JP7202430B2 - Display device - Google Patents

Description

The present invention relates to display devices.

Conventionally, as a technique for improving the contrast of a liquid crystal display device, a technique has been proposed in which two display panels are superimposed and an image is displayed on each display panel based on an input video signal (for example, Patent Document 1). reference). Specifically, for example, of two display panels arranged in front and behind, the display panel on the front side (viewer side) displays a color image, and the display panel on the rear side (backlight side) displays a black-and-white image. This is intended to improve the contrast.

Japanese Patent Application Laid-Open No. 2007-310161

However, in the above conventional liquid crystal display device, for example, in two display panels arranged in front and behind, when the end of the display screen is viewed from an oblique direction, the non-display area of the display panel arranged on the rear side is As a result, the problem arises that the edges of the displayed image are not displayed normally. Specifically, the edges of the display image become dark, and the edges of the original display image appear to be missing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent display abnormalities at edges of a display image in a display device configured by overlapping a plurality of display panels.

In order to solve the above problems, a display device according to the present invention is a display device in which a plurality of display panels are superimposed and arranged to display an image on each of the display panels, and the display device is arranged at a position close to an observer. a second display panel arranged at a position farther from the viewer than the first display panel; and a first image in an image display area of the first display panel based on an input video signal. and an image processing unit that generates first image data for displaying and second image data for displaying a second image in an image display area of the second display panel, wherein the second display The image display area of the panel is larger than the image display area of the first display panel, and the image display area of the second display panel is an opposing display area facing the image display area of the first display panel when viewed in plan. and an extended display area around the opposed display area, wherein the image processing unit generates image data for the opposed display area based on the input video signal, and generates image data for the opposed display area. The second image data is generated by generating the image data for the extended display area based on.

In the display device according to the present invention, an outer peripheral portion of the image display area of the second display panel may be located outside an outer peripheral portion of the image display area of the first display panel when viewed in plan.

In the display device according to the present invention, the image display area of each of the plurality of display panels may be larger as the position where the display panel is arranged is farther from the observer.

In the display device according to the aspect of the invention, the second display panel may display, in the extended display area, the same image as the image displayed at the end of the opposing display area.

In the display device according to the present invention, the width of the extended display area constitutes the second display panel from the observer side surface of the glass substrate on the second display panel side, which constitutes the first display panel. , the distance to the surface of the glass substrate on the first display panel side opposite to the viewer side, and the refractive index of each of the glass substrates.

を満たしてもよい（ただし、ｎ＝（ｎ１＋ｎ２）／２とする。）。 In the display device according to the present invention, the width of the extended display area is set to t1, and the refractive index of the glass substrate on the side of the second display panel, which constitutes the first display panel, is set to n1 to form the second display panel. Then, the refractive index of the glass substrate on the first display panel side is n2, and the second display panel is viewed from the observer side of the glass substrate on the second display panel side, which constitutes the first display panel. When the distance to the surface of the glass substrate on the first display panel side opposite to the viewer side is d,

may be satisfied (where n=(n1+n2)/2).

In the display device according to the present invention, the first image data for displaying a color image in the image display area of the first display panel and the black-and-white image in the image display area of the second display panel are displayed on the basis of the input video signal. may further include an image processing unit that generates second image data for displaying the .

In the display device according to the aspect of the invention, the image display area of the second display panel is provided with a plurality of signal lines to which signals for image display are supplied from the driving circuit, and the extended display area includes the driving A plurality of signal lines may be electrically connected to one output terminal in the circuit.

In the display device according to the present invention, the number of signal lines electrically connected to one output terminal may be smaller as the position of the output terminal is closer to the counter display area.

In the display device according to the present invention, in the extended display area, the image display signals may be simultaneously supplied to the plurality of signal lines electrically connected to the one output terminal.

In the display device according to the present invention, the plurality of pixels arranged in the extended display area may overlap a black matrix formed around the image display area of the first display panel when viewed two-dimensionally. .

In the display device according to the aspect of the invention, some of the pixels arranged in the extended display area may be larger than the pixels arranged in the counter display area.

を満たす（ただし、ｎ＝（ｎ１＋ｎ２）／２とする。）、ことを特徴とする。 Further, still another aspect of the display device according to the present invention is a display device in which a plurality of display panels are superimposed and an image is displayed on each of the display panels, and the display device is arranged at a position close to the observer. and a second display panel disposed farther from the viewer 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 display area of the second display panel includes a counter display area facing the image display area of the first display panel in plan view, and an extended display area surrounding the counter display area; Let t1 be the width of the display area, n1 be the refractive index of the glass substrate on the side of the second display panel that constitutes the first display panel, and n1 be the refractive index of the glass substrate on the side of the first display panel that constitutes the second display panel. Observation on the first display panel side glass substrate constituting the second display panel from the observer side surface of the second display panel side glass substrate constituting the first display panel, with a refractive index of n2. When the distance to the surface on the opposite side to the person's side is d,

is satisfied (where n=(n1+n2)/2).

According to the display device of the present invention, it is possible to prevent display abnormalities at the edges of the display image in the display device configured by overlapping a plurality of display panels.

1 is a plan view showing a schematic configuration of a liquid crystal display device according to an embodiment; FIG. 2 is a plan view showing a schematic configuration of a first display panel according to the embodiment; FIG. FIG. 4 is a plan view showing a schematic configuration of a second display panel according to the embodiment; FIG. 4 is a cross-sectional view taken along line A-A' of FIGS. 2 and 3. FIG. 1 is a cross-sectional view schematically showing a conventional liquid crystal display device; FIG. (a) is a plan view schematically showing a characteristic configuration of the liquid crystal display device according to the present embodiment, and (b) is a cross-sectional view taken along the line B-B' of (a). It is the figure which expanded the left end part of FIG.6(b). It is a top view which shows a part of 1st image display area of a said 1st display panel. It is a top view which shows a part of 2nd image display area of a said 2nd display panel. 9 is a diagram showing pixel information corresponding to each pixel of the first display panel shown in FIG. 8; FIG. FIG. 10 is a diagram showing pixel information corresponding to each pixel of the second display panel shown in FIG. 9; FIG. It is a figure for demonstrating the method to define the extended display area of a said 2nd display panel. FIG. 10 is a diagram for explaining an example of a method of determining the width of the extended display area based on the inter-panel distance and the refractive index; 4 is a timing chart showing timings for driving the gate lines of the first display panel and timings for driving the gate lines of the second display panel; FIG. 11 is a plan view showing the configuration of a second display panel according to Modification 1; FIG. 10 is a diagram showing pixel information corresponding to each pixel of the second display panel according to Modification 1; FIG. 11 is a plan view showing the configuration of a second display panel according to modification 2; FIG. 12 is a plan view showing the configuration of a second display panel according to modification 3; FIG. 13 is a diagram showing pixel information corresponding to each pixel of the second display panel according to Modification 3; 3 is a block diagram showing a specific configuration of an image processing unit according to the embodiment; FIG.

An embodiment of the present invention will be described below with reference to the drawings. Although a liquid crystal display device is taken as an example in the following embodiments, the display device according to the present invention is not limited to a liquid crystal display device, and may be an organic EL display device or the like.

The liquid crystal display device according to the present embodiment includes a plurality of display panels that display images, a plurality of drive circuits (a plurality of source drivers and a plurality of gate drivers) that drive the respective display panels, and controls the respective drive circuits. an image processing unit that performs image processing on input video signals input from the outside and outputs image data to each of the timing controllers; and a plurality of display panels that irradiate light from the rear side. Backlight and . The number of display panels is not limited as long as it is two or more. Further, the plurality of display panels are arranged so as to overlap each other in the front-rear direction when viewed from the observer side, and each display an image. A liquid crystal display device 10 including two display panels will be described below as an example.

FIG. 1 is a plan view showing a schematic configuration of a liquid crystal display device 10 according to this embodiment. As shown in FIG. 1, the liquid crystal display device 10 includes a first display panel 100 arranged at a position closer to the viewer (front side) and a position farther from the viewer than the first display panel 100 (rear side). a second display panel 200, a first timing controller 140 that controls the first source driver 120 and the first gate driver 130 provided in the first display panel 100, and a second source provided in the second display panel 200 It includes a second timing controller 240 that controls the driver 220 and the second gate driver 230 , and an image processing section 300 that outputs image data to the first timing controller 140 and the second timing controller 240 . The first display panel 100 displays a color image according to the input video signal, and the second display panel 200 displays a monochrome image (monochrome image) according to the input video signal. The image processing unit 300 receives an input video signal Data transmitted from an external system (not shown), executes image processing to be described later, and then outputs first image data DAT1 to the first timing controller 140, It outputs the second image data DAT2 to the second timing controller 240 . The image processing unit 300 also outputs control signals such as synchronization signals (not shown in FIG. 1) to the first timing controller 140 and the second timing controller 240 . The first image data DAT1 is image data for color display, and the second image data DAT2 is image data for black-and-white display. A backlight (not shown in FIG. 1) is arranged on the back side of the second display panel 200 . A specific configuration of the image processing unit 300 will be described later.

2 is a plan view showing a schematic configuration of the first display panel 100, and FIG. 3 is a plan view showing a schematic configuration of the second display panel 200. FIG. FIG. 4 is a cross-sectional view taken along line A-A' of FIGS. 2 and 3. FIG.

The configuration of the first display panel 100 will be described with reference to FIGS. 2 and 4. FIG. As shown in FIG. 4 , the first display panel 100 includes a thin film transistor substrate 101 (hereinafter referred to as a TFT substrate) arranged on the backlight 400 side, and a color filter arranged on the observer side and facing the TFT substrate 101 . It includes a substrate 102 (hereinafter referred to as a CF substrate) and a liquid crystal layer 103 arranged between the TFT substrate 101 and the CF substrate 102 . A polarizing plate 104 is arranged on the backlight 400 side of the first display panel 100, and a polarizing plate 105 is arranged on the viewer side.

As shown in FIG. 2, the TFT substrate 101 has a plurality of data lines 111 extending in a first direction (e.g., column direction) and a plurality of data lines 111 extending in a second direction (e.g., row direction) different from the first direction. A plurality of gate lines 112 are formed, and thin film transistors 113 (hereinafter referred to as TFTs) are formed in the vicinity of intersections of the plurality of data lines 111 and the plurality of gate lines 112 . A region surrounded by two adjacent data lines 111 and two adjacent gate lines 112 is defined as one pixel 114 when the first display panel 100 is viewed two-dimensionally, and the pixels 114 are arranged in a matrix ( are arranged in multiple rows and columns). The plurality of data lines 111 are arranged at equal intervals in the row direction, and the plurality of gate lines 112 are arranged at equal intervals in the column direction. A pixel electrode 115 is formed for each pixel 114 on the TFT substrate 101, and one common electrode (not shown) common to a plurality of pixels 114 is formed. A drain electrode constituting the TFT 113 is electrically connected to the data line 111 , a source electrode is electrically connected to the pixel electrode 115 , and a gate electrode is electrically connected to the gate line 112 .

As shown in FIG. 4, the CF substrate 102 is formed with a plurality of colored portions 102a corresponding to each pixel 114. As shown in FIG. Each colored portion 102a is surrounded by a black matrix 102b that blocks light transmission, and is formed in, for example, a rectangular shape. The plurality of colored portions 102a are formed of a red (R color) material and transmit red light, and a green portion is formed of a green (G color) material and transmits green light. , and a blue portion formed of a blue (B color) material and transmitting blue light. Red portions, green portions, and blue portions are repeatedly arranged in this order in the row direction, colored portions of the same color are arranged in the column direction, and a black matrix 102b is formed at the boundary between the colored portions 102a adjacent to each other in the row and column directions. is formed. Corresponding to each colored portion 102a, the plurality of pixels 114 are, as shown in FIG. and includes

The black matrix 102b includes a plurality of first light-shielding stripes B1 (see FIG. 4) arranged at the boundary between two colored portions 102a adjacent to each other in the row direction, and two stripes corresponding to each adjacent to each other in the column direction. and a plurality of second light-shielding stripes (not shown) arranged at the boundaries of the two colored portions 102a. The plurality of first light-shielding stripes B1 and the plurality of second light-shielding stripes are arranged in a first image display area 110a, which will be described later. Furthermore, the black matrix 102b includes a light shielding frame B2 (see FIG. 4) arranged in the first non-display area 110b. A light-shielding frame B2 surrounds the plurality of first light-shielding stripes B1 and the plurality of second light-shielding stripes and connects to the ends of each of the first light-shielding stripes B1 and each of the second light-shielding stripes.

The first timing controller 140 has a well-known configuration. For example, the first timing controller 140 outputs the first image data DA1 based on the first image data DAT1 output from the image processing unit 300 and the first control signal CS1 (clock signal, vertical synchronization signal, horizontal synchronization signal, etc.). and various timing signals (data start pulse DSP1, data clock DCK1, gate start pulse GSP1, gate clock GCK1) for controlling the driving of the first source driver 120 and the first gate driver 130 (see FIG. 2). ). The first timing controller 140 outputs the first image data DA1, the data start pulse DSP1, and the data clock DCK1 to the first source driver 120, and outputs the gate start pulse GSP1 and the gate clock GCK1 to the first gate driver 130. Output.

The first source driver 120 outputs a data signal (data voltage) corresponding to the first image data DA1 to the data line 111 based on the data start pulse DSP1 and the data clock DCK1. The first gate driver 130 outputs a gate signal (gate voltage) to the gate line 112 based on the gate start pulse GSP1 and the gate clock GCK1.

A data voltage is supplied from the first source driver 120 to each data line 111 , and a gate voltage is supplied to each gate line 112 from the first gate driver 130 . A common voltage Vcom is supplied to the common electrode from a common driver (not shown). When a gate voltage (gate-on voltage) is supplied to the gate line 112, the TFT 113 connected to the gate line 112 is turned on, and a data voltage is supplied to the pixel electrode 115 through the data line 111 connected to the TFT 113. . An electric field is generated by a difference between the data voltage supplied to the pixel electrode 115 and the common voltage Vcom supplied to the common electrode. An image is displayed by driving the liquid crystal with this electric field and controlling the transmittance of the light from the backlight 400 that has passed through the second display panel 200 . In the first display panel 100, a color image is displayed by supplying desired data voltages to the data lines 111 connected to the pixel electrodes 115 of the red pixels 114R, the green pixels 114G, and the blue pixels 114B. A well-known configuration can be applied to the first display panel 100 .

Next, the configuration of the second display panel 200 will be described with reference to FIGS. 3 and 4. FIG. As shown in FIG. 4, the second display panel 200 includes a TFT substrate 201 arranged on the backlight 400 side, a CF substrate 202 arranged on the observer side and facing the TFT substrate 201, the TFT substrate 201 and the CF substrate 202 arranged on the observer side. and a liquid crystal layer 203 disposed between the substrates 202 . A polarizing plate 204 is arranged on the backlight 400 side of the second display panel 200, and a polarizing plate 205 is arranged on the viewer side. A diffusion sheet 301 is arranged between the polarizing plate 104 of the first display panel 100 and the polarizing plate 205 of the second display panel 200 .

As shown in FIG. 3, the TFT substrate 201 has a plurality of data lines 211 extending in the column direction and a plurality of gate lines 212 extending in the row direction. A TFT 213 is formed near each intersection with the gate line 212 . A region surrounded by two adjacent data lines 211 and two adjacent gate lines 212 in a plan view of the second display panel 200 is defined as one pixel 214, and the pixels 214 are arranged in a matrix ( are arranged in multiple rows and columns). The plurality of data lines 211 are arranged at equal intervals in the row direction, and the plurality of gate lines 212 are arranged at equal intervals in the column direction. A pixel electrode 215 is formed for each pixel 214 on the TFT substrate 201, and one common electrode (not shown) common to a plurality of pixels 214 is formed. A drain electrode constituting the TFT 213 is electrically connected to the data line 211 , a source electrode is electrically connected to the pixel electrode 215 , and a gate electrode is electrically connected to the gate line 212 .

As shown in FIG. 4, on the CF substrate 202, a black matrix 202b is formed at a position corresponding to the boundary portion of each pixel 214 to block the transmission of light. A region 202a surrounded by a black matrix 202b is not formed with a colored portion, but is formed with, for example, an overcoat film.

The second timing controller 240 controls the second image data DA2 and the , various timing signals (data start pulse DSP2, data clock DCK2, gate start pulse GSP2, gate clock GCK2) for controlling the driving of the second source driver 220 and the second gate driver 230 (see FIG. 3). . The second timing controller 240 outputs the second image data DA2, the data start pulse DSP2, and the data clock DCK2 to the second source driver 220, and outputs the gate start pulse GSP2 and the gate clock GCK2 to the second gate driver 230. Output.

The second source driver 220 outputs a data voltage corresponding to the second image data DA2 to the data line 211 based on the data start pulse DSP2 and the data clock DCK2. The second gate driver 230 outputs a gate voltage to the gate line 212 based on the gate start pulse GSP2 and the gate clock GCK2.

Each data line 211 is supplied with a data voltage from the second source driver 220 , and each gate line 212 is supplied with a gate voltage from the second gate driver 230 . A common voltage Vcom is supplied to the common electrode from a common driver. When a gate voltage (gate-on voltage) is supplied to the gate line 212, the TFT 213 connected to the gate line 212 is turned on, and the data voltage is supplied to the pixel electrode 215 through the data line 211 connected to the TFT 213. . An electric field is generated by a difference between the data voltage supplied to the pixel electrode 215 and the common voltage Vcom supplied to the common electrode. An image is displayed by driving the liquid crystal with this electric field and controlling the light transmittance of the backlight 400 . A black-and-white image is displayed on the second display panel 200 .

Here, in the conventional liquid crystal display device configured by overlapping a plurality of display panels, as described above, there arises a problem that the edges of the displayed image become dark. FIG. 5 is a cross-sectional view schematically showing a conventional liquid crystal display device. In the conventional liquid crystal display device, the image display area 1100a of the display panel 1000 on the observer side and the image display area 2100a of the display panel 2000 on the backlight side have the same size. The positions of the ends match. In the configuration shown in FIG. 5, the image display area 1100a is the display screen of the liquid crystal display device, and the non-display area 1100b around the image display area 1100a is the frame portion of the liquid crystal display device. In the configuration shown in FIG. 5, when the end of the display screen is viewed obliquely (dotted line arrow in FIG. 5), a part of the non-display area 2100b of the display panel 2000 on the backlight side becomes part of the display panel on the observer side. By overlapping with the image display area 1100a of 1000, the end portion of the original display image displayed on the display screen appears dark and missing.

On the other hand, the liquid crystal display device 10 according to the present embodiment has a characteristic configuration in which the original image can be visually recognized up to the edge of the displayed image. FIG. 6(a) is a plan view showing an outline of the characteristic configuration of the liquid crystal display device 10, and FIG. 6(b) is a cross-sectional view taken along the line B-B' of FIG. 6(a). In the liquid crystal display device 10, the second image display area 210a of the second display panel 200 on the backlight side is formed larger than the first image display area 110a of the first display panel 100 on the observer side. The panel 100 and the second display panel 200 are arranged so that the end (periphery) of the second image display area 210a surrounds the first image display area 110a when viewed two-dimensionally. Further, the backlight 400 is configured such that the light emitting surface is larger than the first image display area 110a and the second image display area 210a. 6, the first image display area 110a serves as the display screen of the liquid crystal display device 10, and the area around the first image display area 110a serves as the frame portion of the liquid crystal display device 10. As shown in FIG. FIG. 7 is an enlarged view of the left end of FIG. 6(b). As shown in FIG. 7, the second image display area 210a of the second display panel 200 has a size obtained by enlarging the first image display area 110a of the first display panel 100. As shown in FIG. An area of the second image display area 210a that is extended with respect to the first image display area 110a is referred to as an extended display area 210c. In the liquid crystal display device 10 , the second non-display area 210 b of the second display panel 200 is formed smaller than the first non-display area 110 b of the first display panel 100 . According to the configuration of the liquid crystal display device 10, the second non-display area 210b of the second display panel 200 overlaps the first display panel 100 when the edge of the display screen is viewed from an oblique direction (dotted line arrow in FIG. 7). It is possible to prevent the edges of the displayed image from becoming dark (see FIG. 5) without overlapping the first image display area 110a.

In addition, in the liquid crystal display device 10, the second display panel 200 has, for example, an extended display area 210c (see FIG. 7) so that the original display image can be viewed when the end of the display screen is viewed from an oblique direction. , the same image as the image at the end of the second image display area 210a facing the first image display area 110a (hereinafter referred to as the facing display area 210d) is displayed. That is, the opposing display area 210d is an area that overlaps with the first image display area 110a in plan view. A specific configuration of the extended display area 210c will be described below.

8 is a plan view showing part of the first image display area 110a of the first display panel 100. FIG. 9 is a plan view showing part of the second image display area 210a of the second display panel 200. FIG. FIGS. 8 and 9 show an enlarged configuration of the upper left portion (the portion surrounded by a dotted line) of the second display panel 200 shown in FIG. 6(a). In FIG. 8, "SD1-1" to "SD1-6" indicate the first to sixth output terminals of the first source driver 120, and "GD1-1" to "GD1-3" indicate the first gate. The first to third output terminals of driver 130 are shown. Also, in FIG. 9, "SD2-1" to "SD2-16" indicate the first to sixteenth output terminals of the second source driver 220, and "GD2-1" to "GD2-13" indicate the second source driver 220. The first to thirteenth output terminals of the two gate driver 230 are shown.

As shown in FIGS. 8 and 9, in the first display panel 100, the pixels 114 are not arranged in the region facing the frame portion, and the black matrix 102b (see FIG. 4) is formed. In the second display panel 200, a plurality of pixels 214 are arranged in a region (extended display region 210c) facing the frame portion. For this reason, the plurality of pixels 214 arranged in the extended display region 210c are arranged so as to overlap the black matrix 102b facing the frame portion when viewed two-dimensionally. More specifically, the plurality of pixels 214 arranged in the extended display area 210c are arranged so as to overlap the light shielding frame B2 arranged in the frame portion of the first display panel 100 when viewed two-dimensionally. In the example shown in FIG. 9, ten pixels 214 are arranged in the row direction and ten columns in the extended display region 210c so as to overlap the black matrix 102b in a plan view. Note that when the first display panel 100 and the second display panel 200 are superimposed so that their center positions in the row direction and the column direction match each other when viewed two-dimensionally, the pixels 214 in the extended display region 210c are , 10 are arranged around the first image display area 110a.

FIG. 10 is a diagram showing pixel information corresponding to each pixel 114 of the first display panel 100 shown in FIG. The pixel information includes, for example, information indicating the gradation of the image displayed on each pixel 114 . In the example shown in FIG. 10, for example, an image corresponding to the gradation of "R11" is displayed in the upper left pixel (red pixel 114R), and "G12" is displayed in the pixel on the right (green pixel 114G). An image corresponding to the gradation of is displayed. Accordingly, a color image corresponding to the input video signal Data is displayed in the first image display area 110a of the first display panel 100. FIG.

FIG. 11 is a diagram showing pixel information corresponding to each pixel 214 of the second display panel 200 shown in FIG. In the opposite display area 210d of the second image display area 210a of the second display panel 200, an image corresponding to the gradation of "C11" is displayed in the pixel 214 (enclosed with a thick line in FIG. 11) at the upper left corner, An image corresponding to the gradation of "C12" is displayed in the pixel 214 on the right. As a result, a black-and-white image corresponding to the input video signal Data is displayed in the opposing display area 210d.

In addition, in the extended display area 210c of the second image display area 210a of the second display panel 200, the same image as the image displayed in the pixels 214 at the end of the opposing display area 210d is displayed. Specifically, in the extended display region 210c, the pixels 214 included in the first to tenth columns and the first to tenth rows of the second image display region 210a have the upper left corner of the counter display region 210d. The pixels 214 on the 11th column display an image corresponding to the gradation of "C11" similarly to the pixels 214 in the upper end of the counter display region 210d. In this manner, the pixels 214 on the 12th column display an image corresponding to the gradation of “C12”, and the pixels 214 on the 13th column display an image corresponding to the gradation of “C13”. An image is displayed. In the extended display region 210c, the pixels 214 on the 11th row display an image corresponding to the gradation of "C11" in the same manner as the pixels 214 on the upper end of the opposing display region 210d. An image corresponding to the gradation of “C21” is displayed on the pixels 214 of the 13th row, and an image corresponding to the gradation of “C31” is displayed on the pixels 214 of the 13th row. In this way, when the display screen is viewed from an oblique direction (see FIG. 7), the extended display area 210c of the second display panel 200 overlaps the first image display area 110a of the first display panel 100, and the extended display is performed. Since the same image as the edge of the opposing display area 210d is displayed in the area 210c, the image corresponding to the input video signal can be visually recognized even at the edge of the display screen.

As described above, the liquid crystal display device 10 has the first display panel 100 arranged at a position closer to the viewer and the second display panel 200 arranged at a position farther from the viewer than the first display panel 100. The second image display area 210 a of the display panel 200 has a configuration larger than the first image display area 110 a of the first display panel 100 . The size of the second image display area 210 a is set according to the structure of the liquid crystal display device 10 . A method for defining the difference between the first image display area 100a and the second image display area 210a (that is, the extended display area 210c) will be described below.

FIG. 12 is a diagram for explaining a method of defining extended display area 210c. FIG. 12(a) is a cross-sectional view showing a state when the display screen is viewed from an oblique direction of 60 degrees with respect to the vertical direction. FIG. 12(b) is a diagram showing a cross-sectional structure near the boundary between the first display panel 100 and the second display panel 200. As shown in FIG. For example, the width t1 of the extended display area 210c is set to a value such that the second non-display area 210b does not overlap the first image display area 110a when the display screen is viewed from an oblique direction of 60 degrees. The width t1 of the extended display area 210c mainly depends on the inter-panel distance shown in FIG. 12(b). Specifically, the inter-panel distance is determined by the thickness of the glass substrate 101a and the polarizing plate 104 that constitute the first display panel 100, the thickness of the glass substrate 202c and the polarizing plate 205 that constitute the second display panel 200, and the thickness of the first display panel 200. It is calculated by summing the thickness of the diffusion sheet 301 arranged between the display panel 100 and the second display panel 200 . The width t1 of the extended display area 210c is also affected by the refractive indices of the glass substrates 101a and 202c. Therefore, the width t1 of the extended display area 210c is set based on the inter-panel distance and the refractive indices of the glass substrates 101a and 202c. For example, the width t1 of the extended display area 210c is set to a larger value as the inter-panel distance is larger, and is set to a smaller value as the refractive indices of the glass substrates 101a and 202c are larger.

When the width t1 of the extended display area 210c is calculated based on the inter-panel distance and the refractive index, the number and size of the pixels 214 arranged in the extended display area 210c are determined. Thus, the structure of extended display area 210c is defined.

FIG. 13 is a diagram for explaining an example of a method of determining the width t1 of the extended display area 210c based on the inter-panel distance and the refractive index. As shown in FIG. 13, when the display screen is observed from a direction inclined at an angle θ with respect to the normal direction nd to the surface of the first display panel 100, the image light from the second display panel 200 is reflected by the liquid crystal display device. After being refracted in accordance with the refractive index of each layer constituting 10, it faces the observer's eye from a direction inclined at an angle θ. Here, as shown in FIG. 13, from the pixel 214 of the second display panel 200, the light passes through the pixel 114 positioned at the end of the first image display area 110a and enters the observer's eye from a direction inclined at an angle θ. Focus on the light L1. Assuming that the amount by which this light L1 deviates from the boundary between the extended display region 210c and the opposing display region 210d on the surface of the layer on which the black matrix 202b of the CF substrate 202 is formed is the parallax countermeasure width X, the width of the extended display region 210c is When t1 is equal to or greater than the parallax countermeasure width X, even when the observer observes the display screen from a direction inclined at an angle θ, the image at the edge can be confirmed with desired brightness.

As described above, in order to strictly obtain the required parallax countermeasure width X, a layer in which the black matrix 102b of the first display panel 100 is arranged, a layer in which the black matrix 202b of the second display panel 200 is arranged, It is necessary to calculate by considering the refractive index and thickness of each layer located between. However, the difference in refractive index between these layers is slight, and the glass substrate 101a constituting the TFT substrate 101 of the first display panel 100, which has a large thickness, and the second glass substrate 101a which greatly contributes to the determination of the parallax countermeasure width X. It is a glass substrate 202 c that constitutes the CF substrate 202 of the display panel 200 . Therefore, each layer positioned between the layer in which the black matrix 102b of the first display panel 100 is arranged and the layer in which the black matrix 202b of the second display panel 200 is arranged is regarded as a single layer. The refractive index n of one layer is regarded as the average value of the refractive index n1 of the glass substrate 101 a of the first display panel 100 and the refractive index n2 of the glass substrate 202 c of the second display panel 200 . i.e.
Single layer refractive index n=(refractive index n1+refractive index n2)/2 (1)
and

According to this assumption, the layer in which the black matrix 102b of the first display panel 100 is arranged and the layer in which the black matrix 202b of the second display panel 200 is arranged can be regarded as a single layer. Therefore, if the distance between the layer in which the black matrix 102b of the first display panel 100 is arranged and the layer in which the black matrix 202b of the second display panel 200 is arranged is d', the geometry shown in FIG. due to the relationship
Parallax countermeasure width X = distance d' x tan θ' (2)
becomes. Here, due to the geometrical relationship shown in FIG. 13,
n×sin θ′=1×sin θ (3)
meet.

が得られる。式（４）を式（２）に代入して

が得られる。ここで、液晶層１０３の厚みは他の層に比べて無視できるほど狭いため無視することができる。したがって、距離ｄ’は、第１表示パネル１００を構成する、第２表示パネル２００側のガラス基板１０１ａ（すなわち、第１表示パネル１００のＴＦＴ基板１０１を構成するガラス基板１０１ａ）における観察者側の面から、第２表示パネル２００を構成する、第１表示パネル１００側のガラス基板２０２ｃ（すなわち、第２表示パネル２００のＣＦ基板２０２を構成するガラス基板２０２ｃ）における観察者側とは反対側の面までの距離ｄとみなすことができる（図１３参照）。したがって、距離ｄ’＝距離ｄを式（５）に代入すると、

が得られる。上述のように、拡張表示領域２１０ｃの幅ｔ１が視差対策幅Ｘ以上であれば、端部の表示不良を防ぐことができることから、式（６）より、

を満たす場合、端部の表示不良を有効に防ぐことができるといえる。 Even with an in-plane switching (IPS) type liquid crystal display panel, which is said to have the widest viewing angle, when an observer observes the display screen from a direction inclined by 60 degrees, display abnormalities occur at the edges of the displayed image. Experiments conducted by the inventors of the present invention have found that if there is no display abnormality, there is no sense of incompatibility when viewing from a direction inclined by 60 degrees or more. Therefore, setting the angle θ to 60 degrees is preferable for obtaining the required parallax countermeasure width X. If the angle θ is 60 degrees and tan θ′ is calculated from the equation (3),

is obtained. Substituting equation (4) into equation (2) gives

is obtained. Here, the thickness of the liquid crystal layer 103 can be ignored because it is so narrow that it can be ignored compared to other layers. Therefore, the distance d′ is the distance between the observer side and the second display panel 200 side glass substrate 101a constituting the first display panel 100 (that is, the glass substrate 101a constituting the TFT substrate 101 of the first display panel 100). From the front, the glass substrate 202c on the side of the first display panel 100 (that is, the glass substrate 202c constituting the CF substrate 202 of the second display panel 200), which constitutes the second display panel 200, is opposite to the viewer side. It can be regarded as the distance d to the surface (see FIG. 13). Therefore, substituting distance d′=distance d into equation (5), we get

is obtained. As described above, if the width t1 of the extended display area 210c is equal to or greater than the parallax countermeasure width X, display defects at the edges can be prevented.

is satisfied, it can be said that display defects at the edges can be effectively prevented.

Table 1 is a table showing the result of simulating the required parallax countermeasure width X by changing the thickness of each layer with the observation angle θ of the observer set to 60 degrees. As the refractive index of each layer, a typical refractive index value of each layer was adopted, and specifically, the values shown in Table 1 were used.

When the required parallax countermeasure width X′ was calculated in consideration of the refractive index of each layer, 2.03 mm and 1.33 mm were obtained for samples 1 and 2, respectively, as shown in Table 1. On the other hand, when the required parallax countermeasure width X is calculated from Equation (6), 2.05 mm and 1.34 mm are obtained for samples 1 and 2, respectively. Since the size of one pixel is at least about 0.13 mm, the difference between the parallax countermeasure width X′ obtained from the actual calculation and the parallax countermeasure width X obtained from Equation (6) is the size of the pixel. This is a sufficiently acceptable value compared to , and it can be seen that Equation (6) can be used as the parallax countermeasure width X.

Next, a method for driving the liquid crystal display device 10 will be described. In the liquid crystal display device 10, the number of pixels 114 of the first display panel 100 and the number of pixels 214 of the second display panel 200 are different from each other, and accordingly the number of signal lines (data lines, gate lines) is also different. . Therefore, in the first display panel 100 and the second display panel 200, it is necessary to adjust the timing of driving each signal line.

FIG. 13 is a timing chart showing the timing of driving the gate lines 112 of the first display panel 100 and the timing of driving the gate lines 212 of the second display panel 200. As shown in FIG. Here, it is assumed that the first display panel 100 has n gate lines 112 and the second display panel 200 has m gate lines 212 . Also, it is assumed that the number of pixels 114 and signal lines arranged on the first display panel 100 is equal to the number of pixels 214 and signal lines arranged on the opposing display area 210d of the second display panel 200. FIG. Further, as shown in FIGS. 8 and 9, it is assumed that the second display panel 200 has 10 more gate lines 212 than the first display panel 100 in the vertical direction. In FIG. 13, GL1(1) indicates a gate signal supplied to the first row gate line 112 of the first display panel 100, and GL1(n) indicates a gate signal supplied to the last n-th row gate line 112. shows the gate signal. GL2(1) indicates the gate signal supplied to the first row gate line 212 of the second display panel 200, and GL2(m) indicates the gate signal supplied to the final m-th row gate line 212. is shown. GL2(1) to GL2(10) and GL2(m-9) to GL2(m) indicate gate signals supplied to the gate lines 212 arranged in the extended display area 210c. Therefore, when the liquid crystal display device 10 is viewed two-dimensionally, gate lines 112 on the first to n rows of the first display panel 100 and gate lines 112 on the eleventh to (m−10) rows of the second display panel 200 are shown. The gate lines 212 are arranged so as to overlap each other.

In the above configuration, in the first frame F1, first, in the second display panel 200, gate signals GL2(1) to GL2(10) are sequentially supplied to the gate lines 212 of the 1st to 10th rows. A data voltage corresponding to image information indicated by 11 is supplied to the pixel electrode 215 . Subsequently, in the first display panel 100, the gate signals GL1(1) to GL1(n) are sequentially supplied to the gate lines 112 from the 1st row to the nth row. Gate signals GL2(11) to GL2(m-10) are sequentially supplied to the gate lines 212 from the (m−10)th row, and the data voltages corresponding to the image information shown in FIG. , a data voltage corresponding to the image information shown in FIG. 11 is supplied to the pixel electrode 215 . Subsequently, in the second display panel 200, gate signals GL2(m-9) to GL2(m) are sequentially supplied to the gate lines 212 from the (m-9)th row to the mth row. Data voltages corresponding to image information are supplied to the pixel electrodes 215 . In this way, in the periods t11 and t13 of the first frame F1, an image is displayed in the extended display area 210c of the second display panel 200, and in the period t12, the first image display area 110a and the first image display area 110a of the first display panel 100 are displayed. Image display is performed in the opposing display area 210 d of the second display panel 200 . In the second frame F2, the same operation as in the first frame F1 is performed. Similar operations are performed in subsequent frames.

The liquid crystal display device 10 performs the display operation as described above. Note that the display operation method is not limited to the above method.

The configuration of the liquid crystal display device 10 is not limited to the configuration described above. For example, various configurations can be applied to the configuration of the extended display area 210c of the second display panel 200. FIG. Other configuration examples of the extended display area 210c will be described below.

As described above, the same image is displayed on some of the plurality of pixels 214 arranged in the extended display area 210c. For example, in FIG. 11, 11 pixels 214 arranged in the row direction on the first row display an image corresponding to the gradation of “C11”, and ten pixels 214 arranged in the row direction on the 12th row display , an image corresponding to the gradation of "C21" is displayed. Therefore, as shown in FIGS. 14 and 15, a configuration may be adopted in which signal lines (data lines 211 and gate lines 212) corresponding to a plurality of pixels displaying the same image are driven simultaneously. 14 is a plan view showing the configuration of the second display panel 200 according to Modification 1, and FIG. 16 is a plan view showing the configuration of the second display panel 200 according to Modification 2. As shown in FIG.

In the second display panel 200 shown in FIG. 14, seven data lines 211 from the 1st to 7th columns are connected to one output terminal SD2-7, and the 7 data lines 211 from the 1st to the 7th rows are connected to one output terminal SD2-7. This gate line 212 is connected to one output terminal GD2-7. That is, a signal line connected to one output terminal SD2-7 is branched to seven data lines 211, and a signal line connected to one output terminal GD2-7 is branched to seven gate lines 212. there is In FIG. 14, for the sake of convenience, the output terminals are denoted by numbers corresponding to the positions of the output terminals shown in FIG. The same applies to subsequent figures. As shown in FIG. 15, the display panel 200 according to Modification 1 also displays an image in the same manner as the above-described display panel 200 (see FIG. 11).

In the second display panel 200 shown in FIG. 16, four data lines 211 from the first to fourth columns are connected to one output terminal SD2-7, and three data lines from the fifth to seventh columns are connected to one output terminal SD2-7. 2 data lines 211 are connected to one output terminal SD2-8, two data lines 211 from the 8th to 9th columns are connected to one output terminal SD2-9, and 10 columns are connected to one output terminal SD2-9. The second data line 211 is connected to one output terminal SD-10. Similarly, four gate lines 212 from the 1st to 4th rows are connected to one output terminal GD2-7, and three gate lines 212 from the 5th to 7th rows are connected to one output terminal GD2-7. Two gate lines 212 from the eighth to ninth rows are connected to one output terminal GD2-9, and one gate line 212 on the tenth row is connected to the output terminal GD2-8. It is connected to the output terminal GD-10. That is, the signal line connected to one output terminal SD-7 is branched into four data lines 211, the signal line connected to one output terminal SD-8 is branched into three data lines 211, A signal line connected to one output terminal SD-9 branches to two data lines 211 . Similarly, a signal line connected to one output terminal GD-7 is branched into four gate lines 212, and a signal line connected to one output terminal GD-8 is branched into three gate lines 212. , a signal line connected to one output terminal GD- 9 is branched to two gate lines 212 . In this manner, the display panel 200 is configured such that the number of branches of the data lines 211 and the number of branches of the gate lines 212 decrease as the display panel 200 approaches the opposing display area 210d (first image display area 110a).

Although each of the plurality of pixels 214 has the same size in each of the configurations shown in FIGS. 9, 14, and 16, the present invention is not limited to this. For example, some pixels 214 among the plurality of pixels 214 arranged in the extended display region 210c may have sizes different from those of the other pixels 214 . FIG. 17 is a plan view showing the configuration of the second display panel 200 according to Modification 3. As shown in FIG. In the second display panel 200 shown in FIG. 17, the size of the plurality of pixels 214 arranged in the extended display area 210c increases with increasing distance from the opposing display area 210d (first image display area 110a). is configured as For example, when the row-direction pitch of the plurality of pixels 214 arranged in the opposing display region 210d is s1, the plurality of pixels 214 arranged in the extended display region 210c has a pitch of s1 in the fourth column. The pixels 214 are arranged so that the pitch of the pixels 214 in the third column is s1×2, the pitch of the pixels 214 in the second column is s1×3, and the pitch of the pixels 214 in the first column is s1×4. That is, compared to the pixels 214 arranged in the opposing display region 210d, the pixels 214 in the fourth column are 1 times larger in the row direction, the pixels 214 in the third column are 2 times larger in the row direction, and the pixels 214 in the 2nd column are 2 times larger in the row direction. The size is three times larger in the row direction, and the pixels 214 in the first column are four times larger in the row direction. Similarly, for example, when the pitch in the column direction of the plurality of pixels 214 arranged in the opposing display region 210d is g1, the plurality of pixels 214 arranged in the extended display region 210c is the same as the pitch of the pixels 214 in the fourth row. is g1, the pitch of the pixels 214 in the third row is g1×2, the pitch of the pixels 214 in the second row is g1×3, and the pitch of the pixels 214 in the first row is g1×4. That is, compared to the pixels 214 arranged in the opposing display region 210d, the pixels 214 in the fourth row are 1 times larger in the column direction, the pixels 214 in the third row are 2 times larger in the column direction, and the pixels 214 in the 2nd row are larger. The size is three times larger in the column direction, and the pixels 214 in the first row are four times larger in the column direction. As shown in FIG. 18, the second display panel 200 according to Modification 3 also displays an image in the same manner as the second display panels 200 described above.

According to the second display panels 200 according to Modifications 1 to 3, the number of outputs of each driver can be reduced compared to the configuration shown in FIG. Further, according to the second display panel 200 according to Modifications 1 and 2, a plurality of gate lines 212 can be driven (selected) at the same time. The display time (driving time) of the area 210c can be shortened. As described above, the pixels 214 arranged in the extended display region 210c can have a configuration different from that of the pixels 214 arranged in the opposing display region 210d. It is preferable that the configuration be close to the conditions (the number of branches of signal lines and the size of pixels) corresponding to the pixels 214 in the region 210d.

Next, a specific configuration of the image processing section 300 will be described. FIG. 19 is a block diagram showing a specific configuration of the image processing section 300. As shown in FIG. The image processing unit 300 includes a first delay unit 311, a first gamma processing unit 312, a second delay unit 313, a first image output unit 314, a monochrome image data generation unit 321, and a second gamma processing unit 322. , a maximum filter processing unit 323 , an average filter processing unit 324 , an extended display image data generation unit 325 and a second image output unit 326 .

When the image processing unit 300 receives the input image signal Data transmitted from the external system, the image processing unit 300 transfers the input image signal Data to the first delay unit 311 and the monochrome image data generation unit 321 . The input video signal Data includes, for example, luminance information (gradation information) and color information. The black-and-white image data generator 321 generates black-and-white image data corresponding to a black-and-white image based on the input video signal Data. The second gamma processing unit 322 performs gamma processing on the black-and-white image displayed on the second display panel 200 based on the black-and-white image data. For example, the second gamma processing unit 322 sets the gamma value (second gamma value) to 0.3.

Based on the input video signal Data output from the first delay unit 311 and the second gamma value (γ=0.3) output from the second gamma processing unit 322, the first gamma processing unit 312 performs the first 1 Gamma processing is performed on a color image displayed on the display panel 100 . For example, the first gamma processing unit 312 sets the gamma value (first gamma value) of the color image to 1.9 so that the composite gamma value of the display image obtained by combining the black-and-white image and the color image is 2.2. set. The first gamma processing section 312 outputs the gamma-processed color image data (first image data) to the second delay section 313 .

The maximum value filtering unit 323 executes maximum value filtering based on the black-and-white image data output from the second gamma processing unit 322 . The maximum value filtering unit 323 can apply well-known maximum value filtering. For example, the maximum value filtering unit 323 sets a circular region of 11 pixels×11 pixels as the filter size and executes maximum value filtering. Thereby, for example, a high brightness area (white area) can be enlarged.

The average filter processing unit 324 executes average filter processing based on the black-and-white image data output from the maximum filter processing unit 323 . The mean filter processing unit 324 can apply well-known mean filter processing. For example, the average filter processing unit 324 sets a circular area of 11 pixels×11 pixels as the filter size and executes the average filter processing. As a result, for example, high-frequency components are removed, so luminance changes can be smoothed.

Based on the black-and-white image data output from the average filter processing unit 324, the extended display image data generation unit 325 generates a black-and-white image corresponding to the second image display area 210a including the extended display area 210c (see FIG. 9, etc.). Extended display image data (second image data) is generated. For example, the extended display image data generator 325 generates the second image data based on the number of pixels 214 in the extended display area 210c defined by the method shown in FIG. The extended display image data generation section 325 outputs the generated second image data to the second image output section 326 .

The second delay unit 313 outputs the first image data output from the first gamma processing unit 312 to the first image output unit 314 in synchronization with the output timing of the extended display image data generation unit 325 .

The first image output section 314 outputs the first image data DAT1 to the first timing controller 140 , and the second image output section 326 outputs the second image data DAT2 to the second timing controller 240 . The image processing unit 300 also outputs a first control signal CS1 to the first timing controller 140 and a second control signal CS2 to the second timing controller 240 (FIGS. 2 and 3).

The image processing unit 300 is not limited to the above configuration. For example, the extended display image data generator 325 may be provided between the second gamma processor 322 and the maximum value filter processor 323 . That is, the image processing section 300 may perform maximum value filtering and average value filtering on the extended display image data.

In the above-described embodiment, the second display panel 200 displays a black-and-white image and includes the black matrix 202. However, the black matrix 202b of the second display panel 200 is not necessarily provided. good.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and may be appropriately modified from the above embodiments by those skilled in the art without departing from the scope of the present invention. Needless to say, it is included in the technical scope of the present invention.

Claims (12)

A display device in which a plurality of display panels are superimposed and arranged to display an image on each of the display panels,
a first display panel arranged at a position close to an observer;
a second display panel positioned farther from the viewer than the first display panel;
First image data for displaying a first image in the image display area of the first display panel and for displaying a second image in the image display area of the second display panel based on an input video signal and an image processing unit that generates the second image data of
the 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 counter display area facing the image display area of the first display panel in plan view, and an extended display area surrounding the counter display area,
The image processing unit generates the second image data by generating image data for the opposed display area and image data for the extended display area based on the input video signal ,
In the extended display area, the same image as the end portion of the opposed display area is displayed.
A display device characterized by: The image processing unit delays the output timing of the first image data in accordance with the output timing of the second image data including the image data for the extended display area and the image data for the opposite display area. including the part
2. The display device according to claim 1, wherein: The image processing unit
a first gamma processing unit that generates the first image data;
a second gamma processing unit that generates image data for the opposing display area of the second image data;
with
The first gamma processing unit performs gamma processing on the image displayed on the first display panel based on the input video signal and the gamma value output from the second gamma processing unit.
3. The display device according to claim 1, wherein: The image processing unit further includes a black-and-white image data generation unit that generates black-and-white image data from the input video signal,
The second gamma processing unit performs gamma processing on the image displayed on the second display panel based on the black-and-white image data output from the black-and-white image data generation unit.
4. The display device according to claim 3, characterized in that: The image processing unit further includes a maximum value filtering unit that performs maximum value filtering based on the black-and-white image data output from the second gamma processing unit,
5. The display device according to claim 4, wherein: The image processing unit further includes a mean value filtering unit that performs mean value filtering based on the black-and-white image data output from the maximum value filtering unit,
6. The display device according to claim 5, wherein: The image processing unit generates black-and-white image data including image data for the extended display area and image data for the opposite display area based on the black-and-white image data output from the average filter processing unit. further comprising a generator;
7. The display device according to claim 6, wherein: The image processing section generates black-and-white image data including image data for the extended display area and image data for the opposite display area based on the black-and-white image data output from the second gamma processing section. a generator;
further comprising
5. The display device according to claim 4, wherein: The image processing unit further includes a maximum value filtering unit that performs maximum value filtering based on the black-and-white image data output from the image data generating unit,
9. The display device according to claim 8, characterized by: The image processing unit further includes a mean value filtering unit that performs mean value filtering based on the black-and-white image data output from the maximum value filtering unit,
10. The display device according to claim 9, characterized in that: Further comprising a backlight provided on the back side of the second display panel,
an emission surface of the backlight is larger than the image display area of the first display panel and the image display area of the second display panel;
The display device according to any one of claims 1 to 10, characterized in that: Let t1 be the width of the extended display area, n1 be the refractive index of the glass substrate on the side of the second display panel constituting the first display panel, and n1 be the glass substrate on the side of the first display panel constituting the second display panel. The refractive index of the substrate is n2, and the glass substrate on the first display panel side that constitutes the second display panel is viewed from the observer side of the glass substrate on the second display panel side that constitutes the first display panel. When the distance to the surface opposite to the observer side in is d,

satisfies (where n = (n1 + n2) / 2),
The display device according to any one of claims 1 to 11 , characterized in that:

Images