U.S. patent application number 11/441442 was filed with the patent office on 2007-05-10 for applications of light movable liquid crystal.
Invention is credited to Sadeg M. Faris.
Application Number | 20070103759 11/441442 |
Document ID | / |
Family ID | 34375309 |
Filed Date | 2007-05-10 |
United States Patent
Application |
20070103759 |
Kind Code |
A1 |
Faris; Sadeg M. |
May 10, 2007 |
Applications of light movable liquid crystal
Abstract
Practical applications of a class of nematic elastomer which has
light avoidance characteristics are disclosed. Such practical
applications include a switching device, a load carrying device and
programmable mask. The use of different light sources, including
the use of an autonomous device are further disclosed.
Inventors: |
Faris; Sadeg M.;
(Pleasantville, NY) |
Correspondence
Address: |
REVEO, INC.
3 WESTCHESTER PLAZA
ELMSFORD
NY
10523
US
|
Family ID: |
34375309 |
Appl. No.: |
11/441442 |
Filed: |
May 25, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10941294 |
Sep 15, 2004 |
7197204 |
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11441442 |
May 25, 2006 |
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60503083 |
Sep 15, 2003 |
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Current U.S.
Class: |
359/244 |
Current CPC
Class: |
G02F 1/13 20130101; C09K
19/02 20130101 |
Class at
Publication: |
359/244 |
International
Class: |
G02F 1/07 20060101
G02F001/07 |
Claims
1-22. (canceled)
23. A load carrying device comprising: an LMLC configured for
carrying a load, wherein said LMLC transports said load upon
activation by a light source.
24. The load carrying device of claim 23 wherein said load is DNA.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit under 35 U.S.C. .sctn.
119(e) of U.S. Provisional Application No. 60/503,083 filed on Sep.
15, 2003 entitled "Applications of Light Movable Liquid Crystal,"
which is herein incorporated by reference.
TECHNICAL FIELD
[0002] The present invention relates to light movable liquid
crystal, and more particularly to applications of light movable
liquid crystal.
BACKGROUND OF THE INVENTION
[0003] Certain nematic elastomers have optomechanical capabilities.
It has been shown that certain nematic elastomers have the property
of being able to change their shape by up to 400% in a relatively
narrow temperature range. Further, it has been demonstrated that if
the nematic order is suppressed, certain elastomers demonstrate
mechanical responses in response to optical signal application on
the elastomer.
[0004] As disclosed in the Physical Review Letters by Finkelmann
and Nishikawa in their article "A New Opto-Mechanical Effect in
Solids," Physical Review Letters, Vol. 87, Number 1 (Jul. 2, 2001),
which is herein fully incorporated by reference. They demonstrate
optomechanical effect on photoisomerizable molecular rods which
absorb light when illumination occurs on polarization along the
polarization direction. At present, the only disclosure of movement
of such materials lateral displacement within a body of fluid.
[0005] Finkelmann et al. note that the order parameter, back
reaction and other related dynamic parameters may determine the
rate of photoisomerization depending on the polarization of the
rods in the nematic elastomer,
[0006] Potentially, the discovery may result in a rubber-like
liquid crystal which changes shape when placed in a beam of light,
the crystal seems to swim away from the point of light impingement.
The molecules in the liquid crystal line up in one direction and in
the electric field of a laser the rods compress the surface of the
material.
[0007] Finkelmann et al. have shown that when an azo dye is applied
to the nematic elastomer the molecules in the nematic elastomer
tends to line up in one direction. When a nematic liquid crystal is
applied an azo dye, the dye molecules "fold up" when they absorb
light.
[0008] Referring to FIG. 1, there is shown a schematic diagram of a
nematic liquid crystal with an azo dye applied. A light of
wavelength .lamda. is incident on liquid crystal 10 in FIG. 1(a).
Referring to FIG. 1(b), the dye molecules, in reaction to the
incident light applied on liquid crystal 10, "fold up." Referring
to FIG. 1(c), the dye molecules enable the liquid crystal 10 to
speed up and avoid the light while losing the contraction. The
liquid crystal 10 speeds across a direction 15.
[0009] The nematic elastomer additionally has the capability of
accelerating motion proportional to the intensity of the light.
[0010] Although the discovery of the light avoiding properties of
the particular liquid crystal has been surprising, there remains a
need for practical applications of such light or laser movable
liquid crystal ("LMLC").
[0011] The LMLC is an elastomer liquid crystal that moves in
response to an illumination that moves in response to a laser
movement or light source. The LMLC is on the order of micrometers.
The LMLC may be formed in different shapes, such as rectangular,
elliptical or longitudinal.
SUMMARY OF THE INVENTION
[0012] The above-described problems and deficiencies are solved by
the present invention. Generally the invention provides:
[0013] In one aspect, the invention is a switching device
actuatable with a light source for transmitting an optical signal
therethrough, said switching device comprising: a light movable
liquid crystal ("LMLC") positionable between a first position and a
second position, wherein said LMLC is configured for mechanical
actuation upon activation with said light source.
[0014] In another aspect, the invention is a switching device
actuatable with a light source for transmitting an optical signal
therethrough, said switch device comprising: a light movable liquid
crystal ("LMLC") rotatable between a first position and a second
position, wherein said LMLC is configured for mechanical rotation
upon activation with said light source at an angular moment.
[0015] In another aspect, the invention is a semiconductor
fabrication mask for fabricating a predetermined pattern on a
wafer, said mask comprising: a plurality of LMLC arranged in a
predetermined array, wherein each LMLC is positioned between a
first position and a second position upon activation with a light
source.
[0016] In another aspect, the invention is a load carrying device
comprising: an LMLC configured for carrying a load, wherein said
LMLC transports said load upon activation by a light source.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Further features of the present invention will become
apparent to those skilled in the art to which the present invention
relates from reading the following specification with reference to
the accompanying drawings, in which:
[0018] FIG. 1 is a schematic diagram of the operation of a class of
nematic elastomer with light avoidance characteristics;
[0019] FIG. 2 is a schematic diagram of a light movable liquid
crystal in accordance with the principles of the present
invention;
[0020] FIG. 3 is a schematic diagram of a LMLC configured as a load
carrying device in accordance with the principles of the present
invention;
[0021] FIG. 4 is a schematic diagram of a LMLC configured as a load
carrying device in accordance with the principles of the present
invention;
[0022] FIG. 5 is a schematic diagram of a LMLC configured as a load
carrying device in accordance with the principles of the present
invention;
[0023] FIG. 6 is a schematic diagram of a LMLC configured for
rotatable actuation in accordance with the principles of the
present invention;
[0024] FIG. 7 is a schematic diagram of a LMLC configured as an
autonomous device in accordance with the principles of the present
invention;
[0025] FIG. 8 is a schematic diagram of a plurality of LMLC
configured as a load carrying device in accordance with the
principles of the present invention; and
[0026] FIG. 9 is a schematic diagram of a LMLC configured as a
programmable mask in accordance with the principles of the present
invention.
DETAILED DESCRIPTION OF THE FIGURES
[0027] To review, referring to FIG. 2, a light movable liquid
crystal ("LMLC") is a nematic elastomer which has light avoidance
characteristics which enable movement in a viscous fluid to avoid
the light. In one embodiment, the LMLC 10 is moved between a first
position and a second position (as illustrated by the dotted lines)
in a direction 15.
[0028] Various optical switches and switching devices may be formed
by utilizing the unique properties of the LMLC. Referring to FIG.
3, there is shown a LMLC optical switch in accordance with the
principles of the invention which takes advantage of the
optomechanical switch.
[0029] Optomechanical switches offer many advantages over
electro-optical switches. Typically, optomechanical switches
involves physical motion of some optical elements. Electrooptic
switches, on the other hand, employ a change of refractive index to
perform optical switching. The change of refractive index is
typically accomplished by electro-optic or thermo-optic
effects.
[0030] Generally optomechanical switches feature lower insertion
loss, and lower crosstalk and higher isolation between the ON and
OFF states. The switches of the present invention can also be made
bi-directional further realizing savings on valuable chip real
estate. Optomechanical switches, unlike electrooptic switches, are
also independent of optical wavelengths, polarization and data
modulation format. The crosstalk of electro-optic waveguide
switches is limited to a range above -30 dB, and can often be in
the range of -10 to -15 dB.
[0031] An optomechanical switch can be implemented either in free
space, in fibers or in waveguides. An optomechanical free space
switch is disclosed in the invention.
[0032] The movement from a first position and a second position
upon application of light, as shown in FIG. 2, can be used to
create other types of practical applications, upon application of
light. This movement can be used to create a flip-flop for
phototransistor devices. Other applications of this movement
include reflectors, polarizers, filters, phase shifters, plungers,
pistons, oscillators, tuners, choppers or scanners. For example, as
a reflectable device, a plurality of LMLCs may be arrayed to form a
reflective liquid crystal device, e-paper or switchable window.
[0033] Another application of the LMLC is as a load-carrying
device. Referring to FIG. 3, the LMLC 10 is used to pull a load 30,
for example, a strand of molecules (e.g. DNA). Referring to FIG. 4,
the LMLC 10 may be used to push a load 30. Referring now to FIG. 5,
an LMLC 10 may be used as a "raft" to carry a load 30 such as
molecules or a nano or micro scale structure. Although not
illustrated in the figures, the load may be attached to the
underside of the LMLC to allow exposure to the light source.
Alternatively, the LMLC may include a cargo area to support a load,
leaving the light activated portions of the LMLC exposed.
[0034] In another embodiment, and referring to FIG. 6, a rotational
movement of the LMLC may be accomplished by an appropriate incident
light source. For example, the light source or laser may direct the
beam of light used to initiate movement at an angle to the
LMLC.
[0035] In another embodiment, the range and path of motion may be
predetermined by a suitable channel, track, guide wire, or other
guidance system. The guidance system may be built of etched
substrate on a viscous fluid. Conventional etching techniques can
be used.
[0036] In still further embodiments, any desired path or range of
motion may be determined by a suitable light or laser scanning
device.
[0037] In another application an autonomous device may be formed,
referring to FIG. 7, the autonomous device may include its own
light source 70. The light source may be fashioned conventionally
on a substrate. Conventional light sources can include eximer
lasers, free electron lasers or dye lasers. Thee light source is
electrically coupled to a power source 75. The power source may be
a metal air or electrochemical battery or fuel cell which can
provide a mobile autonomous source of power. Accordingly, a
self-propelled and a self-powered LMLC may be formed. The
self-powered self-controlled LMLC may include, for example, radio
frequency antennas (not shown) for accepting control signals,
sensors for determining information about characteristics of a
subject, loads to carry, or even may be used in a drug release
environment. In a still further embodiment, and referring to FIG.
8, a plurality of LMLCs may be arranged in parallel to combine
strengths to pull a load.
[0038] Many applications may be derived from the above-described
generic applications of LMLC. Various features may also be
imparted. For example, for continuous movement, a laser scanning
may be used. Further, various beam steering devices, including
those invented by Reveo, may be used.
[0039] In another embodiment, the LMLCs may be arranged to move in
circular or elliptical fashion, referring back to FIG. 6. Based on
the angle of incidence of the laser beam, LMLC will gain angular
momentum, causing circular or elliptical motion.
[0040] One very important application of the LMLCs, which has been
sought after for some time, is a programmable mask. A programmable
mask may be used in conventional semiconductor wafer processing to
etch structures and devices. In this embodiment, as shown in FIG.
9, an array of LMLCs may be formed, for example, in the shape of a
wafer to be used in a mask in lithography. In FIG. 9, wafer mask 93
and 95 are aligned vertically. The second array 95 for the LMLCs
positioned in the initial state opposite the first array, is
provided. By applying light to selected LMLCs, any desired pattern
may be formed.
[0041] Each LMLC based pixel of the array generally may include an
LMLC attached to a suitable mask structure (for e.g., Al), referred
to as a "light movable half pixel". The light movable half pixel
may be moved between a first position and a second position. When
two arrays of such light movable half pixels are registered
appropriately, the mask may be configured for desired complex
pattern etching over any conventional wafer. Numerous conventional
semiconductor fabrication methods may be used to further customize
the fabrication process.
[0042] While preferred embodiments have been shown and described,
various modifications and substitutions may be made thereto without
departing from the spirit and scope of the invention. Accordingly,
it is to be understood that the present invention has been
described by way of illustrations and not limitation.
* * * * *