U.S. patent application number 13/874447 was filed with the patent office on 2013-11-14 for color filter to prevent color errors in a roll up display.
The applicant listed for this patent is Creator Technology B.V.. Invention is credited to Hjalmar Edzer Ayco HUITEMA, Petrus Johannes Gerardus van LIESHOUT.
Application Number | 20130301154 13/874447 |
Document ID | / |
Family ID | 37865726 |
Filed Date | 2013-11-14 |
United States Patent
Application |
20130301154 |
Kind Code |
A1 |
HUITEMA; Hjalmar Edzer Ayco ;
et al. |
November 14, 2013 |
COLOR FILTER TO PREVENT COLOR ERRORS IN A ROLL UP DISPLAY
Abstract
A conformable, flexible or roll up display includes a matrix
display layer including lines of sub-pixels. Each line has an
associated color assigned to the line, and each line extends along
a roll up or bend direction. A display effect layer is formed on
the matrix layer. A color filter layer includes striped color
filters which extend in the roll up or bend direction. The striped
color filters each include a filter color corresponding with the
lines of sub-pixels in the matrix layer to address misalignment and
color errors due to bending or rolling up the display. Methods for
fabricating flexible displays are also disclosed.
Inventors: |
HUITEMA; Hjalmar Edzer Ayco;
(Veldhoven, NL) ; van LIESHOUT; Petrus Johannes
Gerardus; (Beek on Donk, NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Creator Technology B.V. |
Breda |
|
NL |
|
|
Family ID: |
37865726 |
Appl. No.: |
13/874447 |
Filed: |
April 30, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12091710 |
Jun 19, 2008 |
8446549 |
|
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PCT/IB2006/054256 |
Nov 14, 2006 |
|
|
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13874447 |
|
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60740469 |
Nov 29, 2005 |
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Current U.S.
Class: |
359/891 ;
445/24 |
Current CPC
Class: |
G02B 5/201 20130101;
G02F 1/133305 20130101; G02F 1/1677 20190101; G02B 5/20 20130101;
G02F 1/167 20130101; G02F 1/133516 20130101; G02F 1/133514
20130101 |
Class at
Publication: |
359/891 ;
445/24 |
International
Class: |
G02B 5/20 20060101
G02B005/20 |
Claims
1-26. (canceled)
27. A flexible, rollable or conformable display, comprising: a
matrix display layer including lines of sub-pixels, each line
having an associated color assigned to the line, each line
extending along a roll up or bend direction; a display effect layer
formed on the matrix layer; a color filter layer including striped
color filters which extend in the roll up or bend direction, the
striped color filters each include a filter color corresponding
with the lines of sub-pixels in the matrix layer to address
misalignment and color errors due to bending or rolling up the
display; and a fixing material applied at an end portion of the
display to couple and fix the display effect layer to the color
filter layer.
28. The display as recited in claim 27, wherein the striped color
filters are manufactured separately from the display and are
attached to the display by an adhesive.
29. The display as recited in claim 27, wherein the striped color
filters are formed by deposition and patterning using
photolithography.
30. The display as recited in claim 27, further comprising a spool
configured to roll up the display.
31. The display as recited in claim 27, wherein the fixing material
includes a stripe applied perpendicularly to the roll up or bend
direction at an end portion of the color filter layer.
32. The display as recited in claim 27, wherein the fixing material
includes a plurality of spots applied at end portions of the color
filter layer.
33. A flexible, rollable or conformable display, comprising: a
matrix display layer including lines of sub-pixels, each line
having an associated color assigned to the line, each line
extending along a roll up or bend direction, the lines being
arranged to include a single color component; a display effect
layer formed on the matrix layer; a color filter layer formed on
the display effect layer and including striped color filters, each
striped color filter being associated with the single color
component of a corresponding line of sub-pixels and the striped
color filter formed to cover the line of sub-pixels, the striped
color filters extending in the roll up or bend direction to address
misalignment and color errors due to bending or rolling up the
display; and a fixing material applied at an end portion of the
display to couple and fix the display effect layer to the color
filter layer.
34. The display as recited in claim 33, further comprising a spool
configured to roll up the display.
35. The display as recited in claim 33, wherein the fixing material
includes a stripe applied perpendicularly to the roll up or bend
direction at an end portion of the color filter layer.
36. The display as recited in claim 33, wherein the fixing material
includes a plurality of spots applied at end portions of the color
filter layer.
37. A method for fabricating a flexible display device, comprising:
forming a matrix layer having sub-pixels arranged in lines such
that each sub-pixel in a line provides illumination for a given
color component; forming a display effect layer on the matrix
layer; and on the display effect layer, forming color filter
stripes longitudinally in a roll up or bend direction, each stripe
corresponding to and covering a line of sub-pixels to reduce
misalignment and color errors due to bending; and securing the
color filter stripes with a fixing material applied at an end
portion of the display.
38. The method as recited in claim 37, wherein forming color filter
stripes includes depositing and patterning the color filter stripes
using photolithography.
39. The method as recited in claim 37, wherein forming the color
filter stripes includes ink jet printing the color filter
stripes.
40. The method as recited in claim 37, wherein forming the color
filter stripes includes silk screening/shadow masking to form the
color filter stripes.
41. The method as recited in claim 37, wherein forming the color
filter stripes includes manufacturing the color filter stripes
separately from the display and attaching the color filter stripes
to the display by an adhesive.
42. The method as recited in claim 37, wherein the fixing material
includes a stripe applied perpendicularly to the roll up direction
at an end portion of the color filter stripes.
43. The method as recited in claim 37, wherein the fixing material
includes a plurality of spots applied at end portions of the color
filter stripes.
Description
[0001] This application is a continuation of U.S. application Ser.
No. 12/091,710, filed on Nov. 14, 2006, which is a national stage
entry of PCT/1B2006/054256, filed on Nov. 14, 2006, which claims
priority to a Provisional application No. 60/740,469, filed on Nov.
29, 2005, the disclosures of which are hereby incorporated by
reference herein in their entirety.
TECHNICAL FIELD
[0002] This disclosure relates to flexible displays, and more
particularly to devices and methods for forming color filters on
such displays.
BACKGROUND
[0003] Flat panel displays include color filters to remove
particular color components from light illuminating from sub-pixels
of the display. Non-intrinsic color displays include a display
effect layer, which reflects or emits light with a broad spectrum
(white), and a color filter layer, which changes the white light
into colored light. The display effect layer and the color filter
layer need to be properly aligned to prevent parallax or aperture
problems. When making a conformable, flexible or even roll-up
display in this way, alignment problems between the display effect
layer and the color filter layer can occur due to the different
radii of these layers during bending or rolling.
[0004] Referring to FIG. 1, an illustrative roll up display 10 is
shown to illustrate alignment between pixel structures 22 in an
active matrix layer 12 and color filters 14, 16, and 18 in a color
filter layer 20. Pixel structures 22 reflect or emit white light
which passes through a display effect layer 15 and then an
appropriately aligned color filter 14, 16 or 18 corresponding to
each sub-pixel 22. Three sub-pixels 22 form a pixel image that
includes a red, green and blue components supplied by color filters
14, 16 and 18 respectively. Lines 24 are shown to illustrate
alignment between sub-pixels 22 and color filters 14, 16 and
18.
[0005] Referring to FIG. 2, display 10 is shown being rolled up
onto a roller or spool 30. Due to the radius of the spool 30,
misalignment occurs between color filters 14, 16 and 18 and
sub-pixels 22. Misalignment between color filters 14, 16 and 18 in
layer 20 and sub-pixels 22 is illustrated by lines 24. The
misalignment can cause parallax problems, decrease brightness and
cause color errors and moire effects in the displayed image.
SUMMARY
[0006] Embodiments of the present disclosure describe color filters
formed or applied to a conformable, roll up or flexible display. A
rollable/flexible color display has a display effect layer,
reflecting or emitting white light, combined with a color filter
layer. Colored sub-pixels of the display are arranged into rows or
columns in a roll-up direction.
[0007] Embodiments may include active and/or passive-matrix
displays. Color filter stripes are formed extending in a roll up
direction. The color filter can be arranged in the direction of the
row electrodes or in the direction of the column electrodes as long
as this direction is parallel to the roll direction. The stripes
may be in combination with a fixing strip along one of the edges
perpendicular to the rolling direction. The fixing strip thus binds
the display effect layer and color filter layer along one of the
non-rolling display edges. This secures the color filter, but
permits movement between the pixel layer and the color filter
layer.
[0008] Brightness decrease or color errors caused by alignment
problems during display bending or rolling are avoided by
patterning color filters into continuous stripes which extend in
the roll up direction. The radius difference between a display
effect layer and a color filter layer is substantially eliminated
since misalignment between the color filters and the underlying
pixels is eliminated. A conformable, flexible or roll up display
includes a matrix display including lines of sub-pixels. The
display can be any matrix display, active or passive. Each line has
an associated color assigned to the line, and each line extends
along a roll up or bend direction. A display effect layer is formed
on the matrix layer. A color filter layer includes striped color
filters which extend in the roll up or bend direction. The striped
color filters each include a filter color corresponding with the
lines of sub-pixels in the active matrix layer to address
misalignment and color errors due to bending or rolling up the
display. Methods for fabricating flexible displays are also
disclosed.
[0009] It should be understood that the present claims and
disclosure refer to rows, but the alignment of pixels may be
performed in the column direction. The word row is employed for
convenience to refer to a line of pixels having the same color
designation. Advantages gained by the color filters being applied
in accordance with these principles include elimination of
misalignment problems that cause color error, parallax or other
ill-effects, and ease of manufacture of the color filter layer.
[0010] These and other objects, features and advantages of the
present disclosure will become apparent from the following detailed
description of illustrative embodiments thereof, which is to be
read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] This disclosure will present in detail the following
description of preferred embodiments with reference to the
following figures wherein:
[0012] FIG. 1 is a cross-sectional view of a flexible display in
accordance with the prior art;
[0013] FIG. 2 is a cross-sectional view of the flexible display of
FIG. 1 showing misalignment between sub-pixels and color
filters;
[0014] FIG. 3 is a cross-sectional view of a flexible display in
accordance with one embodiment;
[0015] FIG. 4 is a perspective view of a sub-pixel array in
accordance with another illustrative embodiment;
[0016] FIG. 5 is a perspective view of the sub-pixel array with a
display effect layer having color filter stripes formed thereon in
accordance with an illustrative embodiment; and
[0017] FIG. 6 is a top view of an illustrative color filter
sheet;
[0018] FIG. 7 is a top view of the flexible display showing a
fixing strip and/or spots for securing the color filter stripes;
and
[0019] FIG. 8 is a flow diagram showing illustrative methods for
fabricating a color filter in accordance with embodiments of the
present invention.
DETAILED DESCRIPTION
[0020] The present disclosure provides embodiments for a flexible
or roll up display that includes improved alignment between
sub-pixels and a color filter to improve display viewing
quality.
[0021] It should be understood that the elements shown in the FIGS.
may be implemented in various configurations. For illustrative
purposes, embodiments will be described herein in terms of an
electrophoretic display type that includes polymeric substrates,
which permit conformable, flexible or roll up displays to be
formed. Other types of displays may also benefit from the teachings
herein. For example, liquid crystal, electroluminescent displays,
etc. may employ the teachings herein.
[0022] Referring now to the drawings in which like numerals
represent the same or similar elements and initially to FIG. 3, a
cross-sectional view of a conformable, flexible or roll up display
100 is shown in accordance with principles of one embodiment. A
display effect layer 128 includes materials for the transmission
and dispersion of light. In the embodiment of FIG. 3, the display
effect layer 128 may include liquid crystal, electrophoretic
display medium or any other emitting or reflective material for
guiding light to a viewer. A backplane substrate 114 may include a
flexible polymer material on which an active matrix layer 115 is
formed including sub-pixels 116 and other electronic components.
These electronic components may include transistors (thin film
transistors TFT), capacitors, conductive lines, etc. For simplicity
only sub-pixels 116 are shown. For a back lit embodiment, light is
passed through substrate 114 or other back end device to provide
light through sub-pixels 116. Other embodiments may include
reflective displays where light is reflected from sub-pixels 116
from the viewing side of the sub-pixels 116. A cell gap 118 is
filled with a display effect material, such as, e.g., liquid
crystal, electrophoretic display medium (e.g., the capsules
containing electrophoretic ink from the manufacturer E Ink
Corporation) or other display effect material which is responsive
to pixels 116. For example, when activated the pixels 116 cause
orientation of the liquid crystal or a change in the E ink capsules
as is known in the art. A substrate 121 may include a common
electrode 120 formed thereon. The common electrode 120 cooperates
with the sub-pixels 116 to orient or adjust the state of the
adjacent display effect material. A color filter layer 152 is
provided as part or substrate 121.
[0023] Referring to FIG. 4, a sub-pixel array 150 includes an
arrangement of sub-pixels 116 which are configured to be assigned
same color values in a linear relationship, e.g., in same rows or
columns 132, 134 and 136 (referred to hereinafter as rows for ease
of reference). Each row 132, 134 and 136 corresponds to a same
color. Colored sub-pixels 116 of the display 100 are arranged into
rows in a roll-up direction 140 (a roll 142 is shown in this view
for illustrative purposes). The three color rows (e.g., Red 134,
Green 136 and Blue 138) repeat across the display. While three
color components are illustratively depicted and described, other
arrangements may be provided. For example, in one embodiment, four
row types may be employed (e.g., Red, Green, Blue and White
(RGBW)). Each row (132, 134, and 136) is oriented in the roll up
direction 140, which is transverse to a longitudinal axis of a
spool or roll 142.
[0024] Referring to FIG. 5, the rollable color display 100 has the
display effect layer 128 formed and a color filter layer 152 is to
be placed in alignment with the sub-pixels 116 on an active/passive
matrix layer 115. The color filter layer 152 may be fabricated and
placed in a plurality of different ways. The color filter layer 152
may be formed by a deposition and photolithographic patterning over
the display effect layer 128. For example, a first color is
deposited followed by a patterning process which forms longitudinal
stripes 154 of the first color in the direction of the roll up 140.
Each stripe 154 of the first color corresponds to and is aligned in
a direction transverse to the roll up direction 140. Similar
processing is performed to define stripes 154 for the other color
filters corresponding to the sub-pixels 116 of that color. Color
filters may include materials of between about 100 nm and about 10
microns in thickness and are preferably polymeric materials, which
may be known.
[0025] In alternate embodiments, a color filter layer 152 may be
formed by spin coating, spray coating, evaporating, doctor blading
or similar deposition methods. In one embodiment, the color filter
layer is formed as a sheet having alternating color components as
illustratively shown in FIG. 6. A color filter sheet 160 may be
formed in a single sheet having different colors 161-163
alternating thereon. Sheet 160 may include a thin polymeric
material fabricated in an extrusion process. Sheet 160 may be glued
or other wise adhered to the display 100 (FIG. 3) to provide color
filter layer 152.
[0026] Advantageously, the color filter layer 152 need only be
concerned about a sub-pixel pitch in a direction transverse to the
roll-up direction 140. This makes alignment much easier between the
sub-pixels 116 and the color filters. In the present disclosure,
colored sub-pixels 116 are arranged in horizontal stripes. This can
have implications on the arrangement of rows and columns on the
display and thereby the performance needed from driving or
backplane electronics.
[0027] Referring to FIG. 7, color filter stripes 170 may be secured
using a fixing strip 172 along one of the edges perpendicular to
the rolling direction 140. The fixing strip 172 binds the display
effect layer 128 and color filter layer 152 along one of the
non-rolling display edges. As described, brightness decreases
and/or color errors caused by alignment problems during display
bending or rolling are avoided by patterning color filters into
continuous stripes 170 which extend in the roll up direction 140. A
radius difference between the display effect layer 128 and the
color filter layer 152 is substantially eliminated since
misalignment between the color filters and the underlying pixels is
eliminated. No brightness decrease or color errors will occur.
[0028] FIG. 7 illustratively shows an RGB (red, green, blue) color
display 200 according to one embodiment. However, arrangements
other than RGB, such as RGBW RBG White) or CMY (Cyan, Magenta,
Yellow) may be employed. Black stripes (boot shown) may also be
employed between the colored stripes 170 to separate or delineate
the stripes 170. It should be understood that pixels comprised of
three sub-pixels are arranged together such that three adjacent
rows cover the three sub-pixels needed for a pixel image. The color
filter stripes need not continuously alternate, e.g., RGB; RGB,
etc.; instead other arrangement are possible, e.g., RGB, BGR, RGB,
so that the same colors in this case B and R can be formed adjacent
to one another. This may ease tolerances and improve
manufacturability.
[0029] Depending on the lamination glue properties of fixing strip
172, fixing strip may be employed to fix the display effect layer
128 and color filter layer 152 along one of the non-rolling display
edges to prevent un-wanted drifting of the two layers with respect
to each other. Fixing strip 170 may be employed along one side of
the display 200, and permit the movement of color filter layer 152
relative to the display effect layer without color errors due to
bending or roll up. Other arrangements are also possible, such as,
e.g., employing one or more fixing spots 176 at opposite sides of
the display 200.
[0030] Referring to FIG. 8, a flow diagram describing methods for
fabricating a flexible/roll-up display with a striped color filter
is shown. Horizontal and vertical will be illustratively used to
designate relative orientation of color filters and sub-pixels.
Other directions and orientations may also be employed. In block
302, a display device is provided having an active/passive matrix
with sub-pixels being arranged in alternating horizontal rows in
accordance with color. A display effect layer is formed or provided
in block 303 along with other components as needed in preparation
of a color filter layer. In block 304, a color filter layer is
formed by forming striped color filters horizontally over a
corresponding color sub-pixel row. Many processes may be employed
for forming the color filter. For example, spin coating, spray
coating, evaporating, doctor blading or similar deposition methods
may be employed to form the color filters. The formation of the
color filter may include photolithography to pattern color filters
into stripes or patches, followed by a next color filter deposition
and patterning until all color filters are formed. Screen-printing
or inkjet printing may be employed to directly deposit patterned
color filters. The color filter may be separately manufactured and
placed in alignment as follows.
[0031] In block 306, alignment of the color filter is performed
relative to the sub-pixel pitch. Advantageously, alignment is only
needed in the vertical direction along the length of the display.
In block 308, a fixing strip, strips or spots are placed to secure
the color filter layer to the display effect layer. Processing
continues as needed.
[0032] Having described preferred embodiments for a roll up display
with color filters and methods for fabrication of the same (which
are intended to be illustrative and not limiting), it is noted that
modifications and variations can be made by persons skilled in the
art in light of the above teachings. It is therefore to be
understood that changes may be made in the particular embodiments
of the disclosure disclosed which are within the scope and spirit
of the embodiments disclosed herein as outlined by the appended
claims. Having thus described the details and particularity
required by the patent laws, what is claimed and desired protected
by Letters Patent is set forth in the appended claims.
[0033] In interpreting the appended claims, it should be understood
that: [0034] a) the word "comprising" does not exclude the presence
of other elements or acts than those listed in a given claim;
[0035] b) the word "a" or "an" preceding an element does not
exclude the presence of a plurality of such elements; [0036] c) any
reference signs in the claims do not limit their scope; [0037] d)
several "means" may be represented by the same item or hardware or
software implemented structure or function; and [0038] e) no
specific sequence of acts is intended to be required unless
specifically indicated.
* * * * *