Patent Publication Number: US-11398198-B2

Title: Display device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. application Ser. No. 16/244,975, filed: Jan. 10, 2019, which is a bypass continuation of international patent application PCT/JP2016/003331, filed: Jul. 14, 2016 designating the United States of America, the entire disclosure of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a display device. 
     BACKGROUND 
     A technology, in which two display panels overlap each other and an image is displayed on each display panel based on an input video signal, is conventionally proposed to improve contrast of a liquid crystal display device (for example, see Japanese published document 2007-310161). Specifically, for example, a color image is displayed on a front-side (observer-side) display panel in two display panels disposed back and forth, and a monochrome image is displayed on a rear-side (backlight-side) display panel, thereby improving contrast. 
     SUMMARY 
     However, in the conventional liquid crystal display device, for example, in the case that an end of the display screen is viewed from an oblique direction in two display panels disposed at front and rear sides, a problem that the end of the display image is not normally displayed arises due to an influence of a non-display region of the display panel disposed on the rear side. Specifically, an end of the display image becomes dark, and the end of the original display image is seen while lacked. 
     The present invention prevents a display abnormality at an end of a display image in a liquid crystal display device in which a plurality of display panels overlap each other. 
     To solve the above problem, a display device according to a present disclosure in which a plurality of display panels are disposed while overlapping each other, an image is displayed on each of the display panels, includes a first display panel disposed closer to an observer and a second display panel disposed farther from the observer than the first display panel. An image display region of the second display panel is larger than an image display region of the first display panel. 
     In the liquid crystal display device according to the present disclosure, an outer periphery of the image display region of the second display panel may be located outside an outer periphery of the image display region of the first display panel in planar view. 
     In the display device according to the present disclosure, the image display region of each of the plurality of display panels may become larger as a position at which the display panel is disposed is farther from the observer. 
     In the display device according to the present disclosure, the image display region of the second display panel may include an opposed display region facing the image display region of the first display panel in planar view and an extended display region around the opposed display region, and the second display panel may display an image identical to an image displayed at an end of the opposed display region in the extended display region. 
     In the display device according to the present disclosure, a width of the extended display region may be set based on a distance from a surface on an observer side in a glass substrate constituting the first display panel on a second display panel side to a surface on an opposite side to the observer side in a glass substrate constituting the second display panel on a first display panel side and a refractive index of each of the glass substrates. 
     In the display device according to the present disclosure, assuming that t 1  is a width of the extended display region, that n 1  is a refractive index of a glass substrate constituting the first display panel on a second display panel side, that n 2  is a refractive index of a glass substrate constituting the second display panel on a first display panel side, and that d is a distance from a surface on an observer side in the glass substrate constituting the first display panel on the second display panel side to a surface on an opposite side to the observer side in the glass substrate constituting the second display panel on the first display panel side, 
               t   ⁢           ⁢   1     ≥     d   ×       3           4   ⁢           ⁢     n   2       -   3                 
May be satisfied, where n=(n 1 +n 2 )/2.
 
     The display device according to the present disclosure may further include an image processor that generates first image data for displaying a color image in the image display region of the first display panel and second image data for displaying a black-and-white image in the image display region of the second display panel based on an input video signal. 
     In the display device according to the present disclosure, the image display region of the second display panel may include an opposed display region facing the image display region of the first display panel in planar view and an extended display region around the opposed display region, and the image processor may generate the second image data by generating image data for the opposed display region based on the input video signal and generating image data for the extended display region based on the image data for the opposed display region. 
     In the display device according to the present disclosure, the image display region of the second display panel may include an opposed display region facing the image display region of the first display panel in planar view and an extended display region around the opposed display region, a plurality of signal lines to which a signal for image display is supplied from a drive circuit may be arranged in the image display region of the second display panel, and a plurality of the signal lines may be electrically connected to a first output terminal of the drive circuit in the extended display region. 
     In the display device according to the present disclosure, a plurality of another signal lines may be electrically connected to a second output terminal of the drive circuit in the extended display region, the first output terminal may be closer to the opposed display region than the second output terminal, and a number of signal lines electrically connected to the first output terminal may be smaller than a number of signal lines electrically connected to the second output terminal. 
     In the display device according to the present disclosure, in the extended display region, the signal for the image display may be simultaneously supplied to the plurality of signal lines electrically connected to the first output terminal. 
     In the display device according to the present disclosure, a plurality of pixels arranged in the extended display region may overlap a black matrix formed around the image display region of the first display panel in planar view. 
     In the display device according to the present disclosure, the image display region of the second display panel may include an opposed display region facing the image display region of the first display panel in planar view and an extended display region around the opposed display region, and a part of the plurality of pixels arranged in the extended display region may be larger than a pixel arranged in the opposed display region. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a plan view illustrating a schematic configuration of a liquid crystal display device according to an exemplary embodiment. 
         FIG. 2  is a plan view illustrating a schematic configuration of a first display panel of the exemplary embodiment. 
         FIG. 3  is a plan view illustrating a schematic configuration of a second display panel of the exemplary embodiment. 
         FIG. 4  is a sectional view taken along line A-A′ in  FIGS. 2 and 3 . 
         FIG. 5  is a sectional view schematically illustrating a conventional liquid crystal display device. 
         FIG. 6A  is a plan view schematically illustrating a characteristic configuration of the liquid crystal display device of the exemplary embodiment. 
         FIG. 6B  is a sectional view taken along line B-B′ in  FIG. 6A . 
         FIG. 7  is an enlarged view of a left end in  FIG. 6B . 
         FIG. 8  is a plan view illustrating a part of a first image display region of the first display panel. 
         FIG. 9  is a plan view illustrating a part of a second image display region of the second display panel. 
         FIG. 10  is a view illustrating pixel information corresponding to each pixel of the first display panel in  FIG. 8 . 
         FIG. 11  is a view illustrating pixel information corresponding to each pixel of the second display panel in  FIG. 9 . 
         FIG. 12A  is a view illustrating a method for defining an extended display region of the second display panel. 
         FIG. 12B  is a view illustrating a method for defining an extended display region of the second display panel. 
         FIG. 13  is a view illustrating an example of a method for deciding a width of the extended display region based on an inter-panel distance and a refractive index. 
         FIG. 14  is a timing chart illustrating timing of driving a gate line of the first display panel and timing of driving a gate line of the second display panel. 
         FIG. 15  is a plan view illustrating a configuration of a second display panel according to Modification 1. 
         FIG. 16  is a view illustrating pixel information corresponding to each pixel of the second display panel of Modification 1. 
         FIG. 17  is a plan view illustrating a configuration of a second display panel according to Modification 2. 
         FIG. 18  is a plan view illustrating a configuration of a second display panel according to Modification 3. 
         FIG. 19  is a view illustrating pixel information corresponding to each pixel of the second display panel of Modification 3. 
         FIG. 20  is a block diagram illustrating a specific configuration of an image processor of the exemplary embodiment. 
     
    
    
     EMBODIMENT 
     Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. A display device according to the present disclosure is not limited to a liquid crystal display device, but may be an organic electro luminescence display. 
     A liquid crystal display device according to an exemplary 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 display panels, a plurality of timing controllers that control the drive circuits, an image processor that performs image processing on an input video signal input from an outside and outputs image data to each of the timing controllers, and a backlight that irradiates the plurality of display panels with light from a back surface side. There is no limitation to a number of display panels, but it is only necessary to provide at least two display panels. When viewed from the observer side, the plurality of display panels are disposed while superimposed on each other in a front-back direction. An image is displayed on each of the display panels. Liquid crystal display device  10  including two display panels will be described below by way of example. 
       FIG. 1  is a plan view illustrating a schematic configuration of liquid crystal display device  10  of the exemplary embodiment. As illustrated in  FIG. 1 , liquid crystal display device  10  includes first display panel  100  disposed closer to an observer (front side), second display panel  200  disposed farther away from the observer (rear side) than first display panel  100 , first timing controller  140  that controls first source drivers  120  and first gate drivers  130 , first source drivers  120  and first gate drivers  130  being provided in first display panel  100 , second timing controller  240  that controls second source drivers  220  and second gate drivers  230 , second source drivers  220  and second gate drivers  230  being provided in second display panel  200 , and image processor  300  that outputs image data to first timing controller  140  and second timing controller  240 . First display panel  100  displays a color image according to the input video signal, and second display panel  200  displays a black-and-white image (monochrome image) according to the input video signal. Image processor  300  receives input video signal Data transmitted from an external system (not illustrated), performs image processing (to be described later) on input video signal Data, outputs first image data DAT 1  to first timing controller  140 , and outputs second image data DAT 2  to second timing controller  240 . Image processor  300  also outputs a control signal (not illustrated in  FIG. 1 ) such as a synchronizing signal to first timing controller  140  and second timing controller  240 . First image data DAT 1  is image data used to display the color image, and second image data DAT 2  is image data used to display the black-and-white image. The backlight (not illustrated in  FIG. 1 ) is disposed on the back surface side of second display panel  200 . A specific configuration of image processor  300  will be described later. 
       FIG. 2  is a plan view illustrating a schematic configuration of first display panel  100 , and  FIG. 3  is a plan view illustrating a schematic configuration of second display panel  200 .  FIG. 4  is a sectional view taken along line A-A′ in  FIGS. 2 and 3 ; 
     A configuration of first display panel  100  will be described with reference to  FIGS. 2 and 4 . As illustrated in  FIG. 4 , first display panel  100  includes thin film transistor substrate  101  (hereinafter, referred to as a TFT substrate) disposed on the side of backlight  400 , color filter substrate  102  (hereinafter, referred to as a CF substrate), which is disposed on the observer side while being opposite to TFT substrate  101 , and liquid crystal layer  103  disposed between TFT substrate  101  and CF substrate  102 . Polarizing plate  104  is disposed on the side of backlight  400  of first display panel  100 , and polarizing plate  105  is disposed on the observer side. 
     In TFT substrate  101 , as illustrated in  FIG. 2 , a plurality of data lines  111  extending in a first direction (for example, a column direction) and a plurality of gate lines  112  extending in a second direction (for example, a row direction) different from the first direction are formed, and thin film transistors  113  (hereinafter, referred to as a TFT) are formed near an intersection between each of the plurality of data lines  111  and each of the plurality of gate lines  112 , respectively. In planar view of first display panel  100 , a region surrounded by two data lines  111  adjacent to each other and two gate lines  112  adjacent to each other is defined as one pixel  114 , and a plurality of pixels  114  are disposed in a matrix form (the row direction and the column direction). The plurality of data lines  111  are disposed at equal intervals in the row direction, and the plurality of gate lines  112  are disposed at equal intervals in the column direction. In TFT substrate  101 , pixel electrode  115  is formed in each pixel  114 , and one common electrode (not illustrated) common to the plurality of pixels  114  is formed. A drain electrode constituting TFT  113  is electrically connected to data line  111 , a source electrode constituting TFT  113  is electrically connected to pixel electrode  115 , and a gate electrode constituting TFT  113  is electrically connected to gate line  112 . 
     As illustrated in  FIG. 4 , a plurality of colored portions  102   a  each of which corresponds to pixel  114  are formed on CF substrate  102 . Each colored portion  102   a  is surrounded by black matrix  102   b  blocking light transmission. For example, each colored portion  102   a  is formed into a rectangular shape. The plurality of colored portions  102   a  include red portions made of a red (R color) material to transmit red light, green portions made of a green (G color) material to transmit green light, and blue portions made of a blue (B color) material to transmit blue light. The red portion, the green portion, and the blue portion are repeatedly arranged in this order in the row direction, the colored portions having the same color are arranged in the column direction, and black matrix  102   b  is formed at a boundary portion between colored portions  102   a  adjacent in the row and column directions. According to colored portions  102   a , the plurality of pixels  114  include red pixels  114 R corresponding to the red portions, green pixels  114 G corresponding to the green portions, and blue pixels  114 B corresponding to the blue portions as illustrated in  FIG. 2 . 
     Black matrix  102   b  includes a plurality of first light shielding stripes B 1  (see  FIG. 4 ) arranged at each boundary portion between two colored portions  102   a  adjacent to each other in the row direction and a plurality of second light shielding stripes (not illustrated) arranged at each boundary portion between two colored portions  102   a  adjacent to each other in the column direction. The plurality of first light shielding stripes B 1  and the plurality of second light shielding stripes are arranged in first image display region  110   a  (to be described later). Black matrix  102   b  further includes light shielding frame B 2  (see  FIG. 4 ) disposed in first non-display region  110   b . Light shielding frame B 2  surrounds the periphery of the plurality of first light shielding stripes B 1  and the plurality of second light shielding stripes, and is connected to ends of each first light shielding stripe B 1  and each second light shielding stripe. 
     First timing controller  140  has a known configuration. For example, based on first image data DAT 1  and first control signal CS 1  (such as a clock signal, a vertical synchronizing signal, and a horizontal synchronizing signal), which are output from image processor  300 , first timing controller  140  generates various timing signals (data start pulse DSP 1 , data clock DCK 1 , gate start pulse GSP 1 , and gate clock GCK 1 ) in order to control first image data DA 1  and drive of first source driver  120  and first gate driver  130  (see  FIG. 2 ). First timing controller  140  outputs first image data DA 1 , data start pulse DSP 1 , and data clock DCK 1  to first source driver  120 , and outputs gate start pulse GSP 1  and gate clock GCK 1  to first gate driver  130 . 
     First source driver  120  outputs a data signal (data voltage) corresponding to first image data DA 1  to data lines  111  based on data start pulse DSP 1  and data clock DCK 1 . First gate driver  130  outputs a gate signal (gate voltage) to gate lines  112  based on gate start pulse GSP 1  and gate clock GCK 1 . 
     The data voltage is supplied from first source driver  120  to each data line  111 , and the gate voltage is supplied from first gate driver  130  to each gate line  112 . Common voltage Vcom is supplied from a common driver (not illustrated) to the common electrode. When the gate voltage (gate-on voltage) is supplied to gate line  112 , TFT  113  connected to gate line  112  is turned on, and the data voltage is supplied to pixel electrode  115  through data line  111  connected to TFT  113 . An electric field is generated by a difference between the data voltage supplied to pixel electrode  115  and common voltage Vcom supplied to the common electrode. The liquid crystal is driven by the electric field to control a transmittance of light from backlight  400  through second display panel  200 , thereby displaying the image. In first display panel  100 , the color image is displayed by supplying the desired data voltage to data line  111  connected to pixel electrode  115  of each of red pixel  114 R, green pixel  114 G, and blue pixel  114 B. A known configuration can be applied to first display panel  100 . 
     A configuration of second display panel  200  will be described below with reference to  FIGS. 3 and 4 . As illustrated in  FIG. 4 , second display panel  200  includes TFT substrate  201  disposed on the side of backlight  400 , CF substrate  202  that is disposed on the observer side while opposed to TFT substrate  201 , and liquid crystal layer  203  disposed between TFT substrate  201  and CF substrate  202 . Polarizing plate  204  is disposed on the side of backlight  400  of second display panel  200 , and polarizing plate  205  is disposed on the observer side. Diffusion sheet  301  is disposed between polarizing plate  104  of first display panel  100  and polarizing plate  205  of second display panel  200 . 
     In TFT substrate  201 , as illustrated in  FIG. 3 , a plurality of data lines  211  extending in the column direction, a plurality of gate lines  212  extending in the row direction are formed, and TFTs  213  are formed near an intersection between each of the plurality of data lines  211  and each of the plurality of gate lines  212 , respectively. In planar view of second display panel  200 , a region surrounded by two data lines  211  adjacent to each other and two gate lines  212  adjacent to each other is defined as one pixel  214 , and a plurality of pixels  214  are arranged in a matrix form (the row direction and the column direction). The plurality of data lines  211  are disposed at equal intervals in the row direction, and the plurality of gate lines  212  are disposed at equal intervals in the column direction. In TFT substrate  201 , pixel electrode  215  is formed in each pixel  214 , and one common electrode (not illustrated) common to the plurality of pixels  214  is formed. A drain electrode constituting TFT  213  is electrically connected to data line  211 , a source electrode is electrically connected to pixel electrode  215 , and a gate electrode is electrically connected to gate line  212 . 
     As illustrated in  FIG. 4 , in CF substrate  202 , black matrix  202   b  blocking light transmission is formed at a position corresponding to a boundary portion of each pixel  214 . The colored portion is not formed in region  202   a  surrounded by black matrix  202   b . For example, an overcoat film is formed in region  202   a.    
     Based on second image data DAT 2  and second control signal CS 2  (such as a clock signal, a vertical synchronizing signal, and a horizontal synchronizing signal), which are output from image processor  300 , second timing controller  240  generates various timing signals (data start pulse DSP 2 , data clock DCK 2 , gate start pulse GSP 2 , and gate clock GCK 2 ) in order to control second image data DA 2  and drive of second source driver  220  and second gate driver  230  (see  FIG. 3 ). Second timing controller  240  outputs second image data DA 2 , data start pulse DSP 2 , and data clock DCK 2  to second source driver  220 , and outputs gate start pulse GSP 2  and gate clock GCK 2  to second gate driver  230 . 
     Second source driver  220  outputs the data voltage corresponding to second image data DA 2  to data lines  211  based on data start pulse DSP 2  and data clock DCK 2 . Second gate driver  230  outputs the gate voltage to gate lines  212  based on gate start pulse GSP 2  and gate clock GCK 2 . 
     The data voltage is supplied from second source driver  220  to each data line  211 , and the gate voltage is supplied from second gate driver  230  to each gate line  212 . Common voltage Vcom is supplied from the common driver to the common electrode. When the gate voltage (gate-on voltage) is supplied to gate line  212 , TFT  213  connected to gate line  212  is turned on, and the data voltage is supplied to pixel electrode  215  through data line  211  connected to TFT  213 . The electric field is generated by a difference between the data voltage supplied to pixel electrode  215  and common voltage Vcom supplied to the common electrode. The liquid crystal is driven by the electric field to control the transmittance of light from backlight  400 , thereby displaying the image. The black-and-white image is displayed on second display panel  200 . 
     At this point, as described above, the problem that the end of the display image becomes dark arises in the conventional liquid crystal display device configured by superimposing the plurality of display panels.  FIG. 5  is a sectional view schematically illustrating the conventional liquid crystal display device. In the conventional liquid crystal display device, image display region  1100   a  of display panel  1000  on the observer side and image display region  2100   a  of display panel  2000  on the backlight side have the same size, and the positions of the ends are matched with each other in planar view. In the configuration of  FIG. 5 , image display region  1100   a  constitutes the display screen of the liquid crystal display device, and non-display region  1100   b  around image display region  1100   a  constitutes a frame portion of the liquid crystal display device. In the configuration of  FIG. 5 , when the end of the display screen is viewed from an oblique direction (a dotted-line arrow in  FIG. 5 ), a part of non-display region  2100   b  of backlight-side display panel  2000  overlaps image display region  1100   a  of observer-side display panel  1000 , the end of the original display image displayed on the display screen is seen while darkly lacked. 
     On the other hand, liquid crystal display device  10  of the exemplary embodiment has a configuration capable of visually recognizing the original image up to the end of the display image.  FIG. 6A  is a plan view schematically illustrating the configuration in liquid crystal display device  10 , and  FIG. 6B  is a sectional view taken along line B-B′ in  FIG. 6A . In liquid crystal display device  10 , second image display region  210   a  of backlight-side second display panel  200  is formed larger than first image display region  110   a  of observer-side first display panel  100 , and first display panel  100  and second display panel  200  are disposed such that the end (outer periphery) of second image display region  210   a  surrounds first image display region  110   a  in planar view. Backlight  400  is configured such that a light emission surface is larger than first image display region  110   a  and second image display region  210   a . In the configuration of  FIGS. 6A and 6B , first image display region  110   a  constitutes the display screen of liquid crystal display device  10 , and the region around first image display region  110   a  constitutes the frame portion of liquid crystal display device  10 .  FIG. 7  is an enlarged view of the left end in  FIG. 6B . As illustrated in  FIG. 7 , second image display region  210   a  of second display panel  200  has a size in which first image display region  110   a  of first display panel  100  is enlarged. In second image display region  210   a , a region extended with respect to first image display region  110   a  is defined as extended display region  210   c . In liquid crystal display device  10 , second non-display region  210   b  of second display panel  200  is formed smaller than first non-display region  110   b  of first display panel  100 . According to the configuration of liquid crystal display device  10 , when the end of the display screen is viewed from the oblique direction (a dotted-line arrow in  FIG. 7 ), second non-display region  210   b  of second display panel  200  does not overlap first image display region  110   a  of first display panel  100 , and the end of the display image can be prevented from becoming dark (see  FIG. 5 ). 
     In liquid crystal display device  10 , extended display region  210   c  (see  FIG. 7 ) of second display panel  200  displays the same image as the image at the end of the region (hereinafter, referred to as opposed display region  210   d ) opposed to first image display region  110   a  in second image display region  210   a  such that the original display image can visually be recognized when the end of the display screen is viewed from the oblique direction. That is, opposed display region  210   d  is a region overlapping first image display region  110   a  in planar view. A specific configuration relating to extended display region  210   c  will be described below. 
       FIG. 8  is a plan view illustrating a part of first image display region  110   a  of first display panel  100 .  FIG. 9  is a plan view illustrating a part of second image display region  210   a  of second display panel  200 .  FIGS. 8 and 9  illustrate an enlarged configuration of an upper left portion (dotted-line circled portion) of second display panel  200  in  FIG. 6A . In  FIG. 8 , “SD 1 - 1 ” to “SD 1 - 6 ” indicate first to sixth output terminals of first source driver  120 , and “GD 1 - 1 ” to “GD 1 - 3 ” indicate first to third output terminals of first gate driver  130 . In  FIG. 9 , “SD 2 - 1 ” to “SD 2 - 16 ” indicate first to sixteenth output terminals of second source driver  220 , and “GD 2 - 1 ” to “GD 2 - 13 ” indicate first to thirteenth output terminals of second gate driver  230 . 
     As illustrated in  FIGS. 8 and 9 , in first display panel  100 , pixel  114  is not disposed in the region opposed to the frame portion, but black matrix  102   b  (see  FIG. 4 ) is formed. On the other hand, in second display panel  200 , a plurality of pixels  214  are arranged in the region (extended display region  210   c ) opposed to the frame portion. For this reason, the plurality of pixels  214  arranged in extended display region  210   c  are arranged so as to overlap black matrix  102   b  opposed to the frame portion in planar view. More particularly, the plurality of pixels  214  arranged in extended display region  210   c  are arranged so as to overlap light shielding frame B 2  disposed in the frame portion of first display panel  100  in planar view. In the example of  FIG. 9 , ten pixels  214  are arranged in the row direction and the column direction respectively in the extended display region  210   c  so as to overlap black matrix  102   b  in planar view. In the case that first display panel  100  and second display panel  200  are superimposed such that the center positions in the row direction and the column direction are matched with each other in planar view, ten pixels  214  are arranged around first image display region  110   a  in the extended display region  210   c.    
       FIG. 10  is a view illustrating pixel information corresponding to each pixel  114  of first display panel  100  in  FIG. 8 . For example, the pixel information includes information indicating a gradation of the image displayed on each pixel  114 . In the example of  FIG. 10 , for example, the image corresponding to the gradation of “R 11 ” is displayed in the pixel (red pixel  114 R) at the upper left end, and the image corresponding to the gradation of “G 12 ” is displayed in the pixel (green pixel  114 G) adjacent to the right of red pixel  114 R. Consequently, the color image corresponding to input video signal Data is displayed in first image display region  110   a  of first display panel  100 . 
       FIG. 11  is a view illustrating pixel information corresponding to each pixel  214  of second display panel  200  in  FIG. 9 . In opposed display region  210   d  of second image display region  210   a  of second display panel  200 , the image corresponding to the gradation of “C 11 ” is displayed in pixel  214  (a thick-line enclosed portion in  FIG. 11 ) at the upper left end, and the image corresponding to the gradation of “C 12 ” is displayed in pixel  214  adjacent to the right. Consequently, the black-and-white image corresponding to input video signal Data is displayed in opposed display region  210   d.    
     The same image as the image displayed in pixel  214  at the end of opposed display region  210   d  is displayed in extended display region  210   c  of second image display region  210   a  of second display panel  200 . Specifically, in extended display region  210   c , the image corresponding to the gradation of “C 11 ” is displayed in pixels  214  included in the first to tenth columns and the first to tenth rows of second image display region  210   a  in the same manner as pixel  214  at the upper left end of opposed display region  210   d , the image corresponding to the gradation of “C 11 ” is displayed in pixel  214  of the eleventh column in the same manner as pixel  214  at the upper end of opposed display region  210   d , the image corresponding to the gradation of “C 12 ” is displayed in pixel  214  of the twelfth column, and the image corresponding to the gradation of “C 13 ” is displayed in pixel  214  of the thirteenth column. In extended display region  210   c , the image corresponding to the gradation of “C 11 ” is displayed in pixel  214  of the eleventh row in the same manner as pixel  214  at the upper end of opposed display region  210   d , the image corresponding to the gradation of “C 21 ” is displayed in pixel  214  of the twelfth row, and the image corresponding to the gradation of “C 31 ” is displayed in pixel  214  of the thirteenth row. In this way, when the display screen is viewed from the oblique direction (see  FIG. 7 ), extended display region  210   c  of second display panel  200  overlaps first image display region  110   a  of first display panel  100 , and the same image as the end of opposed display region  210   d  is displayed in extended display region  210   c , so that the image corresponding to the input video signal can also visually be recognized at the end of the display screen. As described above, in liquid crystal display device  10 , second image display region  210   a  of second display panel  200  is larger than first image display region  110   a  of first display panel  100  in first display panel  100  disposed closer to the observer and second display panel  200  disposed farther from the observer than first display panel  100 . The size of second image display region  210   a  is set according to a structure of liquid crystal display device  10 . A method for defining a difference between first image display region  100   a  and second image display region  210   a  (that is, extended display region  210   c ) will be described below. 
       FIGS. 12A and 12B  are views illustrating the method for defining extended display region  210   c .  FIG. 12A  is a sectional view illustrating a state in which the display screen is viewed from the oblique direction of 60 degrees with respect to the vertical direction.  FIG. 12B  is a view illustrating a sectional structure near the boundary portion between first display panel  100  and second display panel  200 . For example, width t 1  of extended display region  210   c  is set to a value such that second non-display region  210   b  does not overlap first image display region  110   a  when the display screen is viewed from the 60-degree oblique direction. Width t 1  of extended display region  210   c  mainly depends on an inter-panel distance in  FIG. 12B . Specifically, the inter-panel distance is calculated from a total of thicknesses of glass substrate  101   a  and polarizing plate  104  that constitute first display panel  100 , thicknesses of glass substrate  202   c  and polarizing plate  205  that constitute second display panel  200 , and a thickness of diffusion sheet  301  disposed between first display panel  100  and second display panel  200 . Width t 1  of extended display region  210   c  is also affected by refractive indices of glass substrates  101   a ,  202   c . Thus, width t 1  of extended display region  210   c  is set based on the inter-panel distance and the refractive indices of glass substrates  101   a ,  202   c . For example, width t 1  of extended display region  210   c  is set to a larger value with increasing inter-panel distance, and width t 1  is set to a smaller value with decreasing refractive indices of glass substrates  101   a ,  202   c.    
     A number and a size of pixels  214  arranged in extended display region  210   c  are decided when width t 1  of extended display region  210   c  is calculated based on the inter-panel distance and the refractive indices. In this way, the structure of extended display region  210   c  is defined. 
       FIG. 13  is a view illustrating an example of a method for deciding width t 1  of extended display region  210   c  based on the inter-panel distance and the refractive indices. As illustrated in  FIG. 13 , in the case that the display screen is observed from the direction inclined by angle θ with respect to direction nd normal to the surface of first display panel  100 , video light from second display panel  200  is refracted according to the refractive index of each of the layers constituting liquid crystal display device  10 , and then is directed from the direction inclined by angle θ to observer&#39;s eyes. At this point, as illustrated in  FIG. 13 , attention is paid to light L 1  that passes through pixel  114  located at the end of first image display region  110   a  from pixel  214  of second display panel  200  and enters the observer&#39;s eyes from the direction inclined by angle θ. Assuming that parallax countermeasure width X is an amount in which light L 1  is shifted from the boundary portion between extended display region  210   c  and opposed display region  210   d  on the surface of the layer on which black matrix  202   b  of CF substrate  202  is formed. In the case that width t 1  of extended display region  210   c  is greater than or equal to parallax countermeasure width X, the image at the end can be checked with desired brightness even if the observer observes the display screen from the direction inclined by angle θ. 
     As described above, in order to strictly obtain necessary parallax countermeasure width X, it is necessary to perform a calculation in consideration of the refractive index and the thickness of each layer located between the layer in which black matrix  102   b  of first display panel  100  is disposed and the layer in which black matrix  202   b  of second display panel  200  is disposed. However, the refractive index difference between these layers is small, and glass substrate  101   a  constituting TFT substrate  101  of first display panel  100  and glass substrate  202   c  constituting CF substrate  202  of second display panel  200  contribute largely to the decision of parallax countermeasure width X because glass substrate  101   a  and glass substrate  202   c  are thick. For this reason, each layer located between the layer in which black matrix  102   b  of first display panel  100  is disposed and the layer in which black matrix  202   b  of second display panel  200  is disposed is regarded as a single layer, and refractive index n of the single layer is regarded as an average value of refractive index n 1  of glass substrate  101   a  of first display panel  100  and refractive index n 2  of glass substrate  202   c  of second display panel  200 . That is, the following equation (1) is given.
 
Refractive index of single layer  n =(refractive index  n 1+refractive index  n 2)/2  (1)
 
     According to this assumption, the layer between the layer in which black matrix  102   b  of first display panel  100  is disposed and the layer in which black matrix  202   b  of second display panel  200  is disposed can be regarded as the single layer. Consequently, assuming that d′ is a distance between the layer in which black matrix  102   b  of first display panel  100  is disposed and the layer in which black matrix  202   b  of second display panel  200  is disposed, the following equation (2) is given by a geometrical relationship in  FIG. 13 .
 
parallax countermeasure width  X =distance  d′× tan θ′  (2)
 
     At this point the following equation (3) is satisfied due to the geometrical relationship in  FIG. 13 .
 
 n ×sin θ′=1×sin θ  (3)
 
     Even in the lateral electric field (IPS) system liquid crystal display panel that is said to have the widest viewing angle, the inventors have found by experiments that the observer is free from a sense of discomfort even if a display abnormality is generated when the observer observes the display screen from the direction inclined by at least 60 degrees, unless the display abnormality is generated at the end of the display image when the observer observes the display screen from the direction inclined by 60 degrees. Thus, preferably angle θ is set to 60 degrees in order to obtain necessary parallax countermeasure width X. Assuming that angle θ is 60 degrees, when tan θ′ is calculated from the equation (3), the following equation (4) is obtained. 
     
       
         
           
             
               
                 
                   
                     tan 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     
                       θ 
                       ′ 
                     
                   
                   = 
                   
                     
                       3 
                     
                     
                       
                         
                           4 
                           ⁢ 
                           
                               
                           
                           ⁢ 
                           
                             n 
                             2 
                           
                         
                         - 
                         3 
                       
                     
                   
                 
               
               
                 
                   ( 
                   4 
                   ) 
                 
               
             
           
         
       
     
     The following equation (5) is obtained by substituting the equation (4) into the equation (2). 
     
       
         
           
             
               
                 
                   
                     parallax 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     countermeasure 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     width 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     X 
                   
                   = 
                   
                     distance 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     
                       d 
                       ′ 
                     
                     × 
                     
                       
                         3 
                       
                       
                         
                           
                             4 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             
                               n 
                               2 
                             
                           
                           - 
                           3 
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   5 
                   ) 
                 
               
             
           
         
       
     
     At this point, the thickness of liquid crystal layer  103  can be ignored because the thickness of liquid crystal layer  103  is negligibly small as compared with other layers. Thus, distance d′ can be regarded as distance d from the observer-side surface in glass substrate  101   a  (that is, glass substrate  101   a  constituting TFT substrate  101  of first display panel  100 ) constituting first display panel  100  on the side of second display panel  200  to the surface on the opposite side to the observer side in glass substrate  202   c  (that is, glass substrate  202   c  constituting CF substrate  202  of second display panel  200 ) constituting second display panel  200  on the side of first display panel  100  (see  FIG. 13 ). Thus, the following equation (6) is obtained by substituting distance d′=distance d into the equation (5). 
     
       
         
           
             
               
                 
                   
                     parallax 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     countermeasure 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     width 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     X 
                   
                   = 
                   
                     distance 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     d 
                     × 
                     
                       
                         3 
                       
                       
                         
                           
                             4 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             
                               n 
                               2 
                             
                           
                           - 
                           3 
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   6 
                   ) 
                 
               
             
           
         
       
     
     As described above, the display defect at the end can be prevented when width t 1  of extended display region  210   c  is greater than or equal to parallax countermeasure width X, so that the display defect at the end can efficiently be prevented from the expression (6) when 
                       width   ⁢           ⁢   t   ⁢           ⁢   1   ⁢           ⁢   of   ⁢           ⁢   extended   ⁢           ⁢   display   ⁢           ⁢   region   ⁢           ⁢   210   ⁢           ⁢   c     ≥   parallax     ⁢           ⁢     
     ⁢           ⁢       countermeasure   ⁢           ⁢   width   ⁢           ⁢   X     =     distance   ⁢           ⁢   d   ×       3           4   ⁢           ⁢     n   2       -   3                     (   7   )               
is satisfied.
 
     Table 1 is a table illustrating the result in which necessary parallax countermeasure width X is simulated by changing the thickness of each layer while observation angle θ of the observer is set to 60 degrees. A typical refractive index value of each layer are used. Specifically, the values illustrated in Table 1 are used. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                 REFRACTIVE 
                   
                   
               
               
                   
                 INDEX 
                 SAMPLE 1 
                 SAMPLE 2 
               
               
                   
               
             
            
               
                 GLASS 101a OF TFT 
                 1.50 
                 1.0 mm 
                 0.5 mm 
               
               
                 SUBSTRATE 101 
                   
                   
                   
               
               
                 POLARIZING PLATE 104 
                 1.49 
                 0.2 mm 
                 0.3 mm 
               
               
                 DIFFUSION SHEET 301 
                 1.58 
                 0.5 mm 
                 0.3 mm 
               
               
                 POLARIZING PLATE 205 
                 1.49 
                 0.2 mm 
                 0.3 mm 
               
               
                 GLASS 202c OF CF 
                 1.50 
                 1.0 mm 
                 0.5 mm 
               
               
                 SUBSTRATE 202 
                   
                   
                   
               
               
                 DISTANCE d 
                   
                 2.9 mm 
                 1.9 mm 
               
               
                 NECESSARY PARALLAX 
                   
                 2.03 mm  
                 1.33 mm  
               
               
                 COUNTERMEASURE  
                   
                   
                   
               
               
                 WIDTH X′ 
               
               
                   
               
            
           
         
       
     
     When necessary parallax countermeasure width X′ is calculated in consideration of the refractive index of each layer, as illustrated in Table 1, 2.03 mm and 1.33 mm are obtained for samples 1, 2, respectively. On the other hand, when necessary parallax countermeasure width X is calculated from the equation (6), 2.05 mm and 1.34 mm are obtained for samples 1, 2, respectively. Because the size of one pixel is at least about 0.13 mm, the difference between parallax countermeasure width X′ obtained from the actual calculation and parallax countermeasure width X obtained from the expression (6) is a value enough to be acceptable as compared with the size of the pixel, and the expression (6) can be used as parallax countermeasure width X. 
     A method for driving liquid crystal display device  10  will be described below. In liquid crystal display device  10 , the number of pixels  114  of first display panel  100  is different from the number of pixels  214  of second display panel  200 , and therefore first display panel  100  is different from second display panel  200  in the number of signal lines (data lines, gate lines). For this reason, in first display panel  100  and second display panel  200 , it is necessary to adjust timing of driving each signal line. 
       FIG. 14  is a timing chart illustrating timing of driving gate line  112  of first display panel  100  and timing of driving gate line  212  of second display panel  200 . At this point, it is assumed that n gate lines  112  are provided in first display panel  100  and m gate lines  212  are provided in second display panel  200 . It is also assumed that the numbers of pixels  114  and signal lines arranged in first display panel  100  are equal to the numbers of pixels  214  and signal lines arranged in opposed display region  210   d  of second display panel  200 . Additionally, as illustrated in  FIGS. 8 and 9 , it is assumed that ten more gate lines  212  than that of first display panel  100  are vertically arranged in second display panel  200 . In  FIG. 13 , GL 1 ( 1 ) indicates the gate signal supplied to gate line  112  of the first row of first display panel  100 , and GL 1 ( n ) indicates the gate signal supplied to gate line  112  of the last nth row. GL 2 ( 1 ) indicates the gate signal supplied to gate line  212  of the first row of second display panel  200 , and GL 2 ( m ) indicates the gate signal supplied to gate line  212  of the last mth row. GL 2 ( 1 ) to GL 2 ( 10 ), GL 2 ( m− 9) to GL 2 ( m ) indicate the gate signals supplied to gate lines  212  arranged in extended display region  210   c . Thus, gate lines  112  from the first row to the nth row of first display panel  100  and gate lines  212  from the eleventh row to the (m−10)th row of second display panel  200  are arranged while overlapping each other in planar view of liquid crystal display device  10 . 
     In first frame F 1  of the above configuration, in second display panel  200 , gate signals GL 2 ( 1 ) to GL 2 ( 10 ) are sequentially supplied to gate lines  212  from the first row to the tenth row, and the data voltage corresponding to the image information in  FIG. 11  is supplied to pixel electrode  215 . Subsequently, gate signals GL 2 ( 11 ) to GL 2 ( m− 10) are sequentially supplied to gate lines  212  from the eleventh row to the (m−10)th row in second display panel  200  at the same time as gate signals GL 1 ( 1 ) to GL 1 ( n ) are sequentially supplied to gate lines  112  from the first row to the nth row in first display panel  100 , and the data voltage corresponding to the image information in  FIG. 11  is supplied to pixel electrode  215  at the same time as the data voltage corresponding to the image information in  FIG. 10  is supplied to pixel electrode  115 . Subsequently, in second display panel  200 , gate signals GL 2 ( m− 9) to GL 2  ( m ) are sequentially supplied to gate lines  212  from the (m−9)th row to the mth row, and the data voltage corresponding to the image information in  FIG. 11  is supplied to pixel electrode  215 . As described above, the image is displayed in extended display region  210   c  of second display panel  200  during periods t 11 , t 13  in first frame F 1 , and the image is displayed in first image display region  110   a  of first display panel  100  and opposed display region  210   d  of second display panel  200  during period t 12 . The same operation as first frame F 1  is performed in second frame F 2 . The same operation is also performed in subsequent frames. 
     Liquid crystal display device  10  performs the display operation as described above. The display operation is not limited to the above method. 
     Liquid crystal display device  10  is not limited to the above configuration. For example, various modes can be applied to the configuration of extended display region  210   c  of second display panel  200 . Another configuration example of extended display region  210   c  will be described below. 
     As described above, the same image is displayed on a part of the plurality of pixels  214  arranged in extended display region  210   c . For example, in  FIG. 11 , the images corresponding to the gradation of “C 11 ” are displayed in eleven pixels  214  arranged in the row direction in the first row, and the images corresponding to the gradation of “C 21 ” are displayed in ten pixels  214  arranged in the row direction in the twelfth row. As illustrated in  FIGS. 15 and 16 , the signal lines (data lines  211  and gate lines  212 ) corresponding to the plurality of pixels in which the same image is displayed may be driven at the same time.  FIG. 15  is a plan view illustrating a configuration of second display panel  200  according to Modification 1, and  FIG. 17  is a plan view illustrating a configuration of second display panel  200  according to Modification 2. 
     In second display panel  200  of  FIG. 15 , seven data lines  211  from the first column to the seventh column are connected to one output terminal SD 2 - 7 , and seven gate lines  212  from the first row to the seventh row are connected to one output terminal GD 2 - 7 . That is, the signal line connected to one output terminal SD 2 - 7  is branched into seven data lines  211 , and the signal line connected to one output terminal GD 2 - 7  is branched into seven gate lines  212 . In  FIG. 15 , for convenience, the output terminal is indicated by the number corresponding to the position of the output terminal in  FIG. 9 . The same holds true for the following drawings. In display panel  200  of Modification 1, as illustrated in  FIG. 16 , the image is displayed in the same manner as display panel  200  (see  FIG. 11 ). 
     In second display panel  200  of  FIG. 17 , four data lines  211  from the first column to the fourth column are connected to one output terminal SD 2 - 7 , three data lines  211  from the fifth column to the seventh column are connected to one output terminal SD 2 - 8 , two data lines  211  of the eighth column and the ninth column are connected to one output terminal SD 2 - 9 , and data line  211  of the tenth column is connected to one output terminal SD- 10 . Similarly, four gate lines  212  from the first row to the fourth row are connected to one output terminal GD 2 - 7 , three gate lines  212  from the fifth row to the seventh row are connected to one output terminal GD 2 - 8 , two gate lines  212  of the eighth row and the ninth row are connected to one output terminal GD 2 - 9 , and gate line  212  on the tenth row is connected to 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 , and the signal line connected to one output terminal SD- 9  is branched into two data lines  211 . Similarly, the signal line connected to one output terminal GD- 7  is branched into four gate lines  212 , the signal line connected to one output terminal GD- 8  is branched into three gate lines  212 , and the signal line connected to one output terminal GD- 9  is branched into two gate lines  212 . In this way, display panel  200  is configured such that the number of branches of data line  211  and the number of branches of gate line  212  are decreased as data line  211  and gate line  212  approach opposed display region  210   d  (first image display region  110   a ). 
     In each of the configurations in  FIGS. 9, 15, and 17 , the plurality of pixels  214  have the same size as each other. However, the present invention is not limited this configuration. For example, a part of the plurality of pixels  214  arranged in extended display region  210   c  may have a size different from other pixels  214 .  FIG. 18  is a plan view illustrating a configuration of second display panel  200  according to Modification 3. In second display panel  200  of  FIG. 18 , the plurality of pixels  214  arranged in extended display region  210   c  is configured such that the size of pixel  214  is enlarged with increasing distance from opposed display region  210   d  (first image display region  110   a ). For example, assuming that s 1  is a pitch in the row direction of the plurality of pixels  214  arranged in opposed display region  210   d , the plurality of pixels  214  are arranged in extended display region  210   c  such that the pitch of pixel  214  in the fourth column becomes s 1 , such that the pitch of pixel  214  in the third column becomes s 1 ×2, such that the pitch of pixel  214  in the second column becomes s 1 ×3, and such that the pitch of pixel  214  in the first column becomes s 1 &gt;4. That is, as compared with pixels  214  arranged in opposed display region  210   d , pixel  214  in the fourth column has the size multiplied by one in the row direction, pixel  214  in the third column has the size multiplied by two in the row direction, pixel  214  in the second column has the size multiplied by three in the row direction, and pixel  214  in the first column has the size multiplied by four in the row direction. Similarly, for example, assuming that g 1  is a pitch in the column direction of the plurality of pixels  214  arranged in opposed display region  210   d , the plurality of pixels  214  arranged in extended display region  210   c  are arranged such that the pitch of pixels  214  of the fourth row becomes g 1 , such that the pitch of pixels  214  in the third row becomes g 1 ×2, such that the pitch of pixels  214  in the second row becomes g 1 ×3, and such that the pitch of pixels  214  in the first row becomes g 1 ×4. That is, as compared with pixels  214  arranged in opposed display region  210   d , pixel  214  in the fourth row has the size multiplied by one in the column direction, pixel  214  in the third row has the size multiplied by two in the column direction, pixel  214  in the second row has the size multiplied by three in the column direction, and pixel  214  in the first row has the size multiplied by four in the column direction. In second display panel  200  of Modification 3, as illustrated in  FIG. 19 , the image is displayed in the same manner as each of second display panels  200  described above. 
     According to second display panel  200  of Modifications 1 to 3, the number of outputs of each driver can be decreased as compared with the configuration in  FIG. 9 . According to second display panel  200  of Modifications 1 and 2, the plurality of gate lines  212  can simultaneously be driven (selected), so that the display time (drive time) of extended display region  210   c  can be shortened as compared with the configurations in  FIGS. 9 and 13 . As described above, pixels  214  arranged in extended display region  210   c  can have the configuration different from that of pixels  214  arranged in opposed display region  210   d . However, preferably pixels  214  arranged in extended display region  210   c  is configured to come close to the condition (the number of branches of the signal line or the size of the pixel) corresponding to pixel  214  of opposed display region  210   d  as pixel  214  comes close to opposed display region  210   d.    
     A specific configuration of image processor  300  will be described below.  FIG. 20  is a block diagram illustrating the specific configuration of image processor  300 . Image processor  300  includes first delay part  311 , first gamma processor  312 , second delay part  313 , first image output part  314 , black-and-white image data generation part  321 , second gamma processor  322 , maximum value filter processing part  323 , average value filter processing part  324 , extended display image data generator  325 , and second image output part  326 . 
     When receiving input video signal Data transmitted from an external system, image processor  300  transfers input video signal Data to first delay part  311  and black-and-white image data generation part  321 . For example, input video signal Data includes luminance information (gradation information) and color information. Black-and-white image data generation part  321  generates black-and-white image data corresponding to the black-and-white image based on input video signal Data. Second gamma processor  322  performs gamma processing on the black-and-white image displayed on second display panel  200  based on the black-and-white image data. For example, second gamma processor  322  sets a gamma value (second gamma value) to 0.3. 
     Based on input video signal Data output from first delay part  311  and the second gamma value (γ=0.3) output from second gamma processor  322 , first gamma processor  312  performs the gamma processing on the color image displayed on first display panel  100 . For example, first gamma processor  312  sets the gamma value (first gamma value) of the color image to 1.9 such that a combined gamma value of the display image in which the black-and-white image and the color image are combined becomes 2.2. First gamma processor  312  outputs the color image data (first image data) subjected to the gamma processing to second delay part  313 . 
     Maximum value filter processing part  323  performs the maximum value filter processing based on the black-and-white image data output from second gamma processor  322 . Maximum value filter processing part  323  can apply known maximum value filter processing. For example, maximum value filter processing part  323  sets a circular area of 11 pixels×11 pixels to a filter size, and performs the maximum value filter processing. Consequently, for example, a high-luminance region (white region) can be enlarged. 
     Average value filter processing part  324  performs average value filter processing based on the black-and-white image data output from maximum value filter processing part  323 . Average value filter processing part  324  can apply known average value filter processing. For example, average value filter processing part  324  sets the circular area of 11 pixels×11 pixels to the filter size, and performs the average value filter processing. Consequently, for example, a high-frequency component is eliminated, so that a luminance change can be smoothed. 
     Based on the black-and-white image data output from average value filter processing part  324 , extended display image data generator  325  generates the extended display image data (second image data) of the black-and-white image corresponding to second image display region  210   a  including extended display region  210   c  (see  FIG. 9 ). For example, extended display image data generator  325  generates the second image data based on the number of pixels  214  in extended display region  210   c  defined by the method in  FIG. 12 . Extended display image data generator  325  outputs the generated second image data to second image output part  326 . 
     Second delay part  313  outputs the first image data output from first gamma processor  312  to first image output unit  314  in synchronization with output timing of extended display image data generator  325 . 
     First image output part  314  outputs first image data DAT  1  to first timing controller  140 , and second image output part  326  outputs second image data DAT  2  to second timing controller  240 . Image processor  300  outputs first control signal CS 1  to first timing controller  140 , and outputs second control signal CS 2  to second timing controller  240  (see  FIGS. 2 and 3 ). 
     Image processor  300  is not limited to the above configuration. For example, extended display image data generator  325  may be provided between second gamma processor  322  and maximum value filter processing part  323 . That is, image processor  300  may perform the maximum value filter processing and the average value filter processing on extended display image data. 
     In the exemplary embodiment, second display panel  200  displays the black-and-white image and includes black matrix  202 . However, black matrix  202   b  of second display panel  200  may not necessarily be provided. 
     In the above, the specific embodiments of the present application have been described, but the present application is not limited to the above-mentioned embodiments, and various modifications may be made as appropriate without departing from the spirit of the present application.