WO2012130302A1 - Dispositif à cristaux liquides, à deux cellules et à commutation rapide - Google Patents

Dispositif à cristaux liquides, à deux cellules et à commutation rapide Download PDF

Info

Publication number
WO2012130302A1
WO2012130302A1 PCT/EP2011/054944 EP2011054944W WO2012130302A1 WO 2012130302 A1 WO2012130302 A1 WO 2012130302A1 EP 2011054944 W EP2011054944 W EP 2011054944W WO 2012130302 A1 WO2012130302 A1 WO 2012130302A1
Authority
WO
WIPO (PCT)
Prior art keywords
liquid crystal
crystal cell
cell
state
birefringence
Prior art date
Application number
PCT/EP2011/054944
Other languages
English (en)
Inventor
Lachezar Komitov
Original Assignee
Lachezar Komitov
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 Lachezar Komitov filed Critical Lachezar Komitov
Priority to JP2014501450A priority Critical patent/JP5797323B2/ja
Priority to KR1020137028670A priority patent/KR20140024354A/ko
Priority to CN201180069865.8A priority patent/CN103718094B/zh
Priority to PCT/EP2011/054944 priority patent/WO2012130302A1/fr
Priority to TW101111284A priority patent/TW201300891A/zh
Publication of WO2012130302A1 publication Critical patent/WO2012130302A1/fr

Links

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
    • G02F1/01—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
    • G02F1/1347—Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
    • G02F1/13471—Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells in which all the liquid crystal cells or layers remain transparent, e.g. FLC, ECB, DAP, HAN, TN, STN, SBE-LC cells
    • 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
    • G02F1/1347—Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
    • 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
    • G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
    • G02F1/133738—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers for homogeneous alignment
    • 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
    • G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
    • G02F1/133742—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers for homeotropic alignment

Definitions

  • the present invention relates to a liquid crystal device for modulating light passing through the liquid crystal device.
  • the present invention further relates to a method for controlling such a liquid crystal device.
  • Liquid crystal devices can, for example, be used as light shutters to achieve switching between a bright state and a dark state, but it has turned out to be difficult to achieve a sufficiently high switching speed especially with the conventional nematic liquid crystal materials, widely used at present in a variety of LCDs, and the available electronic driving techniques. In particular, the relaxation of nematic liquid crystal materials is a slow process.
  • a liquid crystal device for modulating light passing through the liquid crystal device, comprising: a first liquid crystal cell having a liquid crystal material comprising a plurality of liquid crystal molecules sandwiched between a first pair of substrates; and a second liquid crystal cell having a liquid crystal material comprising a plurality of liquid crystal molecules sandwiched between a second pair of substrates, the first liquid crystal cell and the second liquid crystal cell being arranged in a layered configuration such that light having passed through the first liquid crystal cell hits the second liquid crystal cell, and each of the first liquid crystal cell and the second liquid crystal cell being individually controllable between a relaxed state in which the liquid crystal cell exhibits a first birefringence and a switched state in which the liquid crystal cell exhibits a second birefringence, wherein the liquid crystal cells are arranged and configured such that: a transition of the first liquid crystal cell from the relaxed state to the switched state, while the second liquid crystal cell remains in its relaxed state, results in a change in a
  • a nematic liquid crystal cell with uniform alignment behaves optically as a uniaxial (birefringent) optical plate with its optic axis coinciding with the preferred direction of orientation of the liquid crystal molecules in the cell. Inserted between two crossed polarizers, the intensity of the light / transmitted through the cell and the polarizers, when the cell is oriented with its optic axis at 45° to the polarizer transmission direction, is given simply by:
  • ⁇ 2 ⁇ ⁇ / ⁇ represents the phase retardation of the cell due to its birefringence
  • An n e -n 0 ⁇ n e and n 0 are extraordinary and ordinary refractive index of the liquid crystal material, respectively)
  • ⁇ is the wavelength of the light.
  • the gap thickness of the cells in the double cell device is a permanent cell parameter, i.e. does not depend on the applied electric field.
  • the birefringence of the cells is controllable through the application of an electric field. Therefore "birefringence” and “phase retardation” can be considered to be synonymous for the liquid crystal device according to the various aspects of the present invention.
  • the “relaxed” state may also be referred to as a "Field OFF” state in which no switching electric field exists in the liquid crystal cell, and the
  • switched state may be referred to as a "Field ON” state in which a switching electric field exists in the liquid crystal cell.
  • the present invention is based on the realization that the relaxation of the liquid crystal material in the liquid crystal cells (the duration of which is determined by the viscosity and the elastic constant of the liquid crystal material as well as by the thickness of the cell gap and anchoring strength) is a limiting factor for the switching speed back and forth between a bright state and a dark state, and that the relaxation process can be optically "cancelled out” by properly arranging two suitable liquid crystal cells in series.
  • the present inventor has further realized that the total birefringence of two liquid crystal cells arranged in series can be used to switch the liquid crystal device between two light-modulation states (such as dark and bright) by actively switching the individual liquid crystal cells. The liquid crystal cells can then relax simultaneously while the liquid crystal device remains in one of its light- modulation states, after which the liquid crystal device is once again ready to be actively switched between light-modulation states.
  • both the switching from the first light-modulation state of the liquid crystal device to the second light-modulation state of the liquid crystal device and the switching back to the first light-modulation state can be achieved using the fast process of actively reorienting the liquid crystal molecules in the respective liquid crystal cells through the application of an electric field.
  • the liquid crystal device is ready to be switched to the second light-modulation state again, by controlling the first liquid crystal cell from its relaxed state to its switched state.
  • the liquid crystal molecules of the first and second liquid crystal cells are substantially parallel to each other in the relaxed states of the first and second liquid crystal cells.
  • the orientation of the liquid crystal molecules of the first liquid crystal cell will be changed so that the liquid crystal molecules are again substantially parallel to each other, but in another general direction than was the case for the relaxed state. This will result in a change in the birefringence of the first liquid crystal cell, which will in turn result in a change in the total birefringence of the liquid crystal device, since the second liquid crystal cell remains in its relaxed state.
  • the intensity level of the light passing through the first and second liquid crystal cells placed between crossed polarizers, for instance, will also change, which results in the transition from the first light-modulation state to the second light- modulation state.
  • this birefringence based control of the transmitted light intensity level is quite different from the polarization control performed by a gradually changing director throughout a liquid crystal cell, as for instance in the twisted nematic cells.
  • the use of birefringence-based control of the liquid crystal device according to various embodiments of the present invention enables designs in which it can be selected which of the above-mentioned first and second light-modulation states should be a bright/dark state. This means that it, through the design of the liquid crystal cells, can be determined, for example, if the simultaneous relaxation of the first and second liquid crystal cells should take place in the dark state or in the bright state.
  • utilizing birefringence-based control of the liquid crystal cells allows for adaptation of the properties of the liquid crystal cell to various requirements on, for example, optical performance, production yield, robustness etc. Furthermore, the sensitivity to misalignment between the polarizer, the analyzer and the liquid crystal cells can be reduced.
  • Each of the first and second liquid crystal cells may advantageously be configured for so-called "out-of-plane” switching, which means that the liquid crystal molecules are reoriented in a plane that is perpendicular to the substrates of the liquid crystal cell, when the above-mentioned electric field is applied.
  • the liquid crystal material of the first and second liquid crystal cells may advantageously be in a nematic phase (for the expected operating conditions of the liquid crystal device).
  • the first and second liquid crystal cells may be arranged and configured such that a sum of the birefringence of the first liquid crystal cell and the birefringence of the second liquid crystal cell remains
  • the total birefringence of the device remains constant due to the birefringence compensation effect that takes place during the relaxation process in the cells.
  • a peculiar feature of the relaxation process in the cells is that while the birefringence of the first liquid crystal cell increases/decreases the birefringence of the second liquid crystal cell decreases/increases which results in a constant value of the total birefringence thus hiding optically the relaxation process.
  • the liquid crystal device could in principle be controllable through control means arranged externally to the liquid crystal device.
  • the liquid crystal device may advantageously be configured such that the first liquid crystal cell comprises a first control electrode and a second control electrode arranged to enable control of the first liquid crystal cell from the relaxed state to the switched state through application of a voltage between the first control electrode and the second control electrode of the first liquid crystal cell; and the second liquid crystal cell comprises a first control electrode and a second control electrode arranged to enable control of the second liquid crystal cell from the relaxed state to the switched state through application of a voltage between the first control electrode and the second control electrode of the second liquid crystal cell.
  • Such control electrodes may advantageously be arranged to provide the above-mentioned out-of-plane switching of the liquid crystal cells.
  • the first birefringence of the first liquid crystal cell may be non-zero and the first birefringence of the second liquid crystal cell may be substantially zero, the first and second liquid crystal cells being arranged such that the first total birefringence is non-zero.
  • the liquid crystal device according to these embodiments is placed between crossed polarizers, with the optic axis of at least one of the first and second liquid crystal cells making an angle ⁇ with the transmission direction of one of the polarizers being in the interval 0° ⁇ ⁇ 90°, preferably substantially equal to 45°, the first modulation state (when both the first liquid crystal cell and the second liquid crystal cells are in their relaxed states) will be a bright state.
  • the second birefringence of the first liquid crystal cell may be substantially zero, such that the second total birefringence is substantially zero. This will result in the second modulation state being a dark state when the liquid crystal device is properly arranged between crossed polarizers.
  • the first liquid crystal cell may be in a planar alignment configuration in the relaxed state, such that the liquid crystal molecules comprised in the first liquid crystal cell are arranged substantially in parallel with the substrates, and the second liquid crystal cell may be in a vertical alignment configuration in the relaxed state such that the liquid crystal molecules comprised in the second liquid crystal cell are arranged
  • a liquid crystal cell that is in a planar alignment configuration in the relaxed state will be referred to as a "PA-cell”
  • a liquid crystal cell that is in a vertical alignment configuration in the relaxed state will be referred to as a "VA-cell”.
  • a liquid crystal device in which the first liquid crystal cell is a PA-cell and the second liquid crystal cell is a VA-cell will be referred to as a "VA PA-double cell device”.
  • the liquid crystal molecules comprised in the VA-cell may be any liquid crystal molecules comprised in the VA-cell.
  • the liquid crystal molecules in the VA-cell can be controlled from the vertically aligned state (with a birefringence that is substantially equal to zero) to a state with a non- zero birefringence, such as a planarly aligned state with liquid crystal molecules that are aligned in parallel to the substrates.
  • the liquid crystal molecules of the VA-cell may exhibit positive dielectric anisotropy, in which case the first and second control electrodes may be arranged on the same substrate to generate so-called in- plane electric field or fringe electric field.
  • a VA-cell may advantageously be configured in such a way that the liquid crystal molecules, when the VA-cell is in its switched state, are directed in substantially the same direction as the liquid crystal molecules of the PA- cell in a VA PA-double cell device, when the PA-cell is in its relaxed state.
  • the magnitude of the first birefringence of the first cell may be substantially equal to the magnitude of the first birefringence of the second cell.
  • the first and second liquid crystal cells may have a substantially identical configuration in respect of liquid crystal material, cell gap, anchoring properties, electrode structure, etc. This will facilitate designing the liquid crystal device in such a way that the total birefringence of the liquid crystal device remains constant during simultaneous relaxation of the liquid crystal cells (the simultaneous transition from the switched state to the relaxed state for the first and second liquid crystal cells.)
  • the first liquid crystal cell and the second liquid crystal cell may be arranged in relation to each other in such way that the total birefringence of the liquid crystal device, when the first liquid crystal cell is in its relaxed state and the second liquid crystal cell is in its relaxed state, is substantially zero.
  • the optic axis of the first cell may be substantially perpendicular to the optic axis of the second cell.
  • the first light modulation state (when both the first liquid crystal cell and the second liquid crystal cell are in their relaxed states) will be a dark state, since the birefringence of the liquid crystal device will be substantially zero and the incoming light will not pass through the crossed polarizers where the device is inserted in between.
  • the first liquid crystal cell and the second liquid crystal cell may be arranged in relation to each other in such way that the total birefringence of the liquid crystal device, when the first liquid crystal cell is in its second state and the second liquid crystal cell is in its first state, is non-zero. Accordingly, when the first liquid crystal cell is controlled to transition from its relaxed state to its switched state, the total birefringence of the liquid crystal device will be non-zero, which means that the incoming light will pass through the crossed polarizers, i.e. through the device, so that the liquid crystal device transitions to a bright state. This, of course, requires that crossed polarizers are arranged properly with respect to the in-plane direction of the liquid crystal molecules, which is well known to those skilled in the art.
  • each of the first and second liquid crystal cells may be in a planar alignment configuration in the relaxed state, such that the liquid crystal molecules comprised in each of the first and second liquid crystal cells are arranged substantially in parallel with the substrates.
  • both the first and second liquid crystal cells may be PA-cells, which means that the liquid crystal device is a "PA PA-double cell device”.
  • the magnitude of the first birefringence of the first liquid crystal cell should be non-zero and
  • each of the liquid crystal cells of the PA PA-double cell device may be configured to be switched from the parallel alignment state to a vertical alignment state in which the liquid crystal molecules comprised in the liquid crystal cell become aligned substantially perpendicular to the substrates.
  • the PA/PA double cell device will be switched from bright state back to dark state. Switching off the cells in this state the relaxation process in the cells will be not noticeable by an observer due to the birefringence
  • the liquid crystal molecules comprised in each liquid crystal cell may advantageously exhibit positive dielectric anisotropy, and each liquid crystal cell may advantageously comprise a first control electrode arranged on the first substrate and a second control electrode arranged on the second substrate.
  • the liquid crystal molecules in each of the liquid crystal cells can be controlled from the relaxed planarly aligned state (with a non-zero birefringence) to a switched vertically aligned state with a birefringence that is substantially equal to zero.
  • both the first and the second liquid crystal cells may be in a vertical alignment configuration in the relaxed state such that the liquid crystal molecules comprised in the first liquid crystal cell are arranged substantially perpendicular to the substrates.
  • both the first and the second liquid crystal cells may be VA-cells, which means that the liquid crystal device is a "VAA/A-double cell device".
  • the liquid crystal molecules comprised in the VA-cell may exhibit negative or positive dielectric anisotropy, and may comprise appropriately arranged control electrodes.
  • a method of controlling operation of the liquid crystal device comprising the steps of: controlling the first liquid crystal cell from the relaxed state to the switched state of the first liquid crystal cell while allowing the second liquid crystal cell to remain in its relaxed state; controlling the second liquid crystal cell from the relaxed state to the switched state of the second liquid crystal cell, while maintaining the first liquid crystal cell in its switched state; and simultaneously controlling each of the first liquid crystal cell and the second liquid crystal cell to relax from its respective switched state to its respective relaxed state.
  • each of the first and second liquid crystal cells may be controlled to relax from its respective switched state to its respective relaxed state in such a way that the total birefringence of the liquid crystal device remains substantially constant during relaxation of said first and second liquid crystal cells.
  • the first aspect of the invention relates to a liquid crystal device comprising a first liquid crystal cell and a second liquid crystal cell arranged in a layered configuration such that light having passed through the first liquid crystal cell hits the second liquid crystal cell.
  • Each of the first liquid crystal cell and the second liquid crystal cell is individually controllable between a relaxed state in which the liquid crystal cell exhibits a first birefringence and a switched state in which the liquid crystal cell exhibits a second birefringence.
  • a transition of the first liquid crystal cell from the relaxed state to the switched state results in a change in a total birefringence of the liquid crystal device from a first total birefringence to a second total birefringence being such that the liquid crystal device transitions from a first light modulation state to a second light modulation state, and a subsequent transition of the second liquid crystal cell from the relaxed state to the switched state results in a change in the total birefringence of the liquid crystal device from the second total birefringence to the first total
  • Fig 1 is a schematic perspective view of a liquid crystal device according to various embodiments of the present invention.
  • Fig 2 is a diagram schematically illustrating an exemplary driving scheme for a liquid crystal device according to a first embodiment of the present invention
  • Figs 3a-d schematically illustrate the state of the liquid crystal device according to the first embodiment of the invention in different stages of the driving scheme in fig 2;
  • Fig 4 is a diagram schematically illustrating an exemplary driving scheme for a liquid crystal device according to a second embodiment of the present invention.
  • Figs 5a-d schematically illustrate the state of the liquid crystal device according to the second embodiment of the invention in different stages of the driving scheme in fig 4. Detailed description of preferred embodiments
  • Fig 1 is a schematic perspective view of a liquid crystal device 1 according to various embodiments of the present invention.
  • the liquid crystal device 1 comprises a first liquid crystal cell 2 and a second liquid crystal cell 3 that are arranged in a layered configuration between crossed polarizer plates 4, 5 - a "polarizer” 4 closest to the light-source 7, and an "analyzer” 5 closest to the viewer 8.
  • the respective polarization directions of the polarizer 4 and the analyzer 5 are indicated by the dashed lines in fig 1 .
  • Each of the first 2 and the second 3 liquid crystal cells is individually controllable between a relaxed state in which the liquid crystal cell exhibits a first birefringence and a switched state in which the liquid crystal cell exhibits a second birefringence that is different from the first birefringence.
  • the total birefringence corresponds to the sum of the birefringence of the first liquid crystal cell 2 and the birefringence of the second liquid crystal cell 3, it follows that the total birefringence can be controlled by controlling either of the first 2 and second 3 liquid crystal cells.
  • the liquid crystal device 1 can be actively switched between a dark state and a bright state, and back to the dark state, which means that the switching can be made considerably faster than using a single cell liquid crystal device, in which one of the state transitions in nematic liquid crystals takes place through elastic relaxation of the liquid crystal material, usually very slow.
  • the first 2 and the second 3 liquid crystal cells are configured in such way that the double cell device 1 is in the same light-modulation state (such as bright or dark) when both liquid crystal cells are switched as when both liquid crystal cells are relaxed.
  • the liquid crystal device can be allowed to relax between switching events, so that switching between light-modulation states can always be active, that is, brought about through the application of an electric field which aligns the liquid crystal molecules in a selected direction.
  • a VA PA-double cell device 10 and an exemplary driving scheme for a VA PA-double cell device will be described with reference to fig 2 and figs 3a-d.
  • Figs 3a-d are exploded cross-section illustrations of embodiments of the liquid crystal device 1 in fig 1 with the section taken along the line A-A' in fig 1 .
  • the VA PA-double cell device 10 comprises a first liquid crystal cell 1 1 and a second liquid crystal cell 12 arranged in a layered configuration between crossed polarizers 4, 5.
  • the first liquid crystal cell 1 1 comprises a nematic liquid crystal material sandwiched between first 14 and second 15 substrates.
  • first 16 and second 17 control electrodes are provided, as well as alignment layers (not shown) for aligning the liquid crystal molecules 18 of the liquid crystal material in a planar alignment as is schematically indicated in fig 3a.
  • liquid crystal molecules 18 are aligned to be angled about 45° relative the polarization direction of the incoming light defined by the polarizer 4. In this configuration, the liquid crystal material in the first liquid crystal cell 1 1 will exhibit a certain non-zero birefringence ⁇ ⁇ .
  • the second liquid crystal cell 12 also comprises a nematic liquid crystal material (which may be the same material as that comprised in the first liquid crystal cell 1 1 ) sandwiched between first 19 and second 20 substrates.
  • first 21 and second 22 control electrodes are provided, as well as alignment layers (not shown) for aligning the liquid crystal molecules 23 of the liquid crystal material in a vertical (homeotropic) alignment as is schematically indicated in fig 3a.
  • the voltage V PA provided across the electrodes 16, 17 of the first liquid crystal cell, the PA-cell, 1 1 and the voltage V V A across the electrodes 21 , 22 of the second liquid crystal cell, the VA-cell, 12 are shown in the top two diagrams as indicated in the figure.
  • the birefringence of the PA-cell 1 1 dashed line
  • the birefringence of the VA-cell 12 dotted line
  • the optical response of the VA PA-double cell 10 solid line
  • the voltage V PA across the PA-cell 1 1 is 0 V
  • the voltage V V A across the VA-cell 12 is also 0 V
  • the VA PA-double cell 10 is in the state shown in fig 3a, with the liquid crystal molecules 18 in the PA-cell 1 1 in planar alignment and the liquid crystal molecules 23 in the VA-cell 12 in vertical alignment.
  • the light having passed the polarizer 4 in fig 3b will pass through the PA-cell 1 1 and the VA-cell without any change in its polarization state, which means that the VA/PA-double cell device 10 is switched to a dark state as is also indicated in fig 2.
  • the voltages are removed across both the PA-cell 1 1 and the VA-cell 12.
  • the liquid crystal cells 1 1 and 12 simultaneously relax back to their relaxed states.
  • the liquid crystal molecules 18 relax back to planar alignment and in the VA-cell 12, the liquid crystal molecules 23 relax back to vertical alignment, as is schematically indicated in fig 3d.
  • a voltage is again applied across the PA-cell 1 1 to bring the VA/PA-double cell 10 back to the dark state shown in fig 3b.
  • a PA PA-double cell device 30 and an exemplary driving scheme for a PA PA-double cell device will be described with reference to fig 4 and figs 5a-d.
  • figs 5a-d are exploded cross- section illustrations of embodiments of the liquid crystal device 1 in fig 1 with the section taken along the line A-A' in fig 1 .
  • a PA PA-double cell device 30 is schematically shown without any control voltages applied.
  • the PA/PA-double cell device 30 comprises a first liquid crystal cell 31 and a second liquid crystal cell 32 arranged in a layered configuration between crossed polarizers 4, 5.
  • the first liquid crystal cell 31 comprises a nematic liquid crystal material sandwiched between first 14 and second 15 substrates.
  • first 16 and second 17 control electrodes are provided, as well as alignment layers (not shown) for aligning the liquid crystal molecules 33 of the liquid crystal material in a planar alignment as is schematically indicated in fig 5a.
  • the second liquid crystal cell 32 also comprises a nematic liquid crystal material (which may be the same material as that comprised in the first liquid crystal cell 31 ) sandwiched between first 19 and second 20 substrates.
  • first 21 and second 22 control electrodes are provided, as well as alignment layers (not shown) for aligning the liquid crystal molecules 34 of the liquid crystal material in a planar alignment as is schematically indicated in fig 5a.
  • PA PA-double cell 30 between different light-modulation states (dark and bright) will now be described with reference to fig 4 and figs 5a-d.
  • the PA/PA-double cell 30 is in the state shown in fig 5a, with the liquid crystal molecules 33 in the first PA-cell 31 in planar alignment in the plane of the paper and the liquid crystal molecules 34 in the second PA-cell 32 in planar alignment in a plane perpendicular to the paper.
  • the total birefringence ⁇ ⁇ 0, which means that no light will pass through the crossed polarizers 4 and 5 where the PA/PA-double cell 30 device is inserted.
  • the device will be in a dark state as is indicated in fig 4.
  • a voltage is applied across the first PA-cell 31 causing the liquid crystal molecules 33 to reorient to a vertical alignment as is schematically indicated in fig 5b.
  • the voltage across the second PA-cell 32 is still 0 V (or at least too low to cause the liquid crystal molecules 34 in the second PA-cell 32 to reorient).
  • this switch is relatively fast, and will result in a transition of the total birefringence so that An to t ⁇ 0, which means that the PA PA-double cell device 30 is switched to a bright state as is also indicated in fig 4.
  • a voltage is applied across the second PA-cell 32 causing the liquid crystal molecules 34 to reorient to a vertical alignment as is schematically indicated in fig 5c.
  • the voltage across the first PA-cell 31 is still applied so that the liquid crystal molecules 33 in the first PA-cell 31 remain in the vertical alignment.
  • the voltages are removed across both the first PA-cell 31 and the second PA-cell 32.
  • the liquid crystal cells 31 , 32 simultaneously relax back to their relaxed states.
  • the liquid crystal molecules 33 relax back to the planar alignment in the plane of the paper
  • the liquid crystal molecules 34 relax back to the planar alignment in a plane perpendicular to the paper, as is schematically indicated in fig 5d.
  • a voltage is again applied across the first PA-cell 31 to bring the PA PA-double cell 30 back to the bright state shown in fig 5b.
  • figs 3a-d and figs 5a-d are simplified and schematic illustrations that are provided to explain various aspects of the present invention, and that the proportions are not representative to a real situation.
  • a real liquid crystal cell contains many more layers of liquid crystal molecules so that any slight deviations closest to the substrates will only have a negligible effect on the birefringence of the liquid crystal cell.

Landscapes

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

Abstract

Un dispositif à cristaux liquides (10) comprenant des première (11) et seconde (12) cellules de cristaux liquides agencées en une configuration en couches de sorte que la lumière ayant traversé la première cellule (11) heurte la seconde (12). Chacune des première (11) et seconde (12) cellules de cristaux liquides peut être commandée individuellement entre un état relâché dans lequel la cellule de cristaux liquides présente une première biréfringence, et un état commuté dans lequel la cellule de cristaux liquides présente une seconde biréfringence. La transition de la première cellule de cristaux liquides (11) de l'état relâché à l'état commuté provoque une modification de biréfringence totale du dispositif à cristaux liquides (10), passant d'une première à une seconde biréfringence totale, de sorte que le dispositif à cristaux liquides (10) passe d'un premier à un second état de modulation de lumière. Une transition ultérieure de la seconde cellule de cristaux liquides (12) de l'état relâché à l'état commuté provoque une modification de biréfringence totale du dispositif à cristaux liquides (10), passant de la seconde à la première biréfringence totale, de sorte que le dispositif à cristaux liquides (10) revienne du second au premier état de modulation de lumière. De ce fait, la commutation du premier au second état de modulation de lumière du dispositif à cristaux liquides (10) et la commutation de retour au premier état de modulation de lumière sont effectuées en utilisant le processus rapide de réorientation active des molécules de cristaux liquides (18, 23) dans les cellules de cristaux liquides respectives (11, 12) par l'application d'un champ électrique.
PCT/EP2011/054944 2011-03-30 2011-03-30 Dispositif à cristaux liquides, à deux cellules et à commutation rapide WO2012130302A1 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
JP2014501450A JP5797323B2 (ja) 2011-03-30 2011-03-30 急速なスイッチングを行う二重セル液晶装置
KR1020137028670A KR20140024354A (ko) 2011-03-30 2011-03-30 고속 스위칭 이중 셀 액정 디바이스
CN201180069865.8A CN103718094B (zh) 2011-03-30 2011-03-30 快速切换的双盒液晶装置
PCT/EP2011/054944 WO2012130302A1 (fr) 2011-03-30 2011-03-30 Dispositif à cristaux liquides, à deux cellules et à commutation rapide
TW101111284A TW201300891A (zh) 2011-03-30 2012-03-30 快速切換之雙晶胞液晶顯示器

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2011/054944 WO2012130302A1 (fr) 2011-03-30 2011-03-30 Dispositif à cristaux liquides, à deux cellules et à commutation rapide

Publications (1)

Publication Number Publication Date
WO2012130302A1 true WO2012130302A1 (fr) 2012-10-04

Family

ID=44625572

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2011/054944 WO2012130302A1 (fr) 2011-03-30 2011-03-30 Dispositif à cristaux liquides, à deux cellules et à commutation rapide

Country Status (5)

Country Link
JP (1) JP5797323B2 (fr)
KR (1) KR20140024354A (fr)
CN (1) CN103718094B (fr)
TW (1) TW201300891A (fr)
WO (1) WO2012130302A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015151298A1 (fr) * 2014-04-02 2015-10-08 Essilor International (Compagnie Generale D'optique) Modulateur de phase achromatique et dispositif optique
EP2937665A1 (fr) * 2014-04-23 2015-10-28 Hexagon Technology Center GmbH Module de mesure de distance doté d'une unité d'atténuation optique variable à partir d'une cellule LC
CN114326216A (zh) * 2021-12-29 2022-04-12 绵阳惠科光电科技有限公司 显示面板及显示装置
US20220382080A1 (en) * 2021-05-26 2022-12-01 Meta Platforms Technologies, Llc Polarization modulator

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI611326B (zh) * 2016-07-26 2018-01-11 互動式顯示及讀取系統
AU2018368783A1 (en) * 2017-11-17 2020-07-02 Gary Sharp Innovations, Inc. Self-compensating liquid crystal retardation switch
WO2020097295A1 (fr) * 2018-11-07 2020-05-14 Alphamicron Incorporated Ensemble optique à transmission pixelisée variable
CN109656068B (zh) * 2018-12-29 2020-11-24 武汉华星光电技术有限公司 一种显示装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62147434A (ja) * 1985-12-20 1987-07-01 Victor Co Of Japan Ltd 液晶光シヤツタ
JPH01191123A (ja) * 1988-01-27 1989-08-01 Seiko Epson Corp 液晶光シャッター
WO2010146948A1 (fr) * 2009-06-19 2010-12-23 日本電気株式会社 Obturateur à cristaux liquides et lunettes d'obturateur à cristaux liquides

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6289925A (ja) * 1985-10-16 1987-04-24 Sharp Corp 立体映像再生システム用液晶眼鏡
JPS62153833A (ja) * 1985-12-26 1987-07-08 Sharp Corp 液晶光シヤツタ−の駆動方式
JPH05297402A (ja) * 1992-04-23 1993-11-12 Sharp Corp 液晶表示装置
US5818548A (en) * 1995-11-07 1998-10-06 Rolic Ag Ferroelectric liquid crystal display in which the switching angle does not exceed ± 22.5°
JP4285350B2 (ja) * 2004-02-26 2009-06-24 セイコーエプソン株式会社 視角制御素子およびその製造方法、液晶表示装置、電子機器
EP2014102B1 (fr) * 2006-04-19 2016-03-09 Setred AS Obturateur d'affichage à grande vitesse destiné à un affichage autostéréoscopique
CN101408692B (zh) * 2007-10-11 2010-07-14 宣茂科技股份有限公司 立体液晶显示器
CN201259593Y (zh) * 2008-08-13 2009-06-17 天马微电子股份有限公司 2d/3d切换型液晶显示装置
JP2011186331A (ja) * 2010-03-10 2011-09-22 Seiko Epson Corp 液晶装置および液晶メガネ
JP2011186334A (ja) * 2010-03-10 2011-09-22 Seiko Epson Corp 液晶装置および液晶メガネ

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62147434A (ja) * 1985-12-20 1987-07-01 Victor Co Of Japan Ltd 液晶光シヤツタ
JPH01191123A (ja) * 1988-01-27 1989-08-01 Seiko Epson Corp 液晶光シャッター
WO2010146948A1 (fr) * 2009-06-19 2010-12-23 日本電気株式会社 Obturateur à cristaux liquides et lunettes d'obturateur à cristaux liquides

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015151298A1 (fr) * 2014-04-02 2015-10-08 Essilor International (Compagnie Generale D'optique) Modulateur de phase achromatique et dispositif optique
US20170017104A1 (en) * 2014-04-02 2017-01-19 Essilor International (Compagnie Generale D'optique) Achromatic phase modulator and optical device
CN106462017A (zh) * 2014-04-02 2017-02-22 埃西勒国际通用光学公司 消色差相位调制器和光学器件
US10073316B2 (en) * 2014-04-02 2018-09-11 Essilor International Achromatic phase modulator and optical device
CN106462017B (zh) * 2014-04-02 2019-08-09 依视路国际公司 消色差相位调制器和光学器件
EP2937665A1 (fr) * 2014-04-23 2015-10-28 Hexagon Technology Center GmbH Module de mesure de distance doté d'une unité d'atténuation optique variable à partir d'une cellule LC
US10215854B2 (en) 2014-04-23 2019-02-26 Hexagon Technology Center Gmbh Distance measuring module comprising a variable optical attenuation unit including an LC cell
US20220382080A1 (en) * 2021-05-26 2022-12-01 Meta Platforms Technologies, Llc Polarization modulator
US11693265B2 (en) * 2021-05-26 2023-07-04 Meta Platforms Technologies, Llc Polarization modulator
CN114326216A (zh) * 2021-12-29 2022-04-12 绵阳惠科光电科技有限公司 显示面板及显示装置

Also Published As

Publication number Publication date
CN103718094B (zh) 2016-04-27
KR20140024354A (ko) 2014-02-28
JP2014509756A (ja) 2014-04-21
TW201300891A (zh) 2013-01-01
CN103718094A (zh) 2014-04-09
JP5797323B2 (ja) 2015-10-21

Similar Documents

Publication Publication Date Title
WO2012130302A1 (fr) Dispositif à cristaux liquides, à deux cellules et à commutation rapide
TWI515495B (zh) 高速液晶偏極化調變器
US10146093B2 (en) Mirror display
KR101222951B1 (ko) 시야각 제어 액정표시장치
US8023052B1 (en) High-speed liquid crystal polarization modulator
KR100778167B1 (ko) 액정 표시 소자
JP2008309957A (ja) 透過型液晶表示装置
US10281731B2 (en) 2D/3D switchable liquid crystal lens unit
KR20150137367A (ko) 고투과율 광시야각 수직정렬 액정표시장치
KR20130064692A (ko) 전기-광 위상 변조기
Chigrinov et al. Photoalignment of liquid crystals: applications to fast response ferroelectric liquid crystals and rewritable photonic devices
RU2582208C2 (ru) Способ управления амплитудой и направлением электрического поля в слое жидкого кристалла, устройство для управления амплитудой и направлением электрического поля в слое жидкого кристалла и жидкокристаллический модулятор света
KR20000066806A (ko) 광시야각과 협시야각 모드전환이 가능한 액정표시장치
JPH06281927A (ja) 液晶表示装置
JP7053178B2 (ja) 液晶表示装置
KR20080047689A (ko) 액정표시장치
CN107209431B (zh) 立式螺旋铁电液晶显示单元
Jiao et al. Broadband wide-view LCDs with small color shift
Chigrinov et al. 9.1: Invited Paper: Fast High Resolution Ferroelectric Liquid Crystal Displays
TW576939B (en) Color liquid crystal display device
JP2002258306A (ja) 液晶表示装置
Jhun et al. P‐155: a novel liquid crystal display device applicable to memory and dynamic modes with a single panel
Jiang et al. P‐104: A Novel Fringe‐Field Switching Mode with High Picture Quality
JP2012141488A (ja) 反強誘電性液晶素子
Komitov et al. P‐106: Future Generation Ultra‐Fast Liquid Crystal Light Shutters

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 201180069865.8

Country of ref document: CN

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 11711103

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2014501450

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 20137028670

Country of ref document: KR

Kind code of ref document: A

122 Ep: pct application non-entry in european phase

Ref document number: 11711103

Country of ref document: EP

Kind code of ref document: A1