WO1997002510A1 - Dispositif a cristal liquide - Google Patents
Dispositif a cristal liquide Download PDFInfo
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- WO1997002510A1 WO1997002510A1 PCT/JP1996/001834 JP9601834W WO9702510A1 WO 1997002510 A1 WO1997002510 A1 WO 1997002510A1 JP 9601834 W JP9601834 W JP 9601834W WO 9702510 A1 WO9702510 A1 WO 9702510A1
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- liquid crystal
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- layer structure
- substrates
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- 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
- G02F1/133753—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers with different alignment orientations or pretilt angles on a same surface, e.g. for grey scale or improved viewing angle
-
- 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
- G02F1/137—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
- G02F1/139—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent
- G02F1/141—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent using ferroelectric liquid crystals
- G02F1/1416—Details of the smectic layer structure, e.g. bookshelf, chevron, C1 and C2
-
- 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
- G02F1/133753—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers with different alignment orientations or pretilt angles on a same surface, e.g. for grey scale or improved viewing angle
- G02F1/133761—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers with different alignment orientations or pretilt angles on a same surface, e.g. for grey scale or improved viewing angle with different pretilt angles
-
- 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
- G02F2203/30—Gray scale
Definitions
- the present invention relates to a liquid crystal device, and more particularly to a liquid crystal device used for an electro-optical device using a liquid crystal display element or a liquid crystal light shutter array. More specifically, the present invention relates to a liquid crystal device using a ferroelectric liquid crystal or an antiferroelectric liquid crystal having a characteristic in a layer structure and a molecular arrangement.
- a liquid crystal device using a ferroelectric liquid crystal utilizes the spontaneous polarization of liquid crystal molecules as shown by Clark et al.
- the spontaneous polarization of a ferroelectric crystal is due to the molecular structure.
- the structure is a racemic body having an asymmetric carbon in the molecule and has a dipole moment perpendicular to the long axis of the molecule, the long axes of the liquid crystal molecules are aligned and the long axis In the SmC * phase, whose rotation is inhibited, the dipole moments are aligned, and spontaneous polarization occurs there.
- two stable molecular arrangements can be obtained by controlling the direction of the spontaneous polarization by the direction of an externally applied electric field.
- bistable states white is displayed in either state, and black is displayed in the other state.
- bistable states since these stable states are maintained even after the electric field is removed, they also have memory properties.
- the response of ferroelectric liquid crystal by voltage application is fast because of the electric field and the first-coupled response, and ferroelectric liquid crystals are attracting attention as being replaced with paraelectric liquid crystals and have been put to practical use. Many attempts have been made Have been.
- the ferroelectric liquid crystal is a system having asymmetric carbon and therefore has a helical property, and since the SmC * phase forms a layer structure, it is difficult to control the direction of spontaneous polarization. For this reason, it was difficult to fabricate a liquid crystal device using a ferroelectric liquid crystal having the bistability and memory characteristics shown by Clark et al. Above all, the layer structure of ferroelectric liquid crystal is complicated, and in addition to the originally proposed bookshelf structure, twisted structures and chevron structures have become known, and liquid crystal devices using ferroelectric liquid crystals have become known. It has become clear that the layer structure is also involved in various properties.
- Kanbe et al. (1992, published by CMC, “Next-Generation Liquid Crystal Displays and Liquid Crystal Materials”) found that c-directors exist near both substrates.
- a liquid crystal device using a ferroelectric liquid crystal having a rotationally symmetric pretilt having a rotation center at the center of the substrate and exhibiting a silicon type layer structure and a splay alignment was announced (Japanese Patent Laid-Open No. 63-124040). See No. 30).
- ferroelectric liquid crystal is originally an enantiomeric system having asymmetric carbon, so that it was not energy-stable in a chevron-type layer structure. Therefore, if the ferroelectric liquid crystal is stored for a long time on the stable side, the stable side becomes more stable, and switching to the other side becomes impossible. This is called hemi-stable.) As a result, there was also a lack of long-term reliability.
- an antiferroelectric liquid crystal which is also a liquid crystal having a layer structure, has a higher layer structure than a ferroelectric liquid crystal.
- the main cause is said to be its multi-domain structure.
- a multi-domain structure is a state in which fine layer structures are mixed in a very small region of the wavelength level. Ideally, many pillars stand in a narrow region. It is thought that the antagonism of the layer causes rigidity of the layer structure.
- an antiferroelectric liquid crystal when an electric field is applied, an electric field-induced phase transition occurs in the ferroelectric phase, and the polarity of the electric field at this time causes two stable molecular arrangements as in the case of the ferroelectric liquid crystal. Is obtained. However, the difference from ferroelectric liquid crystal is that there is no memory consistency between these two stable molecular configurations. Therefore, in an antiferroelectric liquid crystal, when the electric field is removed, these two stable molecular arrangements are repeated even more, and the spontaneous polarization is canceled out, that is, retransition to the antiferroelectric phase.
- antiferroelectric liquid crystals have multiple sub-phases (ferri-phases), also called the steps of the devil, and the possibility of gradation display by performing an electric field-induced phase transition to this ferri-phase.
- this electric-field-induced phase transition is sensitive to a slight voltage difference, and it is difficult to selectively cause a partial phase transition, and satisfactory gradation display has not been obtained.
- ferroelectric liquid crystal again, since it does not have a sub-fizzle like an antiferroelectric liquid crystal, it is impossible to realize a gradation display method by partially switching.
- ferroelectric liquid crystals are formed with a uniform layer structure over a wide range without taking a multi-domain structure. Due to its mono-domain structure, it has a weak point in stress because it is a structure that supports a large roof with few pillars. Disclosure of the invention
- an object of the present invention is to provide a liquid crystal device using a liquid crystal exhibiting a layer structure, which has a structure capable of eliminating defects caused by the conventional layer structure.
- a ferroelectric liquid crystal when used, a gradation display can be realized, and a high contrast without a contrast difference between memory and driving can be realized, and flickering during driving can be realized. It is another object of the present invention to provide a highly reliable liquid crystal device that can secure long-term bistability without any problems. Another object of the present invention is to provide a liquid crystal device that can selectively control an electric field-induced phase transition when an antiferroelectric liquid crystal is used. According to a first embodiment of the present invention, there is provided a liquid crystal device in which a liquid crystal having a layer structure is sandwiched between a pair of parallel substrates provided with electrodes, and pixels are formed between the electrodes.
- the layer structure is arranged such that the substrate interface layer inclination angle formed by a perpendicular line on one of the substrates and the layer plane in the layer structure has at least two types of angles. At least one of the layer structures has a substrate interface layer inclination angle of (1) 0 to 3 degrees, (2) 4 to 7 degrees, and (3) 8 to 20 degrees.
- the c-director which is either a degree and is the unit vector projected on the layer plane of the liquid crystal molecules at the substrate interface, and the angle formed by the component parallel to the substrate on the layer plane High power of pre-tilt, 3 to 5 degrees in (1), 0 to 3 degrees in (2), (3)
- the liquid crystal device is provided, which is a from at 9 degrees 9 0 degrees.
- the liquid crystal is either a ferroelectric liquid crystal or an antiferroelectric liquid crystal.
- a ferroelectric liquid crystal having a layer structure is sandwiched between a pair of parallel substrates having electrodes, and pixels are formed between the electrodes.
- the inclination angle of the substrate interface layer which is the angle between the perpendicular to one of the substrates and the layer plane, is (1) 0 to 3 degrees, (2) 4 to 7 degrees, and (3) ) C director, which is between 8 degrees and 20 degrees and is the angle between the c director and the component parallel to the substrate on the layer plane.
- the pretilt is (1)
- FIG. 1A is a perspective view of a first model of the layer structure and molecular arrangement in the liquid crystal device of the present invention.
- FIG. 1B is a perspective view showing a movable range of one liquid crystal molecule.
- FIG. 1C is a view of the conical bottom surface of FIG. 1B as viewed from a direction perpendicular to the layer plane.
- FIG. 1D is an arrow view of the layer structure of the first model shown in FIG.
- FIG. 1E shows the layer structure of the layer adjacent to the layer shown in FIG. 1D when the liquid crystal is an antiferroelectric liquid crystal.
- FIG. IF is a cross-sectional view of the first model shown in FIG. 1A, taken along a plane perpendicular to both substrates.
- FIG. 1G is an explanatory diagram illustrating various forms of a layer structure having at least two types of angles in an actual liquid crystal device.
- FIG. 1H is an explanatory diagram illustrating a pixel in a liquid crystal device using a scanning electrode and a signal electrode.
- FIG. 2A is a model diagram of a second model of the layer structure and molecular arrangement in the liquid crystal device of the present invention using a ferroelectric liquid crystal, and shows a part of the liquid crystal device when the c director is viewed from the layer plane side.
- FIG. 2B is a sectional view taken along line BB of FIG. 2A.
- FIG. 4 is a diagram showing distributions of y-axis component, and y-axis component in the y-axis direction, with a horizontal axis representing a distance between both substrates as 1;
- FIG. 3E is a cross-sectional view of the layer structure in the liquid crystal device of the present invention estimated from FIG. 3A.
- FIG. 4A to 4D show a second example of the configuration of the layer structure and the molecular arrangement in the liquid crystal device of the present invention, in which the a-axis component of the a director, the X-axis component of the c director,
- FIG. 4 is a diagram showing distributions of a y-axis component and a z-axis component in a direction of the y-axis, in which a horizontal axis represents a distance between both substrates as 1;
- FIG. 4E is a cross-sectional view of the layer structure in the liquid crystal device of the present invention estimated from FIG. 4A.
- FIG. 9 is a diagram showing distributions of the x-axis component, the y-axis component, and the z-axis component of the c director in the y-axis direction, with the horizontal axis representing the distance between the two substrates as 1;
- FIG. 5E is a cross-sectional view of the layer structure in the liquid crystal device of the present invention estimated from FIG. 5A.
- FIGS. 6A to 6D show a fourth example of the configuration of the layer structure and molecular arrangement in the liquid crystal device of the present invention, in which the y-axis component of the a director, the X-axis component of the c director,
- FIG. 4 is a diagram showing distributions of a y-axis component and a z-axis component in a direction of the y-axis, in which a horizontal axis represents a distance between both substrates as 1;
- FIG. 6E is a cross-sectional view of the layer structure in the liquid crystal device of the present invention estimated from FIG. 6A.
- FIGS. 7A to 7D show a fourth example of the configuration of the layer structure and the molecular arrangement in the liquid crystal device not included in the present invention, in which the y-axis component of the a director and the c-director are shown.
- FIG. 7 is a diagram showing distributions of an X-axis component, a y-axis component, and a z-axis component in the y-axis direction, with the horizontal axis representing the distance between both substrates as 1;
- FIG. 7E is a cross-sectional view of the layer structure in the liquid crystal device estimated from FIG. 7A.
- FIG. 8 is a drawing showing the relationship between the polarization vector p and other vector parameters in the ferroelectric liquid crystal.
- FIG. 9A is a drawing showing an evaluation experiment waveform (white writing waveform) in the example of the present invention.
- FIG. 9B is a drawing showing transmittance after application of an evaluation experiment waveform (white writing waveform) in the example of the present invention.
- FIG. 1OA is a drawing showing an evaluation experiment waveform (black writing waveform) in the example of the present invention.
- FIG. 10B is a drawing showing transmittance after application of an evaluation experiment waveform (black writing waveform) in the example of the present invention.
- FIG. 11 is a graph showing the results of the half-stable evaluation in the example of the present invention.
- FIG. 1A to 1F are model diagrams of the molecular arrangement (c director) and the layer structure of ferroelectric liquid crystals and antiferroelectric liquid crystals.
- c director molecular arrangement
- FIG. 1A in the liquid crystal device of the present invention, a liquid crystal molecule 1 is sandwiched between a pair of parallel substrates 21 and 22, and the position of the center of gravity of the liquid crystal molecule 1 moves from the lower substrate to the upper substrate. Thus, the layer structure 3 is formed.
- Reference numeral 23 in FIG. 1A indicates a symmetry plane equidistant from both substrates 21 and 22.
- some or all of the layer structures 3 in the same pixel are asymmetric with respect to the symmetry plane 23 which is equidistant from both substrates 21 and 22. Has become.
- the X-axis and the z-axis are in a plane parallel to the substrates 21 and 22 and the y-axis is in the direction perpendicular to the substrates 21 and 22. I will explain.
- the movable range of one liquid crystal molecule 1 can be modeled as a cone as shown in FIG. 1B, and the bottom of the cone is located at the same position as the layer plane 31.
- FIG. 1C is a diagram of the bottom surface of the cone of FIG. 1B viewed from a direction perpendicular to the layer plane 31.
- the unit vector projected on the layer plane (cone bottom surface) 31 of the liquid crystal molecule 1 is called the c director 4.
- the angle 6 between the c director 14 and the component 8 parallel to the substrates 21 and 22 on the layer plane 31 will be referred to herein as a c director pretilt 6. .
- Figure 1D shows the layer structure 3 of the first model shown in Figure 1A in the direction of arrow A. Seen from the direction (z-axis direction). The bottom of the cone in the layer plane 31 in FIG. 1D looks elliptical because the layer plane 31 is inclined in the Cieblonn-type layer structure. Although only one layer is depicted in FIG. 1D, a layer structure 3 similar to the layer structure 3 shown in FIG. 1D is continuous in the ferroelectric liquid crystal. The ferroelectric liquid crystal has a structure in which the directions of the c directors 14 are all aligned in the same direction.
- the antiferroelectric liquid crystal shows the same layer structure 3, but the layer structure 3 of the antiferroelectric liquid crystal has an odd-numbered layer and an even-numbered layer, and the direction of the c director 4 is alternately changed. It has a structure that is aligned. Therefore, assuming that the layer structure 3 shown in FIG. 1D is the odd-numbered layer structure of the antiferroelectric liquid crystal, the even-numbered layer structure 3 of the antiferroelectric liquid crystal becomes as shown in FIG. 1E. Become.
- FIG. 1F is a cross-sectional view of the first model shown in FIG. 1A in a plane perpendicular to the X axis.
- reference numeral 5 indicates an angle formed by the layer plane 31 with the perpendicular line 20 on one of the substrates 21 and 22.
- this angle 5 is defined as It is referred to as layer inclination angle 5.
- FIGS. 2A and 2B a second model according to the present invention will be described with reference to FIGS. 2A and 2B.
- the same reference numerals are used for the same components and villages as those in the first model.
- Figure 2A is a model diagram of the layer plane 3 1 with the c-director 4, which is the unit vector projected on the layer plane 3 1 of the liquid crystal molecules 1 of the ferroelectric liquid crystal, viewed from the z-axis side. A part of the device is shown in a partially enlarged manner.
- FIG. 2B is a cross-sectional view taken along line BB of FIG. 2A.
- a liquid crystal molecule 1 of a ferroelectric liquid crystal is sandwiched between a pair of parallel substrates 21 and 22.
- the center of gravity should be aligned from the lower board to the upper board
- a layer structure 3 is formed.
- Reference numeral 23 denotes a symmetry plane equidistant from both substrates 21 and 22.
- part or all of the layer structure 3 in the same pixel is symmetric with respect to the symmetry plane 23 equidistant from both substrates 21 and 22. It is shaped.
- a parameter representing the structural arrangement of the layer structure 3 is a layer normal vector located vertically from the layer plane 31.
- the present invention will be described in detail using the director 7 and the c director 4 which is a parameter representing the molecular arrangement.
- the layer structure having a substrate interface layer inclination angle of 5 with the layer plane 31 in FIG. 3 and at least two kinds of angles has various forms in the inclination direction.
- the ATR method (Attenuated Total Reflection: Attenuated Total Reflection method), which is a means for confirming the a director 7 and the c director 1 in an actual liquid crystal cell, and the method of determining the layer structure and molecular arrangement are described. .
- the ATR method is powerful as detailed in the paper by Sambles et al. (Samb 1 es; Liquid Crystals, 1993, Vol. 13, No. 1, 1-11, etc.), and the outline is as follows. .
- a film that absorbs as an electrode (usually gold or silver with a thickness of 30 to 5 O nm)
- a liquid crystal cell equipped with a P-polarized light (there is an electric field vector in the entrance plane) is made into this liquid crystal cell. Most of the light is reflected by the metal film up to a certain incident angle, but within the range exceeding the total reflection angle specified by the dielectric tensor, a phenomenon that causes the transfer of light energy to and from the metal film is induced. It is known to exhibit a unique reflection intensity profile determined by the alignment film and the liquid crystal.
- This reflection intensity profile is particularly sensitive to the properties of the material immediately below the metal film (the layer structure and molecular arrangement of the liquid crystal), and the relationship between the absolute value of the reflection intensity and the incident angle that gives the intensity (hereinafter referred to as the ATR curve). From), the layer structure and molecular arrangement of the liquid crystal can be discussed in detail and sufficiently.
- the c-director and a-director are used to describe the layer structure and molecular arrangement.
- the free energy density F of the liquid crystal considering the elastic deformation of the c director and the a director is given by the following equation (Nakagawa; Liquid Crystals 1990, Vol. 8, No. 5, 651-675). ).
- dA is the layer thickness in the smectic A phase
- dc * is the layer thickness in the smectic C * phase
- ⁇ is the unit vector in the layer normal direction
- p I is a polarization vector, and is orthogonal to a and c vectors as shown in Fig. 8.
- ⁇ 0 is the lower substrate side of c director director 6 shown in Fig. 1C
- D d is Similarly, the upper side of the c director pretilt 6 is the substrate side.
- Equations (1), (2), and (3) are calculated by numerical calculation, and the ATR curve for this layer structure and molecular configuration is calculated.
- the elastic constants, coefficients, and parameters are set to match the ATR curves obtained by experiments. By fitting one or the like, it is possible to confirm an energetically stable layer structure and molecular arrangement in the liquid crystal cell.
- the energy level is calculated based on the formulas (1), (2), and (3) using the c-director and the a-director of the layer structure and molecular configuration obtained by fitting the ATR curve. This can be obtained.
- an IT0 electrode is provided on a pair of glass substrates, An alignment film is applied on each electrode.
- the alignment film material there is an optimum value for each alignment film material with respect to the film forming conditions such as the film thickness, and therefore, in the first embodiment, P01iX08 made by Hext Co. is used as the alignment film. Describe the case when used. Two types of chiral materials with different pitches are mixed in 0.5% each in Poly X 08, and rubbing treatment is performed after forming a film of about 6 nm thickness on the IT 0 electrode on the glass substrate. I do. At this time, the direction of the rubbing process should be almost the same as the z-axis shown in Figs. 1A, 1D, IE, and IF.
- the pair of substrates are opposed to each other with the alignment film surfaces facing each other, the periphery thereof is fixed with a resin, and baked under pressure.
- a ferroelectric liquid crystal material Feixix-T2552 manufactured by Hexst Co., Ltd. is injected, the injection port is sealed with a resin, and then an isotropic treatment is performed to obtain a liquid crystal cell.
- the phase sequence of F e 1 i X — ⁇ 25 2 is as follows.
- FIGS. 3A to 3D and FIGS. 5A to 5D show ay, which is the y-axis component of the a-director, and x-, c-, y-, and cy-components of the c-director.
- the respective distributions in the y-axis direction are shown by normalizing the distance between the two substrates to 1 on the horizontal axis.
- the substrate interface layer inclination angle 5 can be estimated, and the shape of the layer structure can be estimated from the locus of the y-axis component ay of the a director.
- the angle of the c director in the cell is T an- 1 (ay), which can be calculated almost everywhere.
- the inclination angle 5 of the substrate interface layer obtained from FIG. 3A was 4 degrees.
- This layer structure with a substrate interface layer inclination angle 5 of 4 degrees is estimated as shown in Fig. 3E.
- the c director pretilt 6 at the substrate interface can be calculated from the values of the vertical axis at 0.0 and 1.0 of the X axis component c x of the c director of FIG. 3B.
- the c director pretilt 6 obtained from Fig. 3B was 1 degree.
- the sign of the X-axis component cx of the c director is positive and constant in Fig. 3B, but even if the X-axis component cX of the c director is negative and constant, the energy calculated from equation (1) is equivalent. It was.
- the substrate interface layer inclination angle 5 obtained from FIGS. 5A and 5B was 10 degrees
- the c director pretilt 6 at the substrate interface was 10 degrees.
- the y-axis component ay of the a director has a symmetric axis at an equal distance from both substrates, that is, a horizontal axis of 0.5
- an asymmetric distribution from 0.0 to 1.0 is obtained. It changes continuously while taking. This indicates that the layer structure is asymmetric with respect to a plane of symmetry equidistant from both substrates.
- the layer structure where the substrate interface layer inclination angle 5 is 10 degrees is estimated as shown in FIG. 5E.
- the sign of the X-axis component c X of the c director is negative and constant.
- the energy is equivalent even when the X-axis component cx of the c director is positive and constant.
- the force mixed into the alignment film of the liquid crystal cell prepared in the first embodiment By adjusting the concentration, type, number, and properties of the enamel material, the properties that indicate the layer structure and molecular arrangement in the same pixel as shown in Figs. 4A to 4D and the characteristics shown in Figs. 6A to 6D We could confirm the characteristics showing the layer structure and molecular arrangement, and the state in which they were mixed.
- FIGS. 4A to 4D and FIGS. 6A to 6D are also examples of characteristics showing the same layer structure and molecular configuration as those in FIGS. 3A to 3D and FIGS. 5A to 5D.
- 4A to 4D and 6A to 6D show the y-axis component ay of the a-director, the x-axis component cx, the y-axis component cy, and the z-axis component cz of the c director.
- the distribution in the y-axis direction is shown on the horizontal axis, with the spacing between both substrates normalized to 1.
- the substrate interface layer inclination angle 5 can be calculated as 1 degree, and the c-director-pretilt 6 at the substrate interface can be calculated as 3 degrees.
- the layer structure in which the substrate interface layer inclination angle 5 is 3 degrees is estimated as shown in FIG. 4E.
- the sign of the X-axis component c X of the c director in FIG. 4B is positive and constant.
- the energy is equivalent when the X-axis component cX of the c director is negative.
- the inclination angle 5 of the substrate interface layer is 15 degrees
- the angle of the c director-pretilt 6 at the substrate interface is 15 degrees from the substrate plane.
- the configuration of the liquid crystal cell obtained from these characteristics is not as remarkable as the examples in Figs. 5A and 5B, but the y-axis component ay of the a director is 0.5 If is taken as the axis of symmetry, it changes continuously with an asymmetric distribution from 0.0 to 1.0.
- the layer structure with the substrate interface layer inclination angle 5 of 15 degrees is estimated as shown in FIG. 6E.
- the sign of the X-axis component c X of the c director is negative and constant.
- the energy is equivalent even when the X-axis component cX of the c director is positive.
- the Polix 08 manufactured by Hexst Co., Ltd. used in the first embodiment was used as an alignment film without mixing a chiral material, and other conditions were the same as in the first embodiment.
- a liquid crystal cell according to a second embodiment was prepared.
- the c director pretilt 6 at one substrate interface can be calculated from the value of the vertical axis on the horizontal axis 0.0 of the X-axis component c X of the c director in FIG. 3B.
- the c-director pretilt 6 at the other substrate interface can be calculated from the value of the vertical axis at the horizontal axis of 1.0.
- the values of the vertical axis at the horizontal axis of 0.0 and 1.0 are the same, so that the c-director pretilt 6 at both substrate interfaces was calculated as 1 degree.
- the sign of the x-axis component c x of the c director is positive and constant in FIG. 3B, and thus it was found that the c directors at the substrate interface are arranged in plane symmetry.
- the first embodiment is an embodiment showing that it has at least two types of layer structures, but the second embodiment is an embodiment showing that the c director is symmetric. Yes, as described above, there are multiple layers in the same pixel. Therefore, in Example 2, the same layer structure as in Example 1 exists, and the layer structure estimated from FIGS. 3A to 3D is as shown in FIG. 3E.
- the alignment film used was a Polix 08 made by Hexst on one electrode of the substrate, and a helix on the other electrode. After forming a film of Po1ix004 manufactured by Co., Ltd. and performing rubbing treatment, assembly was performed in the same procedure as in the second embodiment, and a similar experiment was performed. As a result, from the ATR curve, characteristics indicating the configuration of the layer structure and the molecular arrangement as shown in FIGS. 4A to 4D could be confirmed.
- the c director pretilt 6 at both substrate interfaces was calculated to be 3 degrees.
- the sign of the X-axis component c X of the c director is positive and constant, and thus it is found that the c directors at the substrate interface are arranged in plane symmetry.
- the layer structure estimated from FIGS. 4A to 4D is as shown in FIG. 4E.
- the liquid crystal cell of the fourth embodiment was formed using the same material as the second and third embodiments except that the alignment film used for one substrate of the second embodiment was changed.
- P01iX08 made by Hexst Co. was formed on the electrode of one substrate and then rubbed, and an LB film was formed on the electrode of the other substrate.
- the characteristics indicating the configuration of the layer structure and the molecular arrangement as shown in FIGS. 5A to 5D could be confirmed from the ATR curves.
- the c-director pretilt 6 at the interface between both substrates was 10 degrees.
- the sign of the x-axis component c x of the c director was negative and constant, and it was found that the c directors at the substrate interface were arranged in plane symmetry.
- the layer structure estimated from Figs. 5A to 5D is as shown in Fig. 5E.
- a liquid crystal cell was prepared in the same manner as in the first embodiment, and an alternating-current electric field treatment with a lower voltage value than that in the first embodiment was performed to prepare a comparative example.
- the liquid crystal cell of this comparative example was measured by the ATR method, the characteristics indicating all the layer structures and molecular arrangements within the same pixel were as shown in Figs. 7A to 7D. As shown.
- FIGS. 7A to 7D are examples of characteristics showing the layer structure and the molecular arrangement that are not suitable for the present invention. From FIGS. 7A and 7B, the substrate interface layer inclination angle 5 is 4 degrees, and It was found that the c-director pretilt at the interface was 10 degrees. The layer structure in which the substrate interface layer inclination angle 5 is 4 degrees is estimated as shown in FIG. 7E.
- the sign of the X-axis component c X of the c director changes from positive to negative between the pair of substrates, so-called splay alignment.
- the value of c director pretilt 6 at the interface of one substrate is different from the value of c director pretilt 6 at the interface of the other substrate, and they are not arranged in plane symmetry.
- the splay orientation is out of the range of the configuration as shown in the present invention, and it becomes impossible to obtain a sufficient contrast.
- the sign of the X-axis component cX of the c director has both positive and negative signs between a pair of substrates.
- the substrate interface layer inclination angle 5 is 0 to 3 degrees (when 0 degree, there is a layer plane perpendicular to the substrate.)
- the c-director 4, which is a projection vector to the substrate, and the c-director pretilt 6, which is a component parallel to the substrate on the layer plane, are 3 to 5 degrees, or the substrate interface layer inclination angle 5 is 4 to 7 degrees, and c director pretilt 6 from 0 degrees (that is, c director is parallel to the substrate) to 3 degrees, or substrate interface layer inclination angle 5 from 8 degrees to 2 degrees It is calculated that 0 degrees and the c-director pre-tilt 6 is 9 degrees to 90 degrees.
- the layer structure and the molecular arrangement as shown in FIGS. 3A to 3D have a lower threshold voltage than the layer structure and the molecular arrangement as shown in FIGS. 4A to 4D. .
- the threshold voltage of the layer structure and the molecular arrangement was lower than that of the layer structure and the molecular arrangement as shown in FIGS.
- each layer structure is stable in terms of energy, and the liquid crystal cell prepared in the first embodiment has a plurality of layer structures in the same pixel, a liquid crystal device that is strong in stress can be obtained.
- selective partial driving was enabled by the difference in threshold voltage, and gradation display was obtained.
- Comparative example (Figs. 7A to 7E) 0.6 1.0 From Table 1, the liquid crystal cell having the layer structure shown in Figs. 7A to 7D of the comparative example shows the amount of transmitted light (TW) immediately after application of the white writing waveform and the amount of light transmitted after 1 minute. In contrast to the difference in transmitted light (T mW), the layer structure shown in FIGS. 3A to 3D, FIGS. 4A to 4D, and FIGS. It was also confirmed that there was no change in the existing liquid crystal cell. This means that when driving This indicates that there is no difference in contrast between the memory and the memory.
- FIG. 11 shows the results of measuring the change over time in the amount of transmitted light after applying the white writing waveform and applying the black writing waveform.
- the amount of transmitted light on the vertical axis is normalized using the amount of transmitted light (TW) immediately after application of the white writing waveform and the amount of transmitted light (TB) immediately after application of the black writing waveform, and the horizontal axis shows the number of days left unattended.
- Open circles (101) indicate changes in the amount of transmitted light when applying a white writing waveform to the liquid crystal cell of the present invention shown in FIGS. 3A to 3D.
- the open triangles (102) indicate changes in the amount of transmitted light when the white writing waveform was applied to the liquid crystal cells of the comparative examples shown in FIGS. 7A to 7D.
- a black circle (104) indicates a change in the amount of transmitted light when a black writing waveform is applied to the liquid crystal cell of the present invention shown in FIGS.
- the black triangles (103) indicate changes in the amount of transmitted light when the black writing waveform is applied to the liquid crystal cells of the comparative examples shown in FIGS. 7A to 7D.
- bistability was exhibited even after the white writing waveform application (101) 7, whereas the liquid crystal cell of the comparative example ( In 102), it was confirmed that the black side gradually changed to a more stable half-stable state.
- Similar half-stable evaluation experiments were performed on the liquid crystal cells having the configurations shown in Figs. 4A to 4D and Figs. 5A to 5D, and the results were the same as those of the liquid crystal cells shown in Figs. 3A to 3D.
- a longer-term bistable state could be obtained as compared with the liquid crystal cell of the comparative example.
- the layer structure of the present invention that is, in order to form the substrate interface layer inclination angle and the c director-pretilt within the angle range of the present invention
- various other than the present embodiment are required.
- Method is available. For example, a ferroelectric liquid crystal is injected into a rubbed liquid crystal cell after a thin insulating film with a coarse particle is formed on the IT0 electrode using a sputter, and then an alignment film that does not mix with a force-iral material is applied and rubbed. Even when an AC electric field is applied, the multiple layer structure is stable due to the distribution of particles in the insulating film.
- the film could be formed to include the layer structure as described above.
- a metal thin film of about 10 nm was provided on the ITO electrode, and an orientation film was applied and rubbed.
- a plurality of layer structures including the above-described layer structure that is stable in terms of energy can be formed by performing an AC electric field treatment.
- the cell gap itself has a structure having a distribution, or the cell gap itself is formed in the electrode film. It can also be achieved by means such as creating a resistance distribution.
- the layer structure can also be controlled without applying an AC electric field treatment or by using the chirality of the alignment film.For example, when a side chain has a plurality of strongly conductive liquid crystalline functional groups Even if the liquid crystal polymer is used as the alignment film, the layer structure as described above can be formed.
- the liquid crystal cells having the respective configurations shown in FIGS. 5A to 5D are formed from FIGS. 3A to 3D by changing the type of one alignment film material. Even if a film material is used, the liquid crystal cell having the configuration shown in FIGS. 3A to 3D, FIGS. 4A to 4D, and FIGS. 5A to 5D can be obtained by changing the film forming conditions. It could be confirmed. In addition, it was confirmed that there was a condition for obtaining a similar configuration in other combinations of alignment film materials. Industrial applicability
- the structure of the liquid crystal device having a layer structure and a molecular arrangement having at least two types of tilt angles of the substrate interface layer shown in the present invention is obviously excellent in rigidity, but due to the special layer structure.
- the switching region within the pixel can be controlled, and the anti-ferroelectric liquid crystal
- the region of the electric field induced phase transition can be controlled. For this reason, analog gradation display using a threshold voltage with high stress resistance is possible.
- the configuration of the liquid crystal device having the layer structure and the molecular arrangement in which the c-director and the pretilt are symmetrically arranged on both substrates as shown in the present invention is the layer structure and the molecule during the white writing and the black writing.
- the arrangement is energy-equivalent, and it has a stable molecular arrangement that can obtain almost the same amount of transmitted light between when driving and when in memory. There is no contrast difference. Therefore, it is very effective for obtaining a good liquid crystal electro-optical device having high long-term reliability and no flicker during driving.
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- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Mathematical Physics (AREA)
- Liquid Crystal (AREA)
- Liquid Crystal Substances (AREA)
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE69625889T DE69625889D1 (de) | 1995-07-03 | 1996-07-02 | Flüssigkristallvorrichtung |
US08/793,462 US5764328A (en) | 1995-07-03 | 1996-07-02 | Liquid crystal device with plural ferroelectric or antiferroelectric layer tilt angles per pixel |
EP96921147A EP0784225B1 (en) | 1995-07-03 | 1996-07-02 | Liquid crystal device |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16744595 | 1995-07-03 | ||
JP7/167445 | 1995-07-03 | ||
JP7/202969 | 1995-08-09 | ||
JP20296995 | 1995-08-09 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1997002510A1 true WO1997002510A1 (fr) | 1997-01-23 |
Family
ID=26491486
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP1996/001834 WO1997002510A1 (fr) | 1995-07-03 | 1996-07-02 | Dispositif a cristal liquide |
Country Status (4)
Country | Link |
---|---|
US (1) | US5764328A (ja) |
EP (1) | EP0784225B1 (ja) |
DE (1) | DE69625889D1 (ja) |
WO (1) | WO1997002510A1 (ja) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008102288A (ja) * | 2006-10-18 | 2008-05-01 | Toshiba Matsushita Display Technology Co Ltd | 液晶表示装置 |
US8065018B2 (en) | 2005-09-12 | 2011-11-22 | Medtronic, Inc. | System and method for unscheduled wireless communication with a medical device |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3144329B2 (ja) * | 1996-12-25 | 2001-03-12 | 日本電気株式会社 | 液晶表示素子 |
JPH10333152A (ja) * | 1997-03-31 | 1998-12-18 | Denso Corp | 液晶セル |
US6175401B1 (en) * | 1997-05-02 | 2001-01-16 | Casio Computer Co., Ltd. | Liquid crystal display device having a liquid crystal layer which contains liquid crystal molecules in a plurality of alignment state and method for driving the same |
JP2006317656A (ja) * | 2005-05-12 | 2006-11-24 | Dainippon Printing Co Ltd | 異方性光学素子 |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04240820A (ja) * | 1991-01-25 | 1992-08-28 | Sharp Corp | 液晶表示装置 |
JPH04267223A (ja) * | 1991-02-22 | 1992-09-22 | Sharp Corp | 強誘電性液晶素子 |
JPH04316019A (ja) * | 1991-04-15 | 1992-11-06 | Canon Inc | 強誘電性液晶素子 |
JPH07128690A (ja) * | 1992-10-24 | 1995-05-19 | Sony Corp | 液晶素子 |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL8901481A (nl) * | 1989-06-12 | 1991-01-02 | Philips Nv | Passieve ferro-elektrisch vloeibaar kristal weergeefinrichting en werkwijze ter vervaardiging daarvan. |
ATE180580T1 (de) * | 1990-03-02 | 1999-06-15 | Canon Kk | Flüssigkristallelement und flüssigkristallvorrichtung, die dieses element verwendet |
JP2802685B2 (ja) * | 1991-01-08 | 1998-09-24 | キヤノン株式会社 | 強誘電性液晶装置 |
DE69320073T2 (de) * | 1992-01-24 | 1999-02-25 | Canon K.K., Tokio/Tokyo | Verfahren zur Behandlung einer chiralen smektischen Flüssigkristallvorrichtung |
JPH05273554A (ja) * | 1992-01-29 | 1993-10-22 | Canon Inc | 強誘電性液晶素子 |
JPH06265907A (ja) * | 1993-03-16 | 1994-09-22 | Citizen Watch Co Ltd | 強誘電性液晶素子 |
JPH06337442A (ja) * | 1993-03-31 | 1994-12-06 | Citizen Watch Co Ltd | メモリー性を有する液晶パネル |
-
1996
- 1996-07-02 WO PCT/JP1996/001834 patent/WO1997002510A1/ja active IP Right Grant
- 1996-07-02 DE DE69625889T patent/DE69625889D1/de not_active Expired - Lifetime
- 1996-07-02 US US08/793,462 patent/US5764328A/en not_active Expired - Fee Related
- 1996-07-02 EP EP96921147A patent/EP0784225B1/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04240820A (ja) * | 1991-01-25 | 1992-08-28 | Sharp Corp | 液晶表示装置 |
JPH04267223A (ja) * | 1991-02-22 | 1992-09-22 | Sharp Corp | 強誘電性液晶素子 |
JPH04316019A (ja) * | 1991-04-15 | 1992-11-06 | Canon Inc | 強誘電性液晶素子 |
JPH07128690A (ja) * | 1992-10-24 | 1995-05-19 | Sony Corp | 液晶素子 |
Non-Patent Citations (1)
Title |
---|
See also references of EP0784225A4 * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8065018B2 (en) | 2005-09-12 | 2011-11-22 | Medtronic, Inc. | System and method for unscheduled wireless communication with a medical device |
US8280521B2 (en) | 2005-09-12 | 2012-10-02 | Medtronic, Inc. | System and method for unscheduled wireless communication with a medical device |
JP2008102288A (ja) * | 2006-10-18 | 2008-05-01 | Toshiba Matsushita Display Technology Co Ltd | 液晶表示装置 |
Also Published As
Publication number | Publication date |
---|---|
EP0784225A1 (en) | 1997-07-16 |
EP0784225B1 (en) | 2003-01-22 |
US5764328A (en) | 1998-06-09 |
DE69625889D1 (de) | 2003-02-27 |
EP0784225A4 (en) | 2000-03-22 |
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