Image display device, image display method, and image display program

Abstract

The present invention provides an image display device, an image display method, and an image display program which make it possible to suppress display abnormalities at an end of a display image in a

Description

Title of Invention: IMAGE DISPLAY DEVICE, IMAGE DISPLAY METHOD, AND IMAGE DISPLAY P ROGRAM Technical Field

[0001] The present invention relates to an image display device, an image display method, and a n image display program. Background Art

[0002] Conventionally, as a technology for improving the contrast of a liquid crystal display devic e, a technology has been proposed in which two display panels are stacked, and an image is displ ayed on each display panel based on an input video signal (see, for example, Patent Literature 1). Specifically, for example, the contrast is improved by displaying a color image on a front-side (obs erver-side) display panel of the two display panels arranged one behind the other, and displaying a monochrome image on a rear-side (backlight-side) display panel. Citation List Patent Literature

[0003] [Patent Literature 1] Japanese Unexamined Patent Application Publication No. 2007-310161 Summary of Invention Technical Problem

[0004] However, in the conventional liquid crystal display device described above, there has been a problem in that, for example, in two display panels arranged one behind the other, when an edg e of a display screen is viewed from an oblique direction, an edge of a display image is not displa yed normally due to an influence of a non-image display area of the rear-side display panel. For example, the edge of the display image may become dark, making it appear as if the edge of the o riginal display image is missing (an image loss state). Furthermore, the edge of the display image may become bright, making it appear as if the edge of the original display image is illuminated (a light leakage state).

[0005] An object of the present invention is to provide an image display device, an image display method, and an image display program capable of suppressing a display abnormality at an edge of a display image in an image display device configured by stacking a plurality of display panels. Solution to Problem

[0006] According to the present invention, an image display device having the following configura tion is provided. [1] An image display device, wherein a plurality of display panels are arranged to overlap each oth er, and an image is displayed on each of the display panels, the image display device comprising: a first display panel arranged at a position close to an observer; a second display panel arranged at a position farther from the observer than the first display panel; and an image generation unit configured to generate, based on input image data, first image data for displaying a first image in an image display area of the first display panel, and second image data for displaying a second im age in an image display area of the second display panel, wherein the image display area of the s econd display panel is larger than the image display area of the first display panel, the image disp lay area of the second display panel includes a first display area and a second display area locate d outside the first display area, the image generation unit generates, using a boundary pixel area 1 ocated near a boundary of the first and second display areas as a reference, a second pixel group including a plurality of pixels continuously arranged in a second direction heading toward an outsi de of the second display area, by using a first pixel group including a plurality of pixels continuou sly arranged in a first direction heading toward an inside of the first display area, and a change mode of pixel values in the second direction for the second pixel group is the same as a change mode of pixel values in the first direction for the first pixel group.

[0007] According to the present invention, in the second display panel arranged at the position f arther from the observer than the first display panel, the second pixel group is generated using th e first pixel group using the boundary pixel area located near the boundary of the first and secon d display areas as a reference, such that the change mode of pixel values in the second direction for the second pixel group is the same as the change mode of pixel values in the first direction fo r the first pixel group. Therefore, it is possible to suppress the display abnormality at the edge of the display image when the observer views the edge of the display screen of the image display de vice from the oblique direction.

[0008] Hereinafter, various embodiments of the present invention will be illustrated. The embodi ments shown below can be combined with each other. [2] The image display device according to [1], wherein the image generation unit generates, as an i mage obtained by enlarging an image based on the input image data, an image to be displayed in the first display area. [3] The image display device according to [2], wherein the image to be displayed in the first displa y area is an image obtained by enlarging the image based on the input image data with a precisio n of less than one pixel. [4] The image display device according to any one of [1] to [3], wherein the boundary pixel area in eludes one or more pixels located along the first direction within the first display area from the bo undary of the first and second display areas. [5] The image display device according to any one of [1] to [3], wherein the boundary pixel area in eludes one or more pixels located along the first direction within the first display area from the bo undary of the first and second display areas, and one or more pixels located along the second dire ction within the second display area from the boundary of the first and second display areas. [6] An image display method for displaying an image on each of a plurality of display panels arran ged to overlap each other, the image display method comprising: an image generation step of gene rating, based on input image data, first image data for displaying a first image in an image displa y area of a first display panel arranged at a position close to an observer, and second image data for displaying a second image in an image display area of a second display panel arranged at a po sition farther from the observer than the first display panel, wherein the image display area of the second display panel is larger than the image display area of the first display panel, the image dis play area of the second display panel includes a first display area and a second display area locat ed outside the first display area, in the image generation step, a second pixel group including a pl urality of pixels continuously arranged in a second direction heading toward an outside of the sec ond display area is generated by using a first pixel group including a plurality of pixels continuou sly arranged in a first direction heading toward an inside of the first display area, using a bounda ty pixel area located near a boundary of the first and second display areas as a reference, and a change mode of pixel values in the second direction for the second pixel group is the same as a c hange mode of pixel values in the first direction for the first pixel group. [7] An image display program that causes a processor to execute the image display method accordi ng to [6].

[0009] According to the present invention, in an image display device configured by stacking a plurality of display panels, a display abnormality at an edge of a display image can be suppressed. Brief Description of Drawings

[0010] FIG. 1 is a block diagram showing a functional configuration of an image display device 10 according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing a positional relationship between a display unit 30 of the image display device 10 and an observer's viewpoint eO. FIG. 3 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and the observer's viewpoint eO. FIG. 4 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and an observer's viewpoint el. FIG. 5 is a diagram showing examples of image display areas A0, Al, and A2 corresponding to respective widths W0, Wl, and W2 when a second display panel 32 is viewed from a normal direction of a stacked display panel. FIG. 6 is a diagram showing a concept of enlarging and displaying a second image generated with a size of the image display area A0 to a size obtained by adding the image display area A0 and the image display area Al. FIG. 7 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and the observer's viewpoint eO when a second image generated with the size of the image display area A0 is displayed, and the image display area Al and the image display area A2 are displayed in solid black. FIG. 8 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and the observer's viewpoint eO when a second image generated with the size of the image display area A0 is enlarged to a size obtained by adding the image display area A0 and the image display area Al and displayed, and the image display area A2 is displayed in solid black. FIG. 9 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and the observer's viewpoint el when the observer views an edge of the stacked display panel. FIG. 10 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and an observer's viewpoint e2 when the observer views the edge of the stacked display panel. FIG. 11 is a diagram illustrating an example of a predetermined second extension process. FIG. 12 is a diagram illustrating an example of the predetermined second extension process. FIG. 13 is a diagram illustrating an example of the predetermined second extension process. FIG. 14A is a diagram showing an example of an image showing an edge of the image display area Al after a predetermined first extension process is performed by a first extension unit 25. FIG. 14B is a diagram showing an example of an image showing the edge of the image display area Al and the image display area A2 after the predetermined second extension process is performed by a second extension unit 26 using the image shown in FIG. 14A. FIG. 14C is a diagram showing an example of an image showing the edge of the image display area Al and the image display area A2 after a process different from the predetermined second extension process by the second extension unit 26 is performed using the image shown in FIG. 14A. FIG. 15A is a diagram showing an example of an image showing an edge of the image display area Al after the predetermined first extension process is performed by the first extension unit 25. FIG. 15B is a diagram showing an example of an image showing the edge of the image display area Al and the image display area A2 after the predetermined second extension process is performed by the second extension unit 26 using the image shown in FIG. 15A. FIG. 15C is a diagram showing an example of an image showing the edge of the image display area Al and the image display area A2 after a process different from the predetermined second extension process by the second extension unit 26 is performed using the image shown in FIG. 15A. FIG. 16 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and the observer's viewpoint el when the observer views the edge of the stacked display panel after the predetermined second extension process is performed by the second extension unit 26. FIG. 17 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and the observer's viewpoint e2 when the observer views the edge of the stacked display panel after the predetermined second extension process is performed by the second extension unit 26. FIG. 18 is a flowchart showing an example of an image display process performed by the image display device 10. FIG. 19 is a diagram illustrating an interpolation process performed in the first extension process when the first extension process by the first extension unit 25 is executed after the execution of the second extension process by the second extension unit 26. Description of Embodiments

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Features shown in the embodiments described below can be combined with each other. In addition, an invention can be established independently for each feature.

[0012] FIG. 1 is a block diagram showing a functional configuration of an image display device 10 according to an embodiment of the present invention. As shown in FIG. 1, the image display device 10 is a color liquid crystal display device using three colors of RGB, and includes an image generation unit 20 and a display unit 30 as its configuration. The image generation unit 20 and the display unit 30 are communicably connected to each other by a signal cable.

[0013] Each component of the image display device 10 may be realized by software or hardware. When realized by software, a CPU can realize various functions by executing a computer program. The program may be stored in a built-in storage unit or in a computer-readable non-transitory recording medium. Alternatively, the program stored in an external storage unit may be read out and realized by so-called cloud computing. When realized by hardware, it can be realized by various circuits such as an ASIC, an FPGA, or a DRP (Dynamically Reconfigurable Processor). In this embodiment, various types of information and concepts including them are handled, which are represented by high and low signal values as a binary bit set configured by Os or Is, and communication or calculation can be executed by the software or hardware aspects described above.

[0014] The image display device 10 is equipped with a contrast improvement technology as a technology for improving the contrast of an image displayed by the display unit 30, in which two display panels are stacked, and an image is displayed on each display panel based on input image data (for example, an input video signal). Specifically, the contrast improvement technology is a technology that improves the contrast of a displayed image by displaying a color image on a front-side (observer-side) display panel of the two display panels arranged one behind the other, and displaying a monochrome image on a rearside (backlight-side) display panel.

[0015] FIG. 2 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and an observer's viewpoint eO (an ideal viewpoint serving as a sweet spot, hereinafter the same). As shown in FIG. 2, the display unit 30 includes a light source 33 (backlight) arranged on a back side of the display unit 30, and a plurality of display panels arranged to overlap (stack). The display unit 30 includes, as the plurality of display panels, two liquid crystal panels: a first display panel 31 arranged on a front side of the display unit 30, that is, at a position close to the observer, and a second display panel 32 arranged between the first display panel 31 and the light source 33.

[0016] When viewed from the observer's viewpoint eO located in front of the display unit 30, the second display panel 32 is arranged at a position farther from the observer than the first display panel 31. In the contrast improvement technology, it is necessaiy for light L emitted from an edge side of the light source 33 to pass through the first display panel 31 and the second display panel 32 to reach the observer's viewpoint eO. Therefore, the image display area of the second display panel 32 is larger than the image display area of the first display panel 31 in both a row direction and a column direction, and as shown in FIG. 2, the second display panel 32 has an image display area with a width W outside the first display panel 31 in both the row direction and the column direction. In the following description, an entirety of the plurality of display panels (in this embodiment, the first display panel 31 and the second display panel 32) may be referred to as a "stacked display panel".

[0017] The image generation unit 20 acquires input image data from an input device (not shown), performs a predetermined image process on the acquired input image data to generate first image data and second image data, and outputs the generated first image data and second image data to the display unit 30. The input device is an information processing device (for example, a personal computer) and is configured to be able to output various data such as image data.

[0018] The first display panel 31 of the display unit 30 displays a first image based on the first image data generated by the image generation unit 20, in accordance with a control signal or data sent from the image generation unit 20 via the signal cable. The second display panel 32 of the display unit 30 displays a second image based on the second image data generated by the image generation unit 20, in accordance with the control signal or data sent from the image generation unit 20 via the signal cable. In this embodiment, the first display panel 31 is a color liquid crystal panel and displays the first image, which is a color image. Further, the second display panel 32 is a monochrome liquid crystal panel and displays the second image, which is a monochrome image.

[0019] A desired image is displayed on the stacked display panel by the first display panel 31 and the second display panel 32 displaying the first image and the second image, respectively, and controlling a transmittance of the light L emitted from the light source 33.

[0020] Next, the image display area with the width W that the second display panel 32 has outside the first display panel 31 will be described. As shown in FIGS. 3 and 4, the image display area with the width W can be divided into an image display area Al with a width W1 and an image display area A2 with a width W2.

[0021] First, the image display area Al with the width W1 will be described with reference to FIG. 3. FIG. 3 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and the observer's viewpoint eO. As shown in FIG. 3, the image display area Al with the width W1 corresponds to an observer's viewpoint range that can be practically assumed outside the first display panel 31 in the second display panel 32 when the observer views a central portion of the stacked display panel. The width W1 can be defined by a distance dl between a surface of the first display panel 31 and a surface of the second display panel 32 in the normal direction (vertical direction in the drawing) of the stacked display panel, a distance d2 between the observer's viewpoint eO and the surface of the first display panel 31 in the normal direction of the stacked display panel, and an angle 01 formed by the observer's viewpoint eO and an edge position of the first display panel 31. The width WO corresponds to the width of the first display panel 31, that is, a width of a range where the first display panel 31 and the second display panel 32 overlap.

[0022] Next, the image display area A2 with the width W2 will be described with reference to FIG. 4. FIG. 4 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and an observer's viewpoint el (a viewpoint that deviates from the ideal viewpoint serving as the sweet spot but can be practically assumed, hereinafter the same). As shown in FIG. 4, the image display area A2 with the width W2 corresponds to an observer's viewpoint range that can be practically assumed outside the first display panel 31 in the second display panel 32 when the observer views the edge of the stacked display panel. The width W2 is the maximum width among widths that can be defined by the distance dl between the surface of the first display panel 31 and the surface of the second display panel 32 in the normal direction (vertical direction in the drawing) of the stacked display panel, a distance d3 between the observer's viewpoint el and the surface of the first display panel 31 in the normal direction of the stacked display panel, and an angle 02 formed by the observer's viewpoint el and the edge position of the first display panel 31.

[0023] FIG. 5 is a diagram showing examples of the image display areas AO, Al, and A2 corresponding to the respective widths WO, Wl, and W2 when the second display panel 32 is viewed from the normal direction of the stacked display panel. As shown in FIG. 5, the image display area Al corresponding to the width Wl is located outside the image display area AO corresponding to the width WO, and the image display area A2 corresponding to the width W2 is located outside the image display area Al.

[0024] Here, in the technology for improving the contrast of a displayed image by displaying a color image on the first display panel 31, which is the front-side (observer-side) display panel, and displaying a monochrome image on the second display panel 32, which is the rear-side (backlight-side) display panel, in order to ensure that the first image displayed on the first display panel 31 and the second image displayed on the second display panel 32 are viewed properly overlapped when viewed from the observer's viewpoint eO (the ideal viewpoint serving as the sweet spot) located in front of the display unit 30, it is necessary to enlarge and display the second image, generated with the size of the image display area AO corresponding to the entire image display area of the first display panel 31, to a size obtained by adding the image display area AO and the image display area Al. FIG. 6 is a diagram showing a concept of enlarging and displaying the second image generated with the size of the image display area AO to the size obtained by adding the image display area AO and the image display area Al.

[0025] FIG. 7 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and the observer's viewpoint eO when, in the second display panel 32, the second image generated with the size of the image display area AO is displayed instead of being enlarged, and the image display area Al and the image display area A2 are displayed in solid black. In this case, as a problem that the edge of the display image is not displayed normally due to the influence of the image display area Al of the second display panel 32, for example, the edge of the display image may become dark, making it appear as if the edge of the original display image is missing (an image loss state).

[0026] FIG. 8 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and the observer's viewpoint eO when the second image generated with the size of the image display area A0 is enlarged to the size obtained by adding the image display area A0 and the image display area Al and displayed, and the image display area A2 is displayed in solid black. In this case, for example, the edge of the display image becomes bright, which prevents it from appearing as if the edge of the original display image is missing (the image loss state), and the problem that the edge of the display image is not displayed normally due to the influence of the image display area Al of the second display panel 32 does not occur.

[0027] However, when the second image is enlarged and displayed, there has been a problem in that when the observer views the edge of the stacked display panel, the edge of the display image (the first image) is not displayed normally due to the influence of the image display area A2 of the rear-side second display panel 32. For example, the edge of the display image may become dark, making it appear as if the edge of the original display image is missing (an image loss state). Furthermore, the edge of the display image may become bright, making it appear as if the edge of the original display image is illuminated (a light leakage state).

[0028] FIG. 9 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and the observer's viewpoint el when the observer views the edge of the stacked display panel. As shown in FIG. 9, when a right-side edge (in the drawing) of the display image (the first image) is bright and the image display area A2 corresponding to the width W2 (right side in the drawing) in the second display panel 32 is displayed in solid black, the edge of the display image visible to the observer becomes dark, making it appear as if the edge of the original display image is missing (an image loss state).

[0029] FIG. 10 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and an observer's viewpoint e2 (a viewpoint that deviates from the ideal viewpoint serving as the sweet spot but can be practically assumed, hereinafter the same) when the observer views the edge of the stacked display panel. As shown in FIG. 10, when a left-side edge (in the drawing) of the display image (the first image) is dark and the image display area A2 corresponding to the width W2 (left side in the drawing) in the second display panel 32 is displayed in solid white, the edge of the display image visible to the observer becomes bright, making it appear as if the edge of the original display image is illuminated (a light leakage state).

[0030] Therefore, in this embodiment, the image display device 10 has a configuration capable of suppressing the display abnormality at the edge of the display image even when the observer views the edge of the stacked display panel. Hereinafter, the functional configuration of the image display device 10 will be described with reference back to FIG. 1.

[0031] As shown in FIG. 1, the image generation unit 20 of the image display device 10 includes a linear conversion unit 21, a first image generation unit 22, a first non-linear conversion unit 23, a second image generation unit 24, a first extension unit 25, a second extension unit 26, and a second non-linear conversion unit 27. The first image generation unit 22, the second image generation unit 24, the first extension unit 25, and the second extension unit 26 function as the "image generation unit" of the present invention.

[0032] The linear conversion unit 21 performs a predetermined process on the input image data and outputs the result to the first image generation unit 22 and the second image generation unit 24. Specifically, the linear conversion unit 21 receives, as the input image data, an input signal RGBy in which gradation is expressed by 10 bits for each of R, G, and B components. Here, the input signal RGBy is obtained by applying gamma correction corresponding to a gamma characteristic to the gradation of an input image. The linear conversion unit 21 generates a linear signal RGB by converting each component of the input signal RGBy so as to exhibit a linear characteristic in which luminance increases linearly with an increase in a gradation value. In this embodiment, conversion to the linear signal RGB is performed using three LUTs (Lookup tables) provided for each component. Then, the linear conversion unit 21 outputs the generated linear signal RGB to the first image generation unit 22 and the second image generation unit 24.

[0033] As shown in FIG. 1, the first image generation unit 22 includes an arithmetic unit 22A and a coefficient calculation unit 22B. The arithmetic unit 22A receives the linear signal RGB from the linear conversion unit 21 and receives a coefficient F from the coefficient calculation unit 22B. Then, the arithmetic unit 22A generates a first processing signal RGB' by multiplying the linear signal RGB by the coefficient F, and outputs the generated first processing signal RGB' to the first non-linear conversion unit 23.

[0034] The coefficient calculation unit 22B receives a second processing signal D, which will be described later, from the second image generation unit 24, and outputs the coefficient F associated with the second processing signal D using the LUT. In this embodiment, the light emitted from the light source 33 is transmitted by the second display panel 32 with a transmittance based on the second image data, and further transmitted by the first display panel 31 with a transmittance based on the first image data, thereby realizing a desired transmittance corresponding to the input image data in the stacked display panel. The LUT used by the coefficient calculation unit 22B stores the coefficient F as output data associated with the second processing signal D as input data, based on such a relationship between the transmittances of the first display panel 31 and the second display panel 32.

[0035] The first non-linear conversion unit 23 receives the first processing signal RGB' output from the first image generation unit 22 (the arithmetic unit 22A), and converts the first processing signal RGB' into a first image signal RGB'y, which is a non-linear signal, using an LUT created for each color component based on display characteristics of the first display panel 31. The first image signal RGB'y is output to the display unit 30 as the first image data, and the first image based on the first image data is displayed on the first display panel 31.

[0036] As shown in FIG. 1, the second image generation unit 24 includes a luminance conversion unit 24A and a smoothing processing unit 24B. The luminance conversion unit 24A receives the linear signal RGB output from the linear conversion unit 21, and performs a luminance conversion process of outputting a luminance V based on the gradation value of each pixel in the input image. In this embodiment, the luminance conversion unit 24A determines the maximum gradation value among the gradation values of each color component of each pixel as the luminance, and outputs the luminance V, which is a two-dimensional array of the luminances determined for each pixel, to the smoothing processing unit 24B.

[0037] The smoothing processing unit 24B performs a smoothing process, for example, using an averaging filter, on the luminance V output from the luminance conversion unit 24A to generate the second processing signal D. Then, the smoothing processing unit 24B outputs the generated second processing signal D to the first image generation unit 22 (the coefficient calculation unit 22B) and the first extension unit 25. Note that, compared to a low-pass filter (LPF) such as a Gaussian filter that applies weights according to a distance, the averaging filter makes a gradation gradient in an image after the smoothing process constant.

[0038] The first extension unit 25 generates an image to be displayed in the image display areas AO and Al, which is an image obtained by enlarging an image based on the input image data (specifically, an image subjected to the luminance conversion process and the smoothing process by the second image generation unit 24). The image based on the input image data is a concept including an image represented by the input image data, an image obtained by performing an image process on the image represented by the input image data, and the like.

[0039] In this embodiment, the first extension unit 25 receives the second processing signal D output from the second image generation unit 24 (the smoothing processing unit 24B) and performs a predetermined first extension process. The predetermined first extension process is a process of generating an image II for enlarging and displaying an image 10, which is an image corresponding to the second processing signal D, specifically, an image generated with the size of the image display area A0 corresponding to the entire image display area of the first display panel 31, to the size obtained by adding the image display area A0 and the image display area Al. For example, the first extension unit 25 enlarges an image size of the image generated with the size of the image display area A0 by a predetermined factor (converts the image to have a larger number of pixels than an original size) by interpolating between pixels of the image using a general-purpose image interpolation process (for example, a linear interpolation process, a nearest neighbor interpolation process, a bilinear interpolation process, a trilinear interpolation process, or a bicubic interpolation process). Then, the first extension unit 25 outputs a second processing signal D' corresponding to the enlarged and generated image II to the second extension unit 26.

[0040] The second extension unit 26 receives the second processing signal D' output from the first extension unit 25 and performs a predetermined second extension process. The predetermined second extension process is a process of generating an image 12 to be displayed in the image display area A2 by generating a second pixel group including a plurality of pixels continuously arranged in a second direction (for example, a row or column direction) heading toward an outside of the image display area A2, using a first pixel group including a plurality of pixels continuously arranged in a first direction (for example, a row or column direction) heading toward an inside of the image display area Al, using a boundary pixel area located near a boundary between the image display area Al (corresponding to the "first display area" of the present invention) and the image display area A2 (corresponding to the "second display area" of the present invention) as reference. Then, the second extension unit 26 generates an image 13 by adding the image 12 to an outer peripheral portion of the image II corresponding to the second processing signal D', and outputs a second processing signal D" corresponding to the generated image 13 to the second non-linear conversion unit 27. The vicinity of the boundary between the image display area Al and the image display area A2 means, for example, a region extending from the boundary between the image display area Al and the image display area A2 to at least one side of the image display area Al and the image display area A2.

[0041] Here, a change mode of pixel values (specifically, luminance values) in the second direction for the second pixel group is the same as a change mode of pixel values (specifically, luminance values) in the first direction for the first pixel group. The change mode of pixel values in the second direction for the second pixel group means a manner of change, such as an increase or decrease (including cases of non-monotonic increase or decrease) of pixel values along the second direction when the pixel values of the plurality of pixels included in the second pixel group change, in either an intermediate image (an image obtained in a generation process of a final image) or the final image (an image finally displayed and output) (in this embodiment, the final image). Further, the change mode of pixel values in the first direction for the first pixel group means a manner of change, such as an increase or decrease (including cases of non-monotonic increase or decrease) of pixel values along the first direction when the pixel values of the plurality of pixels included in the first pixel group change, in either the intermediate image (an image obtained in the generation process of the final image) or the final image (an image finally displayed and output) (in this embodiment, the final image).

[0042] FIGS. 11 to 13 are diagrams illustrating examples of the predetermined second extension process. In the example shown in FIG. 11, the boundary pixel area located near the boundaiy between the image display area Al and the image display area A2 includes one pixel 100 (pixel value, specifically luminance value: 255) located along a first direction (for example, a row or column direction, a rightward direction in the drawing) within the image display area Al from the boundaiy between the image display area Al and the image display area A2. In other words, the pixel 100 is one pixel adjacent to the boundary between the image display area Al and the image display area A2 and located within the image display area Al.

[0043] The second extension unit 26 generates, using the boundaiy pixel area as a reference, a second pixel group including a plurality of pixels 103, ..., 104 continuously arranged in a second direction (for example, a row or column direction, a leftward direction in the drawing) heading toward the outside of the image display area A2, by using a first pixel group including a plurality of pixels 101, ..., 102 continuously arranged in the first direction (for example, a row or column direction, the rightward direction in the drawing) heading toward the inside of the image display area Al. Here, the manner of an increase change or a decrease change (a decrease change indicated by 192..... 32 in the example of FIG. 11) of pixel values along the second direction when the pixel values of the plurality of pixels 103, ..., 104 included in the second pixel group change is the same as the manner of an increase change or a decrease change (a decrease change indicated by 192, ..., 32 in the example of FIG. 11) of pixel values along the first direction when the pixel values of the plurality of pixels 101, ..., 102 included in the first pixel group change. Specifically, the second extension unit 26 generates the second pixel group using the first pixel group such that a magnitude order (192, ..., 32) in the second direction of the pixel values of the plurality of pixels 103, ..., 104 included in the second pixel group is the same as (including cases where it is not completely the same) a magnitude order (192, ..., 32) in the first direction of the pixel values of the plurality of pixels 101,..., 102 included in the first pixel group.

[0044] In the example shown in FIG. 12, the boundary pixel area located near the boundary between the image display area Al and the image display area A2 includes one pixel 100 (pixel value, specifically luminance value: 255) located along the first direction (for example, a row or column direction, the rightward direction in the drawing) within the image display area Al from the boundary between the image display area Al and the image display area A2, and one pixel 105 (pixel value, specifically luminance value: 255) which has the same pixel value as the pixel 100 and is located along the second direction (for example, a row or column direction, the leftward direction in the drawing) within the image display area A2 from the boundary. In other words, the pixel 100 is one pixel adjacent to the boundary between the image display area Al and the image display area A2 and located within the image display area Al, and the pixel 105 is one pixel adjacent to the boundary between the image display area Al and the image display area A2 and located within the image display area A2.

[0045] The second extension unit 26 generates, using the boundary pixel area as a reference, a second pixel group including a plurality of pixels 106,..., 107 continuously arranged in the second direction (for example, a row or column direction, the leftward direction in the drawing) heading toward the outside of the image display area A2, by using the first pixel group including the plurality of pixels 101, ..., 102 continuously arranged in the first direction (for example, a row or column direction, the rightward direction in the drawing) heading toward the inside of the image display area Al. Here, the manner of an increase change or a decrease change (a decrease change indicated by 192, ..., 32 in the example of FIG. 12) of pixel values along the second direction when the pixel values of the plurality of pixels 106, ..., 107 included in the second pixel group change is the same as the manner of an increase change or a decrease change (a decrease change indicated by 192, ..., 32 in the example of FIG. 12) of pixel values along the first direction when the pixel values of the plurality of pixels 101, ..., 102 included in the first pixel group change. Specifically, the second extension unit 26 generates the second pixel group using the first pixel group such that a magnitude order (192, ..., 32) in the second direction of the pixel values of the plurality of pixels 106, ..., 107 included in the second pixel group is the same as (including cases where it is not completely the same) a magnitude order (192, ..., 32) in the first direction of the pixel values of the plurality of pixels 101, ..., 102 included in the first pixel group.

[0046] In the example shown in FIG. 13, the boundary pixel area located near the boundary between the image display area Al and the image display area A2 includes one pixel 100 (pixel value, specifically luminance value: 255) located along the first direction (for example, a row or column direction, the rightward direction in the drawing) within the image display area Al from the boundary between the image display area Al and the image display area A2, and a plurality of pixels 108, ..., 109 (pixel value, specifically luminance value: 255) which have the same pixel value as the pixel 100 and are located along the second direction (for example, a row or column direction, the leftward direction in the drawing) within the image display area A2 from the boundary, that is, are continuously arranged.

[0047] The second extension unit 26 generates, using the boundary pixel area as a reference, a second pixel group including a plurality of pixels 110,..., 111 continuously arranged in the second direction (for example, a row or column direction, the leftward direction in the drawing) heading toward the outside of the image display area A2, by using the first pixel group including the plurality of pixels 101, ..., 102 continuously arranged in the first direction (for example, a row or column direction, the rightward direction in the drawing) heading toward the inside of the image display area Al. Here, the manner of an increase change or a decrease change (a decrease change indicated by 192, ..., 32 in the example of FIG. 13) of pixel values along the second direction when the pixel values of the plurality of pixels 110,..., 111 included in the second pixel group change is the same as the manner of an increase change or a decrease change (a decrease change indicated by 192, ..., 32 in the example of FIG. 13) of pixel values along the first direction when the pixel values of the plurality of pixels 101, ..., 102 included in the first pixel group change. Specifically, the second extension unit 26 generates the second pixel group using the first pixel group such that a magnitude order (192,..., 32) in the second direction of the pixel values of the plurality of pixels 110, ..., 111 included in the second pixel group is the same as (including cases where it is not completely the same) a magnitude order (192, ..., 32) in the first direction of the pixel values of the plurality of pixels 101, ..., 102 included in the first pixel group.

[0048] FIG. 14A is a diagram showing an example of an image showing an edge of the image display area Al after the predetermined first extension process is performed by the first extension unit 25. As shown in FIG. 14A, a semi-circular white image exists at the edge of the image display area Al.

[0049] FIG. 14B is a diagram showing an example of an image showing the edge of the image display area Al and the image display area A2 after the predetermined second extension process is performed by the second extension unit 26 using the image shown in FIG. 14A. That is, the second extension unit 26 generates, using the boundary pixel area as a reference, the second pixel group including the plurality of pixels continuously arranged in the second direction (for example, a row or column direction, the leftward direction in the drawing) heading toward the outside of the image display area A2, by using the first pixel group including the plurality of pixels continuously arranged in the first direction (for example, a row or column direction, the rightward direction in the drawing) heading toward the inside of the image display area Al. Here, the manner of an increase change or a decrease change (a decrease change in the example of FIG. 14B) of pixel values along the second direction when the pixel values of the plurality of pixels included in the second pixel group change is the same as the manner of a decrease change of pixel values along the first direction when the pixel values of the plurality of pixels included in the first pixel group change.

[0050] FIG. 14C is a diagram showing an example of an image showing the edge of the image display area Al and the image display area A2 after a process different from the predetermined second extension process is performed by the second extension unit 26 using the image shown in FIG. 14A, as a comparative example with respect to FIG. 14B. The process different from the predetermined second extension process is a process of continuously copying the pixels included in the boundaiy pixel area within the image display area Al in a second direction (for example, a row or column direction, a leftward direction in the drawing) heading toward the outside of the image display area A2. That is, unlike the example of the image shown in FIG. 14B, the pixel values along the second direction of the plurality of pixels included in the second pixel group in the image display area A2 do not change, and the display mode is completely different from the change (specifically, the decrease change) of the pixel values along the first direction (for example, a row or column direction, a rightward direction in the drawing) of the plurality of pixels included in the first pixel group in the image display area Al.

[0051] FIG. 15A is a diagram showing an example of an image showing an edge of the image display area Al after the predetermined first extension process is performed by the first extension unit 25. As shown in FIG. 15A, a white image having a shape extending in a vertical direction in the figure and projecting in a rightward direction in the figure at a center portion in the vertical direction in the figure exists at the edge of the image display area Al.

[0052] FIG. 15B is a diagram showing an example of an image showing the edge of the image display area Al and the image display area A2 after the predetermined second extension process is performed by the second extension unit 26 using the image shown in FIG. 15A. That is, the second extension unit 26 generates, using a boundaiy pixel area as a reference, a second pixel group including a plurality of pixels continuously arranged in a second direction (for example, a row or column direction, a leftward direction in the figure) heading toward the outside of the image display area A2, by using a first pixel group including a plurality of pixels continuously arranged in a first direction (for example, a row or column direction, a rightward direction in the figure) heading toward the inside of the image display area Al. Here, a manner of an increase change or a decrease change (a decrease change in the example of FIG. 15B) of the pixel values along the second direction when the pixel values of the plurality of pixels included in the second pixel group change is the same as a manner of a decrease change of the pixel values along the first direction when the pixel values of the plurality of pixels included in the first pixel group change.

[0053] FIG. 15C is a diagram showing an example of an image showing the edge of the image display area Al and the image display area A2 after a process different from the predetermined second extension process by the second extension unit 26 is performed using the image shown in FIG. 15A, as a comparative example with respect to FIG. 15B. The process different from the predetermined second extension process is a process of continuously copying the pixels included in the boundaiy pixel area within the image display area Al in a second direction (for example, a row or column direction, a leftward direction in the figure) heading toward the outside of the image display area A2. That is, unlike the example of the image shown in FIG. 15B, the pixel values along the second direction of the plurality of pixels included in the second pixel group in the image display area A2 do not change, and the display mode is completely different from the change (specifically, the decrease change) of the pixel values along the first direction (for example, a row or column direction, a rightward direction in the figure) of the plurality of pixels included in the first pixel group in the image display area Al.

[0054] FIG. 16 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and an observer's viewpoint el when the observer views an edge of the stacked display panel after the predetermined second extension process is performed by the second extension unit 26. As shown in FIG. 16, a right-side edge (in the figure) of a display image (a first image) is bright, and the image display area A2 corresponding to the width W2 (the right side in the figure) in the second display panel 32 is also displayed brightly, for example, in solid white, and thus the occurrence of a problem in which the edge of the display image visible to the observer becomes dark, making it appear as if the edge of the original display image is missing (an image loss state), is suppressed.

[0055] FIG. 17 is a schematic diagram showing a positional relationship between the display unit 30 of the image display device 10 and an observer's viewpoint e2 when the observer views the edge of the stacked display panel after the predetermined second extension process is performed by the second extension unit 26. As shown in FIG. 17, a left-side edge (in the figure) of the display image (the first image) is dark, and the image display area A2 corresponding to the width W2 (the left side in the figure) in the second display panel 32 is also displayed darkly, and thus the occurrence of a problem in which the edge of the display image visible to the observer becomes bright, making it appear as if the edge of the original display image is illuminated (a light leakage state), is suppressed.

[0056] From the above, according to the image display device 10 of the present embodiment, a display abnormality (for example, an image loss state or a light leakage state) at the edge of the display image can be suppressed even when an observer views the edge of the stacked display panel.

[0057] The second non-linear conversion unit 27 receives the second processing signal D" output from the second extension unit 26, and converts the second processing signal D" into a second processing signal D" y, which is a non-linear signal, using a LUT created for each color component based on the display characteristics of the second display panel 32. The second processing signal D" y is output to the display unit 30 as a second image data, and a second image based on the second image data is displayed on the second display panel 32.

[0058] FIG. 18 is a flowchart showing an example of an image display process (corresponding to an "image display method" of the present invention) performed by the image display device 10 in the present embodiment.

[0059] First, in a step SI00, the linear conversion unit 21 generates a linear signal RGB converted so as to exhibit a linear characteristic in which luminance increases linearly with respect to an increase in a gradation value for each component of an input signal RGB? (in which gradation is expressed by 10 bits for each of R, G, and B components) received as input image data. Then, the linear conversion unit 21 outputs the generated linear signal RGB to the first image generation unit 22 and the second image generation unit 24. When the process of the step S100 is completed, processes of steps SI 10 and S130 start.

[0060] In a step SI 10, the first image generation unit 22 performs a predetermined first image generation process. Specifically, an arithmetic unit 22A included in the first image generation unit 22 receives the linear signal RGB from the linear conversion unit 21 and receives a coefficient F from the coefficient calculation unit 22B. Then, the arithmetic unit 22A generates a first processing signal RGB' by multiplying the linear signal RGB by the coefficient F, and outputs the generated first processing signal RGB' to the first non-linear conversion unit 23. The coefficient calculation unit 22B receives a second processing signal D output from the second image generation unit 24 in a step S130, and outputs the coefficient F associated with the second processing signal D using a LUT to the arithmetic unit 22A. When the process of the step SI 10 is completed, a process of a step S120 starts.

[0061] In the step S120, the first non-linear conversion unit 23 receives the first processing signal RGB' output from the first image generation unit 22 (the arithmetic unit 22A), and performs a first non-linear conversion process of converting the first processing signal RGB' into a first image signal RGB' y, which is a non-linear signal, using a LUT created for each color component based on the display characteristics of the first display panel 31. Then, the first image signal RGB' y is output to the display unit 30 as the first image data, and the first image based on the first image data is displayed on the first display panel 31.

[0062] In a step S130, a luminance conversion unit 24A included in the second image generation unit 24 receives the linear signal RGB output from the linear conversion unit 21, and outputs a luminance V based on the gradation value of each pixel in the input image to a smoothing processing unit 24B. Subsequently, the smoothing processing unit 24B included in the second image generation unit 24 performs a smoothing process, for example, using an averaging filter, on the luminance V output from the luminance conversion unit 24A to generate a second processing signal D. Then, the smoothing processing unit 24B outputs the generated second processing signal D to the first image generation unit 22 (the coefficient calculation unit 22B) and the first extension unit 25. When the process of the step S130 is completed, a process of a step 8140 starts.

[0063] In a step SI40, the first extension unit 25 receives the second processing signal D output from the second image generation unit 24 (the smoothing processing unit 24B) and performs a predetermined first extension process. The predetermined first extension process is a process of generating an image Il for enlarging and displaying an image 10, which is an image corresponding to the second processing signal D, specifically, an image generated with the size of the image display area A0 corresponding to the entire image display area of the first display panel 31, to a size obtained by adding the image display area AO and the image display area Al. Then, the first extension unit 25 outputs a second processing signal D' corresponding to the enlarged and generated image II to the second extension unit 26. When the process of the step S140 is completed, a process of a step S150 starts.

[0064] In a step S150, the second extension unit 26 receives the second processing signal D' output from the first extension unit 25 and performs a predetermined second extension process. The predetermined second extension process is a process of generating an image 12 to be displayed in the image display area A2 by generating a second pixel group including a plurality of pixels continuously arranged in a second direction (for example, a row or column direction) heading toward the outside of the image display area A2, using a first pixel group including a plurality of pixels continuously arranged in a first direction (for example, a row or column direction) heading toward the inside of the image display area Al, using a boundary pixel area located near a boundary between the image display area Al and the image display area A2 as a reference. Then, the second extension unit 26 generates an image 13 by adding the image 12 to an outer peripheral portion of the image II corresponding to the second processing signal D', and outputs a second processing signal D" corresponding to the generated image 13 to the second non-linear conversion unit 27. When the process of the step S150 is completed, a process of a step SI60 starts.

[0065] In a step S160, the second non-linear conversion unit 27 receives the second processing signal D" output from the second extension unit 26, and performs a second non-linear conversion process of converting the second processing signal D" into a second processing signal D" y, which is a non-linear signal, using a LUT created based on the display characteristics of the second display panel 32. The second processing signal D" y is output to the display unit 30 as the second image data, and the second image based on the second image data is displayed on the second display panel 32. When the processes of the steps S120 and S160 are completed, the image display device 10 ends the image display process shown in FIG. 18.

[0066] As described in detail above, in the present embodiment, an image display device 10 includes a plurality of display panels arranged to overlap each other and displays an image on each of the display panels. The image display device 10 includes a first display panel 31 arranged at a position close to an observer, a second display panel 32 arranged at a position farther from the observer than the first display panel 31, and an image generation unit (a first image generation unit 22, a second image generation unit 24, a first extension unit 25, and a second extension unit 26) that generates a first image data for displaying a first image in an image display area of the first display panel 31 and a second image data for displaying a second image in an image display area of the second display panel 32, based on an input image data. The image display area of the second display panel 32 is larger than the image display area of the first display panel 31. The image display area of the second display panel 32 includes the image display areas A0 and Al (a first display area) and an image display area A2 (a second display area) located outside the image display areas A0 and Al (the first display area). The image generation unit (the second extension unit 26) generates a second pixel group including a plurality of pixels continuously arranged in a second direction (for example, a row direction or a column direction) heading toward the outside of the image display area A2, using a first pixel group including a plurality of pixels continuously arranged in a first direction (for example, a row direction or a column direction) heading toward the inside of the image display area Al, using a boundary pixel area located near a boundary between the image display area Al and the image display area A2 as a reference. A change mode of pixel values in the second direction for the second pixel group is the same as a change mode of pixel values in the first direction for the first pixel group.

[0067] According to the present embodiment configured as described above, in the second display panel 32 arranged at a position farther from the observer than the first display panel 31, the second pixel group is generated using the first pixel group such that a change mode of pixel values in the second direction for the second pixel group is the same as a change mode of pixel values in the first direction for the first pixel group, using the boundary pixel area located near the boundary between the image display area Al and the image display area A2 as a reference, so that a display abnormality (an image loss state, a light leakage state) at the edge of the display image when the observer views the edge of a display screen of the image display device 10 from an oblique direction can be suppressed. Furthermore, since the process of generating the second pixel group heading toward the outside of the image display area A2 using the first pixel group heading toward the inside of the image display area Al is a relatively simple process, the display abnormality at the edge of the display image can be suppressed at a low cost.

[0068] Furthermore, when an input image corresponding to the input image data input to the image display device 10 is, for example, an image of a starry sky, and a star (a bright spot) exists at an edge of the image and the edge of the image is stretched as in the generation method described with reference to FIGS. 14C and 15C, a high luminance area will spread outward, causing a display abnormality such as a light leakage state being perceived by the observer at the edge of the image, or the bright spot at the edge appearing relatively brighter when bright spots of the same luminance exist at the edge and at parts other than the edge of the image. However, when the second pixel group is generated using the first pixel group as in the present embodiment, the edge of the image is not simply stretched, so that the occurrence of the aforementioned display abnormality can be suppressed.

[0069] In the above embodiment, the first extension unit 25 may generate an image to be displayed in the image display areas A0 and Al by enlarging an image based on the input image data (specifically, an image subjected to the luminance conversion process and the smoothing process by the second image generation unit 24) by less than one pixel (for example, 0.2 pixels).

[0070] Further, in the above embodiment, the first extension unit 25 may generate an image to be displayed in the image display areas A0 and Al without enlarging an image based on the input image data.

[0071] Further, in the above embodiment, a first extension process by the first extension unit 25 and a second extension process by the second extension unit 26 may be executed simultaneously, or the first extension process by the first extension unit 25 may be executed after the execution of the second extension process by the second extension unit 26. Further, the second extension process by the second extension unit 26 may be executed immediately before or immediately after the linear conversion process by the linear conversion unit 21, or may be executed immediately before or immediately after the smoothing process by the smoothing processing unit 24B. The execution of the first extension process by the first extension unit 25 may be omitted when the image display area Al can be regarded as minute, or the image display area Al may be set within the image display area AO as needed.

[0072] FIG. 19 is a diagram illustrating an interpolation process (for example, a linear interpolation process) performed in the first extension process when the first extension process by the first extension unit 25 is executed after the execution of the second extension process by the second extension unit 26.

[0073] First, the second extension unit 26 generates a second pixel group including a plurality of pixels 123, 124, ... continuously arranged in a second direction (for example, a row or column direction, a leftward direction in the figure) heading toward the outside of the image display area AO, using a first pixel group including a plurality of pixels 121, 122, ... continuously arranged in a first direction (for example, a row or column direction, a rightward direction in the figure) heading toward the inside of the image display area AO, using a boundary pixel area, which is a single pixel 120 (a pixel value, specifically a luminance value: 255), as a reference. Here, a manner of an increase change or a decrease change of pixel values along the second direction (a decrease change indicated by 192, 32,... in the example shown in FIG. 19) when the pixel values of the plurality of pixels 123, 124,... included in the second pixel group change is the same as a manner of an increase change or a decrease change of pixel values along the first direction (a decrease change indicated by 192, 32, ... in the example shown in FIG. 19) when the pixel values of the plurality of pixels 121, 122,... included in the first pixel group change.

[0074] Next, the first extension unit 25 generates an image enlarged by less than one pixel (for example, 0.2 pixels), the image having a pixel group including the plurality of pixels 120, 121, 122, 123, and 124. In FIG. 19, a pixel value of a pixel 125 after the image enlargement is calculated as 96 by a linear interpolation operation (192x0.4+32*0.6) using the pixel values of the pixels 121 and 122 before the image enlargement. Here, 0.4 and 0.6 are determined as weighting coefficients from a ratio of a degree of overlap of the positions of the pixel 125 and the pixels 121 and 122 in a horizontal direction (for example, a row or column direction) in the figure. Similarly, a pixel value of a pixel 126 after the image enlargement is calculated as 217 by a linear interpolation operation (255x0.4+192x0.6) using the pixel values of the pixels 120 and 121 before the image enlargement. Further, a pixel value of a pixel 127 after the image enlargement is calculated as 230 by a linear interpolation operation (192x0.4+255x0.6) using the pixel values of the pixels 123 and 120 before the image enlargement. Further, a pixel value of a pixel 128 after the image enlargement is calculated as 128 by a linear interpolation operation (32x0.4+192x0.6) using the pixel values of the pixels 124 and 123 before the image enlargement. Note that before the interpolation process is executed in the first extension process, a change mode of pixel values of a plurality of pixels along the first direction (for example, a mode in which decrease and increase are alternately repeated) is the same as a change mode of pixel values of a plurality of pixels along the second direction (for example, a mode in which decrease and increase are alternately repeated), that is, a relationship of increase / decrease between pixels along the first direction is strictly the same as a relationship of increase / decrease between pixels along the second direction, while depending on the pixel values of the plurality of pixels included in the first pixel group, after the interpolation process is executed in the first extension process, a case may arise where a change mode of pixel values of a plurality of pixels along the first direction (for example, a mode in which increase and decrease are alternately repeated) and a change mode of pixel values of a plurality of pixels along the second direction (for example, a mode in which increase and decrease are not alternately repeated) are substantially the same, that is, a tendency of an observer's visibility is the same for the change mode of pixel values in the first direction and the change mode of pixel values in the second direction, but the relationship of increase / decrease between pixels along the first direction and the relationship of increase / decrease between pixels along the second direction are strictly partially different. In such a case, since the tendency of an observer's visibility is the same for the change mode of pixel values in the first direction and the change mode of pixel values in the second direction after the interpolation process is executed in the first extension process, this case is included in the "change mode of pixel values in the second direction is the same as the change mode of pixel values in the first direction" of the present invention.

[0075] Further, in the above embodiment, an example has been described in which the image display device 10 includes the first display panel 31 and the second display panel 32 having a larger image display area than the first display panel 31, but the present invention is not limited to this. For example, the image display device 10 may include the first display panel 31 and a second display panel 32 having the same image display area as the first display panel 31. In this case, an edge area of the first display panel 31 may be set as a non-image display area, and the image display area of the second display panel 32 may be made larger than the image display area of the first display panel 31. Further, by displaying the first image in a reduced size on the first display panel 31, the second image displayed on the second display panel 32 may be made larger than the first image displayed on the first display panel 31, and consequently, the image display area of the second display panel 32 may be made larger than the image display area of the first display panel 31.

[0076] Further, in the above embodiment, an example has been described in which the image display area of the second display panel 32 is larger than the image display area of the first display panel 31 in both the row direction and the column direction, but the present invention is not limited to this. For example, the image display area of the second display panel 32 may be larger than the image display area of the first display panel 31 in either the row direction or the column direction.

[0077] Further, in the above embodiment, an example has been described in which the first direction heading toward the inside of the image display area Al is, for example, a row or column direction, and the second direction heading toward the outside of the image display area A2 is, for example, a row or column direction, but the present invention is not limited to this. For example, the first direction heading toward the inside of the image display area Al at a corner part of the image display area Al may be a direction obtained by tilting a row or column direction by 45 degrees in a clockwise direction. In this case, the second direction heading toward the outside of the image display area A2 at a corner part of the image display area A2 adjacent to the corner part of the image display area Al may be a direction obtained by tilting the row or column direction by 45 degrees in the clockwise direction.

[0078] Further, in the above embodiment, an example has been described in which the image display device 10 is a color liquid crystal display device using three colors of RGB, but the present invention is not limited to this. For example, the image display device 10 may be a monochrome liquid crystal display device in which both the first display panel 31 and the second display panel 32 are composed of monochrome liquid crystal panels. Further, the image display device 10 may be a liquid crystal display device in which the number of pixels of the second display panel 32 is different from that of the first display panel 31. Further, the image display device 10 may be a liquid crystal display device using a local dimming technology that controls a light source 33 (a backlight) for each section so that a resolution of the second display panel 32 can be set lower than that of the first display panel 31.

[0079] Further, in the above embodiment, a placement position of the first display panel 31 with respect to the second display panel 32 may be shifted so that a first image displayed on the first display panel 31 and a second image displayed on the second display panel 32 overlap when the observer views the edge of a display screen of the image display device 10 from an oblique direction. Further, a display position of the first image displayed on the first display panel 31 with respect to the second image displayed on the second display panel 32 may be shifted so that the first image displayed on the first display panel 31 and the second image displayed on the second display panel 32 overlap when the observer views the edge of the display screen of the image display device 10 from an oblique direction.

[0080] Although various embodiments according to the present invention have been described above, these are presented as examples and are not intended to limit the scope of the invention. The aforementioned novel embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. The aforementioned embodiments and their variations are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and the equivalent scope thereof. Reference Signs List

[0081] 10: image display device, 20: image generation unit, 21: linear conversion unit, 22: first image generation unit, 22A: arithmetic unit, 22B: coefficient calculation unit, 23: first non-linear conversion unit, 24: second image generation unit, 24A: luminance conversion unit, 24B: smoothing processing unit, 25: first extension unit, 26: second extension unit, 30: display unit, 31: first display panel, 32: second display panel, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 120, 121, 122, 123, 124, 125, 126, 127, 128: pixel.

Claims

1. An image display device, wherein a plurality of display panels are arranged to overlap each other, and an image is displayed on each of the display panels, the image display device comprising:a first display panel arranged at a position close to an observer;a second display panel arranged at a position farther from the observer than the first display panel; andan image generation unit configured to generate, based on input image data, first image data for displaying a first image in an image display area of the first display panel, and second image data for displaying a second image in an image display area of the second display panel, whereinthe image display area of the second display panel is larger than the image display area of the first display panel,the image display area of the second display panel includes a first display area and a second display area located outside the first display area,the image generation unit generates, using a boundary pixel area located near a boundary of the first and second display areas as a reference, a second pixel group including a plurality of pixels continuously arranged in a second direction heading toward an outside of the second display area, by using a first pixel group including a plurality of pixels continuously arranged in a first direction heading toward an inside of the first display area, anda change mode of pixel values in the second direction for the second pixel group is the same as a change mode of pixel values in the first direction for the first pixel group.

2. The image display device according to claim 1, wherein:the image generation unit generates an image to be displayed in the first display area, the image being an image obtained by enlarging an image based on the input image data.

3. The image display device according to claim 2, wherein:the image to be displayed in the first display area is an image obtained by enlarging the image based on the input image data with a precision of less than one pixel.

4. The image display device according to any one of claims 1 to 3, wherein:the boundary pixel area includes one or more pixels located along the first direction within the first display area from the boundary of the first and second display areas.

5. The image display device according to any one of claims 1 to 3, wherein:the boundary pixel area includes one or more pixels located along the first direction within the first display area from the boundary of the first and second display areas, and one or more pixels located along the second direction within the second display area from the boundary of the first and second display areas.

6. An image display method for displaying an image on each of a plurality of display panels arranged to overlap each other, the image display method comprising:an image generation step of generating, based on input image data, first image data for displaying a first image in an image display area of a first display panel arranged at a position close to an observer, and second image data for displaying a second image in an image display area of a second display panel arranged at a position farther from the observer than the first display panel, whereinthe image display area of the second display panel is larger than the image display area of the first display panel,the image display area of the second display panel includes a first display area and a second display area located outside the first display area,in the image generation step, a second pixel group including a plurality of pixels continuously arranged in a second direction heading toward an outside of the second display area is generated by using a first pixel group including a plurality of pixels continuously arranged in a first direction heading toward an inside of the first display area, using a boundary pixel area located near a boundary of the first and second display areas as a reference, anda change mode of pixel values in the second direction for the second pixel group is the same as a change mode of pixel values in the first direction for the first pixel group.

7. An image display program that causes a processor to execute the image display method according to claim 6.INTERNATIONAL SEARCH REPORT International application No. PCT / JP2023 / 032574A. CLASSIFICATION OF SUBJECT MATTER G09G 3 / 20(2OO6.Ol)i; G09G 3 / 36(2006.01)i FI: G09G3 / 20 680E; G09G3 / 20 660C; G09G3 / 36 According to International Patent Classification (IPC) or to both national classification and IPC B. FIELDS SEARCHED Minimum documentation searched (classification system followed by classification symbols) G09G3 / 20: G09G3 / 36 Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched Published examined utility model applications of Japan 1922-1996 Published unexamined utility model applications of Japan 1971-2023 Registered utility model specifications of Japan 1996-2023 Published registered utility model applications of Japan 1994-2023 Electronic data base consulted during the international search (name of data base and, where practicable, search terms used) C. DOCUMENTS CONSIDERED TO BE RELEVANT Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. A A WO 2018 / 011831 Al (PANASONIC LIQUID CRYSTAL DISPLAY CO., LTD.) 18 January 2018 (2018-01-18) entire text, all drawings US 2019 / 0304381 Al (PANASONIC LIQUID CRYSTAL DISPLAY CO., LTD.) 03 October 2019 (2019-10-03) entire text, all drawings 1-7 1-7 A JP 2007-17768 A (HITACHI DISPLAYS LTD.) 25 January 2007 (2007-01-25) entire text, all drawings 1-7 | | Further documents are listed in the continuation of Box C. | J | See patent family annex. * Special categories of cited documents: “T” later document published after the international filing date or priority “A" document defining the general state of the art which is not considered date and not in conflict with the application but cited to understand the to be of particular relevance principle or theory underlying die invention “E” earlier application orpatent but published on or after the international “X” document of particular relevance; the claimed invention cannot be filing date considered novel or cannot be considered to involve an inventive step “L” document which may throw doubts on priority claim(s) or which is when the document is taken alone cited to establish the publication date of another citation or other document of particular- relevance;, the claimed invention cannot be special reason (as specified) considered to involve an inventive step when the document is “O” document referring to an oral disclosure, use, exhibition or other combined with one or more other such documents, such combination means being obvious to a person skilled in the art “P” document published prior to the international filing date but later than document member of the same patent family the priority date claimed Date of the actual completion of the international search 06 November 2023 Date of mailing of the international search report 14 November 2023 Name and mailing address of the ISA / JP Japan Patent Office (ISA / JP) 3-4-3 Kasumigaseki, Chiyoda-ku, Tokyo 100-8915 Japan Authorized officer Telephone No.INTERNATIONAL SEARCH REPORT International application No.Information on patent family membersFC 1 / J 1 ZUZ J / UJZS / 4Patent document cited in search report Publication date (day / month / year) Patent family member(s) Publication date (day / month / year) WO 2018 / 011831 Al 18 January 2018 US 2019 / 0147812 Al CN 109478387 A US 2019 / 0304381 Al 03 October 2019 (Family: none) JP 2007-17768 A 25 January 2007 US 2007 / 0008240 Al

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