JPH04269793A - Large-picture display device - Google Patents

Abstract

PURPOSE:To easily obtain the high-accuracy, high-brightness large-picture display device by combining plural subordinate pictures by varying the brightness distribution in an overlap area between adjacent subordinate pictures at a high speed. CONSTITUTION:The overlap area 6 indicates a fixed area where the frames of respective subordinate pictures 21 and 22 overlap with each other and in this area 6, the brightness distributions of the subordinate pictures 21 and 22 are varied sequentially to enlarge or reduce the area 7 where the displays of the subordinate pictures 21 and 22 substantially overlap with each other in a direction X in a figure. Normalized brightness distributions are switched with time and the image overlap area 7 is varied in width at a high speed and moved fast to boundary lines 41 and 42 to make the boundary lines inconspicuous as compared with an usual display wherein the boundary lines are fixed, thereby displaying an image which seems to be displayed with a single picture.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large screen display device that displays a large screen by combining a plurality of screens.

0002

2. Description of the Related Art Conventionally, display devices have been provided that display one large screen by combining display screens of a plurality of display devices.

FIG. 11 is a schematic diagram illustrating an example of a display method using a conventional large screen display device.

In the figure, (a) shows an example of a large screen displayed by this display device, and (b) shows a normalized luminance distribution at an arbitrary line α on the display screen. In addition,
The image signal input to the display device is subjected to arithmetic processing based on the luminance distribution in (b) and converted into an output image signal (a).
) is output to the display screen. Therefore, the brightness of the image signal is relatively controlled by the brightness distribution in (b), and the final brightness of the image at each point on the display screen is determined.

Further, in this display device, the large screen that is finally combined is called a main screen 1, and the two screens that make up this main screen 1 are called child screens 21 and 22. Also,
In the figure, 3 indicates a display image, and 4 indicates a boundary between each child screen 21, 22.

[0006] In this display device, two sub-screens 2
The parent screen 1 is synthesized by joining images 1 and 22 with just the right amount.

However, in this method, the child screen 21
, 22 can be physically accurately joined, if there is a slight difference in the brightness 51, 52 of each child screen 21, 22, the boundary 4 will be emphasized due to the Mach effect. However, there is a drawback in that it is easily perceived that the image 3 of the main screen 1 is created by joining the child screens 21 and 22.

[0008] In order to solve this inconvenience, it is sufficient to make the brightness of adjacent sub-screens completely match each other, but in reality, control is complicated because there are many components related to brightness. In addition to this, factors such as replacement of parts and changes over time must also be taken into consideration, making accurate adjustment extremely difficult.

[0009] In order to solve this problem, for example, as disclosed in Japanese Patent Laid-Open No. 64-27374,
A device has been proposed in which the boundaries of each child screen overlap. FIG. 12 is a schematic diagram illustrating a display method of such a large screen display device. Note that the same elements as in FIG. 11 above are given the same reference numerals.

In this display device, as shown in (a),
The child screens 21 and 22 overlap each other near their boundaries, and in this overlapping area 6, as shown in (b),
By gently attenuating the brightness distribution of each child screen 21, 22, the boundary line is made less noticeable.

[0011]

[Problem to be Solved by the Invention] However, even in the device in which the overlapping area 6 is provided, new boundary lines 41 and 42 are fixed at the boundary between the overlapping area and the non-overlapping area. This results in noticeable problems.

That is, changing the brightness distribution in the overlapping area 6 of each child screen 21, 22 under certain conditions and harmonizing this overlapping brightness with the brightness of other areas depends on the characteristics of each display device. This is extremely difficult due to variations, complexity of adjustment, etc., and it has been impossible to make the border line completely invisible.

According to the present invention, when a plurality of sub-screens are combined, their boundaries can be made inconspicuous without requiring strict control of the brightness level, and the screen can be displayed as if it were displayed on a single screen. The purpose is to provide a large screen display device that can perform

[0014]

[Means for Solving the Problems] The present invention provides a large screen display device that displays a large screen by combining child screens output from a plurality of display devices, in which each child screen overlaps at the boundary between adjacent child screens. The present invention is characterized in that the brightness distribution of each child screen in this overlapping area is changed at high speed.

[0015]

Embodiment FIGS. 1 to 3 are schematic diagrams illustrating a display method according to a first embodiment of the present invention. Note that elements common to those in the above-mentioned prior art will be described with the same reference numerals.

The present invention can be applied to an apparatus that displays a main screen by combining any number of child screens, but in this embodiment, a case will be described in which two child screens are combined.

The display device of this embodiment has each child screen 21,
The brightness distribution within the 22 overlapping regions 6 is changed over time. In other words, the overlapping area 6 in this embodiment indicates a fixed area where the frames of each child screen 21 and 22 overlap with each other, and within this area 6, the brightness distribution of each child screen 21 and 22 is sequentially adjusted. By changing
Area 7 where the displays of each child screen 21 and 22 substantially overlap
is widened or narrowed in the x direction in the figure. In the following description, the overlapping area 6 of each child screen 21 and 22 will be referred to as a frame overlapping area, and the area 7 where images substantially overlap will be referred to as an image overlapping area.

Furthermore, in the image overlap area 7, the brightness distribution of each child screen 21, 22 gradually becomes smaller and is absorbed by the other child screen, and the sum of the brightnesses of both is larger than that of the other child screen. The brightness is adjusted to be equal to the brightness of the non-overlapping area. Although the brightness distribution of each child screen 21 and 22 is shown to decrease linearly in FIGS. 1 to 3, it may change in a curved manner.

To explain using the illustrated example, at time t shown in FIG.
0, the image overlapping area 7 is the frame overlapping area 6
matches. In this case, the width W0 of the region 7 is the maximum, and the boundaries 41 and 42 substantially created in the displayed image by the image overlapping region 7 are in the widest state.

Furthermore, at time t1 shown in FIG.
The image overlap area 7 is narrower than the frame overlap area 6,
It has an intermediate width W1. Therefore, the boundary lines 41, 4
2 is also in a slightly narrowed state.

Furthermore, at time t2 shown in FIG. 3, the image overlapping area 7 becomes narrowest and has the minimum width W2. Therefore, the boundary lines 41 and 42 are closest to each other.

[0022] Such brightness distribution conversion control is as follows:
This is performed at high speed by a brightness adjustment circuit, which will be described later. For example, if the image signal is a normal NTSC signal, it is controlled at a speed of 1/30 second or 1/60 second on a frame-by-frame or field-by-field basis. Furthermore, when displaying with an image signal converted to twice the field speed, it is possible to control at an even higher speed.

As described above, by temporally switching the normalized luminance distribution, rapidly changing the width of the image overlapping region 7, and moving the boundaries 41 and 42 at high speed, the boundaries can be changed as before. Compared to when the image is stationary, the border line can be made less noticeable, and the image can be displayed as if it were displayed on a single screen.

FIG. 4 is a block diagram showing the structure of an apparatus that implements the display method described above.

This display device includes a pair of displays 10a and 10b that display each child screen 21 and 22, and divides one image signal to generate an image signal for each child screen 21 and 22. It has an image signal generator 9 that supplies the display devices 10a and 10b. Each of the displays 10a and 10b is configured as a general projection type display device.

FIG. 5 is a block diagram showing the configuration of the image signal generator 9. As shown in FIG.

This image signal generator 9 includes an A/D converter 9
1, an image division processing circuit 92, a frame memory 93,
94, brightness adjustment circuits 95, 96, and D/A converter 97
, 98.

The image signal input to this image signal generator 9 is first converted from an analog signal to a digital signal by an A/D converter 91 so that various processes can be easily performed within this device 9. . Next, this digital image signal is sent to the image division processing circuit 92, and each sub-screen 21,
22 and stored in frame memories 93 and 94 for each child screen 21 and 22, respectively.

The image signals stored in each frame memory 93 and 94 are sent to brightness adjustment circuits 95 and 9, respectively.
6, and after being subjected to the luminance distribution processing described above, D
/A converters 97 and 98 convert the digital signal back into an analog signal, and send it to each of the above-mentioned displays 10a and 10b.

FIG. 6 is a schematic diagram conceptually showing the processing in the brightness adjustment circuits 95 and 96.

The brightness adjustment circuits 95 and 96 include a conversion table group 11 for obtaining a normalized brightness signal, and a switching control circuit 12 for selecting a conversion table for each frame in order to change the brightness distribution as described above. and frame memory 93 based on the luminance signal of the selected conversion table.
, 94.

In other words, the conversion table group 11 includes a plurality of conversion tables composed of brightness distribution data each having its own overlapping area 7 in order to perform the above-described conversion control of the brightness distribution. In addition, in FIGS. 1 to 3 above,
Although only three brightness distributions have been illustrated, in reality, the brightness distributions are switched more precisely in multiple stages, and a corresponding conversion table for the number of surfaces is prepared.

The arithmetic circuit 13 also uses the normalized luminance signal obtained from the conversion table and the frame memory 93.
, 94 to obtain an output image signal.

That is, the relationship between the brightness at the coordinate (x, y) point on the screen is that the normalized brightness signal at this point is Txy, the input image signal is Ixy, and the output image signal is Oxy.
If y, then Oxy=Ixy×Txy.

As a result, the input image signal is controlled by the brightness signal of the conversion table, and is output as an image with a changed brightness distribution in the overlapping region 6, as shown in FIGS. 1 to 3.

FIGS. 7 to 9 are schematic diagrams illustrating a display method according to a second embodiment of the present invention. Note that elements common to those in the first embodiment will be described with the same reference numerals.

In the first embodiment, the brightness distribution of each child screen 21 and 22 in the frame overlap area 6 is changed only in the x direction, but in this second embodiment, the brightness distribution is changed in both the x and y directions. This changes the brightness distribution. In other words,
The image overlapping area 7 of the first embodiment is formed in a rectangular shape, and only the width thereof widens or narrows, whereas the image overlapping area 7 of this second embodiment is formed into a rectangular shape.
is formed in a zigzag shape with a triangular waveform within, and at time t0
As time passes from ~t3, it is displaced in the y direction. Therefore, when a certain observation point 8 is set, the overlapping region 7 changes over time in both the x direction and the y direction.

If virtual lines S0 to S2 are set in the direction in which the difference in brightness appears at observation point 8, the direction will change over time as shown in FIGS. 7 to 9.

Therefore, according to this second embodiment, the overlapping region 7 is displaced at high speed in both the x and y directions, and the direction in which the brightness difference appears also changes and disperses at high speed, so that subtle brightness differences are eliminated. Since effects that cancel each other out can be expected, the boundaries 41 and 42 of each child screen 21 and 22 can be made more It can be made difficult to perceive.

In practice, it is desirable to set the period T of the zigzag shape shown in FIG. 7 to a size that is not perceptible to the observer. This may be determined empirically depending on the screen size, etc.

Also in this second embodiment, as a method of changing the overlapping area 7, the above-described brightness adjustment circuit by switching the conversion table can be used. In other words, all you need to do is change the contents of each conversion table.

Note that the shape of the overlapping region 7 is not limited to the example shown in the drawings, and may appropriately adopt, for example, a zigzag shape such as a sinusoidal waveform, a more random distribution shape, or the like.

Furthermore, in the above embodiment, the case where two sub-screens are combined has been described, but the case where more sub-screens are combined vertically and horizontally in a matrix will be briefly described.

FIG. 10 shows m×n child screens 21, 22,
23, 24, . . . are combined in m rows and n columns to form a main screen 1. FIG.

In the figure, a shaded area 14 is a frame overlap area between two child screens, and a shaded area 15 is a frame overlap area between four child screens.

Regarding the frame overlapping area 14, the method explained in the above embodiment is used as is, and the image overlapping area 7
, and change it over time to make the boundary part difficult to perceive. Also, regarding the frame overlap area 15, 4
The above-mentioned image overlap area 7 is set under the condition that the sum of the brightness of the corner parts of the two sub-screens is equal to the brightness of the other areas, and this is changed over time to make the boundary part difficult to perceive. .

Therefore, the present invention can be applied to a large screen display device combining any number of screens.

[0048]

According to the present invention, in a display device that displays a main screen by combining a plurality of child screens, each child screen can be improved by rapidly changing the brightness distribution in the overlapping area between adjacent child screens. Boundaries become less perceivable,
A display state similar to that of an image displayed on a single screen can be obtained. Therefore, by combining a plurality of child screens, it is possible to easily realize a large screen display device with high precision and high brightness.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram illustrating a display method according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a display method according to the first embodiment.

FIG. 3 is a schematic diagram illustrating a display method according to the first embodiment.

FIG. 4 is a configuration diagram showing the configuration of an apparatus that implements the display method according to the first embodiment.

FIG. 5 is a block diagram showing the configuration of an image signal generator of the display device shown in FIG. 4;

6 is a schematic diagram conceptually showing processing in a brightness adjustment circuit of the image signal generator shown in FIG. 5. FIG.

FIG. 7 is a schematic diagram illustrating a display method according to a second embodiment of the present invention.

FIG. 8 is a schematic diagram illustrating a display method according to the second embodiment.

FIG. 9 is a schematic diagram illustrating a display method according to the second embodiment.

FIG. 10 is a schematic diagram illustrating the configuration of a main screen according to a third embodiment of the present invention.

FIG. 11 is a schematic diagram illustrating an example of a display method using a conventional large screen display device.

FIG. 12 is a schematic diagram illustrating another example of a display method using a conventional large screen display device.

[Explanation of symbols]

1...Main screen, 3...Image, 4, 41, 42...Border line, 6...
Frame overlapping area, 7... Image overlapping area, 9... Image signal generator, 10a, 10b... Display device, 11... Conversion table,
12...Switching circuit, 13...Arithmetic circuit, 21-24...Sub screen, 51, 52...Brightness distribution, 95, 96...Brightness adjustment circuit.

Claims (1)

[Claims] Claim 1: In a large screen display device that displays a large screen by combining child screens output from a plurality of display devices, an area where each child screen overlaps is provided at the boundary between adjacent child screens, and an area where each child screen overlaps is provided. 1. A large screen display device characterized by rapidly changing the brightness distribution of each child screen in an area.