Title of Invention

"A DISPLAY COMPRISING SUBPIXEL REPEATING GROUP"

Abstract High brightness displays comprising subpixel repeating groups (102) having at least white (104) with a number of colored subpixels are disclosed. Colored subpixels may comprise: red (108), blue (110), green (106), cyan or magenta in these various embodiments. Figure 1 is the representative figure.
Full Text TECHNICAL FIELD
[01] The present application relates to subpixel layouts for display devices and systems.
Such subpixel layouts may include high brightness white subpixels, together with other color
primary subpixels as well as multiprnnary subpixel layouts.
BACKGROUND
[02] The present invention is a continuation-in-part application of United States Patent
Application Serial Number 10/821,353 entitled "NOVEL SUBPIXEL LAYOUTS AND
ARRANGEMENTS FOR HIGH BRIGHTNESS DISPLAYS" filed on April 9, 2004, herein
incorporated by reference in its entirety, and claims benefit of the priority date thereof.
[03] In commonly owned United States Patent Applications: (1) United States Patent
Application Serial No. 09/916,232 ("the '232 application" ), entitled "ARRANGEMENT OF
COLOR PIXELS FOR FULL COLOR IMAGING DEVICES WITH SIMPLIFIED
ADDRESSING," filed July 25,2001; (2) United States Patent Application Serial No. 10/278,353
("the '353 application"), entitled "IMPROVEMENTS TO COLOR FLAT PANEL DISPLAY
SUB-PKEL ARRANGEMENTS AND LAYOUTS FOR SUB-PIXEL RENDERING WITH
INCREASED MODULATION TRANSFER FUNCTION RESPONSE," filed October 22,2002;
(3) United States Patent Application Serial No. 10/278,352 ("the '352 application"), entitled
"IMPROVEMENTS TO COLOR FLAT PANEL DISPLAY SUB-PIXEL ARRANGEMENTS
AND LAYOUTS FOR SUB-PIXEL RENDERING WITH SPLIT BLUE SUB-PIXELS," filed
October 22, 2002; (4) United States Patent Application Serial No. 10/243,094 ("the '094
application), entitled "IMPROVED FOUR COLOR ARRANGEMENTS AND EMITTERS FOR
SUB-PIXEL RENDERING," filed September 13, 2002; (5) United States Patent Application
Serial No. 10/278,328 ("the '328 application"), entitled "IMPROVEMENTS TO COLOR FLAT
PANEL DISPLAY SUB-PIXEL ARRANGEMENTS AND LAYOUTS WITH REDUCED
BLUE LUMINANCE WELL VISIBILITY," filed October 22, 2002; (6) United States Patent
Application Serial No. 10/278,393 ("the '393 application"), entitled "COLOR DISPLAY
HAVING HORIZONTAL SUB-PIXEL ARRANGEMENTS AND LAYOUTS," filed October
22, 2002; (7) United States Patent Application Serial No. 01/347,001 ("the '001 application")
entitled "IMPROVED SUB-PIXEL ARRANGEMENTS FOR STRIPED DISPLAYS AND
METHODS AND SYSTEMS FOR SUB-PIXEL RENDERING SAME," filed January 16, 2003,
each of which is herein incorporated by rei'erence in its entirety, novel sub-pixel arrangements are
disclosed for improving the cost/performance curves for image display devices.
[04] For certain subpixel repeating groups having an even number of subpixels in a
horizontal direction, the following systems and techniques to affect improvements, e.g. proper dot
inversion schemes and other improvements, are disclosed and are herein incorporated by
reference in their entirety: (1) United States Patent Application Serial Number 10/456,839
entitled "MAGE DEGRADATION CORRECTION IN NOVEL LIQUID CRYSTAL
DISPLAYS"; (2) United States Patent Application Serial No. 10/455,925 entitled "DISPLAY
PANEL HAVING CROSSOVER CONNECTIONS EFFECTING DOT INVERSION"; (3)
United States Patent Application Serial No. 10/455,931 entitled "SYSTEM AND METHOD OF
PERFORMING DOT INVERSION WITH STANDARD DRIVERS AND BACKPLANE ON
NOVEL DISPLAY PANEL LAYOUTS"; (4) United States Patent Application Serial No.
10/455,927 entitled "SYSTEM AND METHOD FOR. COMPENSATING FOR VISUAL
EFFECTS UPON PANELS HAVING FIXED PATTERN NOISE WITH REDUCED
QUANTIZATION ERROR"; (5) United States Patent Application Serial No. 10/456,806 entitled
"DOT INVERSION ON NOVEL DISPLAY PANEL LA.YOUTS WITH EXTRA DRIVERS";
(6) United States Patent Application Serial No. 10/456,838 entitled "LIQUID CRYSTAL
DISPLAY BACKPLANE LAYOUTS AND ADDRESSING FOR NON-STANDARD
SUBPIXEL ARRANGEMENTS"; (7) United States Patent Application Serial No. 10/696,236
entitled "IMAGE DEGRADATION CORRECTION IN NOVEL LIQUID CRYSTAL
DISPLAYS WITH SPLIT BLUE SUBPIXELS", filed October 28, 2003; and (8) United States
Patent Application Serial No. 10/807,604 entitled "IMPROVED TRANSISTOR BACKPLANES
FOR LIQUID CRYSTAL DISPLAYS COMPRISING DIFFERENT SIZED SUBPIXELS", filed
March 23, 2004.
[05] These improvements arc particularly pronounced when coupled with sub-pixel
rendering (SPR) systems and methods further disclosed in those applications and in commonly
owned United States Patent Applications: (1) United States Patent Application Serial No.
10/051,612 ("the '612 application"), entitled "CONVERSION OF RGB PIXEL FORMAT
DATA TO PENTILE MATRIX SUB-PIXEL DATA FORMAT," filed January 16, 2002; (2)
United States Patent Application Serial No. 10/150,355 ("the '355 application"), entitled
"METHODS AND SYSTEMS FOR SUB-PDCEL RENDERING WITH GAMMA
ADJUSTMENT," filed May 17, 2002; (3) United States Patent Application Serial No.
10/215,843 ("the '843 application"), entitled "METHODS AND SYSTEMS FOR SUB-PIXEL
RENDERING WITH ADAPTIVE FILTERING," filed August 8,2002; (4) United States Patent
Application Serial No. 10/379,767 entitled "SYSTEMS AND METHODS FOR TEMPORAL
SUB-PDCEL RENDERING OF IMAGE DATA" filed March 4, 2003; (5) United States Patent
Application Serial No. 10/379,765 entitled "SYSTEMS AND METHODS FOR MOTION
ADAPTIVE FILTERING," filed March 4, 2003; (6) United States Patent Application Serial No.
10/379,766 entitled "SUB-PIXEL RENDERING SYSTEM AND METHOD FOR IMPROVED
DISPLAY VIEWING ANGLES" filed March 4,2003; (7) United States Patent Application Serial
No. 10/409,413 entitled "MAGE DATA SET WITH EMBHDDED PRE-SUBPKEL
RENDERED IMAGE" filed April 7,2003, which are hereby incorporated herein by reference in
their entirety.
[06] Improvements in gamut conversion and mapping are disclosed in commonly
owned and co-pending United States Patent Applications: (1) United States Patent Application
Serial No. 10/691,200 entitled "HUE ANGLE CALCULATION SYSTEM AND METHODS",
filed October 21, 2003; (2) United States Patent Application Serial No. 10/691,377 entitled
"METHOD AND APPARATUS FOR CONVERTING FROM SOURCE COLOR SPACE TO
RGBW TARGET COLOR SPACE", filed October 21,2003; (3) United States Patent Application
Serial No. 10/691,396 entitled "METHOD AND APPARATUS FOR CONVERTING FROM A
SOURCE COLOR SPACE TO A TARGET COLOR SPACE", tiled October 21, 2003; and (4)
United States Patent Application Serial No. 10/690,716 entitled "GAMUT CONVERSION
SYSTEM AND METHODS" filed October 21,2003 which are all hereby incorporated herein by
reference in their entirety.
[07] Additional advantages have been described in (1) United States Patent Application
Serial No. 10/696,235 entitled "DISPLAY SYSTEM HAVING IMPROVED MULTIPLE MODES
FOR DISPLAYING IMAGE DATA FROM MULTIPLE INPUT SOURCE FORMATS", filed
October 28, 2003 and (2) United States Patent Application Serial No. 10/696,026 entitled
"SYSTEM AND METHOD FOR PERFORMING IMAGE RECONSTRUCTION AND
SUBPIXEL RENDERING TO EFFECT SCALING FOR MULTI-MODE DISPLAY" filed October
28,2003.
[08] Additionally, these co-owned and co-pending applications are herein, incorporated
by reference in their entirety: (1) United States Patent Application Serial No. [ATTORNEY
DOCKET NUMBER 08831.0064] entitled "SYSTEM AND METHOD FOR IMPROVING SUBPIXEL
RENDERING OF IMAGE DATA IN NON-STRIPED DISPLAY SYSTEM'S"; (2) United
States Patent Application Serial No. [ATTORNEY DOCKET NUMBER 08831.0065] entitled
"SYSTEMS AND METHODS FOR SELECTING A WHITE POINT FOR IMAGE DISPLAYS";
(3) United States Patent Application Serial No. [ATTORNEY DOCKET NUMBER. 08831.0067]
entitled "SYSTEMS AND METHODS FOR IMPROVED GAMUT MAPPING FROM ONE
IMAGE DATA SET TO ANOTHER"; (4) United States Patent Application Serial No.
[ATTORNEY DOCKET NUMBER 08831.0068] entitled "IMPROVED SUBPJXB'JL
RENDERING FILTERS FOR HIGH BRIGHTNESS SUBPD(EL LAYOUTS"; whi ch arc all
hereby incorporated by reference. All patent applications mentioned in this specification are hereby
incorporated by reference in their entirety.
DISCLOSURE OF THE INVENTION
[09] In one embodiment of the present invention, a display is given tlnat substantially
comprises a subpixel repeating group. The subpixel repeating group may comprise of a white or
unfiltered subpixel, together with other color primary subpixels. Alternatively, the subpixel
repeating group may comprise novel multiprimary subpixels.
[010] hi yet another embodiment of the present application, a display is given that
substantially comprises a novel subpixel repeating group and a backlight wherein the backlight is
adjusted to give a balanced white point when all of the subpixels are fully on.
BRIEF DESCRIPTION OF THE DRAWINGS
[Oil] The accompanying drawings, which are incorporated in, and constitute a part of this
specification illustrate exemplary implementations and embodiments of the invention and, together
with the description, serve to explain principles of the invention.
[012] FIGS. 1 through 4 are several embodiments of high brightness layouts as made in
accordance with the principles of the present invention.
[013] FIGS. 5A and SB are side-by-side comparisons of conventional E.GB stripe layout
next to one embodiment of the present invention, respectively.
[014] FIGS. 6A and 6B are side-by-side comparisons of conventional 'RGB stripe layout
next to another embodiment of the present invention, respectively.
[015] FIGS. 7A and 7B are side-by-side comparisons of conventional RGB stripe layout
next to yet another embodiment of the present invention, respectively.
[016] FIGS. 8 through 11A-C are several other embodiments of high brightness layouts
as made in accordance with the principles of the present invention.
[017] FIG. 12 is one embodiment of locating disclination regions with respect to black
matrix for high brightness and other layouts.
[018] FIG 13 is an embodiment of a high brightness delta triad subpixel layout.
[019] FIG 14 and 15 are additional embodiments similar to Figs. 2 and 3 wherein the
colored subpixels are on a hex grid.
[020] FIG 16 is an additional embodiment similar to Fig. 4 wherein the colored subpixels
form along a different diagonal line.
[021] FIG 17 is an additional embodiment that is similar to Fig 11A but wherein the
colored planes are placed on a square grid.
[022] FIG 18 to 24 are additional embodiments wherein the white subpixels are displaced.
[023] FIG 25 to 28 are additional embodiments of previous embodiraents but shown in
mirror image.
DETAILED DESCRIPTION
[024] Reference will now be made in detail to implementations and embodiments,
examples of which are illustrated in the accompanying drawings. Wherever possible, the same
reference numbers will be used throughout the drawings to refer to the same or like parts.
RGBW Color Liquid Crystal Displays and Natural Images
[025] The "real world" is a subtractive color system. Save for relatively rare emissive
light sources such as LEDs and lasers, high brightness saturated colors are not found in real world
scenes that arc viewed by the human vision system in the course of an individual going about his or
her daily life. In daily experience, colors are formed by relatively bright white light falling onto
pigmented objects that absorb some portion of the light and reflecting the rest. Colors are formed
by selectively absorbing part of the spectrum and reflecting another part of the spectrum. Noncolor-
saturatcd objects such as white or pastel colored objects may substantially reflect most of the
light, thus being radiomelrically and visually brighter than saturated color objects. Conversely,
objects that form saturated colors absorb most of the light and reflect only a narrow band (or bands
in the case of purple or magenta) of the full spectrum of light falling on it. This reduces the
brightness of saturated colored objects compared to non-saturated color objects. This is especially
true for saturated colors that are near the corners of the color triangle of red, green, and blue, as to
achieve these colors, the light must be in very narrow wavelength bands. Further, specular
reflections occur at the surfaces of objects which do not substantially alter the spectrum of light
falling on them, giving reflection highlights that are non-color-saturated, even on objects that aTe
observed to be highly color-saturated in lambertian reflection. These highlights are the brightest
portions of many natural scenes (e.g. the mirror like reflection of an overhead light on a brightly
colored billiard ball is white, not colored). Thus, by their very nature, real world scenes may have
bright non-color-saturated objects and darker color-saturated objects.
[026] Some natural images have highly saturated colors. In these images, the brightest
red, green, and blue colors are far darker than the white found in natural images. Even yellow,
which may be formed from a mixture of red and green - may not be as bright as white. Other
images - typically photographs of indoor objects (e.g. faces) ~ might not have such brightly colored
objects. When examining the statistical occurrence of highly saturated colors vs. non-saturated
colon, one finds that saturated colors are relatively rare in natural images. When saturated colors
do occur, they are quite dark. Further, given the subtractive nature of color formation in natural
scenes, bright saturated colors are almost non-existent
[027J For electronic displays to render natural scenes, it might be best for it to be able to
create very bright non-color-saturated colors and darker highly saturated colors. Upon inspection of
the capabilities of the conventional three primary, RGB, system, one notes that it is a color additive
system whose non-saturated color brightness is limited to the addition of partially-saturated colors.
The brightness/saturation color gamut of the RGB system generally has brighter non-saturated
colors, but fails to reproduce the very bright non-saturated colors.
[028] There is a trade-off between the brightness of the non-saturated colors and the color
saturation gamut of the filtered backlight display. The more saturated the color filters, the less
these filtered colors may add to the non-saturated brightness. This creates a luminance/saturation
compression in which the non-saturated colors are reduced in brightness and saturated colors are
compressed, dcsaturated, to fit within the limitations of the compromise system. Another color
formation system is required to better display natural images.
[029] RCiBW liquid crystal displays provide an additional primary: White. These White
subpixels are substantially brighter than the Red, Green, and Blue subpixels since the White is
formed by using a transparent filter that allows substantially all of the light through, while the other
three colors are formed by filtering out all but a narrow band of the spectrum. Since such filters are
not ideal bandpass filters, the transmissivity is less than 100% even in the desired bandpass
wavelengths, which further darkens the subpixcl. The White subpixel may have up to four or more
times the brightness of the colored subpixels. Thus, the use of a white subpixel significantly
increases the brightness of the panel when displaying non-saturated colors.
[030] If one fourth of the area of the panel is used for the White subpixel, the brightnesses
of the remaining RGB subpixels are reduced by one fourth. However, non-saturated colors may be
formed with a contribution from the bright White subpixel, giving significantly higher brightness.
The resulting panel has a brightness/color gamut envelope shape that is closer to that of the 'real
world'. The loss of brightness of the saturated colors is an acceptable trade-off when considering
the statistics of natural images. However, as the choice of conventional RGB primaries was a
compromise between the desired saturation of the primaries and the brightness of non-saturated
colors, the introduction of the White subpixel offers a new optimization point.
[031] Since the White subpixel provides the majority of the brightness of non-saturated
colors, the saturation of the RGB primaries may be increased with only minor decrease of
brightness of the non-saturated colors. This decrease may be partially offset by increase in the
aperture ratio of the 1:2 aspect ratio subpixel for some (e.g. small) panels, with its reduced
horiamtal subpixel density, compared to the 1:3 aspect ratio subpixel found in conventional RGB
stripe displays. This may result in an RGBW display that has both increased brightness and
saturation envelope at every point compared to the conventional RGB display. Fully saturated
colors may be darker on the optimized RGBW system compared to the RGB system, but at the
saturation maximum color points of the RGB system, the RGBW brightness may be the same or
higher. Thus, no real loss of color brightness occurs.
[032] Such a RGBW system more closely approaches the 'real world' natural image
envelop and statistics, providing higher brightness and deeper saturation. The present invention
discloses a plurality of high brightness layouts for displays. These layouts, in turn, may be driven
by various Gamut Mapping Algorithms (GMA) - either in the prior art or as disclosed in many
applications incorporated herein. Further, with the use of SubPixel Rendering (SPR) algorithms as
disclosed in applications incorporated herein, such panels may maintain color accuracy while
lowering cost and increasing contrast.
[033] As disclosed on other applications incorporated by reference, one embodiment of a
SPR algorithm treats the White subpixel as another color primary. Starting from color theory
basics, this embodiment transforms the values of the input RGB using linear matrix multiplication.
This results in a transform that maintains the hue and saturation of all colors.
[034] The brightness increase from RGB to RGBW may be linear and a constant
multiplier for all colors inside of the RGBW brightness/saturation gamut envelope. In the unlikely
event a bright, saturated color in the image exceeds the RGBW brightness/saturation gamut
envelope, one embodiment maps the color to the brightest color at that same hue and saturation that
the display may render. This may be a reasonable trade-off, as the human vision system does not
measure absolute brightness, only relative brightness. Further, very bright, highly saturated colors
are an infrequent occurrence in natural images. Thus lowering the peak brightness of a highly
saturated color slightly does not severely distort an image; while color saturation and hue are
generally recognized and noticeable when they are distorted.
High Brightness Layouts For Displays
[03 5] Having discussed some of the advantages and trade-offs of high brightness (e.g.
RGBW) layouts, several embodiments of such layouts will now be disclosed. Figure 1 depicts one
embodiment of layout 100. Layout 100 substantially comprises a plurality of repeating subpixel
group 102 further comprising white (e.g. no color filter) 104, green 106, red 108 and blue 110
subpixels. As may be seen, the white subpixels are the majority number of all the subpixels and
may optionally comprise a smaller dimension and/or area than the other colored subpixels. The
value of placing the white on the majority, thinner, subpixels is that they provide high Modulation
Transfer Function (MTF) depth. The same effect is given to the higher occurrence of green
subpixels as compared to red and blue subpixels,
[036] For subpixel rendering this display, the white subpixels may be mapped one to one
with an incoming conventional data set (e.g. RGB or any other suitable data format). The colors
may then be subpixel rendered, filtered to remove chromatic aliasing to maintain proper color, in
the manners described in several applications incorporated by reference. Also, the phase of the
planes may be adjusted to be either coincident with the incoming data set or 180° out of phase with
the white subpixel alignment as desired. The first may be suitable for text and other non bandlimited
images, the second may be suitable for pictures or supersampling subpixel rendering of text,
glyphs, etc. The color subpixel locations may also benefit from interpolation/subpixel rendering for
proper digital image reconstruction of bandlimited images.
[037] It should be noted that the backlight color temperature may be adjusted to have more
magenta, red and blue, energy than that for the typical RGB LCD to give a balanced white.
Alternatively, the green subpixels may be adjusted towards the upper green point on the CIH 1931
chart, decreasing its brightness but increasing its color saturation, to give better color gamut and
proper white balance. Another alternative might be to combine the effects of the above two
embodiments. It should also be noted that this layout has an MTF Limit (MTFL) at the Nyquist
limit of the white subpixels in all directions. MTFL may be thought of as the highest number of
black & white lines that may be simultaneously rendered without chromatic aliasing.
[03 8] It will be appreciated that the present invention encompasses all mirror images of the
repeating subpixel groups and other symmetries possible for Figure 1 and for all Figures disclosed
herein. Additionally, the position assignments of the colored subpixel are also subject to change
without departing from the scope of the present invention. For example, the positions of red and
blue subpixels in Figure 1 may be changed or transposed within the scope of the present invention.
Also, the positions of the green subpixels may be changed with the red and the blue subpixels
within the scope of the present invention.
[039] Another set of embodiments for the present invention included: for every subpixel
layout shown herein having a "white" subpixel, an additional embodiment would replace some or
all of the "white" subpixels with the colors "yellow", "grey", or "blue-grey" (e.g. not colored but
fully transmissive). Yellow, grey, or blue-grey do not have the same transmissivity as white does;
however, yellow, grey or blue-grey do present high transmissivity and would also provide a "high"
brightness performance. For subpixels layouts employing red, green, blue, white, and cyan, it
might be desirable to replace some or all of the white with the color "pink".
[040] Two other embodiments of high brightness layouts are shown in Figures 2 and 3.
As with Figure 1, the white subpixels are the majority subpixels and may optionally be of decreased
size or dimension. This gives high MTF Limit performance. The repeating pattern 202 in Figure 2
comprises red, green, and blue subpixels - as well as a cyan subpixel 204 (shown in finer
horizontal hatching lines than the blue subpixels in these Figures). This may perhaps have more
blue resolution than may be required, but the arrangement should be straight-forward to
manufacture and subpixel render. For white color balance, the backlight may be more red energy,
to counter the increased transmission of cyan, than the typical backlight for an RGB LCD display.
Alternatively, the green and cyan may be darker, purer colors, towards the green peak of the CIE
1931 chart, resulting in a high color temperature display. This arrangement may allow for a bright,
high MTF Limit, high SPR Moir6 Limit, high color gamut display. Given that the white subpixel
adds brightness to the system and that the use of the cyan color tends to give a wider color gamut, it
may be advantageous to set the color points of the minority subpixels to be deeply saturated to
result in a wide color gamut.
[041] Figure 3 depicts an alternative for a five color system, RGMCW system, allowing
even higher MTF Limit performance at the expense of deep blue performance. The repeating
subpixel group 302 comprises red, green, cyan (204) and magenta (304) subpixels. In another
embodiment, it may be possible to vertically displace the white majority subpixels from the
minority subpixel grid ISO0 to expand the SPR Moire Limit to a full circle. As these layouts have a
square grid of white subpixels, the monochromatic MTF Limit displayed is a square MTF Limit
boundary, matching that of the conventional RGB Stripe system.
[042] Figure 4 is yet another embodiment of a high brightness layout 400. Its repeating
subpixel group is a 3 x 6 subpixel group 402 where the colored subpixels comprise red, green and
blue subpixels in a mosaic pattern. Here the white subpixels are again the majority subpixels and
are optionally more narrow that the other colored subpixels. The RGB colored subpixels are equal
in number and size. This display may have the virtue of using a conventional backlight color and
having pure white at maximum brightness when all of the subpixel values are full "on". This panel
may also be immune to color shifts when mask shifts occur during manufacturing.
[043] This panel tends to have high Luminance MTF Limit out into the corners as well as
an extended Moire Limit. However, it may have a highly asymmetrical chrominance MTF Limit,
as with the classic Mosaic pattern. As one third of the panel area is high brightness white, the
brightness is expected to be significantly higher than a traditional RGB panel using the same color
filter points. This added brightness of the white may be used to trade-off some of the brightness
gain for color gamut increase for a TV or HDTV product, by using higher saturation, but lower
transmission color filters, as previously described.
[044] As an alternative, the subpixel width ratio could be altered as desired for white/color
brightness trade-off. For example, one could set the two sizes identically, giving a brighter white
value, but lower saturated color brightness. This example has the added benefit of using the same
size subpixels, with an aspect ratio of one-to-two (1:2) — or, alternatively, one-to-three (1:3) -
being very easy to design and manufacture with present design rules. Yet another alternative might
be to place the red, green and blue subpixels in vertical or horizontal stripes.
[045] In the co-pending '094 application, the layout of Figure 5B has been proposed where
the pixel size has an aspect ratio of 2:3 (width:height). This may result in increased pixel visibility
when compared to RGB stripe at same resolution. Thus, Figure 5B shows a similar layout
repeating group 502 with red, green, blue and white subpixels; but with a one-to-three (1:3) aspect
ratio of conventional RGB stripe, shown for comparison in Figure 5A. One advantage is that the
layout may utilize the existing RGB-stripe TFT array.
[046] It should be noted that the pixel sizes are identical but the color order is changed.
The repeat cycle is 2x3 pixels. The white pixels are shown in line within a row, but they can also
be made to alternate for another embodiment. Resolution for this design should be 2x in horizontal
axis compared to RGB stripe and Ix in vertical. Subpixel rendering can be adjusted to perform
scaling in horizontal, or a video chip can be used to sample the data at 2x rate in horizontal axis. Li
either case, the performance of the LCD should be improved with less Moire noise and higher
MTF. Brightness gain for 25% color filter transmission should be
((5/6)*25-Kl/6)*100)/25=37.5/25=1.5.
[047] Figure 6B is yet another embodiment (shown next to RGB striped panel Figure 6A)
that has a repeating group 602. In this embodiment, the subpixels are of substantially equal size to
maintain white balance. The repeat group 602 is 2x4 subpixels. It should be noted that the number
of colors is the same within a repeat group (R,G,B,W). This should result in balanced white with
existing backlights. In this case the horizontal and vertical resolution should be the same as RGB
stripe, but the number of column drivers and TFTs is reduced by 1/3. Brightness gain depends on
color filter transmission; assuming 25% transmission (typical) for colored filters and 100% for
white, then transmission for white screen is (3/4) 25+(l/4) 100= 175/4 = 43.75% which is roughly
a pin of 43.75/25-1.75.
[048] Figure 7B (shown next to RGB stripe layout Figure 7A for comparison) is a
variation of Figure 6B. In this case, the subpixel repeating group 702 is the same as group 602 but
in the 1:3 aspect ratio, hi this case, the resolution in the horizontal tends to be increased by 1.5x.
This design uses existing TFT array and drive electronics with no cost savings, but resolution and
brightness tends to be increased. Brightness gain is similar as noted above
[049] Now, brightness with the novel high brightness layouts disclosed herein may have
an impact in the portable (e.g. cell phone) application and the TV market as a consequence. As
with typical RGB-stripe LCDs utilize, the transmissivity of the LCD is typically 5-10%, depending
on color filter and polarizer transmission, as well as "aperture ratio" of TFT array, Thus to achieve
500 cd/m2 output, as much as 5000-10000 cd/m2 output from the backlight may be required. This
can increase cost and increase heat of the TV system. In portable applications, it can reduce battery
life.
[050] With the novel high brightness layouts disclosed herein, the backlight brightness
may be reduced by as much as one half as required by conventional RGB striped systems having
substantially the same resolution. This decrease in backlight brightness is made possible by (a)
increasing the aperture ratio by using these novel layouts, and (b) increasing transmission of the
system by adding white subpixels. In these embodiments, the brightness of the system may
improve by up to 1.75x or, alternatively, the power can be reduced by more than 40%. In the case
of LCD TV for home use, this can mean a reduction in the number of lamps from 16 to 10, for
significant power, cost, and heat savings, while maintaining average brightness.
[051] For all of these high brightness layouts, it is possible to discuss a "Figure of Merit"
(FOM) to help compare the performance of these layouts. A simplified FOM might be the number
of pixels expressed by the MTFL in each axis divided by the subpixels, expressed as a percentage.
[052] For example, the conventional RGBW "Quad" pattern which has as a repeating
group:
in a square pattern.
[053] For large billboards, the Quad pattern is implemented by four incandescent lamps
arranged in a square pattern repeat unit. The colored primaries are formed by pigment paints on the
lamps. The brightness loss is sipificant, thus the unfiltered white lamp provides much needed
brightness. The Quad pattern is typically treated as a square pixel. Although subpixel rendering
may be applied (and thus improve), the Quad pattern is not as optimal as the novel layouts
disclosed herein - as the Quad requires two lines of subpixels in any axis to draw a single white
line. Since it takes four subpixels to equal one 'pixel', the FOM value is 25%.
[054] Figure 8 is yet another embodiment substantially comprising repeating group 802
with its subpixels in a 1:2 aspect ratio. This layout may have less edge boundaries that give rise to
liquid crystal disinclinations, and thus has higher contrast than an LCD based on the RGBW Quad
and even the RGB Stripe. This layout, like the Quad above, has 25% white area, thus it can have
approximately 75% to 100% higher brightness than an RGB Stripe panel with the same resolution.
It should be noted that each color is on a square grid at 45°. This layout requires only one row of
subpixels to draw a single white line, while it still requires two subpixel columns. Thus, the Figure
of Merit value is thus 50%.
[055] Figure 9 is yet another embodiment substantially comprising repeating group 902. It
may be advantageous for very high resolution (300+ dpi) mobile phones. As blue resolution is
reduced in this layout, it may be desirable to use a high color temperature backlight to ensure that
enough blue light is available to keep the panel at a desired white color when all of the subpixels
are turned on to full value. As the white area is only 17%, the brightness increase is approximately
50%. The aspect ratio of the subpixels may be two-to-three (2:3) (or alternatively 1:3). For the
layout of Figure 9, it may be seen that the FOM for this layout is 66%.
[056] Figure 10 is yet another embodiment having subpixel repeating group 1002. As the
subpixels remain at one-to-three (1:3) aspect ratio, it may be easy to utilize existing backplanes for
this layout. This layout would then have a higher MTFL in the horizontal axis than the
conventional RGB it replaces. It would also be approximately 75% brighter. The additional
horizontal resolution may further reduce moire distortion. If the input signal has higher resolution,
such as scaling down a 10801 signal to a 720p HDTV LCD, or 720p on a 480i TV, this panel may
show up to 50% higher horizontal resolution than the RGB Stripe panel, thus showing the full
horizontal resolution of the higher resolution format.
[057] Figure 11A is yet another embodiment of a high brightness layout having a 4 x 8
subpixel repeating group 1102. As may be seen, the subpixels are of a different shape than the
traditional rectangular. The white subpixels (shown withont hatching) are the majority subpixels
and are optionally of a smaller size or dimension as the colored subpixels which comprise red,
green, blue and cyan in this embodiment. As may be seen, the white subpixels could be interstitial
(e.g. displaced 180 degrees) to the colored subpixels. As may also be seen, the subpixel repeating
group 1102 is larger than the other ones shown in the other figures because the color subpixels are
placed on a hex grid. One possible advantage of a hex grid is that it tends to scatter the Fourier
energies in more directions and points. This may be especially useful for the dark luminance wells
caused by the blue subpixels. Another possible advantage is that each row contains all four colors
as well as the white subpixels, allowing for horizontal lines to be black and white, fully sharpened,
without chromatic aliasing. It will be appreciated that all of the subpixel repeating groups in all of
the Figures shown herein may also be placed on a hex grid in a similar fashion and is contemplated
within the scope of the present invention.
[058] Figure 1 IB is yet another embodiment of a high brightness layout where the white
majority subpixels are vertically displaced from the minority subpixels. This tends to expand the
SPR Moire Limit to a full circle. If the layouts have a square grid of white subpixels, the
monochromatic MTF Limit displayed is a square MTF Limit boundary, matching that of the
conventional RGB stripe system. It will be appreciated that all of the layouts disclosed herein may
be made to have the white subpixels so vertically displaced and the scope of the present invention
encompasses these alternatives. Figure 11C is yet another embodiment of a high brightness layout
in which a white subpixel replaces a blue subpixel in a delta triad pattern. Although the subpixels
are shown as dots in Figure 11C, they may, of course, be implemented as rectangular subpixels - or
in many other shapes - as desired.
[059] As was mentioned above, LCD contrast is set by many parameters, including light
leakage from disclinations or other LC distortions around the edges of subpixels. To cancel the
light coming from these regions, the black matrix may be enlarged to cover this region. This may
reduce light transmission, but also may improves contrast. Figure 12 shows one possible
embodiment. Black matrix is enlarged, adjacent to colored filter 1202, and tends to hide the
disinclination regions 1206 below.
[060] In many of the embodiments disclosed herein (as well as in many applications
incorporated herein), the layout uses subpixels that are wider than normal RGB stripe, which tends
to result in 10-100% increase in aperture ratio, depending on pixel density. The black matrix may
be held constant and the light transmission increases. However, it may also be desirable to "give
up" some of the light transmission gain and increase the black matrix width to cover more of the
disclination region at the edge of the pixel. This may improve the overall contrast by reducing the
dark state brightness of the LCD. The bright state brightness may be higher owing to the increased
transmission; thus the contrast ratio will be improved. Further, roe black matrix may be
differentially adjusted for different colored regions, subpixels, such that the brighter subpixels, such
as white, green, or even cyan, have more area at the periphery covered by the black matrix to reduce
leakage from the disinclinations, thus increasing the contrast while maintaining to some degree, the
saturated brightness of the darker colors such as red and blue. Each of the colored subpixels may
be thus adjusted independently, as desired. For example, the white may have the most area covered
by the black matrix to have the greatest impact on the contrast of images.
[061] While disclinations have been described as the source of light leakage around the
edges of pixels, the present invention is not restricted to this phenomenon alone. In other designs,
light leakage may be caused by field effects caused by the edge of electrodes, such as chevron
patterns in MVA or IPS designs. The enlarged black matrix will help hide these sources of light
leakage as well, ft should be appreciated that this concept applies equally well to layout that are 3-
color (i.e. using only red, green and blue as subpixels) or other multiprimary layout (i.e. not using
white as a subpixel) - as well as any RGBW design.
[062] Although the layouts as described herein are suitable to LCD displays, these layouts
find equal application in the area of incandescent lamp based displays, Light Emitting Diode (both
organic and inorganic) based displays, Plasma display panels (PDF) and many other various display
technologies.
[063] Figure 13 is one embodiment of a delta triad subpixel layout substantially
corresponding to the color assignments in Figure 11C. Of course, the present invention subsumes
mirror images and other symmetries of this particular embodiment.
[064] Figures 14 and 15 are additional embodiments that are similar to Figures 2 and 3
wherein further the individual colored subpixels are placed on hex grid, as opposed to a square grid.
[065] Figure 16 is an additional embodiment that is similar to Figure 4 but further wherein
the colored subpixels form a different diagonal striping pattern as seen in Figure 4.
[066] Figure 17 is another embodiment that is similar to Figure 11A but wherein the single
color planes are placed on a square grid as opposed to a hex grid.
[067] Figures 18 through 24 arc embodiments of other Figures previously shown herein -
but with the white subpixels displaced as shown.
[068] Figures 25, 26, 27 and 28 are embodiments of several of Figures previously shown
herein - but depicted in mirror image.
[069] While the invention has been described with reference to an exemplary embodiment,
it will be understood by those skilled in the art that various changes may be made and equivalents
may be substituted for elements thereof without departing from the scope of the invention. In
addition, many modifications may be made to adapt a particular situation or material to the
teachings without departing from the essential scope thereof. Therefore, it is intended that the
invention not be limited to the particular embodiment disclosed as the best mode contemplated for
carrying out this invention, but that the invention will include all embodiments falling within the
scope of the appended claims.











We claim:
1. A liquid crystal display comprising a two-dimensional arrangement of subpixels. the arrangement
of subpixels consisting of a plurality of a single two-dimensional 2x4 subpixel repeating group
(102) including 2 rows and 4 columns of subpixels . characterized in that said single subpixel
repealing group (102), is one of:
VV C W B W C W M
WRWG. and W R W G.
wherein G, R. B, C and VI represent a green (106). a red (108), a blue {1 lO). a cyan (204) and a magenta (304) color subpixel, respectively and wherein W represents: a white subpixel or a yellow subpixel
2. The liquid crystal display as claimed in Claim 1 wherein the W subpixels (104) are of smaller size than the G. R. B, C or G. R. C. M subpixels.
3. The liquid crystal display as claimed in Claim 1 wherein the subpixels are rectangular and wherein said G. R. B, C or G, R, C, M subpixels each have a first aspect ratio and said W subpixels (104) each have a second aspect ratio different from said first aspect ratio.
4. The liquid crystal displav as claimed in Claim 1 wherein the subpixels are rectangular and wherein said G, R. B. C or G. R. C. M subpixels and said W subpixels (104) have the same aspect ratio.
.5. The liquid crystal display as claimed in Claim 3 wherein said first aspect ratio is 1:2 and said second aspect ratio is 1:3.
6. The liquid crystal display as claimed in Claim 1 wherein said subpixels are of rectangular shape.
7. The liquid crystal display as claimed in Claim 1 wherein a black matrix (1204) is arranged to cover disinclination regions (1206) around the edges of the subpixels.

8. The liquid crystal display as claimed in Claim 7 wherein the black matrix (1204) covers a larger
area of disinclination regions (1206) in the VV suhpixels than in the G, R. B, C or G, R, C, M
subpixels.
9. The liquid crystal display as claimed in Claim 1 wherein said display further comprises a
backlight and (he colour temperature of said backlight is adjusted such that a balanced white
colour is displayed when all subpixels are switched fully on.
10. The liquid crystal display as claimed in Claim 1 wherein the W subpixels (104) are vertically
displaced with respect to the G, R. B, C or the G. R. C. M subpixels.
11. The liquid crystal display as claimed in claim 1 further comprising a backlight wherein the
display has a balanced white point when all subpixels are switched fully on; and
wherein at least one of the G, R, B. C or G, R, C, M subpi.xels has a greater pixel area than said W subpixels.
12. The liquid crystal display as claimed in Claim 11 wherein said display further comprises a black
tnatrix (1204). said black matrix (1204) being formed in an area covering regions of
disinclinations around the edges of the subpixels,
13. The liquid crystal display as claimed in Claim 12 wherein said black matrix covers a larger area
over W subpixels (104) than over the G, R, B, C or G. R. C, M subpixels.
14. The liquid crystal display as claimed in Claim 11 wherein said W subpixels (104) are vertically displaced from said G. R. B, C or G, R. C. M subpixels.

Documents:

5179-delnp-2006-(Complete)-Specification-Granted.pdf

5179-DELNP-2006-Abstract-(12-07-2010).pdf

5179-delnp-2006-abstract.pdf

5179-delnp-2006-Claims-(05-01-2012).pdf

5179-DELNP-2006-Claims-(12-07-2010).pdf

5179-DELNP-2006-Claims-(20-01-2011).pdf

5179-delnp-2006-claims.pdf

5179-delnp-2006-Correspodence Others-(05-01-2012).pdf

5179-DELNP-2006-Correspondence Others-(20-01-2012).pdf

5179-DELNP-2006-Correspondence-Others-(12-07-2010).pdf

5179-DELNP-2006-Correspondence-Others-(20-01-2011).pdf

5179-delnp-2006-correspondence-others-1.pdf

5179-delnp-2006-correspondence-others.pdf

5179-delnp-2006-description (complete).pdf

5179-DELNP-2006-Form-1-(12-07-2010).pdf

5179-delnp-2006-form-1.pdf

5179-delnp-2006-form-18.pdf

5179-DELNP-2006-Form-2-(12-07-2010).pdf

5179-delnp-2006-form-2.pdf

5179-DELNP-2006-Form-3-(12-07-2010).pdf

5179-DELNP-2006-Form-3-(20-01-2011).pdf

5179-DELNP-2006-Form-3-(20-01-2012).pdf

5179-delnp-2006-form-3.pdf

5179-delnp-2006-form-5.pdf

5179-DELNP-2006-GPA-(12-07-2010).pdf

5179-delnp-2006-gpa.pdf

5179-delnp-2006-pct-101.pdf

5179-delnp-2006-pct-210.pdf

5179-delnp-2006-pct-220.pdf

5179-delnp-2006-pct-237.pdf

5179-delnp-2006-pct-304.pdf

5179-delnp-2006-pct-311.pdf

5179-delnp-2006-pct-401.pdf

5179-delnp-2006-pct-409.pdf

5179-delnp-2006-pct-416.pdf

5179-DELNP-2006-Petition 137-(12-07-2010).pdf

5179-DELNP-2006-Petition 138-(12-07-2010).pdf


Patent Number 251249
Indian Patent Application Number 5179/DELNP/2006
PG Journal Number 10/2012
Publication Date 09-Mar-2012
Grant Date 02-Mar-2012
Date of Filing 08-Sep-2006
Name of Patentee CLAIRVOYANTE, INC.
Applicant Address 874 GRAVENSTEIN HWY S, SUITE 14, SEBASTOPOL, CA 95472, USA.
Inventors:
# Inventor's Name Inventor's Address
1 BROWN ELLIOTT, CANDICE, HELLEN 531 YORK STREET, VALLEJO, CA 94950, USA.
2 THOMAS, LLOYD, CREDELLE 407 SCOTTS BLUFF PLACE, MORGAN HILL, CA 95037, USA.
PCT International Classification Number G09G 3/36
PCT International Application Number PCT/US2005/010023
PCT International Filing date 2005-03-23
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10/961,506 2004-10-07 U.S.A.
2 10/821,353 2004-04-09 U.S.A.