U.S. patent application number 10/990797 was filed with the patent office on 2006-05-18 for spatial light modulator.
This patent application is currently assigned to Hewlett-Packard Development Company, L.P.. Invention is credited to Paul Benning, Kenneth James Faase.
Application Number | 20060103909 10/990797 |
Document ID | / |
Family ID | 36272318 |
Filed Date | 2006-05-18 |
United States Patent
Application |
20060103909 |
Kind Code |
A1 |
Benning; Paul ; et
al. |
May 18, 2006 |
SPATIAL LIGHT MODULATOR
Abstract
A spatial light modulator includes a first portion and a second
portion. Both the first portion and the second portion include a
planar electrode, a polar solvent, and a non-polar solvent. The
polar solvent and the non-polar solvent are supported by the first
planar electrode. A coating of molecules is attached to the first
planar electrode and includes a head end. The head end changes
between a first shape and a second shape.
Inventors: |
Benning; Paul; (Corvallis,
OR) ; Faase; Kenneth James; (Corvallis, OR) |
Correspondence
Address: |
HEWLETT PACKARD COMPANY
P O BOX 272400, 3404 E. HARMONY ROAD
INTELLECTUAL PROPERTY ADMINISTRATION
FORT COLLINS
CO
80527-2400
US
|
Assignee: |
Hewlett-Packard Development
Company, L.P.
|
Family ID: |
36272318 |
Appl. No.: |
10/990797 |
Filed: |
November 17, 2004 |
Current U.S.
Class: |
359/237 |
Current CPC
Class: |
G02B 26/004 20130101;
B82Y 30/00 20130101 |
Class at
Publication: |
359/237 |
International
Class: |
G02B 26/00 20060101
G02B026/00 |
Claims
1. A spatial light modulator comprising: a first portion that
includes: a first planar electrode; a polar solvent; a first
non-polar solvent, wherein the polar solvent and the first
non-polar solvent are supported by the first planar electrode; and
a first coating of molecules attached at one end to the first
planar electrode, wherein the first coating includes a free end
changing between a first shape and a second shape in response to a
change in voltage on the first planar electrode; and a second
portion that includes: a second planar electrode; the polar
solvent; and a second non-polar solvent, wherein the polar solvent
and the second non-polar solvent are supported by the second planar
electrode; and a second coating of molecules attached at one end to
the second planar electrode, wherein the second coating includes a
free end changing between the first shape and the second shape in
response to a change in voltage on the second planar electrode.
2. The spatial light modulator of claim 1 wherein the first portion
is stacked on the second portion.
3. The spatial light modulator of claim 1 wherein the first portion
is adjacent the second portion.
4. The spatial light modulator of claim 1 wherein a portion of
molecules of the first coating of molecules attracts the polar
solvent when in the first shape and repels the polar solvent when
in the second shape.
5. The spatial light modulator of claim 1 wherein one of the first
non-polar solvent and the polar solvent includes a dye of a first
color, and wherein one of the second non-polar solvent and the
polar solvent includes a dye of a second color.
6. The spatial light modulator of claim 1 wherein one of the first
non-polar solvent and the polar solvent includes a pigment of a
first color, and wherein one of the second non-polar solvent and
the polar solvent includes a pigment of a second color.
7. The spatial light modulator of claim 6 further comprising a
third portion that includes: a third planar electrode; the polar
solvent; and a third non-polar solvent, wherein the polar solvent
and the third non-polar solvent are supported by the third planar
electrode; and a third coating of molecules attached at one end to
the third planar electrode, wherein the third coating of molecules
includes a head end of the molecules changing between the first
shape and the second shape in response to a change in voltage on
the third planar electrode.
8. The spatial light modulator of claim 7 wherein the first
portion, the second portion and the third portion are stacked with
respect to each other.
9. The spatial light modulator of claim 7 wherein one of the first
non-polar solvent and the polar solvent includes a pigment of a
first color, and wherein one of the second non-polar solvent and
the polar solvent includes a pigment of a second color, and wherein
one of the third non-polar solvent and the polar solvent includes a
pigment of a third color.
10. The spatial light modulator of claim 9 further comprising a
light source positioned to project light through the first portion,
the second portion and the third portion.
11. The spatial light modulator of claim 9 further comprising a
reflective surface positioned adjacent at least one of the first
portion, second portion or third portion.
12. The spatial light modulator of claim 6 further comprising a
fourth portion that includes: a fourth planar electrode; the polar
solvent; a fourth non-polar solvent, wherein the polar solvent and
the fourth non-polar solvent are supported by the fourth planar
electrode; and a fourth coating of molecules attached at one end to
the fourth planar electrode, wherein the fourth coating includes a
free end changing between the first shape and the second shape in
response to a change in voltage on the fourth planar electrode.
13. The spatial light modulator of claim 12 wherein at least one of
the first non-polar solvent and the polar solvent includes a
pigment of a first color, and wherein one of the second non-polar
solvent and the polar solvent includes a pigment of a second color,
and wherein one of the third non-polar solvent and the polar
solvent includes a pigment of a third color, and wherein one of the
fourth non-polar solvent and the polar solvent includes a pigment
of a fourth color.
14. The spatial light modulator of claim 13 wherein the first
color, the second color, the third color and the fourth color
include cyan, yellow, magenta, and black, respectively.
15. The spatial light modulator of claim 1 further comprising: an
area of the first planar electrode that is devoid of the first
coating of molecules; and an area of the second first planar
electrode that is devoid of the second coating of molecules.
16. The spatial light modulator of claim 1 further comprising a
lens positioned adjacent one of the first portion and the second
portion.
17. A method comprising: adding a polar solvent to a first cell and
to a second cell; adding a non-polar solvent to the first cell and
to the second cell; stacking the first cell and the second cell;
applying a first external force to a first electrode of the first
cell to move molecules coupled to the first electrode between a
first surface that attracts a polar solvent and a second surface
that repels the polar solvent; and applying a second external force
to a second electrode of the second cell to move molecules coupled
to the second electrode between a third surface that attracts a
polar solvent and a fourth surface that repels the polar
solvent.
18. The method of claim 17 further comprising: dying one of the
polar solvent and the non-polar solvent in the first cell with a
first color; and dying one of the polar solvent and the non-polar
solvent in the second cell with a second color.
19. The method of claim 18 further comprising at least one of
applying the first external force to the first cell to cause the
dyed one of the non-polar solvent and the polar solvent to be
interposed into a light path traversing the first cell, and
applying the second external force to the second cell to cause the
dyed one of the non-polar solvent and the polar solvent to be
interposed into a light path traversing the second cell.
20. The method of claim 18 wherein applying one of the first and
second external forces to one of the first cell and the second cell
concentrates the dyed one of the non-polar solvent or polar solvent
in a position within one of the first cell and the second cell.
21. The method of claim 18 further comprising transmitting light
through the first cell and the second cell.
22. The method of claim 18 further comprising applying the first
external force to the first cell to cause the dyed one of the
non-polar solvent and the polar solvent to be positioned across the
first cell; and removing the second external force to the second
cell to cause the dyed one of the non-polar solvent and the polar
solvent to be positioned in one area with respect to the first
cell, wherein light is transmitted through the first cell and the
second cell and the transmitted light is colored by the dyed one of
the non-polar solvent and the polar solvent extending across the
first cell.
23. The method of claim 21 wherein transmitting light through the
first cell and the second cell includes reflecting the light
transmitted through the first cell and the second cell.
24. The method of claim 18 further comprising wherein applying an
external force on the first cell and on the second cell includes
controlling a voltage on the electrode of the first cell and on the
electrode of the second cell.
25. A display device comprising: a plurality of display elements
capable of controlling light within a visible light spectrum, the
plurality of display elements positioned over a display surface of
the display, at least some of the display elements further
comprising: a first portion that includes: a first planar
electrode; a polar solvent; a first non-polar solvent, the polar
solvent and the first non-polar solvent supported by the first
planar electrode; and a first coating of molecules attached at one
end to the first planar electrode, the first coating including
molecules having a free end changing between a first shape and a
second shape in response to a change in voltage on the first planar
electrode; and a second portion that includes: a second planar
electrode; a polar solvent; and a second non-polar solvent, the
polar solvent and the second non-polar solvent supported by the
second planar electrode; and a second coating of molecules attached
at one end to the second planar electrode, the second coating
including molecules having a free end changing between a first
shape and a second shape in response to a change in voltage on the
second planar electrode; and means for controlling the first
portion and the second portion to control the light passing through
the display element.
26. The display device of claim 25 wherein the first portion is
stacked on the second portion.
27. The display device of claim 26 further comprising a plurality
of receivers coupled to the plurality of display elements and
adapted to receive transmitted image information and activate the
display elements in response to the image information.
28. The display device of claim 27 wherein the means for
controlling the first portion and the second portion controls at
least some of the portions of the display elements in response to
image information received at the plurality of receivers.
29. The display device of claim 26 further comprising a light
source for projecting light through the plurality of display
elements.
30. The display device of claim 29 further comprising a reflective
surface positioned near the plurality of display elements.
31. The display device of claim 29 wherein the light source is
ambient light.
32. A system comprising: a display including plurality of display
elements capable of controlling light within a visible light
spectrum, the plurality of display elements positioned over a
display surface of the display, at least some of the display
elements further comprising: a first portion that includes: a first
planar electrode; a polar solvent; a first non-polar solvent, the
polar solvent and the first non-polar solvent supported by the
first planar electrode; and a first coating of molecules attached
at one end to the first planar electrode, the first coating
including molecules having a free end changing between a first
shape and a second shape in response to a change in voltage on the
first planar electrode; and a second portion that includes: a
second planar electrode; a polar solvent; and a second non-polar
solvent, the polar solvent and the second non-polar solvent
supported by the second planar electrode; and a second coating of
molecules attached at one end to the second planar electrode, the
second coating including molecules having a free end changing
between a first shape and a second shape in response to a change in
voltage on the second planar electrode; and a controller
controlling the first portion and the second portion to control
light passing through the display.
33. The system of claim 32 wherein the controller further
comprises: a microprocessor; and a memory device coupled to the
microprocessor.
34. The system of claim 32 further comprising image information,
the controller controlling the first portion and the second portion
in response to the image information.
Description
BACKGROUND
[0001] Displays are used in televisions and computers. Projectors
are most commonly used in televisions. Display types include
cathode ray tubes (CRTs) and liquid crystal displays (LCDs). CRTs
use electron beam technology that has been present for many years
in consumer products such as television (TV) tubes and computer
monitors. CRTs use hot cathode electrodes to create a source of
electrons that are directed to and focused on the viewing screen.
The viewing screen generally includes glass. Directing the
electrons to the viewing screen requires some distance. In
addition, the viewing screen is generally made of glass, so CRTs
are heavy, especially in larger displays or monitors. Consequently,
CRTs are heavy and use a relatively large space when compared to
LCD monitors.
[0002] LCD monitors are lightweight and thin in comparison to CRTs.
An LCD may use two pieces of polarized glass. A special polymer is
dispensed on a side of the glass that does not have a polarizing
film on it. A special polymer creates microscopic grooves in the
glass surface to form a first light filter. The grooves are in the
same direction as the polarizing film. The grooves are coated with
pneumatic liquid crystals to finish a light filter. The grooves
cause the first layer of molecules to align with the filter's
orientation. The second piece of polarized glass is supported by
the first piece of polarized glass at a right angle. Each
successive layer of molecules gradually twists until the uppermost
layer or portion of the molecule is at a 90-degree angle to the
bottom layer or portion. The twisted molecules, therefore, act as
light guides that twist to match the polarized glass filters.
[0003] As light strikes the first filter, it is polarized. The
molecules in each layer then guide the light they receive to the
next layer. As the light passes through the liquid crystal layers,
the molecules also change the light's plane of vibration to match
their own angle. When the light reaches the far side of the liquid
crystal substance, it vibrates at the same angle as the final layer
of molecules. If the final layer is matched up with the second
polarized glass filter, then the light may pass through.
[0004] Applying an electric charge to the liquid crystal molecules
causes the molecules to straighten out or untwist. When they
straighten out, they change the angle of the light passing through
them so that it no longer matches the angle of the top polarizing
filter. Consequently, no light can pass through that "charged" area
of the LCD, which makes that area darker than the surrounding
areas. LCDs switch pixels through polarization.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a schematic diagram of a display device, according
to an example embodiment.
[0006] FIG. 2 is a schematic diagram of a display device, according
to an example embodiment.
[0007] FIG. 3 is a schematic diagram of a cell of a spatial light
generator, according to an example embodiment.
[0008] FIG. 4 is a schematic diagram showing a monolayer of
molecules attached to an electrode of a cell of a spatial light
generator with the molecules in a first orientation, according to
an example embodiment.
[0009] FIG. 5 is a schematic diagram showing a monolayer of
molecules attached to an electrode of a cell of a spatial light
generator with the molecules in a second orientation, according to
an example embodiment.
[0010] FIG. 6 is a schematic diagram of a cell of a spatial light
generator with the monolayer of molecules in the second
orientation, according to an example embodiment.
[0011] FIG. 7 is a schematic diagram of a spatial light generator
that includes a plurality of stacked cells controlled by a
controller, according to an example embodiment.
[0012] FIG. 8 is a schematic diagram of a spatial light generator
that includes a plurality of adjacent cells controlled by a
controller, according to an example embodiment.
[0013] FIG. 9 is a schematic diagram of a cell that includes an
area on the electrode free of the molecular monolayer, according to
an example embodiment.
[0014] FIG. 10 is a flow diagram of a method, according to an
example embodiment.
DETAILED DESCRIPTION
[0015] In the following description, the drawings illustrate
specific embodiments sufficiently to enable those skilled in the
art to practice it. Other embodiments may incorporate structural,
logical, electrical, process, and other changes. Examples merely
typify possible variations. Individual components and functions are
optional, and the sequence of operations may vary. Portions and
features of some embodiments may be included in or substituted for
those of others. The scope encompasses the full ambit of the claims
and all available equivalents. The following description is,
therefore, not to be taken in a limited sense, and the scope of the
embodiments is defined by the appended claims.
[0016] FIG. 1 is a schematic diagram of a display device 100,
according to an example embodiment. The display device 100 includes
a light source 110, a spatial light modulator 120, and optics 130
for directing light from the light source 110 toward the spatial
light modulator 120. The spatial light modulator 120 includes at
least one cell 300. The spatial light modulator 120 can include one
cell or can include a plurality of cells 300. In some embodiments,
each of the cells 300 corresponds to a pixel on the display device
100. Attached to the spatial light modulator 120 is a controller
140. The controller 140 receives image information for the spatial
light modulator 120 and controls the spatial light modulator to
produce an image or series of images. The controller 140 controls
at least one cell 300 of the spatial light modulator 120. In
another embodiment, the controller 140 controls a plurality or
multiplicity of cells 300 associated with the spatial light
modulator 120 in order to produce an image. In the embodiments
where there is a plurality or multiplicity of cells or pixels 300,
the cells or pixels 300 are individually connected to the
controller 140. Each cell or pixel 300 can be individually
addressed or controlled in order to produce a desired image. The
controller 140 may include a dedicated controller, a microprocessor
or a computer that includes memory, inputs and outputs, and a user
interface. The controller may include one or a combination of the
above. As shown in FIG. 1, white light, as depicted by reference
numeral 150, is transmitted to the spatial light modulator 120,
passes through the spatial light modulator 120 and exits as
filtered light 152. The spatial light modulator 120 may be read
directly, therefore be an active display or the display device 100
can be provided with a screen onto which the filtered light 152 is
projected. In this latter embodiment, the display device is a
projection device. The screen is not shown in FIG. 1.
[0017] FIG. 2 is a schematic diagram of a display device 200,
according to an example embodiment. The display device 200 includes
a light source 210, optics 230, and a spatial light modulator 120.
The spatial light modulator 120 includes a reflector or reflective
surface 220 which is attached or placed adjacent the spatial light
modulator 120. The optics 230 direct white, incident light 250
toward the spatial light modulator 120. The light is transmitted
through the spatial light modulator 120 to the reflector or
reflective surface 220 and then is reflected as filtered light 252
from the spatial light modulator 120. The spatial light modulator
120 also includes at least one cell 300 or pixel. In some
embodiments, the spatial light modulator 120 includes a plurality
or multiplicity of cells or pixels 300. A controller 140 is also
attached to the spatial light modulator 120. Specifically, the
controller receives image information and outputs it to the spatial
light modulator 120 so that images are produced on the spatial
light modulator. More specifically, the controller 140 is connected
to one or more of the cells or pixels. The controller 140 controls
the individual cells or pixels to produce a desired image which can
be either viewed directly by looking at the surface of the spatial
light modulator 120 or projected onto a screen (not shown). It
should be noted that the spatial light modulator 120 can be made up
of a single cell 300 or a multiplicity or plurality of cells 300.
In another example embodiment of the display device 200, ambient
light is substituted for the light source 210. In other words,
there is no integrated light source and the reflected light is
ambient light.
[0018] FIG. 3 is a schematic diagram of a cell 300 of a spatial
light generator 120 (shown in FIGS. 1 and 2), according to an
example embodiment. The cell 300 includes a housing 310 and an
electrode 320. As shown in FIG. 3, the electrode 320 is planar. A
planar electrode 320 is covered by or supports a polar solvent 312
and a non-polar solvent 314. The polar solvent 312 and the
non-polar solvent 314 are immiscible fluids. One of the non-polar
solvent 314 or the polar solvent 312 is provided with a colorant.
In the example shown in FIG. 3, the non-polar solvent 314 contains
the colorant. As shown in FIG. 3, white light 150 is transmitted
through the cell 300 and emerges as filtered light 152. Therefore
the example shown is a cell 300 from FIG. 1. It should be noted
that the cell 300 in FIG. 2 works in the same way as described
below. The light output in FIG. 2 is reflected light rather than
transmitted light.
[0019] FIG. 4 is a schematic diagram showing a coating of
molecules, such as a monolayer of molecules 400 attached to the
electrode 320 of a cell 300 with the monolayer of molecules 400 in
a first conformation or orientation, according to an example
embodiment. The molecules in the monolayer of molecules 400 include
a tether 410 and a free end 412. As shown in FIG. 4, the free end
412 carries a charge or includes a polarized group. Therefore, when
the planar electrode 320 is positively charged or when a positive
potential is applied to the electrode 320, the negatively charged
heads at the free ends 412 are attracted to the oppositely charged
electrode 320. The tethers 410 of the molecules 400 bend to allow
the negatively charged heads or free ends 412 to be more closely
positioned to the positively charged electrode 320. Now referring
to both FIGS. 3 and 4, as the tethers bend, a hydrophobic alkyl
chain is exposed thereby creating a hydrophobic surface at or
substantially near the surface of the electrode 320. The
hydrophobic surface causes the non-polar, colorant containing
solvent 314 to spread out across the electrode 320. When the
colorant containing non-polar solvent 314 spreads out across the
planar electrode 320, the colorized, non-polar solvent 314 is
interposed in to the light path of the cell 300. The light path
corresponds to the light path depicted by the two arrows 150, 152
in FIG. 3. In other words, the dyed or pigment-containing
(colorized) non-polar solvent 314 is placed in a filtering position
across the planar electrode 320 of the cell 300, as shown in FIG.
3. FIG. 3 shows a transmissive type of cell 300. Therefore,
incident white light 150 directed toward the cell 300 passes
through the cell and passes through the dyed or pigment-containing
(colorized) non-polar solvent 314 and exits the cell as filtered
light 152.
[0020] It should be noted that in the example shown in FIGS. 3-6, a
transmissive spatial light modulator 120, such as the one shown in
FIG. 1, is shown. It should be understood that the same cell 300
discussed in FIGS. 3-6 could also be used in a reflective type of
spatial light modulator 120, such as the one shown in FIG. 2.
[0021] FIGS. 5 and 6 will now be discussed. FIG. 5 is a schematic
diagram showing a monolayer of molecules 400 attached to an
electrode 320 of a cell 300 of a spatial light generator with the
molecules in a second orientation or confirmation, according to an
example embodiment. FIG. 6 is a schematic diagram of a monolayer of
molecules attached to a planar electrode 320 of a cell 300 of a
spatial light generator with the molecules in a second orientation
or confirmation, according to an embodiment. As shown in FIG. 5 and
6, a negative charge or voltage is placed on the electrode 320. The
negatively charged heads or free ends 412 of molecules of the
molecular monolayer 400 are repelled by the negatively charged
planar electrode 320. The negatively charged heads or ends 412 of
the molecules 400 are then in a position or present a surface which
is hydrophilic. This causes the polar solvent 312 to wet to the
surface or free ends 412 of the monolayer of molecules 400, and
specifically to the monolayer of molecules 400 attached to the
planar electrode 320 by the tethers 410. When the polar solvent 312
wets to the surface of the molecular monolayer 400 attached to the
planar electrode 320, the non-polar solvent 314, which includes the
colorant, is concentrated or balls up. This reduces the
cross-sectional area of the colorized non-polar solvent 314. The
reduced cross-sectional area of the non-polar solvent 314 allows
most of the incident light 150 traveling through the cell 300 to
pass through the cell 300 substantially unfiltered. Of course, some
of the light is transmitted through some of the concentrated
colorant containing non-polar solvent. However, most of the light
traveling through the substantially transparent cell continues
unfiltered through the cell 300.
[0022] It should be noted that in the example discussed, the
non-polar solvent 314 includes the colorant. The polar portion of
the solvent 312 could also be provided with the colorant with
similar results. The amount of colorant that is placed into either
the polar or non-polar solvent is sufficient to filter the light
when the colorized portion of either the non-polar solvent 314 or
the polar solvent 312 is distributed across the cell or over the
planar electrode 120. The polar solvent and the non-polar solvent
are immiscible. Therefore, the polar solvent 312 does not mix with
the non-polar solvent 314. Any number of solvents may be used.
Water is one common polar solvent that may be used.
[0023] In one embodiment, the molecules of the monolayer of
molecules 400 include chainlike polymers called alkanethiols, which
naturally assemble into what looks like rows of tightly packed
miniature cornstalks. The chain-like polymers act as tethers 410.
The molecules of the monolayer of molecules 400 include synthesized
alkanethiols with different chemical properties on their tops and
sides which are attached to the planar electrode 320. In one
embodiment, sulfur atoms are placed on one end of the alkanethiols.
The sulfur atoms at one end of the molecules 400 bind to a gold
surface on the electrode 320. The molecular stalks or tethers 410
have little choice but to stand straight up if packed in densely
enough. To bend over, however, the alkanethiols use additional
space. Initially, the alkanethiol stalks 410 are synthesized with
bulky mushroom-like heads 412. A solution of them is poured over a
gold plate. The molecules 400, named (16-mercapto) hexade-canoic
acid (2-chlorophenyl) diphenyl-methyl ester, or MHAE, latch onto
the gold surface. The bulky headgroups 412 prevent them from
packing tightly together. Then hydrolysis is used to lop off the
tops of the mushrooms or from a smaller head 412 on each tether
410. Hydrolysis leaves each molecular cornstalk or tether 410
tipped with a negatively charged, water-loving carboxylic acid
group 412.
[0024] The surface wettability of the planar electrode 320 exploits
conformational transitions (switching) of the molecules above
confined as a low-density film on the surface of the electrode 320
(FIGS. 3-6). The films discussed herein are based on a dual
conformation system and are, in one embodiment, nanolayers or
monolayers. The two conformation states, shown in FIGS. 3-6, of the
nanolayer or monolayer film provide different surface properties to
the surface of the electrode 320 on which the film is deposited.
Switching between the two different states changes the surface
wettability of the electrode 320. When a stimulus is applied to the
film, the conformation state changes, and thereby causes the
surface properties to switch. A large number of molecular
assemblies amplify a microscopic effect into a macroscopic surface
chemistry. Each molecular assembly includes a tether 410, an active
group (charged head end 412), and at least two information
carriers. The tether 410 establishes the conformation of the
molecular assembly and enables each assembly to achieve a
conformation consistent with that of other assemblies in the film.
The active group (head end 412) interacts with an external stimulus
(charge on electrode 320) to change the conformation of the tether
410 and thus the conformation of the molecular assembly 400. The
information carriers determine the surface properties of the
substrate for each conformation of the tether.
[0025] In some embodiments, the molecules of the monolayer of
molecules 400 may include an anchor that retains the assembly on
the substrate. One molecular group may serve more than one role in
the molecular assembly 400. For example, in the single chain
molecular assembly 410 (shown in FIGS. 4 and 6), the chain 410
tethers the monolayer of molecules 400 to the electrode 320 and
also includes the information carrier, a hydrophobic group, for one
of the conformations. The charged group at the free end 412 of the
assembly 400 is the second information carrier and also interacts
with the external stimulus, in this case, an electrical charge on
the electrode 320. Another group anchors the monolayer of molecules
400 to the electrode 320.
[0026] The surface properties that may be switched using the
methods disclosed herein include any surface property. FIGS. 3-6
illustrate a change in hydrophobicity or hydrophilicity. These
changes, in turn, change the surface wettability of the electrode
320. The film including the monolayer of molecules 400 can be used
in a variety of cells 300. The cells 300 can include liquids or
gases, or other materials.
[0027] In an embodiment, any substrate, including all classes of
materials such as metals, ceramics, glasses, non-crystalline
materials, semiconductors, polymers and composites, can be used or
adapted for use herein. Substrates may also be combined. For
example, a substrate of one material may be coated or patterned
with a second material. Such coatings may be desirable to provide a
specifically tailored set of bulk and surface properties for the
substrate. Exemplary deposition techniques for such coatings
include chemical vapor deposition (CVD), metal oxide CVD,
sputtering, sol-gel techniques, evaporation, pulsed laser
deposition, ion beam assisted deposition, and CVD polymerization.
It is not necessary to coat the entire substrate with the second
material. The second material may be deposited according to a
periodic or other pattern. For example, an electrical circuit may
be deposited on the material. The substrates may also be pretreated
before deposition of the molecular assemblies. A range of methods
are known in the art that can be used to charge, oxidize, or
otherwise modify the composition of a surface if desired, including
but not limited to plasma processing, corona processing, flame
processing, and chemical processing, e.g., etching, microcontact
printing, and chemical modification. Optical methods, such as UV or
other high energy electromagnetic radiation or electron beams, may
also be employed.
[0028] Films including the monolayer of molecules 400 can be
deposited on a surface, such as the electrode 320, using a variety
of techniques. For example, the any of the deposition techniques
described above may be used to form the films herein. In addition,
any thin film deposition technique can be used to apply the films
containing the monolayer of molecules 400. The films may be easily
patterned on a surface using photolithographic or lithographic
techniques. For instance, inkjet printing and automated (robotic)
techniques can precisely deposit small spots of material containing
the monolayer of molecules 400 on a portion of the electrode
320.
[0029] In one embodiment, the tether 410 may include an anchor
group that facilitates molecular self assembly. Anchor groups form
chemical bonds with functional groups on the surface of the
electrode 320 to form a self assembled monolayer (SAM). SAMs having
different anchor groups, such as silane and thiol can be deposited
on a wide variety of electrodes 320. SAMs may be deposited from
both the solution and the gas phases onto the substrate.
[0030] Single chain molecular assemblies may be used in both dense
and low-density nanolayers to tailor the surface properties of a
substrate. Spontaneous self-assembly allows free energy
considerations to determine the distance between individual
molecular assemblies. Favorable interactions between tethers, for
example, non-covalent interactions, may lead to densely packed
SAMs. As discussed below, the assemblies in such monolayers are
typically too closely packed to undergo the change in conformation
shown in FIGS. 2 and 4.
[0031] Low density nanolayers of single chain molecular assemblies
400 can be produced by temporarily attaching a bulky endgroup to
the assembly, as shown in FIGS. 2 and 4. Cl-triphenyl ester group
on the free or head end 412 increases the effective size of the
assembly 400, causing the SAM to form with a larger inter-assembly
spacing. The triphenylmethyl group is easily hydrolyzed to leave a
low-density carboxyl terminated SAM. Other bulky molecular groups,
such as tert-butyl and isopropyl, may be used as well. End groups
on the free or head end 412 used herein may be easily cleavable
from the molecular assembly without affecting the chemical and
mechanical stability of the monolayer. The size for the endgroup
may be defined in part by the application for the molecular
monolayer 400. For example, different active groups at the head end
412 may use different areas for energetically favorable
conformational changes.
[0032] In other embodiments, alternative methods besides bulky
endgroups or head ends 412 can be used to control the density of a
nanolayer on the substrate surface. For example, two different
molecules, a long chain molecule and a short bulky molecule may be
co-deposited in a single monolayer or nanolayer.
[0033] In one embodiment, straight chain tethers 410 have between 5
and 30 carbons. The carbon chains of the tethers 410 may be long
enough to bend over, but not so long that solvent interactions with
either the active group or the tether dominate the energetic
considerations leading to a transition between the extended and
bent conformations. However, it is not necessary that the chain be
a hydrocarbon. A polar or other functional group may be disposed in
the middle of the chain. For example, rigid chemical groups such as
double and triple bonds, aromatic, polyaromatic, polycyclic, and
fused aromatic groups may be incorporated into the tether 410.
These groups stiffen the monolayer of molecules 400 in the upright
conformation and help dictate the conformation of the assembly when
it bends.
[0034] In other embodiments, it may be desirable to fabricate a
nanolayer that is more geometrically stable with respect to both
chemical and physical environmental influences. Thus, a nanolayer
with a more rigid tether than the long chain hydrocarbons described
above might be used.
[0035] Several techniques may be used to switch the properties of
the thin film having the monolayer of molecules 400. For example,
the monolayer of molecules 400 with a charged active group exhibits
one conformation when the substrate is neutral and a second
conformation when a voltage is applied to the substrate, as shown
in FIGS. 3-6. If a non-conductive substrate or electrode 320 is
used, the substrate may be charged by applying a charge across the
substrate 320 and allowing it to charge as if it were a capacitor.
A charged or polar active group may still be able to interact with
the substrate via electrostatic interactions, and discharge of the
capacitor releases the active group and permits a change in
conformation.
[0036] FIG. 7 is a schematic diagram of a spatial light modulator
700 that includes a plurality of stacked cells 731, 732, 733, 734
controlled by a controller 750, according to an example embodiment.
A spatial light modulator 700 includes a first portion or cell 731
and a second portion or cell 732. The first portion or cell 731
includes a first planar electrode 721, a polar solvent 712, and a
first non-polar solvent 714. The polar solvent 712 and the first
non-polar solvent 714 cover the first planar electrode 721. A
coating or film of molecules 740 is attached at one end to the
first planar electrode 721. The molecules also have a free end or
head. The free end or head is tethered to the first planar
electrode 721 by a polymer chain. The molecules 740 change between
a first conformation or shape and a second conformation or shape in
response to a change in voltage on the first planar electrode
721.
[0037] The second portion or cell 732 includes a second planar
electrode 722, the polar solvent 712, and a second non-polar
solvent 715. The polar solvent 712 and the second non-polar solvent
715 cover the second planar electrode 722. A coating or film of
molecules 740 is attached at one end to the second planar electrode
722. The molecules also have a free end or head. The molecules
change between a first shape and a second shape in response to a
change in voltage on the second planar electrode 722. The first
portion or cell 731 is stacked on the second portion or cell 732.
As shown in FIG. 7, the spatial light modulator 700 also includes a
third portion or cell 733 and a fourth portion or cell 734. The
third portion or cell 733 and the fourth portion or cell 734 are
similarly constructed to the first cell or portion 731 and/or to
the second cell or portion 732. A difference between the cells 731,
732, 733, 734 includes the colorant associated with either the
polar solvent 712 or the non-polar solvent, in that each cell 731,
732, 733, 734 includes a different color. In one embodiment, the
first color, the second color, the third color and the fourth color
associated with the cells 731, 732, 733, 734, respectively, include
cyan, yellow, magenta, and black. The first portion or cell 731,
the second portion or cell 732, the third portion or cell 733, and
the fourth portion or cell 734 are stacked with respect to one
another.
[0038] Each of the cells 731, 732, 733, 734 is attached to the
controller 750. The controller 750, in response to image data
input, controls the voltage on each of the electrodes 721, 722,
723, and 724 to either place the colorized portion substantially in
a light path through the stacked cells 731, 732, 733, 734 or
substantially remove the colorized portion of the cells 731, 732,
733, 734 from a light path depicted by arrows 770 and 772. By
controlling each cell 731, 732, 733, 734, a selected color of
filtered light is output from the spatial light modulator 700. The
spatial light modulator 700 also includes a light source (arrow
770) positioned to project light through the cells 731, 732, 733,
734. In some embodiments, a reflective surface (such as reflective
surface 220 shown in FIG. 2) is positioned adjacent at least one of
the first portion or cell, second portion or cell, third portion or
cell, or fourth portion or cell.
[0039] FIG. 8 is a schematic diagram of a spatial light modulator
800 that includes a plurality of adjacent cells 831, 832, 833
controlled by a controller 850, according to an example embodiment.
The spatial light modulator 800 includes a first portion or cell
831, a second portion or cell 832 and a third portion or cell 833.
The first portion or cell 831 includes a first planar electrode
821, a polar solvent 812, and a first non-polar solvent 814. The
polar solvent 812 and the first non-polar solvent 814 form
localized concentrations of colorant 814 on the first planar
electrode 821. A coating or film of molecules 840 is attached at
one end to the first planar electrode 821. The molecules also have
a free end or head (shown in FIGS. 4 and 6). The free end or head
end is tethered to the first planar electrode by a polymer chain.
The molecules 840 change between a first shape and a second shape
in response to a change in voltage on the first planar electrode
821. The film or coating of molecules 840 changes between a
hydrophobic or hydrophilic orientation with the change in shape.
The hydrophobic or hydrophilic orientation causes either the
colorized solvent to spread across the cell 831 to filter light
passing through the cell, or concentrate within the cell 831 so
that light passing through the cell 831 is uncolored. Each of the
cells 832, 833 also includes an electrode 822, 823, respectively.
Each of the cells 832 and 833 includes substantially the same
structure as the cell 831. In cell 831, the colorized solvent is
concentrated to allow most light to pass unfiltered. In cell 833,
the colorized portion 814 is spread across a portion of the
electrode 823. The difference between cells is that the colorized
solvents in each of the cells 831, 832, 833 are a different
color.
[0040] Each of the cells 831, 832, 833 is attached to a controller
850. The controller 850, in response to image data input, controls
the voltage on each of the electrodes 821, 822, and 823 to either
place the dyed portion substantially in a light path through the
adjacent cells 831, 832, 833 or substantially remove the colorized
portion of the cells 831, 832, 833 from the light path depicted as
two arrows in FIG. 8. By controlling each cell 831, 832, 833, a
selected color of filtered light is output from the spatial light
modulator 800. A light source (not shown) is positioned to project
light through the cells 831, 832, 833.
[0041] FIG. 9 is a schematic diagram of a cell that includes an
area 960 on the electrode that is free of the molecular monolayer
400, according to an example embodiment. A cell 931 of the spatial
light modulator 900, includes a planar electrode 921 covered by a
polar solvent 912, and a non-polar solvent 914. The planar
electrode 921 includes an area 960 of the planar electrode 921 that
is devoid of a film or a coating of the molecular monolayer 400.
The area 960, in some embodiments, is a patterned dewetting area.
When the planar electrode 921 is charged so that the colorized
portion of either the polar solvent 912 or the non-polar solvent
914 concentrates to allow light, depicted by two arrows, to pass
through the cell 931 substantially unfiltered, the colorized
portion is positioned on the area 960 of the planar electrode 921
that is devoid of a film or a coating of molecules.
[0042] FIG. 10 is a flow diagram of a method 1000, according to an
example embodiment. The method 1000 includes dying one of the polar
solvent or the non-polar solvent in the first cell with a first
color at block 1010, and dying one of the polar solvent or the
non-polar solvent in the second cell with a second color at block
1012. The method 1000 also includes adding a polar solvent to a
first cell and a second cell at block 1014, and adding a non-polar
solvent to the first cell and a second cell at block 1016. The
first cell and the second cell are stacked at block 1018. The
method 1000 also includes applying an external force to an
electrode of 30 the first cell to change the change molecules
attached to the electrode between a surface that attracts a polar
solvent to a surface that repels the polar solvent at block 1020,
and applying an external force to an electrode of the second cell
to change the change molecules attached to the electrode between a
surface that attracts a polar solvent to a surface that repels the
polar solvent at block 1022. Applying the external force to one of
the first cell or the second cell positions the colorized one of
the non-polar solvent or polar solvent in a position across the
cell. Applying the external force to one of the first cell or the
second cell concentrates the colorized one of the non-polar solvent
or polar solvent in a position within the cell. The method also
includes transmitting light through the first cell and the second
cell at block 1024. Removing an external force to the other of the
first cell and the second cell causes the colorized portion of one
of the first or second cell to be concentrated within the cell. In
other words, applying the external force causes the colorized
portion to be interposed in a light path traversing the cell. When
an external force is not applied to the other of the first cell and
the second cell, the colorized portion in the other of the first or
second cell is concentrated in one area with respect to the other
of the first or second cell. Light transmitted through the first
cell and the second cell and the transmitted light is colored by
the colorized portion extending across one of the first cell and
the second cell.
[0043] Transmitting light through the first cell and the second
cell, in some embodiments, includes reflecting the light
transmitted through the first cell and the second cell. Applying an
external force on the first cell and on the second cell includes
controlling a voltage on the electrode of the first cell and on the
electrode of the second cell.
[0044] A display includes a plurality of display elements capable
of controlling light within a visible light spectrum. The display
elements are positioned over a display surface. At least some of
the display elements include a first portion that includes a first
planar electrode, a polar solvent, and a first non-polar solvent.
The polar solvent and the first non-polar solvent cover the first
planar electrode. The first portion of the display element also
includes a coating of molecules attached at one end to the first
planar electrode. A free end of the molecules changes between a
first shape and a second shape in response to a change in voltage
on the first planar electrode. At least some of the display
elements also include a second portion that includes a second
planar electrode, a polar solvent, and a second non-polar solvent.
The polar solvent and the second non-polar solvent cover the second
planar electrode. A coating of molecules is attached at one end to
the second planar electrode. Free ends of the molecular chains in
the molecular layer change between a first shape and a second shape
in response to a change in voltage on the second planar electrode.
The display also includes a device for controlling the first
portion and the second portion to control the light passing through
the display element. In some embodiments of the display, the first
portion is stacked on the second portion. The display also includes
a plurality of receivers coupled to the plurality of display
elements. The plurality of receivers is adapted to receive
transmitted image information and activate the display elements in
response to the image information. The device for controlling the
first portion and the second portion controls at least some of the
portions of the display elements in response to image information
received at the receivers. The display also includes a light source
for projecting light through the plurality of display elements. In
some embodiments, the display further includes a reflective surface
positioned near the plurality of display elements.
[0045] Although specific embodiments have been illustrated and
described herein, those of ordinary skill in the art will
appreciate that any arrangement calculated to achieve the same
purpose can be substituted for the specific embodiments shown. This
disclosure is intended to cover any and all adaptations or
variations of various embodiments of the invention. It is to be
understood that the above description has been made in an
illustrative fashion, and not a restrictive one. Combinations of
the above embodiments, and other embodiments not specifically
described herein will be apparent to those of skill in the art upon
reviewing the above description. The scope of various embodiments
of the invention includes any other applications in which the above
structures and methods are used. Therefore, the scope of various
embodiments of the invention should be determined with reference to
the appended claims, along with the full range of equivalents to
which such claims are entitled.
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