WO2002019018A1 - Modulateur de phase - Google Patents

Modulateur de phase Download PDF

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Publication number
WO2002019018A1
WO2002019018A1 PCT/GB2000/003371 GB0003371W WO0219018A1 WO 2002019018 A1 WO2002019018 A1 WO 2002019018A1 GB 0003371 W GB0003371 W GB 0003371W WO 0219018 A1 WO0219018 A1 WO 0219018A1
Authority
WO
WIPO (PCT)
Prior art keywords
modulator
light
phase
incident light
director
Prior art date
Application number
PCT/GB2000/003371
Other languages
English (en)
Inventor
William Alden Crossland
Maura Michelle Redmond
Timothy David Wilkinson
Original Assignee
Thomas Swan & Co. Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Thomas Swan & Co. Ltd. filed Critical Thomas Swan & Co. Ltd.
Priority to PCT/GB2000/003371 priority Critical patent/WO2002019018A1/fr
Priority to AU2000268585A priority patent/AU2000268585A1/en
Publication of WO2002019018A1 publication Critical patent/WO2002019018A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/29—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the position or the direction of light beams, i.e. deflection
    • G02F1/292—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the position or the direction of light beams, i.e. deflection by controlled diffraction or phased-array beam steering
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1334—Constructional arrangements; Manufacturing methods based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2203/00—Function characteristic
    • G02F2203/50—Phase-only modulation

Definitions

  • the present invention relates to a phase modulator for use in the phase modulation of light, and is concerned particularly with the use of polymer- dispersed liquid crystalline materials to effect such modulation .
  • Polymer dispersed liquid crystalline materials are composite materials made of droplets or regions of liquid crystal (LC) encapsulated within a polymer matrix.
  • the liquid crystalline phase type most frequently used is the nematic phase.
  • the most usual electro optic effect employed is the production of a light shutter which transforms between a scattering and non scattering state by the action of an electric field. Such shutters are most commonly developed for applications such as active windows and displays.
  • This invention relates to the use of polymer dispersed liquid crystal materials, containing liquid crystal particles of very small diameter ( ⁇ 100 nm or less), in the development of polarization insensitive analogue phase modulating devices.
  • binary ferroelectric liquid crystal (FLC) phase modulators are being developed for use in free space holographic routing switches for telecomms applications.
  • FLCs binary ferroelectric liquid crystal
  • the great value of FLCs in this application is their fast operation speed and polarisation-independent operation, (since telecomms light signals have no fixed polarisation direction) .
  • They suffer from an upper limit on their maximum potential diffraction efficiency because of the binary nature of the FLC switching effect.
  • the devices described below involve the use of polymer dispersed liquid crystalline materials to generate a polarisation-independent method of producing analogue phase modulation.
  • Many different devices could be based upon this effect but of particular interest is the use of such materials in the production of reconfigurable spatial light modulators for use as holographic light routing switches for telecomms
  • PDLC materials have been largely developed with particle diameters of the order of the wavelength of the incident light in order to take advantage of the large scattering such a particle size would produce.
  • a device is composed of a layer of polymer dispersed liquid crystalline material placed between transparent electrodes such as Indium-Tin Oxide (ITO) on Glass or Polymer) .
  • ITO Indium-Tin Oxide
  • FIG 1 An example of such a device is shown schematically at Figure 1.
  • the PDLC material may be filled into a preprepared cell as a prepolymer syrup containing monomer units and photosensitive components intended to make the polymerisation action light activated. The LC material is dissolved within this mixture.
  • the LC molecules orient themselves with one of the several characteristic LC director (i.e. mean value of direction of molecular long axes) configurations possible . (Which director arrangement is adopted for a given PDLC material is determined by several parameters) .
  • ⁇ bipolar' for which the directors lie tangentially to the surface of the LC/polymer interface and exhibit two singularities between which there is an axial symmetry of director orientation (a bipolar axis), see Fig 1(a) .
  • a bipolar axis In the absence of an applied field the bipolar axis orientation is random across the sample such that on average each droplet 10 presents a refractive index different to that of the polymer matrix and thus a refractive index discontinuity to the incoming light. In this state incoming light 12 is scattered strongly effectively blocking its transmission, Fig 1 (b) . Once a sufficiently high electric field E is applied the bipolar axes become aligned with the field lines.
  • PDLC prepolymer mixture is illuminated by two coherent beams of light which interfere within the PDLC material to produce an interference pattern.
  • the rate of polymerisation of the pre-polymer syrup is dependent on the intensity of the incident light. Polymerisation is faster in areas for which the light is most intense and within these regions the chemical potential of the LC is raised and the potential of the monomer is lowered. This results in the flow of liquid crystal and monomer components in opposite directions resulting in the seperation of polymer and liquid crystals droplets into different areas.
  • a simple diffraction grating lines are formed alternately composed of regions high in concentrations of LC and polymer.
  • the operation of the resulting device now depends on the change in the average refractive index of the LC layers .
  • the average refractive index n(lc)in the high LC density region does not match that n(p) in the low LC density region and the hologram is revealed (see Fig 2a) .
  • Some of the light incident normally to the device will be deflected into the first order diffraction peak.
  • the LC director orientation rotates until the average refractive index of the LC region 22 closely matches that of the polymer 24 effectively ⁇ erasing' the holographic grating. Light incident normally to the device will be transmitted through without deflection (see Fig. 2b) .
  • the hologram is effectively based on an amplitude grating, i.e. light would pass directly through in the field-on state but would be directed to the first order with some large degree of loss in the field-off state.
  • the hologram is essentially a phase grating and the loss to the deflected beam is much reduced.
  • the use of particles with small diameters allows the spatial frequency of such holograms to be maximised.
  • this mechanism for hologram generation restricts each device to one fixed spatial frequency and thus one direction of deflection of the diffracted beam. This effect has been proposed as suitable for the generation of variable focus lenses and stacked sets of holograms for holographic routing switches .
  • the present invention differs from the techniques described above in that it does not use the electric field control of the director profile of the LC particles in order to match or not match the refractive index of permanently recorded PDLC gratings .
  • the present invention differs from such devices in that it does not involve the generation of separate e and o waves i.e. the technique of the present invention does not involve the use of the birefringence of the LC material to change the polarisation state of the outgoing light by superposition of the emerging e and o rays . No e and o rays are generated within the proposed device since the material is arranged to appear isotropic to the transmitted light.
  • phase delay is said to be pure in the sense that it is not the result of polarisation modulation due to the separate optical path lengths experienced by e and o rays.
  • Phase delays produced in this manner are to be used to make efficient analogue - phase, polarisation - independent spatial light modulators .
  • a light modulator for modulating the phase of incident light in an analogue manner
  • the modulator comprising an active electro optical layer of polymer dispersed liquid crystalline (PDLC) material sandwiched between two electrode layers, at least one of which is transparent to the incident light, wherein the PDLC material contains liquid crystal droplets located substantially randomly within the active layer and having a length less than the wavelength of the incident light, such that the application of an electric field across the electrodes influences the director configurations of the droplets to modify the average refractive index of the active layer, and therefore modulates the phase of the incident light in an analogue manner.
  • the modulator may modulate the phase of the incident light in a polarisation-independent manner.
  • the application of the electric field may distort the director configurations of at least some of the droplets .
  • the extent of distortion may be a function of the applied field.
  • the light modulator may be arranged to modulate the phase of transmitted incident light.
  • both of the electrode layers may be transparent.
  • the light modulator may be arranged to modulate the phase of reflected incident light.
  • one of the electrode layers may be arranged to reflect the incident light which has passed through the active layer.
  • the or each electrode layer may comprise a substrate of glass or silicon.
  • the transparent electrode layer may comprise a glass or silicon substrate coated in Indium-Tin oxide (ITO) or a silicon substrate (transparent at telecomms wavelength) .
  • the reflective electrode may comprise a glass or silicon substrate coated in a reflective, conductive material, such as a metal .
  • the liquid crystal material is a nematic material.
  • a light modulator according to the present invention may form an optical switch such as a spatial light modulator (SLM) for the holographic routing of optical signals used in, for example, telecommunications or aerospace applications.
  • SLM spatial light modulator
  • At least one of the electrode layers may have formed upon it individual electrode elements, which may be addressable individually or collectively and may form a one or two dimensional array. Therefore, different regions of the active layer, which may act as pixels, may be made to experience different strengths of applied electric field.
  • the invention also includes a method of modulating the phase of light in an analogue manner, the method comprising causing the light to be incident upon a modulator device comprising an active electro optical layer of polymer-dispersed liquid crystalline (PDLC) material sandwiched between electrode layers, at least one of which is transparent to the incident light, wherein the PDLC material contains liquid crystal droplets located substantially randomly within the active layer and having a length less than the wavelength of the incident light, and applying an electric field across the electrodes to influence the director configurations of the droplets so as to modify the average refractive index of the active region, and thereby modulate the phase of the incident light in an analogue manner.
  • a modulator device comprising an active electro optical layer of polymer-dispersed liquid crystalline (PDLC) material sandwiched between electrode layers, at least one of which is transparent to the incident light, wherein the PDLC material contains liquid crystal droplets located substantially randomly within the active layer and having a length less than the wavelength of the incident light, and applying an electric field across the electrodes
  • the method may comprise modulating the phase of the incident light in a polarisation-independent manner .
  • the method may comprise distorting the director configurations of at least some of the droplets .
  • the extent to which the director configurations become distorted may be a function of the applied field.
  • the method may comprise addressing individually or collectively electrode elements formed on at least one of the electrode layers, so as to apply electrical fields of differing strengths to different regions of the active layer.
  • distinct regions within the active layer may have their average refractive index modified, and may therefore modulate the phase of the incident light, to different extents.
  • Figures 2a and 2b show schematically a known simple diffraction grating device of the prior art
  • Figures 3a and 3b show schematically a phase modulator according to an embodiment of the present invention
  • FIGS. 4a and 4b show schematically the device of
  • Figure 3 under the influence of an applied electric field
  • Figures 5a and 5b depict schematically an alternative model for the device shown in Figures 3 and 4
  • FIGS. 6a and ⁇ b show schematically another embodiment of the present invention.
  • Figures 7a and 7b show, respectively, a transmissive and a reflective holographic optical routing switch such as may incorporate a modulator according to the present invention.
  • the microscopic anisotropy is revealed on a macroscopic level by the careful alignment of the material so that incident light is able to experience the full anisotropy of the LC material used.
  • An isotropic arrangement of LC directors of sufficiently small scale would present incident light with an isotropic medium.
  • the LC is encapsulated within droplets which are small and which, in the case of the bipolar director configuration, may have many different bipolar (average director) orientations. So that on the whole, despite being an inherently anisotropic material, the LC may be presented in an isotropic way to the incident light.
  • the droplet size is large enough to be detected by the light as a region of differing refractive index and thus the source of a large scattering effect.
  • the LC droplets are smaller than the wavelength of the incident light and so simply modify the refractive index the light experiences as it passes through the PDLC. Scattering is still associated with these particles but now it is much reduced.
  • the small size of the PDLC particles restricts the nematic LCs i.e.
  • Figures 3 and 4 show schematically an embodiment of phase modulator in accordance with the present invention wherein Figure 3 (a) is a side view, and Figure 3(b) a plan view of a modulator device.
  • the lower layer 30 is composed of glass or silicon substrate containing a 1-D array of pixels 32 formed from either ITO or aluminium respectively see Fig 3 (b) .
  • the pixel array is one dimensional there is room for SRAM 34 and high voltage circuitry (not shown) .
  • This substrate is covered by an upper glass plate 36 coated uniformly with ITO to make one large transparent electrode.
  • the polymer dispersed LC composite material 38 is sandwiched between them.
  • the polymer dispersed material containing a nematic LC (with positive dielectric) anisotropy may take the forms shown in Fig 4 or Fig 5.
  • this shows the director configuration within the droplets 40 in the field-off condition.
  • This type of droplet director configuration is known as bipolar.
  • the bipolar axis of each droplet is assumed to be randomly oriented.
  • the direction of this axis is assumed to be determined by a slight elongation of the droplet which results in the bipolar axis along the long axis, and/or the random pinning of the director on the interior surface of the droplet wall.
  • Light impinging on this material may encounter small enough scattering centres (close to 50nm) to be suitable for Rayleigh scattering. The scattering is therefore very low especially at telecomms wavelengths (1550 and 1320nm) .
  • the refractive index encountered by the incoming light is polarisation independent.
  • An applied electric field couples to the LC dielectric anisotropy and exerts an electric torque on the directors. This is balanced by an elastic torque generated by the distortion of the director pattern away from its equilibrium position. The balance of these two forces determines an equilibrium position of the director and a rotation of the bipolar axis towards an orientation normal to the plane of the SLM.
  • the device is thus able to provide analogue modulation of the refractive index, and hence phase-delay, encountered by the incoming light.
  • 4(b) shows the final switched configuration in which voltages of different magnitudes have been applied to different pixels 42 to produce several different regions 44 of PDLC, with different switched states, and hence a phase pattern suitable to diffract light into first order spot with high efficiency.
  • Dependent factors for the success of this technology may be random orientation of bipolar axes, and a polymer matrix which is insensitive to polarisation direction.
  • FIGs . 5 (a) , and (b) Another model for this device is shown in Figs . 5 (a) , and (b) .
  • the droplets 50 contain liquid crystal director configurations resulting from normal orientation of the directors at the LC/polymer interface.
  • the resulting configuration is shown pictorially in Figure 5(a) and is described as being ⁇ radial' .
  • the molecular directors adopt all possible orientations and the device in this state is polarisation insensitive to the incoming light 52.
  • E electric field
  • the director configuration within the droplet distorts to a new equilibrium value which changes as E increases towards the final ⁇ axial' configuration shown in Fig 5 (b) .
  • a polarisation insensitive amplitude modulator which could be idealised as being transparent in the field on state and highly absorbing in the field off state can be fabricated by the addition of a dichroic dye component to the above-described structures.
  • Figures 6(a) and (b) show schematically a guest-host structure.
  • the dye would be present as a guest within the LC system and as in typical LC dye guest-host systems would orientate its long axis parallel to that of the LC material.
  • the dye molecule 60 would then follow the motion of the surrounding LC molecules 62 as it is turned in an applied electric field.
  • Dichroic dyes typically exhibit maximum light absorption when the incident light is polarised so that its electric field component lies parallel to the dye/LC molecular long axis as shown schematically in Fig. 6(a) .
  • Such a device provides a polarisation independent light shutter, which is potentially brighter in the bright state than for example any such device which involves crossed polarisers. It may also be possible to tailor the dye to the wavelength of interest. The main difficulty to overcome is to ensure that the dye and liquid crystal come out of solution as much as possible during the polymerization process.
  • SLMs spatial light modulators
  • Spatial light modulators are devices which modulate the properties of light incident upon them. They may modulate amplitude, phase or polarisation state, and at their core is a material which exhibits an electro optic effect such as a liquid crystalline substance.
  • LC SLMs may consist of a LC enclosed between glass plates coated with ITO (see Figures 4a and 4b) .
  • the ITO provides electrodes for addressing the LC whilst being transparent to visible light.
  • SLMs may be based on silicon substrates which may operate in reflection or transmission. Such devices used in reflection may use aluminium layers as electrodes for the LC overlaid on them which function also as mirrors for the light reflection.
  • the Al pixels are connected to individual circuitry in the silicon backplane.
  • the advantage of such technology is the density of circuitry which is possible.
  • FLCs are commonly employed.
  • the advantages of FLCs over other phase modulating LC effects are speed and the fact that the effect is polarisation-insensitive.
  • the helical FLC material, encased within a SLM such that its helix is suppressed, may be switched between two states.
  • the two states represent the effective phase delays of 0 and ⁇ .
  • Any holographic image produced by this arrangement is thus limited by the simple binary nature of the display medium.
  • the limitation placed on the applications of such a binary phase medium may be illustrated by consideration of its use in a free space optical routing switch such as might be used in telecomms applications .
  • One object is to route an input optical signal from one fibre to any of the output fibres by the use of diffraction patterns displayed in the SLM.
  • Light incident on the slm from the input fibre is ⁇ steered' by the SLM to the output fibres.
  • the replay field contains the diffracted spot (plus higher orders) plus its inherent symmetric orders. This is a problem in two respects. Firstly, it limits the maximum efficiency of light coupling from the input fibre to the output fibre via the first order diffraction peak to no greater than 41% due to light directed to the zero and inverse orders being lost. Secondly, it reduces the area of the replay field that is useful to the device. In comparison the introduction of an extra level of modulation to four or more allows, to a large extent, the removal of the unwanted orders from the replay field, the maximum efficiency of a four-level hologram being 81%.
  • the current FLC technology available for this application is limited in several other ways. Whilst the absolute efficiency of the device has been stated as 41% currently it may be less than this if the FLC parameters are not ideal. For maximum efficiency operation the sample must have a half wave thickness and the required tilt angle of 45 degs .
  • Figure 7(a) illustrates the use of a transmissive glass SLM for beam steering. It comprises, two glass plates 70 coated with a layer of ITO, a transparent conductor. The ITO layer on one of the two glass plates has been etched in order to define a row of individual pixels. The other plate is not etched and the ITO layer provides a common ground to all of these pixels. The gap formed by the assembly of these plates is filled with a FLC material 72. Each pixel in the resulting SLM is electrically addressed individually and holographic patterns are displayed on the device by computer 74 control of the pixel switched states.
  • FIG. 7(b) shows the same basic design transformed into a reflective device by the use of a silicon back plane in place of the pixellated glass plate.
  • the incoming signal is now both reflected and diffracted by the reflective SLM 82, through lens 84, and the output fibre array 86 is located next to the input fibre 88.

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Chemical & Material Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Dispersion Chemistry (AREA)
  • Mathematical Physics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Liquid Crystal (AREA)

Abstract

L'invention concerne un modulateur de phase comportant une couche inférieure (30) de substrat de verre ou de silicium contenant un réseau 1-D de pixels (32) réalisé en oxyde d'indium-étain ou en aluminium. Ledit substrat est couvert d'un panneau en verre supérieur (36) revêtu uniformément d'oxyde d'indium-étain de manière à obtenir une grande électrode transparente. Un matériau composite de cristaux liquides à dispersion polymère (38) est logé entre ces couches, le matériau à dispersion polymère contenant des cristaux liquides nématiques (avec un diélectrique positif). La figure (4a) présente la configuration de directrice à l'intérieur des gouttelettes (40) à l'état de champ coupé. Ce type de configuration de directrice de gouttelettes est nommé bipolaire. En l'absence de champ électrique, l'axe bipolaire de chaque gouttelette est supposé comme étant aléatoire. La direction de cet axe est supposée être déterminée par une légère élongation de la gouttelette se traduisant par l'axe bipolaire s'étendant le long de l'axe longitudinal, et/ou le brochage aléatoire de la directrice sur la surface intérieure de la gouttelette. L'incidence de lumière sur ce matériau peut rencontrer des centres de diffusion suffisamment petits pour permettre la diffusion de Rayleigh. Un champ électrique appliqué se couple à l'anisotropie du diélectrique à cristaux liquides et exerce un couple électrique sur les directrices. Ce phénomène est équilibré par un couple élastique produit par la distorsion du modèle de directrice hors de sa position d'équilibre. L'équilibre de ces deux forces détermine une position d'équilibre de la directrice et une rotation de l'axe bipolaire vers une orientation perpendiculaire au plan du modulateur spatial de lumière. Le dispositif selon l'invention permet ainsi une modulation analogique de l'indice de réfraction, et un délai de phase s'appliquant à la lumière incidente. La figure (4b) présente la configuration de commutation finale dans laquelle les tensions de différentes amplitudes ont été appliquées à différents pixels (42) de manière à produire plusieurs régions différentes (44) de cristaux liquides à dispersion polymère avec différents états de commutation, et ainsi un modèle de phase pouvant produire une diffraction efficace de la lumière en spots du premier ordre.
PCT/GB2000/003371 2000-09-01 2000-09-01 Modulateur de phase WO2002019018A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/GB2000/003371 WO2002019018A1 (fr) 2000-09-01 2000-09-01 Modulateur de phase
AU2000268585A AU2000268585A1 (en) 2000-09-01 2000-09-01 Phase modulator

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PCT/GB2000/003371 WO2002019018A1 (fr) 2000-09-01 2000-09-01 Modulateur de phase

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005027101A2 (fr) * 2003-09-18 2005-03-24 Koninklijke Philips Electronics N.V. Systeme pour decaler au moins un point lumineux
EP2085811A1 (fr) * 2006-11-15 2009-08-05 Citizen Holdings Co., Ltd. Élément de modulation optique à cristaux liquides, dispositif de modulation optique à cristaux liquides et procédé de commande d'un élément de modulation optique à cristaux liquides
EP2769254A2 (fr) * 2011-12-01 2014-08-27 Alcon Research, Ltd Domaine technique de sonde laser multi-point électriquement commutable
US11353191B2 (en) * 2018-05-24 2022-06-07 Coelux S.R.L. Tunable white illumination

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
MATSUMOTO S ET AL: "Light processing and optical devices using nano-sized droplets of liquid crystal dispersed in polymer", FOURTH INTERNATIONAL CONFERENCE ON INTELLIGENT MATERIALS, MAKUHARI, JAPAN, 5-7 OCT. 1998, vol. 10, no. 6, Journal of Intelligent Material Systems and Structures, June 1999, Technomic Publishing, USA, pages 489 - 492, XP000998768, ISSN: 1045-389X *
SANSONE M J ET AL: "Large Kerr effects in transparent encapsulated liquid crystals. II. Frequency response", JOURNAL OF APPLIED PHYSICS, 1 FEB. 1994, USA, vol. 75, no. 3, pages 1715 - 1721, XP000430055, ISSN: 0021-8979 *

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005027101A2 (fr) * 2003-09-18 2005-03-24 Koninklijke Philips Electronics N.V. Systeme pour decaler au moins un point lumineux
WO2005027101A3 (fr) * 2003-09-18 2005-06-30 Koninkl Philips Electronics Nv Systeme pour decaler au moins un point lumineux
EP2085811A1 (fr) * 2006-11-15 2009-08-05 Citizen Holdings Co., Ltd. Élément de modulation optique à cristaux liquides, dispositif de modulation optique à cristaux liquides et procédé de commande d'un élément de modulation optique à cristaux liquides
EP2085811A4 (fr) * 2006-11-15 2010-08-25 Citizen Holdings Co Ltd Élément de modulation optique à cristaux liquides, dispositif de modulation optique à cristaux liquides et procédé de commande d'un élément de modulation optique à cristaux liquides
US8310607B2 (en) 2006-11-15 2012-11-13 Citizen Holdings Co., Ltd. Liquid crystal optical modulation element, liquid crystal optical modulation device and method for driving liquid crystal optical modulation element
EP2769254A2 (fr) * 2011-12-01 2014-08-27 Alcon Research, Ltd Domaine technique de sonde laser multi-point électriquement commutable
EP2769254A4 (fr) * 2011-12-01 2014-10-22 Alcon Res Ltd Domaine technique de sonde laser multi-point électriquement commutable
US8939964B2 (en) 2011-12-01 2015-01-27 Alcon Research, Ltd. Electrically switchable multi-spot laser probe
JP2015503120A (ja) * 2011-12-01 2015-01-29 アルコン リサーチ， リミテッド 電気式切り替え可能マルチスポットレーザープローブ
US9910338B2 (en) 2011-12-01 2018-03-06 Alcon Research, Ltd. Electrically switchable multi-spot laser probe
US11353191B2 (en) * 2018-05-24 2022-06-07 Coelux S.R.L. Tunable white illumination

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