Patent Publication Number: US-9887245-B2

Title: Image device with improved chrominance quality

Description:
FIELD 
     The present disclosure relates to an image device, more particularly to a system and method to improve the chrominance quality of an image device or a display by the utilization of RGBW pixels and RGBY pixels. 
     BACKGROUND 
     Referring to  FIG. 1 , it shows a conventional RGBW display  10 . The conventional RGBW display  10  comprises a plurality of RGBW pixels  11 . Each RGBW pixel  11  comprises a green sub-pixel  111 , a red sub-pixel  112 , a blue sub-pixel  113  and a white sub-pixel  114  arranged in a 2×2 matrix. The conventional RGBW display  10  has the merit of enhanced color space and improved brightness and contrast, compared with traditional RGB display. U.S. Pat. No. 4,892,391, U.S. Pat. No. 5,757,452, U.S. Pat. Nos. 7,286,136, 7,742,205, and U.S. Pat. No. 7,583,279 teach RGBW displays. However, the conventional RGBW display  10  has the deficiency of dark yellow. U.S. Pat. No. 4,800,375, U.S. Pat. No. 7,864,271, and U.S. Pat. No. 8,749,727 teach RGBY displays which claim to have better yellow color. However, RGBY display lacks the merits of RGBW displays. U.S. Pat. No. 7,248,314, U.S. Pat. No. 7,995,019, U.S. Pat. No. 8,248,440, U.S. Pat. No. 8,441,601 and U.S. Pat. No. 8,558,857 teach displays with five color sub-pixels. However five color displays have the deficiency of high cost and low brightness and contrast. U.S. Pat. No. 8,384,653 teaches a method to relief the dark yellow problem by classifying the image signal and then adjusts the backlight luminance according to the classification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Implementations of the present technology will now be described, by way of example only, with reference to the attached figures, wherein: 
         FIG. 1  illustrates a conventional RGBW display. 
         FIG. 2  illustrates an image device according to a first embodiment of the present disclosure. 
         FIG. 3  illustrates an example of the image device of  FIG. 2  according to the first embodiment of the present disclosure. 
         FIG. 4  illustrates another image device according to a second embodiment of the present disclosure. 
         FIG. 5  illustrates an example the image device of  FIG. 4  according to the second embodiment of the present disclosure. 
         FIGS. 6-21  illustrate several modified examples of the image device according to the first embodiment of the present disclosure. 
         FIGS. 22-25  illustrate several modified examples of the image devices according to the second embodiment of the present disclosure. 
         FIG. 26  illustrates an image device according to a third embodiment of the present disclosure. 
         FIG. 27  illustrates an example of the image device of  FIG. 26  according to the third embodiment of the present disclosure. 
         FIGS. 28-33  illustrate several modified examples of the image devices according to the third embodiment of the present disclosure. 
         FIG. 34  illustrates an image device according to a fourth embodiment of the present disclosure. 
         FIG. 35  illustrates an example of the image device of  FIG. 34  according to the fourth embodiment of the present disclosure. 
         FIGS. 36-39  illustrate several modified examples of the image devices according to the fourth embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details and features of the present disclosure. 
     Several definitions that apply throughout this disclosure will now be presented. 
     The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The connection can be such that the objects are permanently connected or releasably connected. The term “outside” refers to a region that is beyond the outermost confines of a physical object. The term “inside” indicates that at least a portion of a region is partially contained within a boundary formed by the object. The term “substantially” is defined to be essentially conforming to the particular dimension, shape or other word that substantially modifies, such that the component need not be exact. For example, substantially cylindrical means that the object resembles a cylinder, but can have one or more deviations from a true cylinder. The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series and the like. 
     The present disclosure is relates to an image device with improved chrominance quality. The image device comprises a substrate and a plurality of pixels disposed on the substrate to display an image. The pixels comprise a plurality of sub-pixels. The sub-pixels, e.g., a R sub-pixel representing a red color, a G sub-pixel representing a green color, a B sub-pixel representing a blue color, a W sub-pixel representing a white color, and a Y sub-pixel representing a yellow color, will be described in detail. 
     Referring to  FIG. 2 , it illustrates an image device  20  according to an embodiment of the present disclosure. The image device  20  comprises a plurality of pixels each comprising a plurality of sub-pixels with different colors arranged in a matrix of rows and columns. As shown in  FIG. 2 , the image device  20  comprises a plurality of white sub-pixels  204  and a plurality of yellow sub-pixels  205 . Every other row comprises white sub-pixels  204  and yellow sub-pixels  205 . Namely, in any two adjacent rows, the white sub-pixels  204  and the yellow sub-pixels  205  are arranged in the same row. In this row, white sub-pixels  204  and yellow sub-pixels  205  are separately disposed, and two white sub-pixels  204  are arranged between two yellow sub-pixels  205 . Furthermore, the white sub-pixels  204  are arranged in the columns without yellow sub-pixels  205 , and the yellow sub-pixels  205  are arranged in the columns without white sub-pixels  204 . The white sub-pixels  204  and the yellow sub-pixels  205  arranged in any two adjacent columns are respectively arranged in different rows. The white sub-pixels  204  arranged in any two adjacent columns are respectively arranged in different rows.  FIG. 2  shows an arrangement rule of the sub-pixels. 
     Referring to  FIG. 3 , it illustrates an example of the image device  20  of  FIG. 2  according to the first embodiment of the present disclosure. The image device  20  comprises a plurality of pixels comprising a plurality of sub-pixels with different colors arranged in a matrix of rows and columns. As shown in  FIG. 3 , the image device  20  comprises a plurality of A sub-pixels  201 , a plurality of B sub-pixels  202 , a plurality of C sub-pixels  203 , a plurality of white sub-pixels  204  and a plurality of yellow sub-pixels  205 . In any 2×2 matrix  21 , there are always one A sub-pixel  201 , one B sub-pixel  202 , and one C sub-pixel  203 . In other words, the image device  20  may comprise a plurality of ABCW pixels and a plurality of ABCY pixels. Each ABCW pixel comprises a A sub-pixel  201 , a B sub-pixel  202 , a C sub-pixel  203  and a white sub-pixel  204 . Each ABCY pixel comprises a A sub-pixel  201 , a B sub-pixel  202 , a C sub-pixel  203  and a yellow sub-pixel  205 . The ABCW pixels and the ABCY pixels are mixed in the image device  20 . The A sub-pixel  201 , B sub-pixel  202 , and C sub-pixel  203  may respectively be a red sub-pixel, a green sub-pixel, or a blue sub-pixel, as required or designed. Namely, the A sub-pixel  201  may be a red sub-pixel, a green sub-pixel, or a blue sub-pixel, the B sub-pixel  202  may be a red sub-pixel, a green sub-pixel, or a blue sub-pixel, and the C sub-pixel  203  may be a red sub-pixel, a green sub-pixel, or a blue sub-pixel. 
     Referring to  FIG. 4 , it illustrates an image device according to a second embodiment of the present disclosure. The image device  30  comprises a plurality of pixels comprising a plurality of sub-pixels with different colors arranged in a matrix of rows and columns. As shown in  FIG. 4 , the image device  30  comprises a plurality of white sub-pixels  304  and a plurality of yellow sub-pixels  305 . Every other column comprises white sub-pixels  304  and yellow sub-pixels  305 . Namely, in any two adjacent columns, all of the white sub-pixels  304  and the yellow sub-pixels  305  are arranged in the same column. In this column, white sub-pixels  304  and yellow sub-pixels  305  are separately disposed, and two white sub-pixels  304  are arranged between two yellow sub-pixels  305 . Furthermore, the white sub-pixels  304  are arranged in the rows without yellow sub-pixels  305 , and the yellow sub-pixels  305  are arranged in the rows without white sub-pixels  304 . The white sub-pixels  304  and the yellow sub-pixels  305  arranged in any two adjacent rows are respectively arranged in different columns. The white sub-pixels  304  arranged in any two adjacent rows are respectively arranged in different columns.  FIG. 4  shows an arrangement rule of the sub-pixels, which is similar to arrangement rule shown in  FIG. 2  but rotates 90 degrees. 
     Referring to  FIG. 5 , it illustrates an example of the image device  30  of  FIG. 4  according to the second embodiment of the present disclosure. The image device  30  comprises a plurality of pixels comprising a plurality of sub-pixels with different colors arranged in a matrix of rows and columns. As shown in  FIG. 5 , the image device  30  comprises a plurality of A sub-pixels  301 , a plurality of B sub-pixels  302 , a plurality of C sub-pixels  303 , a plurality of white sub-pixels  304  and a plurality of yellow sub-pixels  305 . In any 2×2 matrix  31 , there are always one A sub-pixel  301 , one B sub-pixel  302 , and one C sub-pixel  303 . In other words, the image device  30  may comprise a plurality of ABCW pixels and a plurality of ABCY pixels. Each ABCW pixel comprises a A sub-pixel  301 , a B sub-pixel  302 , a C sub-pixel  303  and a white sub-pixel  304 . Each ABCY pixel comprises a A sub-pixel  301 , a B sub-pixel  302 , a C sub-pixel  303  and a yellow sub-pixel  305 . The ABCW pixels and the ABCY pixels are mixed in the image device  30 . The A sub-pixel  301 , B sub-pixel  302 , and C sub-pixel  303  may respectively be a red sub-pixel, a green sub-pixel, or a blue sub-pixel, as required or designed. Namely, the A sub-pixel  301  may be a red sub-pixel, a green sub-pixel, or a blue sub-pixel, the B sub-pixel  302  may be a red sub-pixel, a green sub-pixel, or a blue sub-pixel, and the C sub-pixel  303  may be a red sub-pixel, a green sub-pixel, or a blue sub-pixel. 
       FIG. 6  throughout  21  illustrate several modified examples of image devices  40 A- 40 P following the arrangement rule of the white sub-pixels and yellow sub-pixel described above shown in  FIG. 2  according to the first embodiment of the present disclosure. Each of the image devices  40 A- 40 P comprises a plurality of pixels comprising a plurality of sub-pixels with different colors arranged in a matrix of rows and columns. More specifically, each of the image devices  40 A- 40 P comprises a plurality of RGBW pixels  42  and a plurality of RGBY pixels  44 . Each RGBW pixels  42  comprises a red sub-pixel  401 , a green sub-pixel  402 , a blue sub-pixel  403  and a white sub-pixel  404 . Each RGBY pixel comprises a red sub-pixel  401 , a green sub-pixel  402 , a blue sub-pixel  403  and a yellow sub-pixel  405 . The RGBW pixels  42  and the RGBY pixels  44  are mixed in the image device  40 A- 40 P. 
     As shown in  FIGS. 6-21 , each of the image devices  40 A- 40 P comprises a plurality of white sub-pixels  404  and a plurality of yellow sub-pixels  405 . Every other row comprises white sub-pixels  404  and yellow sub-pixels  405 . Namely, in any two adjacent rows, the white sub-pixels  404  and the yellow sub-pixels  405  are arranged in the same row. In this row, white sub-pixels  404  and yellow sub-pixels  405  are separately disposed, and two white sub-pixels  404  are arranged between two yellow sub-pixels  405 . Furthermore, the white sub-pixels  404  are arranged in the columns without yellow sub-pixels  405 , and the yellow sub-pixels  405  are arranged in the columns without white sub-pixels  404 . The white sub-pixels  404  and the yellow sub-pixels  405  arranged in any two adjacent columns are respectively arranged in different rows. The white sub-pixels  404  arranged in any two adjacent columns are respectively arranged in different rows. 
     As shown in  FIGS. 6-21 , a basic repeating unit  46  is defined. The basic repeating unit  46  is a 4×6 matrix with different color sub-pixels. Repeating the basic repeating unit  46  as much as required to form each of the image devices  40 A- 40 P. In the basic repeating unit  46 , a ratio of the number of red sub-pixels  401  to the number of green sub-pixels  402  to the number of blue sub-pixels  403  to the number of white sub-pixels  404  and to the number of yellow sub-pixels  405  is about 3:3:3:2:1. Furthermore, in the basic repeating unit  46 , a ratio of the total area of red sub-pixels  401  to the total area of green sub-pixels  402  to the total area of blue sub-pixels  403  to the total area of white sub-pixels  404  and to the total area of yellow sub-pixels  405  is about 3:3:3:2:1. 
     As shown in  FIGS. 6-21 , a 4×3 matrix  48  is defined. In the 4×3 matrix  48 , a ratio of the number of red sub-pixels  401  to the number of green sub-pixels  402  to the number of blue sub-pixels  403  to the number of white sub-pixels  404  and to the number of yellow sub-pixels  405  is about 3:3:3:2:1. Furthermore, in the 4×3 matrix  48 , a ratio of the total area of red sub-pixels  401  to the total area of green sub-pixels  402  to the total area of blue sub-pixels  403  to the total area of white sub-pixels  404  and to the total area of yellow sub-pixels  405  is about 3:3:3:2:1. 
     More specifically, when chooses any 4×3 matrix in the image devices  40 A- 40 P, a ratio of the number of red sub-pixels  401  to the number of green sub-pixels  402  to the number of blue sub-pixels  403  to the number of white sub-pixels  404  and to the number of yellow sub-pixels  405  is about 3:3:3:2:1. When chooses any 4×3 matrix in the image devices  40 A- 40 P, a ratio of the total area of red sub-pixels  401  to the total area of green sub-pixels  402  to the total area of blue sub-pixels  403  to the total area of white sub-pixels  404  and to the total area of yellow sub-pixels  405  is about 3:3:3:2:1. 
       FIGS. 22-25  illustrate several modified examples of image devices  50 A- 50 D following the arrangement rule of the white sub-pixels and yellow sub-pixel described above shown in  FIG. 4  according to the second embodiment of the present disclosure. Each of the image devices  50 A- 50 D comprises a plurality of pixels comprising a plurality of sub-pixels with different colors arranged in a matrix of rows and columns. More specifically, each of the image devices  50 A- 50 D comprises a plurality of RGBW pixels  52  and a plurality of RGBY pixels  54 . Each RGBW pixels  52  comprises a red sub-pixel  501 , a green sub-pixel  502 , a blue sub-pixel  503  and a white sub-pixel  504 . Each RGBY pixel comprises a red sub-pixel  501 , a green sub-pixel  502 , a blue sub-pixel  503  and a yellow sub-pixel  505 . The RGBW pixels  52  and the RGBY pixels  54  are mixed in each of the image devices  50 A- 50 D. 
     As shown in  FIGS. 22-25 , each of the image devices  50 A- 50 D comprises a plurality of white sub-pixels  504  and a plurality of yellow sub-pixels  505 . Every other column comprises white sub-pixels  504  and yellow sub-pixels  505 . Namely, in any two adjacent columns, the white sub-pixels  504  and the yellow sub-pixels  505  are arranged in the same column. In this column, white sub-pixels  504  and yellow sub-pixels  505  are separately disposed, and two white sub-pixels  504  are arranged between two yellow sub-pixels  505 . Furthermore, the white sub-pixels  504  are arranged in the rows without yellow sub-pixels  505 , and the yellow sub-pixels  505  are arranged in the rows without white sub-pixels  504 . The white sub-pixels  504  and the yellow sub-pixels  505  arranged in any two adjacent rows are respectively arranged in different columns. The white sub-pixels  504  arranged in any two adjacent rows are respectively arranged in different columns. 
     As shown in  FIGS. 22-25 , a basic repeating unit  56  is defined. The basic repeating unit  56  is a 6×4 matrix with different color sub-pixels. Repeating the basic repeating unit  56  as much as required to form each of the image devices  50 A- 50 D. In the basic repeating unit  56 , a ratio of the number of red sub-pixels  501  to the number of green sub-pixels  502  to the number of blue sub-pixels  503  to the number of white sub-pixels  504  and to the number of yellow sub-pixels  505  is about 3:3:3:2:1. Furthermore, in the basic repeating unit  56 , a ratio of the total area of red sub-pixels  501  to the total area of green sub-pixels  502  to the total area of blue sub-pixels  503  to the total area of white sub-pixels  504  and to the total area of yellow sub-pixels  505  is about 3:3:3:2:1. 
     As shown in  FIGS. 22-25 , a 3×4 matrix  58  is defined. In the 3×4 matrix  58 , a ratio of the number of red sub-pixels  501  to the number of green sub-pixels  502  to the number of blue sub-pixels  503  to the number of white sub-pixels  504  and to the number of yellow sub-pixels  505  is about 3:3:3:2:1. Furthermore, in the 3×4 matrix  58 , a ratio of the total area of red sub-pixels  501  to the total area of green sub-pixels  502  to the total area of blue sub-pixels  503  to the total area of white sub-pixels  504  and to the total area of yellow sub-pixels  505  is about 3:3:3:2:1. 
     More specifically, when chooses any 3×4 matrix  58  in the image devices  50 A- 50 D, a ratio of the number of red sub-pixels  501  to the number of green sub-pixels  502  to the number of blue sub-pixels  503  to the number of white sub-pixels  504  and to the number of yellow sub-pixels  505  is about 3:3:3:2:1. When chooses any 3×4 matrix  58  in the image devices  50 A- 50 D, a ratio of the total area of red sub-pixels  501  to the total area of green sub-pixels  502  to the total area of blue sub-pixels  503  to the total area of white sub-pixels  504  and to the total area of yellow sub-pixels  505  is about 3:3:3:2:1. 
       FIG. 26  illustrates an image device  80  according to a third embodiment of the present disclosure. The image device  80  comprises a plurality of pixels comprising a plurality of sub-pixels with different colors arranged in a matrix of rows and columns. As shown in  FIG. 26 , the image device  80  comprises a plurality of W sub-pixels  804  and a plurality of Y sub-pixels  805 . Every other column comprises W sub-pixels  804  or Y sub-pixels  805 . Namely, in any two adjacent columns, the W sub-pixels  804  are arranged in the same column, or the Y sub-pixels  805  are arranged in the same column. The W sub-pixels  804  in the same column are separately disposed. The Y sub-pixels  805  in the same column are separately disposed. Furthermore, the W sub-pixels  804  and the Y sub-pixels  805  arranged in any two nearby columns, which are separated by one column without W sub-pixels  804  or the Y sub-pixels  805 , are respectively arranged in different rows. The W sub-pixels  804  arranged in any two nearby columns, which are separated by one column without W sub-pixels  804  or the Y sub-pixels  805 , are respectively arranged in different rows. 
       FIG. 27  illustrates an example of the image device  80  of  FIG. 26  according to an embodiment of the present disclosure. The image device  80  comprises a plurality of pixels comprising a plurality of sub-pixels with different colors arranged in a matrix of rows and columns. As shown in  FIG. 27 , the image device  80  comprises a plurality of M sub-pixels  801 , a plurality of N sub-pixels  802 , a plurality of O sub-pixels  803 , a plurality of W sub-pixels  804  and a plurality of Y sub-pixels  805 . In any 2×2 matrix  81 , there are always one M sub-pixel  801 , one N sub-pixel  802 , and one O sub-pixel  803 . In other words, the image device  80  may comprise a plurality of MNOW pixels and a plurality of MNOY pixels. Each MNOW pixel comprises a M sub-pixel  801 , a N sub-pixel  802 , an O sub-pixel  803  and a W sub-pixel  804 . Each MNOY pixel comprises a M sub-pixel  801 , a N sub-pixel  802 , an O sub-pixel  803  and a Y sub-pixel  805 . The MNOW pixels and the MNOY pixels are mixed in the image device  80 . 
     The M sub-pixel  801 , the N sub-pixel  802 , and the O sub-pixel  803  may respectively be a R sub-pixel, a G sub-pixel, or a B sub-pixel, as required or designed. Namely, the M sub-pixel  801  may be a R sub-pixel, a G sub-pixel, or a B sub-pixel, the N sub-pixel  802  may be a R sub-pixel, a G sub-pixel, or a B sub-pixel, and the O sub-pixel  803  may be a R sub-pixel, a G sub-pixel, or a B sub-pixel. 
     Furthermore, in the image device  80 , a ratio of the number of M sub-pixels  801  to the number of N sub-pixels  802  to the number of O sub-pixels  803  to the number of W sub-pixels  804  and to the number of Y sub-pixels  805  is m:n:o:w:y. The m is substantially equal to the n. The m is substantially equal to the o. The m is larger than w. The m is larger than y. Sum of the w and the y is substantially equal to the m. 
       FIGS. 28-33  illustrate several modified examples of image devices  90 A- 90 F following the arrangement rule of the W sub-pixels and Y sub-pixel described above shown in  FIG. 26  according to the third embodiment of the present disclosure. Each of the image devices  90 A- 90 F comprises a plurality of pixels comprising a plurality of sub-pixels with different colors arranged in a matrix of rows and columns. More specifically, each of the image devices  90 A- 90 F comprises a plurality of RGBW pixels  92  and a plurality of RGBY pixels  94 . Each RGBW pixels  92  comprises a R sub-pixel  901 , a G sub-pixel  902 , a B sub-pixel  903  and a W sub-pixel  904 . Each RGBY pixel  94  comprises a R sub-pixel  901 , a G sub-pixel  902 , a B sub-pixel  903  and a Y sub-pixel  905 . The RGBW pixels  92  and the RGBY pixels  94  are mixed in the image device  90 A- 90 F. 
     As shown in  FIGS. 28-33 , each of the image devices  90 A- 90 F comprises a plurality of W sub-pixels  904  and a plurality of Y sub-pixels  905 . Every other column comprises W sub-pixels  904  or Y sub-pixels  905 . Namely, in any two adjacent columns, the W sub-pixels  904  are arranged in the same column, or the Y sub-pixels  905  are arranged in the same column. The W sub-pixels  904  arranged in the same column are separately disposed. The Y sub-pixels  905  arranged in the same column are separately disposed. Furthermore, the W sub-pixels  904  and the Y sub-pixels  905  arranged in any two nearby columns, which are separated by one column without W sub-pixels  904  or the Y sub-pixels  905 , are respectively arranged in different rows. The W sub-pixels  904  arranged in any two nearby columns, which are separated by one column without W sub-pixels  904  or the Y sub-pixels  905 , are respectively arranged in different rows. 
     As shown in  FIGS. 28-33 , a basic repeating unit  96  is defined. The basic repeating unit  96  is a 2×12 matrix with different color sub-pixels. Repeating the basic repeating unit  96  as much as required to form each of the image devices  90 A- 90 F. In the basic repeating unit  96 , a ratio of the number of R sub-pixels  901  to the number of G sub-pixels  902  to the number of B sub-pixels  903  to the number of W sub-pixels  904  and to the number of Y sub-pixels  905  is m:n:o:w:y. The m is substantially equal to the n. The m is substantially equal to the o. The m is larger than w. The m is larger than y. Sum of the w and the y is substantially equal to the m. 
     In this embodiment, a ratio of the number of R sub-pixels  901  to the number of G sub-pixels  902  to the number of B sub-pixels  903  to the number of W sub-pixels  904  and to the number of Y sub-pixels  905  is about 3:3:3:2:1. Furthermore, in the basic repeating unit  96 , a ratio of the total area of R sub-pixels  901  to the total area of G sub-pixels  902  to the total area of B sub-pixels  903  to the total area of W sub-pixels  904  and to the total area of Y sub-pixels  905  is about 3:3:3:2:1. 
       FIG. 34  illustrates an image device according to a fourth embodiment of the present disclosure. The image device  60  comprises a plurality of pixels comprising a plurality of sub-pixels with different colors arranged in a matrix of rows and columns. As shown in  FIG. 34 , the image device  60  comprises a plurality of W sub-pixels  604  and a plurality of Y sub-pixels  605 . The W sub-pixels  604  are arranged in the columns without Y sub-pixels  605 , and the Y sub-pixels  605  are arranged in the columns without W sub-pixels  604 . Each of the W sub-pixels  604  and each of the Y sub-pixels  605  are separately arranged in different columns. The W sub-pixels  604  in the same column are separately disposed. The Y sub-pixels  605  in the same column are separately disposed. Furthermore, the W sub-pixels  604  and the Y sub-pixels  605  arranged in any two adjacent columns are respectively arranged in different rows. The W sub-pixels  604  and the Y sub-pixels  605  arranged in any two separated columns are separated by two columns without W sub-pixels  604  or the Y sub-pixels  605 . The W sub-pixels  604  arranged in any two nearby columns, which are separated by one column without W sub-pixels  604  or the Y sub-pixels  605 , are respectively arranged in different rows. 
       FIG. 35  illustrates an example of the image device  60  of  FIG. 34  according to the fourth embodiment of the present disclosure. The image device  60  comprises a plurality of pixels comprising a plurality of sub-pixels with different colors arranged in a matrix of rows and columns. As shown in  FIG. 35 , the image device  60  comprises a plurality of M sub-pixels  601 , a plurality of N sub-pixels  602 , a plurality of O sub-pixels  603 , a plurality of W sub-pixels  604  and a plurality of Y sub-pixels  605 . In a 2×2 matrix  61 , there are always one M sub-pixel  601 , one N sub-pixel  602 , and one O sub-pixel  603 . In other words, the image device  60  may comprise a plurality of MNOW pixels and a plurality of MNOY pixels. Each MNOW pixel comprises a M sub-pixel  601 , a N sub-pixel  602 , an O sub-pixel  603  and a W sub-pixel  604 . Each MNOY pixel comprises a M sub-pixel  601 , a N sub-pixel  602 , an O sub-pixel  603  and a Y sub-pixel  605 . The MNOW pixels and the MNOY pixels are mixed in the image device  60 . 
     The M sub-pixel  601 , the N sub-pixel  602 , and the O sub-pixel  603  may respectively be a R sub-pixel, a G sub-pixel, or a B sub-pixel, as required or designed. Namely, the M sub-pixel  601  may be a R sub-pixel, a G sub-pixel, or a B sub-pixel, the N sub-pixel  602  may be a R sub-pixel, a G sub-pixel, or a B sub-pixel, and the O sub-pixel  603  may be a R sub-pixel, a G sub-pixel, or a B sub-pixel. 
     Furthermore, in the image device  60 , a ratio of the number of M sub-pixels  601  to the number of N sub-pixels  602  to the number of O sub-pixels  603  to the number of W sub-pixels  604  and to the number of Y sub-pixels  605  is m:n:o:w:y. The m is substantially equal to the n. The m is substantially equal to the o. The m is larger than w. The m is larger than y. Sum of the w and the y is substantially equal to the m. 
       FIGS. 36-39  illustrate several modified examples of image devices  70 A- 70 D following the arrangement rule of the W sub-pixels and Y sub-pixel described above shown in  FIG. 34  according to the fourth embodiment of the present disclosure. Each of the image devices  70 A- 70 D comprises a plurality of pixels comprising a plurality of sub-pixels with different colors arranged in a matrix of rows and columns. More specifically, each of the image devices  70 A- 70 D comprises a plurality of RGBW pixels  72  and a plurality of RGBY pixels  74 . Each RGBW pixels  72  comprises a R sub-pixel  701 , a G sub-pixel  702 , a B sub-pixel  703  and a W sub-pixel  704 . Each RGBY pixel  74  comprises a R sub-pixel  701 , a G sub-pixel  702 , a B sub-pixel  703  and a Y sub-pixel  705 . The RGBW pixels  72  and the RGBY pixels  74  are mixed in each of the image devices  70 A- 70 D. 
     As shown in  FIGS. 36-39 , each of the image devices  70 A- 70 D comprises a plurality of W sub-pixels  704  and a plurality of Y sub-pixels  705 . The W sub-pixels  704  are arranged in the columns without Y sub-pixels  705 , and the Y sub-pixels  705  are arranged in the columns without W sub-pixels  704 . The W sub-pixels  704  and the Y sub-pixels  705  are separately arranged in different columns. The W sub-pixels  704  in the same column are separately disposed. The Y sub-pixels  705  in the same column are separately disposed. Furthermore, the W sub-pixels  704  and the Y sub-pixels  705  arranged in any two adjacent columns are respectively arranged in different rows. The W sub-pixels  704  arranged in any two nearby columns, which are separated by one column without W sub-pixels  704  or the Y sub-pixels  705 , are respectively arranged in different rows. 
     As shown in FIGS. a basic repeating unit  76  is defined. The basic repeating unit  76  is a 2×12 matrix with different color sub-pixels. Repeating the basic repeating unit  76  as much as required to form each of the image devices  70 A- 70 D. In the basic repeating unit  76 , a ratio of the number of R sub-pixels  701  to the number of G sub-pixels  702  to the number of B sub-pixels  703  to the number of W sub-pixels  704  and to the number of Y sub-pixels  705  is m:n:o:w:y. The m is substantially equal to the n. The m is substantially equal to the o. The m is larger than w. The m is larger than y. Sum of the w and the y is substantially equal to the m. 
     In this embodiment, a ratio of the number of R sub-pixels  701  to the number of G sub-pixels  702  to the number of B sub-pixels  703  to the number of W sub-pixels  704  and to the number of Y sub-pixels  705  is about 3:3:3:2:1. Furthermore, in the basic repeating unit  76 , a ratio of the total area of R sub-pixels  701  to the total area of G sub-pixels  702  to the total area of B sub-pixels  703  to the total area of W sub-pixels  704  and to the total area of Y sub-pixels  705  is about 3:3:3:2:1. 
     Further, a designated white balance status can be maintained by adjusting the blue information of the image device. In case of liquid-crystal display LCD, for example the backlight color can be adjusted, and/or the thickness, area, and/or pigment of the blue sub-pixels in the color filter can be adjusted, and/or the utilization of quantum dots can be adjusted so as to adjust the blue information and to maintain a designated white balance status of the image device. In case of organic light-emitting diode OLED plus color filter, OLED color can be adjusted to bluish, and/or the thickness, area, and/or pigment of the blue sub-pixels in the color filter can be adjusted, and/or the utilization of quantum dots can be adjusted so as to adjust the blue information and to maintain a designated white balance status of the image device. 
     The present disclosure also provides methods to determine the ratio of the number of RGBW pixels to the number of RGBY pixels in an image device according to the invention. The method according to a first embodiment of the present disclosure comprises a step for determining the ratio by a function of a yellow sub-pixel information, a red sub-pixel information, a green sub-pixel information, a blue sub-pixel information and a white sub-pixel information of the image device. The sub-pixel information comprises the chrominance data and luminance data of the said sub-pixel. In an embodiment, the yellow sub-pixel information comprises the chrominance data and luminance data of the yellow sub-pixel, the red sub-pixel information comprises the chrominance data and luminance data of the red sub-pixel, the green sub-pixel information comprises the chrominance data and luminance data of the green sub-pixel, and the white sub-pixel information comprises the chrominance data and luminance data of the white sub-pixel. 
     The present disclosure further provides a method to determine the ratio of the number of RGBW pixels to the number of RGBY pixels in an image device according to the invention. The method according to a second embodiment of the present disclosure comprises a step for determining the ratio by a function of a yellow sub-pixel information and a white sub-pixel information of the image device. The sub-pixel information comprises the chrominance data and luminance data of the said sub-pixel. In an embodiment, the yellow sub-pixel information comprises the chrominance data and luminance data of the yellow sub-pixel, and the white sub-pixel information comprises the chrominance data and luminance data of the white sub-pixel. 
     By the addition of RGBY pixels, the problem of dark yellow in the conventional RGBW display can be solved and chrominance quality can be improved. The present invention thus can solve the dark yellow problem of conventional RGBW display. The bluish problem can also be solved by the addition of RGBY pixels. 
     The present disclosure also provides a method to determine the ratio of the number of RGBW pixels to the number of RGBY pixels in an image device. The method comprises a step for determining the ratio by a function of a yellow sub-pixel information, a red sub-pixel information, a green sub-pixel information, a blue sub-pixel information and a white sub-pixel information of the image device. 
     The present disclosure also provides a method to determine the ratio of the number of RGBW pixels to the number of RGBY pixels in an image device. The method comprises a step for determining the ratio by a function of a yellow sub-pixel information and a white sub-pixel information of the image device. 
     In another embodiment, the filter of the white sub-pixels can be made bluish so that the emitted light from the white sub-pixels is bluish rather than pure white. The bluish-white color sub-pixels compensate the yellow color of the additional yellow sub-pixels. As a result a designated white balance status of the image device can be maintained. 
     The embodiments shown and described above are only examples. Many details are often found in the art such as the other features of an image device. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the detail, especially in matters of shape, size and arrangement of the parts within the principles of the present disclosure up to, and including the full extent established by the broad general meaning of the terms used in the claims. It will therefore be appreciated that the embodiments described above may be modified within the scope of the claims.