JP2008268246A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problems: there are areas where display is impossible in a display panel requiring to be sealed such as a plasma panel and a liquid crystal panel, and when the display panels are used as an image display unit and parallel display is performed to attempt to obtain a large image display device, the areas where display is impossible form joints and its presence is obtrusive. <P>SOLUTION: The presence of the joints is made inconspicuous by adding the required number of black line display with approximately the same width as that of the joints into a video signal by providing an insertion part which inserts black lines with approximately the same width as that of a non-image display area where an image can not be displayed into the image display area of the display panel, the non-image display area being generated between image display areas of a plurality of display panels constituting the image display unit. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image display device in which a plurality of image display units are arranged in parallel, and particularly to a large-sized one.

  In order to obtain a large image display device, means for displaying image display units in parallel is known. The LED display device disclosed in Patent Document 1 uses an LED panel as an image display unit. Since the LED panel has a structure in which the wiring of the LED element protrudes to the back side (side not viewed), the LED element can be disposed at an arbitrary position on the display surface of the LED panel. Accordingly, as shown in FIG. 15A, the spatial distance between pixels is set to d, and the relationship between the outermost LED of the image display unit and the length D to the end of the image display unit is expressed as D = d / By setting it to 2, when the plurality of LED panels are juxtaposed without gaps, the presence of joints in the entire image display device does not feel uncomfortable (FIG. 15B).

  The size of the LED element is a full-color display and a minimum of 2 mm square, but the pixel pitch is about 30 mm in a main display of a public stadium. Although this is a large value at first glance, there is no problem as an ultra-large display for viewing from a distance. From the above, the LED panel is suitable for an image display device that displays image display units in parallel.

  Next, the image display device disclosed in Patent Document 2 uses a projector as an image display unit. A projector can obtain a large screen without joints by displaying projected images in parallel on a large screen without any gaps, and is also suitable for an image display device that displays image display units in parallel.

  However, if the screen to be projected is not composed of a single large material, joints are produced. In addition, there are other drawbacks such as difficulty in positioning due to the projection type, and the depth of the device is large.

  On the other hand, in recent years, the market for flat-screen televisions such as plasma televisions and liquid crystal televisions for consumer use is rapidly expanding due to the influence of the start of digital broadcasting. While these features have been further enhanced by thinness, high brightness, and high definition, price competition has been fierce in recent years, achieving a cost reduction of about 20% per year.

  As described in Patent Document 3, the structure of a plasma panel that performs display on a plasma television has a discharge gas such as xenon sealed inside the panel portion. In order to hold the xenon gas, there are regions that do not participate in display (non-displayable regions) on the four sides of the plasma panel. The pixel size of plasma panels that are widely distributed is about 0.5 to 0.8 mm.

On the other hand, as shown in FIG. 2 of Patent Document 4, the structure of a liquid crystal panel that performs display on a liquid crystal television has a liquid crystal material sealed inside the panel portion. In order to hold the liquid crystal material, a sealing material is necessary on the four sides of the liquid crystal panel, and the region of the sealing material is a region not related to display (non-image display region). Note that the pixel size of a widely used liquid crystal panel for television is about 0.3 to 0.6 mm.
JP 2006-189606 A JP-A-7-209756 JP 2004-69734 A Japanese Patent Laid-Open No. 11-44885

  As described above, in the plasma panel and the liquid crystal panel, the non-displayable area (non-image display area) is unavoidable. There is no problem when displaying an image with only one image display unit. First, FIG. 1A shows an example in which figures are first displayed on one plasma panel or liquid crystal panel. In this case, it is possible to display a figure without any particular problem.

  Next, FIG. 1 shows an example in which a figure is displayed using a plurality of these plasma panels or liquid crystal panels. However, when a system is used in which a plurality of image display units are arranged in parallel, as shown in FIG. The non-displayable area forms a joint, and its presence is an obstacle. For this reason, it has been considered unsuitable for a method of displaying image display units in parallel.

  However, in spite of having the cost merit due to the recent price reduction and the display performance that can withstand TV applications such as brightness and definition, it is not used in the method of displaying image display units in parallel. The large image display device is inefficient in terms of cost and performance.

  In solving this problem, as shown in FIG. 1C, the image display apparatus of the present invention adds the necessary number of black line displays having the same width as the joint to the presence of the joint. It is characterized by making it inconspicuous.

  It is possible to obtain a large-sized image display device that has a wide range of choices of image display units, low cost, high display performance, and does not mind joints.

  The present invention will be described below with reference to the drawings.

(Embodiment 1)
First, the configuration of the liquid crystal display device of the present invention will be described with reference to the block diagram of FIG. In the first embodiment, 3 × 3 image display units are arranged in parallel. However, the present invention is not limited to this, and any image display unit N × N (N is 2 or more). N × M (N and M are integers greater than or equal to 1 and N and M are different integer values) depending on the location. In addition, signal wiring, power supply wiring necessary for operation, and the like are on the back side (side not viewed) and do not affect viewing. In addition, although the present invention will be described with respect to a liquid crystal display device, the present invention is not limited to this, and can be applied to an applicable panel such as a plasma display.

  The liquid crystal display device of the present invention includes an image processing unit 301 that inputs a received video signal and display number information, and an image display unit 302 that displays a video signal described later in the image processing unit 301. As described above, the image display unit 302 includes a plurality of display panels.

  First, the image processing unit 301 will be described. The image processing unit 301 receives an input video signal, performs image enlargement, region division processing, and the like, and outputs a video signal to be displayed to each of the image display units 1A to 3C. Specifically, in the present embodiment, since the image display unit is composed of 3 × 3 images, an image output to one display panel is usually tripled in the vertical and horizontal directions. Further, the image processing unit 301 receives information on the number of displays p, which will be described later, and adds a black line display having substantially the same width as the joint generated from the structure of the image display unit 302 to the video signal. The features of the present invention will be described in detail below.

  The dimensions of the image display unit 302 are assumed as shown in FIG. It is assumed that the width of an area in which an image can be displayed is W, the height is H, and there are non-displayable areas having a width E due to sealing on four sides. The width of the non-displayable area does not need to be the same on the four sides, but is set to be the same here for simplicity of explanation. Further, it is assumed that an area where an image can be displayed includes pixels of horizontal: h [pixel] and vertical: v [pixel]. Then, the size of one pixel is horizontal: W / h and vertical: H / v.

  When a plurality of such display panels are arranged in parallel to constitute the image display unit 302 as shown in FIG. 3, the joint width between the image display units is 2 × E. Therefore, if a line having the same width as the joint is displayed on the image display unit, a black line is displayed with a width of horizontal: 2 × E × h ÷ W [pixel] and vertical: 2 × E × v ÷ H [pixel]. If you do, you can get a display that mimics the joint. Since the width of the black line varies depending on the joint width of the display panel constituting the image display unit 302, the joint width of the image display unit 302 is recorded in advance in a recording unit (not shown) by a user setting or the like. Keep it.

  As a second calculation method, in the vertical direction, a black line is displayed for each length calculated by y = {H + 2E (1-z)} / z [length, mm, etc.], and the horizontal direction In, it is also possible to display a black line for each length calculated by x = {W + 2E (1-z)} / z [length, mm, etc.]. Also, the values of x and y calculated by the second calculation method are calculated by setting x ′ = x × (v / H) [pixel] and y ′ = y × (h / W) [pixel]. It is also possible to display a black line with a specified width per pixel. Here, z indicates the number of displays, but is a value obtained by subtracting 1 from p described above, and is expressed using another variable z for distinction. Hereinafter, the second calculation method will be described with reference to FIG. 4 using actual specific values.

  FIG. 4 is a diagram for explaining a black line display region when a 42-inch display panel is used. In this 42-inch display panel, the height including the display area and joint width is 700 [mm], the horizontal width is 1080 [mm], and the joint width E is 50 [mm]. Is 600 [mm] and the width W is 980 [mm]. The number of pixels is assumed to be 1280 × 720 [pixels]. FIG. 5 shows the case where the number of displays z is 2 (when converted to p, 1), FIG. 6 shows the case where the number of displays z described above is 3 (when converted with p, 2), and FIG. A case where z is 4 (3 in terms of p) is shown.

  First, the case of FIG. 5 will be described. In this case, one black line is displayed on the display panel. First, the vertical direction will be described. From the above formula, y = {600 + 2 × 50 (1-2)} ÷ 2 = 250 [mm]. Therefore, the display panel displays a black line of 100 [mm] at a position of 250 [mm] from the upper end of the screen, further displays a screen of 250 [mm], and further displays the outer portion (joint) of the image display unit. 100 [mm] corresponding to two widths) exists, and the same configuration is repeated thereafter.

  Next, the horizontal direction will be described. From the above calculation formula, x = {980 + 2 × 50 (1-2)} / 2 = 440 [mm]. Therefore, the display panel displays a black line of 100 [mm] at a position of 440 [mm] from the left end of the screen, and further displays a screen of a period of 440 [mm], and displays the outer portion (joint width) of the image display unit. ) 100 [mm], which is equivalent to two, exists, and the same configuration is repeated thereafter.

  As a result, it is possible to display a black line having the same width as the joint width generated when the display panel is joined to the display panel, and a plurality of display panels are combined and used as one image display unit 302. In this case, it becomes possible to hide the presence of joints.

  Next, the case of FIG. 6 will be described. In this case, two black lines are displayed on the display panel. First, the vertical direction will be described. From the above calculation formula, y = {600 + 2 × 50 (1-3)} ÷ 3 = 133 [mm]. Therefore, the display panel displays a black line of 100 [mm] at a position of 133 [mm] from the upper end of the screen, further displays a screen of 133 [mm], and further displays 100 [mm] on the display panel. A black line is displayed, a screen of 133 [mm] is displayed, and 100 [mm] corresponding to two outer portions (joint widths) of the image display unit exists. Repeated.

  Next, the horizontal direction will be described. From the above formula, x = {980 + 2 × 50 (1-3)} ÷ 3 = 260 [mm]. Therefore, on the display panel, a black line of 100 [mm] is displayed at a position 260 [mm] from the left end of the screen, a screen of a period of 260 [mm] is further displayed, and 100 [mm] is further displayed on the display panel. ] Is displayed, a 260 [mm] period screen is displayed, and 100 [mm] corresponding to two outer portions (joint widths) of the image display unit exists. A similar configuration is repeated.

  As a result, it is possible to display a black line having the same width as the joint width generated when the display panel is joined to the display panel, and a plurality of display panels are combined and used as one image display unit 302. In this case, it becomes possible to hide the presence of joints.

  Next, the case of FIG. 7 will be described. In this case, three black lines are displayed on the display panel. First, the vertical direction will be described. From the above formula, y = {600 + 2 × 50 (1−4)} ÷ 4 = 75 [mm]. Accordingly, the display panel displays a black line of 100 [mm] at a position of 75 [mm] from the upper end of the screen, further displays a screen of 75 [mm], and further displays 100 [mm] on the display panel. A black line of 75 [mm], a screen of a period of 75 [mm], a black line of 100 [mm] on the display panel, and a screen of a period of 75 [mm], There is a configuration in which 100 [mm] corresponding to two outer portions (joint width) of the image display unit exists, and the same configuration is repeated thereafter.

  Next, the horizontal direction will be described. From the above calculation formula, x = {980 + 2 × 50 (1−4)} ÷ 4 = 170 [mm]. Therefore, the display panel displays a black line of 100 [mm] at a position of 170 [mm] from the left end of the screen, further displays a screen of 170 [mm], and further displays 100 [mm] on the display panel. ], A black screen of 170 [mm] is displayed, a black screen of 100 [mm] is further displayed on the display panel, and a black screen of 170 [mm] is displayed. The display has a configuration in which 100 [mm] corresponding to two outer portions (joint width) of the image display unit exists, and the same configuration is repeated thereafter.

  As a result, it is possible to display a black line having the same width as the joint width generated when the display panel is joined to the display panel, and a plurality of display panels are combined and used as one image display unit 302. In this case, it becomes possible to hide the presence of joints.

  In the above description, the description is based on the distance [mm] on the display panel. However, the present invention is not limited to this, and the number of pixels using the above-described conversion formula of x ′ and y ′. Of course, it is also possible to control.

  Next, consider the number of black line displays displayed on the image display unit. The number of displays is p [lines], and examples of p = 2 to 5 [lines] are shown in FIGS. In the description of FIG. 8 to FIG. 11, an example in which 2 × 2 image display units are arranged in parallel has been described, but the present invention is not limited to this case, and is configured by the number of display panels other than this. The same applies to the image display unit.

  The following tendencies can be easily grasped from FIGS. The larger the display number p, the finer the image, and when the image display units are arranged in parallel, there is an advantage that the original image display unit is less noticeable. There is a disadvantage that the luminance is lowered. On the other hand, when the display number p is small, the fineness is reduced, and when the image display units are arranged in parallel, there is a disadvantage that the joints of the image display units themselves become conspicuous, while the area usable for video display is wide. Therefore, there is an advantage that the display luminance is increased.

  From this, in view of the installation location and application, the display number p may be set in accordance with the required level of definition and display brightness. As a specific configuration, in the configuration of the liquid crystal display device shown in FIG. 2, the user can freely set the display number p input to the image processing unit 301 by using a device such as a remote controller (not shown). This can be realized by a configuration that enables this.

  Further, since it may be inconvenient for the user to set with a remote controller or the like, the display number p can be automatically set on the liquid crystal display device side. In this case, at the time of manufacturing the liquid crystal display device, the display number p may be determined to be a fixed value. For example, a lightness detection unit (not shown) is provided in the liquid crystal display device according to the ambient brightness or the like. It would be even better if it could be changed during use. When a pixel display unit is formed by combining a plurality of display panels as in the present invention, it is more likely to be used outdoors than indoors. The user convenience is very high.

  Note that this display number p is either set by the user using a device such as a remote control or automatically set by using the brightness detection unit. (Not shown).

  If the joint width does not become an integer multiple of pixels, or if the number of pixels in the image display area divided into p + 1 by displaying p black line displays does not become an integer, the image is displayed as much as possible. It is good to adjust arbitrarily within one pixel of the display unit. Here, the present invention assumes a large-sized image display device that is viewed from a certain distance, and one pixel in the image display unit is sufficiently small relative to the entire image display device, which greatly deteriorates the display image quality. This is because there is not.

  The display number p can be set separately in the horizontal direction and the vertical direction. This will be described with reference to FIG. FIG. 12 shows a case in which black line display of horizontal 15 [lines] and vertical 8 [lines] is added to an image display unit whose aspect ratio is (width: height) = (16: 9). . By doing so, it is possible to bring the appearance closer to the most common display having square pixels.

  In the first embodiment described above, when a black line is displayed in the display panel, a black line having the same width as the joint is provided so as not to be concerned about the joint of the display panel. However, the present invention is not limited to this, and it is sufficient that the black line has substantially the same width as the joint. With such a configuration, it is possible to provide a black line even when the joint width is not an integral multiple of the pixel.

  As described above, a large-sized display device that does not mind joints even when a display panel having a non-displayable region is used as an image display unit by adopting the configuration of the liquid crystal display device described in Embodiment 1. Can be obtained.

(Embodiment 2)
In the configuration described in the first embodiment, the black line display is added to the display area of the display panel to make the original joint of the image display unit inconspicuous. On the other hand, the black line display is given. As a result, there is a drawback that the display luminance is lowered. Even in that case, there is no problem as long as the original display luminance of the image display unit is high and the necessary luminance can be obtained, but if the display luminance of the image display unit is low, the necessary luminance can be obtained. In some cases, the screen becomes dark on the whole. Therefore, the second embodiment provides a countermeasure against this defect.

  First, the configuration of the liquid crystal display device of the present invention will be described with reference to FIG. As shown in FIG. 13, the liquid crystal display device according to the second embodiment also includes an image processing unit 301, an image display unit 302, and an image quality correction unit 303 as in the first embodiment. Here, in the second embodiment, in addition to the configuration of the first embodiment, the image processing unit 301 is provided with an image quality correction unit 303. To solve the problem. This point will be described in detail below.

  In general, the relationship between the video signal and the display luminance of the image display unit (hereinafter referred to as gamma characteristic) is as shown in FIG. This is a so-called gamma curve and is often an exponential curve around 2.2.

  On the other hand, in the present invention, the display luminance is lowered by providing the black line display, and the gamma characteristic is as shown in FIG. Here, the display luminance indicates the luminance when actually displayed on the image display panel. In FIG. 14B, the characteristics of FIG. 14A are indicated by broken lines for reference. How much the display luminance decreases can be obtained by calculation from the relationship between the total area of the added black line display and the display area of the image display unit.

  Therefore, in the present embodiment, the conversion is performed so that the gamma characteristic becomes as shown in FIGS. In FIG. 14 (c) to FIG. 14 (e), the singularities of FIG. 14 (a) and FIG. 14 (b) are indicated by broken lines for reference. Any conversion means can be used, but it can be performed by digital signal processing using a lookup table, for example. FIG. 14 (c) shows a bright display by reducing the exponent of the exponent curve, FIG. 14 (d) shows an attempt to maintain the curve of FIG. 14 (a) as much as possible, and FIG. 14 (e) shows a diagram. 14 (d), but devised so that gradation can be expressed even in a region where the input signal is large.

  Note that these are examples when the present invention is implemented, and FIG. 14 (c) to FIG. 14 (e) may be combined, and the gamma characteristic obtained as a result of conversion is more than that of FIG. 14 (b). If it is above, an improvement effect can be obtained.

  Note that when the same gamma characteristic is uniformly applied to all the display panels constituting the image display unit 302, the brightness of the entire screen is improved, but the power consumption is increased in proportion to this. In particular, in the case of such a large screen, the power consumption becomes very significant. Therefore, in the present invention, it is also possible to change the brightness for each of the plurality of display panels constituting the image display unit 302 by focusing on the fact that the viewer generally looks at the center portion rather than the end portion of the screen. is there. For example, the brightness of 2B of the image display unit 302 is increased, while the brightness of the other display panels of the image display unit 302 constituting the peripheral portion is reduced. As a result, the power consumption of the entire image display unit can be reduced while improving the display luminance.

  Further, when the degree of conversion is changed according to the number of display lines p, it is possible to maintain average display brightness.

(Embodiment 3)
The present embodiment, like the second embodiment, provides a countermeasure for the defect that the display luminance is lowered by the present invention. Only differences from the second embodiment will be described.

  In the image display device of this embodiment, a transmissive liquid crystal panel including a backlight is used as an image display unit. In this case, the display luminance can be increased relatively easily by increasing the luminance of the backlight. Increasing the brightness of the backlight can be achieved by increasing the number of light sources (generally cold cathode tubes) of the backlight or by increasing the driving voltage of the light source and turning on more power.

  However, there are restrictions respectively, and it is necessary to pay attention to the former for laying area, wiring, and cost increase, and for the latter, increase in power consumption and decrease in efficiency due to temperature rise. Therefore, how much the display brightness is reduced can be calculated from the relationship between the total area of the added black line display and the display area of the image display unit. Display brightness can be maintained.

  Even if the display luminance is not completely maintained, a corresponding effect can be obtained by increasing the luminance of the backlight. Further, it may be combined with the means for converting the gamma characteristic shown in the second embodiment.

  Note that when the above-described backlight is controlled, the luminance of the entire screen is improved, but the power consumption becomes very high in proportion to this. In particular, in the case of such a large screen, the power consumption becomes very significant. Therefore, in the present invention, it is also possible to change the brightness for each of the plurality of display panels constituting the image display unit 302 by focusing on the fact that the viewer generally looks at the center portion rather than the end portion of the screen. is there. For example, the brightness of 2B of the image display unit 302 is increased, while the brightness of the other display panels of the image display unit 302 constituting the peripheral portion is reduced. As a result, the power consumption of the entire image display unit can be reduced while improving the display luminance.

  In the above-described embodiment, the case where the line displayed on the display unit is black has been described. This case has the effect of the present invention in particular, but the present invention is not limited to this. For example, if the joint portion is gray, a gray line is added to the display unit according to the color. It is also possible to adopt a configuration.

  The image display device of the present invention obtains a large screen by arranging display units in parallel, and can use plasma panels and liquid crystal panels that are widely distributed as display units. Useful for improvement.

The figure which shows the screen structure of the display panel at the time of applying this invention The block diagram which shows the structure of this invention The figure which shows the structure of the display panel of this invention The figure which shows the structure of the display panel of this invention The figure which shows the screen structure of the display panel at the time of applying this invention The figure which shows the screen structure of the display panel at the time of applying this invention The figure which shows the screen structure of the display panel at the time of applying this invention The figure which shows the screen structure of the display panel in case the display number p = 2 of this invention. The figure which shows the screen structure of the display panel in case the display number p = 3 of this invention. The figure which shows the screen structure of the display panel in case the display number p = 4 of this invention. The figure which shows the screen structure of the display panel in case the display number p = 5 of this invention. The figure which shows the screen structure of the display panel at the time of applying this invention The block diagram which shows the structure of this invention The figure which shows the gamma characteristic of this invention The figure which shows the structure of the conventional image display unit and an image display apparatus.

Explanation of symbols

301 Image processing unit 302 Image display unit

Claims (10)

An image display device that displays an image by an image display unit configured by combining at least one display panel,
A recording unit for recording a width of a non-image display area where an image generated between image display areas of a plurality of display panels constituting the image display unit cannot be displayed, and a number of the display panels constituting the image display unit;
An image processing unit that performs image processing of a video signal input to each display panel,
The image processing unit is an enlargement / division unit that performs an enlargement or division process on a video signal input to each display panel according to the number of the display panels recorded in the recording unit;
An image display device comprising: an insertion unit that inserts a black line having a width substantially the same as the width of the non-image display region recorded in the recording unit into the image display region of the display panel. The image display device further includes setting means for setting the number of black lines to be displayed in the image display area of the display panel;
A recording unit that records the number of black lines set by the setting unit;
The number of black lines displayed in the image display area of the display panel inserted by the insertion unit is variable according to the number of black lines recorded in the recording unit. Image display device. The image display device further includes a brightness detection unit that detects brightness around the image display unit;
A recording unit storing the number of black lines to be displayed in the image display area of the display panel appropriate for the brightness,
The number of black lines displayed in the image display area of the display panel inserted by the insertion unit is changed according to the number of black lines recorded in the recording unit. Image display device. The image processing unit further includes an image quality correction unit that performs gamma correction of a video signal input to each display panel;
A recording unit that records the predicted luminance from the relationship between the total area of the black line display displayed in the image quality display area and the display area of the image display unit;
The image quality correction unit, when the predicted luminance recorded by the recording unit is less than or equal to a predetermined value, performs gamma correction so that the luminance of the video signal input to each display panel is improved. The image display device according to any one of 1 to 3. The image display device includes a backlight for irradiating the display panel with light,
A recording unit that records the predicted luminance from the relationship between the total area of the black line display displayed in the image quality display area and the display area of the image display unit;
The backlight adjusts the amount of light of the backlight so that the luminance of the video signal input to each display panel is improved when the predicted luminance recorded by the recording unit is equal to or lower than a predetermined value. The image display device according to claim 1. The image display device is configured such that, among the display panels constituting the image display unit, the luminance of the display panel constituting the central portion of the image display unit is set to the luminance of the display panel constituting the end portion of the image display unit. The image quality display device according to claim 4, wherein the image quality display device is set higher than the luminance. N (N is an integer of 2 or more) image display units and an image processing unit. The image display units are arranged vertically, horizontally, or vertically and horizontally to display a larger image than the image display unit. An image display device, characterized in that a black line display having substantially the same width as a joint produced from a structure of a display unit is added to a display image. 8. The image display device according to claim 7, wherein the relationship between the video signal and the display luminance is converted according to the addition of the black line display. 8. The image display device according to claim 7, wherein a transmissive liquid crystal display having a backlight is used as the image display unit, and the luminance of the backlight is increased in accordance with the addition of black line display. Using a transmissive liquid crystal display with a backlight as the image display unit, and combining the conversion of the relationship between the video signal and display luminance and increasing the luminance of the backlight according to the addition of black line display The image display device according to claim 7, characterized in that:

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