BRPI0710770A2 - liquid crystal devices - Google Patents

Abstract

IMPROVEMENTS IN A TRANSPORTABLE HYDROCARBON RECOVERY UNIT This invention relates to improvements in a transportable hydrocarbon recovery unit. More particularly, this invention relates to an integral hydrocarbon recovery unit that comprises a first evaporation system and a condensation system. For its part, the first evaporation system comprises means for feeding the material to be extracted which includes means for controlling the feed, means for transporting said material, means for treating the chamber including means for internal cleaning, means for heating the material , means of increasing the heat transfer area, means of removing the remaining material which include means of increasing impenetrability and means of transporting the extracted vapors to the condensation system. The object of the invention is to provide a unit for the extraction of hydrocarbons and other contaminants from the impregnated material while providing, in less time and greater effectiveness, the recovery process.

Description

LIQUID CRYSTAL DEVICES

The present invention relates to an electrical component, a flat waveguide, an antenna, a beamformer and an electrically tunable dielectric.

The modalities are suitable for use at the frequency of a frequency or in the wavelength region of the meter; others for very high frequency (VHF), ultra high frequency (UHF) and microwave.

In one aspect, the present invention provides an electrical component comprising a liquid crystal cell (LC) substrate, wherein the LC cell comprises a liquid crystal material containing anisotropic particles, at least one conductive member disposed over the substrate and at least one substrate. conductive member arranged over the LC cell, and means for affecting the alignment of anisotropic particles, whereby the responsiveness between the conductive members is varied.

The component can be used in agile frequency antennas, steerable antennas, tunable filters, variable polarization antennas, controlled voltage oscillators, variable delay lines, automatic impedance matching circuits, and active temperature compensation for microwave circuits.

In another aspect, the present invention provides a flat wave imagery comprising a substrate carrying an LC cell, wherein the LC cell comprises a liquid crystal material containing anisotropic particles, at least one conductive member disposed over the substrate and at least one conductive member. arranged on the LC cell, and means for affecting the alignment of anisotropic particles, whereby the permittivity between the conductive members is varied.

In a further aspect, the present invention provides an antenna comprising a substrate carrying a LC cell, wherein the LC cell comprises a liquid crystalline material containing anisotropic particles, at least one conductive member disposed on the substrate and at least one conductive member disposed on the substrate. LC cell, and means for affecting the alignment of anisotropic particles, whereby the permittivity between the conductive members is varied.

In yet another aspect, the invention provides a beamformer for free-range propagation of terahertz frequency probes comprising a substrate carrying an LC cell, wherein the LC cell comprises an anisotropic particle-containing liquid crystal material, at least one conductive member disposed about it. the substrate and at least one conductive member disposed about the LC cell, and means for affecting the alignment of anisotropic particles, whereby the permittivity between the conductive members is varied.

Means for affecting alignment may include conductive limbs.

In yet another aspect, the invention provides an electrically tunable dielectric comprising an LC cell, wherein the LC cell comprises a liquid decrystalline material containing anisotropic particles, and control electrodes for affecting the alignment of anisotropic particles. The LC cell may comprise a dispersed polymer crystalline liquid (PDLC) material.

Anisotropic particles may comprise carbon tubes (CNT).

The present invention will be more clearly understood by reference to the following description in conjunction with the accompanying drawings, in which:

Fig. 1a is a diagram of a liquid crystal cell showing anisotropic particles under "no field" conditions;

Fig. Ib is a diagram of a crystal cell showing anisotropic particles under "bound field" conditions;

Fig. 2 shows a cross-sectional view of a test cell;

Fig. 3 shows a perspective diagram of a patch antenna embodying the invention;

Fig. 4 shows a cross-sectional view along the lines III-III 'of Fig. 2;

Fig. 5 shows a section through a new ribbon line shape embodying the invention;

Fig. 6 shows a beam shaper embodying the invention.

Referring to Figs 1a and 1b, a crystal liquid cell 10 has a layer 20 of liquid crystal material which has anisotropic particles 25 dispersed therein. In this mode, the particles are CNT. In other embodiments, dye doping is used. In still other embodiments, the liquid crystal material is a CNT-free PDLC material. The liquid crystal material 20 is delimited by generally flat and mutually parallel glass substrates 30, 32 carrying indium tin oxide (ITO) electrodes 34, 36, and the substrates are spaced by spacers 33, 35. The electrodes are accessed through conductors 37, 38

The spacing between substrates is substantially smaller than the length and substrates.

In Fig. 1a, anisotropic particles 25 are aligned generally parallel to the substrates by liquid crystal material 20.

In Fig. Ib, a field is applied between the electrodes DEITO 34, 36 to cause the molecules of the liquid crystal material 20 to bend, and thereby to bring the particles 25 to a rotated position - around 35 ° C here. average degrees with the plane of the substrates. The 35 degree angle is not a special feature of this device. A change in alignment of the anisotropic particles results in permittivity between the ITO 34, 36 servariate electrodes.

The birefringence of a range of commercial liquid crystals in the millimeter wave region has been shown by K C Lim et al [Liq Crystal 14 (1993) ρ 327-337] as sending from 46 to 67 percent of visible region values. In addition, custom liquid crystals have been synthesized with improved dielectric anisotropy (Δε = 1) and FR4-like tan δ losses in the mm deplet (see Weil et al. [Electronic Letters 39 (24) 1732-4. (2003) )]).

In making experimental devices in accordance with the present invention, a variety of material systems have been used for making the liquid crystal layer, combining a nematic host and carbon nanotube materials. A suitable material is made of a mixture of carbon nanotubes and a liquid crystal. Carbon nanotubes are dispersed within the crystalline liquid by subjecting the mixture to sonication.

Referring to Fig. 2, a test cell 400, which is thicker than conventional test cells (up to 1 mm) has a support substrate 401, which supports a copper ground planar 410 which is extends across its upper surface. A layer of liquid crystal material 420 is disposed on the base plane, and a cover layer 430 is supported by spacers 435 for defining the liquid crystal cell. In other cells, a polymer is used instead of glass. Detopo 440 electrodes are copper - for example, a demicrophyte copper track. They have a width w and the LC cell has a distance h, so that the characteristic impedance Z0 of the microtite transmission line, of which the lead electrodes are a part, is defined by:

Z0 ~ h / [(w + 2h) and 0 C0 and r1 / 2] and

Electrical length PL ~ 2pL / Xg with λ9 = C0 / [f er]

In order to electrically switch the liquid crystal to tune the device, the following liquid crystals are suggested:

electrically controlled birefringence; two-frequency enemies.

In one embodiment, for tuning range extension, a liquid crystal host carbon nanotube (CNT) doping was employed, as a previous work on dispersion of anisotropic metallic microtubules in a liquid crystal host crystalhost) showed a greater than 50% increase in liquid crystal refraction at 30 GHz due to a 0.2% dispersion (see AM Lackner et al. [Liq Crystal. 14 (1993) 351-359]).

Organically ordered CNTs are also fundamental to other CNT composite applications with liquid crystals or reactive polymers or monomers, in applications such as conducting polymers or optical nonlinear materials for holography.

Good and stable CNT alignment is required so that dielectric anisotropy is maximized. There are CNT functionalization techniques in organic media (eg including liquid crystals and reactive monomers) used for chemical modification (covalent functionalization), envelope polymer ( non-covalent functionalization) and using surfactants for organic media. Other problems include understanding the detailed spectral behavior of the edielectric absorptive properties.

It is apparent that electro-optical devices made from these materials have applications ranging from radiation manipulation, for example, in medical imaging, adaptive microwave antennas, radio and radar applications, for example, mobile phone satellites.

The embodiments include the use of dispersed (non-doped and CNT-doped) empirical LCs for the realization of a 'solid' substrate in which microwave circuits can be fabricated to match existing PTFE and fiberglass substrates suitable for microtiter, line slitting line, slit line and other flat round guide forming techniques. This version allows for simpler manufacture of microwave circuits, at the expense of a narrower tuning range compared to the LC 'cell' type structure in the proposal. In some cases, a limited tuning range may be preferable, for example, for fine tuning of an oscillator.

An example for radio LANs and / or mobile phones is a steerable antenna, for example, to allow a higher density of users in a given area. In the case of phones, a steerable antenna allows for a reduction in radiation exposure by the user. Other non-limiting examples of applications of the invention are loop and line circuitry, phase shifters, combination circuitry, tunable and tunable patch antennas, filters and circulators.

Referring to Figs. 3 and 4, a patch antenna 100 has a dielectric substrate 110 with a copper electrode 114 on its upper side. A crystal liquid cell 120 is disposed on the upper side of the substrate 110 over the copper electrode 114. It is bounded on its four sides by spacers 124 composed of a ferrite particle-bearing take-off seal. Liquid crystal material 128 forms the active material, and comprises dispersed CNT in use Merck BL037 in this embodiment.

At the top of the liquid crystal cell is a copper electrode 122 that forms the patch. Electrode 122 is of adequate thickness to minimize operating frequency-driven losses to obtain an acceptable Q factor.

A connecting conductor 140 allows energy to be introduced into and extracted from patch 122.

In use, ferrite particles form a magnetic field boundary, thereby helping to eliminate a diaphony. High frequency signals, eg degigahertz, are applied to patch 122, and a lower frequency bias (eg dc) is applied to control the permissiveness of the doped CNT 128 LC. The bias can be dc real or may be a low frequency variable potential, bearing in mind that the response time of LC material is of the order of milliseconds.

Turning to Fig. 5, a first waveguide or transmission line 220 is formed on a dielectric substrate 210 having an earth plane 214 on its upper side and a copper conductor 226 forming a ground plane. . Doped CNT LC material 228 forms a cell bounded by spacer side 224 and bounded above by a higher substrate 218 supporting a copper line electrode 222 on its bottom side.

The operation is generally similar to the first mode operation.

A second mode of transmission line is shown in Fig. 6. In this embodiment, the line electrode 222 is bounded on both its upper and lower surfaces by a liquid crystal material, and is between two grounding planes 220, 224. wave and the like are divided.

Turning to Fig. 7, a beam conformer 300 consists of a generally square array of patch antenna electrodes 310, spaced in a plane and spaced above a rear plane 301. In some embodiments, only a small number of antenna elements For example, 4 or 5 elements are required.

In Fig. 8, an alternative arrangement for Fig. 1 is shown which is relevant when using materials of two frequencies. The figure illustrates the situation where only low frequency fields and only high frequency fields (much faster than liquid crystal material response time) are applied.

In Fig. 8a, anisotropic particles 25 are aligned substantially perpendicular to the mutually parallel glass substrates 30, 32. This is caused by the low frequency electric field applied between the ITO electrodes 34, 36. The near perpendicular alignment is purely illustrative.

In Fig. 8b, anisotropic particles 25 are aligned substantially parallel to the mutually parallel glass substrates 30, 32. This is caused by a high frequency electric field applied between the ITO electrodes 34, 36.

In one embodiment, each patch electrode 310 has its own liquid crystal cell below it; In another less preferred version, a single liquid crystal cell is provided. Conductors 3 04a a-d feed epolarization signal to each patch electrode. Polarization causes the permittivity value for each patch to be regulated so as to vary the signal distribution and direct an irradiated beam in a known manner.

Embodiments of the invention have now been described. However, the invention is not to be construed as limited to the details of the embodiments.

Claims (8)

1. Electrical component, characterized in that it comprises a substrate carrying an LC1 cell where the LC cell comprises a liquid crystal material containing anisotropic particles, at least one conductive member disposed on the substrate and at least one conductive member disposed on the LCi cell and media. to determine the alignment of anisotropic particles, so long as the permittivity between the conductive limbs is varied. 2. A flat waveguide characterized in that it comprises a substrate carrying an LC7 cell where the LC cell comprises a liquid crystal material containing anisotropic particles, at least one conductive member disposed on the substrate and at least one conductive member disposed on the LC cell. and means for effecting the alignment of anisotropic particles so that the permittivity between the conductive members is varied. Antenna, characterized in that it comprises a substrate carrying an LC cell, wherein the LC cell comprises a liquid crystal material containing anisotropic particles, at least one conductive member disposed on the substrate and at least one conductive member disposed on the LC cell, and means for affecting the alignment of anisotropic particles, whereby the permittivity between the conductive limbs is varied. 4. A beam conformer for the terahertz frequency wave propagation, characterized in that it comprises a substrate carrying an LC7 cell where the LC cell comprises a liquid decrystalline material containing anisotropic particles, at least one conductive member disposed on the substrate and at least a conductive member disposed on the LC cell means to affect the alignment of the anisotropic particles, whereby the permittivity between the conductive members is varied. 5. Electrically tunable dielectric, characterized in that it comprises an LC cell, wherein the LC cell comprises a liquid crystalline material containing anisotropic particles, and control electrodes to affect the alignment of anisotropic particles. An electrical component according to claim 1, a flat waveguide according to claim 2, an antenna according to claim 3, or a defective conformer according to claim 4, characterized in that the medium for if affecting the alignment of anisotropic particles understand the conductive limbs. An electrical component according to claim 1, a flat waveguide according to claim 2, an antenna according to claim 3, a defective conformer according to claim 4, or an electrically tunable dielectric characterized in that The LC cell cell comprises a PDLC material. An electrical component according to claim 1, a flat waveguide according to claim 2, an antenna according to claim 3, a defective conformer according to claim 4, or an electrically tunable dielectric according to claim 5, characterized in that the anisotropic particles comprise CNT.