible sync signal, the incorporation of noise, and the occurrence of fluctuations, and makes it easier to view images. (2) According to the second aspect of the present invention, even when there is no video synchronization signal, a pulse signal synchronized with the period of the no-signal area is generated based on the free-run synchronization signal, and a mask is applied to the no-signal area using the pulse signal. Claim 1
In addition to the above effects, even when a video signal such as a VTR is interrupted, a mask can be stably applied to a no-signal area. (3) According to the invention of claim 3, when a pulse signal synchronized with the period of the no-signal area is input, the video signal level is forcibly reduced to the common level. An effect similar to the effect described above can be obtained. (4) According to the invention of claim 4, when a pulse signal synchronized with the period of the no-signal area is input, switching from the composite video signal to the RGB signal is performed. Similar effects can be obtained. (5) According to the invention of claim 5, when a pulse signal synchronized with the period of the non-signal area is inputted, the composite video signal is switched to the RGB signal to perform black drawing, so that the black drawing is performed. The same effect as the effect of 2 can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment.

FIG. 2 is a diagram illustrating a muting circuit.

FIG. 3 is a diagram illustrating a display screen when a high-definition broadcast or a wide clear vision broadcast is received by a display device having a display screen having an aspect ratio of 9:16.

FIG. 4 is a diagram illustrating a display screen when a conventional broadcast having an aspect ratio of 3: 4 is received by a display device having a display screen with an aspect ratio of 9:16.

FIG. 5 is a diagram for explaining disturbance in a no-signal area when a conventional display device having a display screen with an aspect ratio of 9:16 receives a conventional broadcast having an aspect ratio of 3: 4.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Switching circuit 1a Muting circuit 2 Video interface circuit 3 Wide controller 4 Source driver 5 Gate driver 6 Liquid crystal panel

Claims (5)

[Claims] 1. A display device for forming a non-signal area on the left and right sides of a display screen to display an image having a width smaller than the width of the display screen, comprising a mask circuit for masking the left and right non-signal areas. Characteristic display device. 2. The display device according to claim 2, wherein a free-run synchronization signal generating circuit that outputs a free-run synchronization signal even when there is no video synchronization signal; And a pulse signal generation circuit for generating a pulse signal synchronized with a period, wherein the mask circuit masks the non-signal area with the pulse signal. 3. The display device according to claim 2, wherein the mask circuit forcibly reduces the video signal level to a common level when the pulse signal is input. 4. The display device according to claim 2, wherein the mask circuit switches from a composite video signal to an RGB signal when the pulse signal is input. 5. The display device according to claim 2, wherein the mask circuit performs black drawing by switching from a composite video signal to an RGB signal when the pulse signal is input.