text:
|Publication number
|Publication type
|Application number
|Publication date
|2 Jun 1992
|Filing date
|26 Jun 1990
|Priority date
|30 Jun 1989
|Fee status
|Also published as
|Publication number
|Masahiro Terada, Masataka Yamashita, Shosei Mori, Shinichi Nakamura, Kenji Shinjo, Kazuharu Katagiri
|Original Assignee
|Canon Kabushiki Kaisha
|Export Citation
|BiBTeX, EndNote, RefMan
|Patent Citations (11), Non-Patent Citations (4), Referenced by (16), Classifications (18), Legal Events (7)
|External Links: USPTO, USPTO Assignment, Espacenet
|(V.sub.A -V.sub.B)/(V.sub.A +V.sub.B)|>0.1
|P.sub.S |≦5+0.25(T.sub.CA -T) [nC/cm.sup.2 ]
|(V.sub.A -V.sub.B)/(V.sub.A +V.sub.B)|>0.1
|P.sub.S |≦5+0.25(T.sub.CA -T) [nC/cm.sup.2 ]
|(V.sub.A -V.sub.B)/(V.sub.A +V.sub.B)|>0.1
|P.sub.S |≦5+0.25(T.sub.CA -T) [nC/cm.sup.2 ]
|(V.sub.A -V.sub.B)/(V.sub.A +V.sub.B)|>0.1
|(V.sub.A -V.sub.B)/(V.sub.A +V.sub.B)|>0.1
|(V.sub.A -V.sub.B)/(V.sub.A +V.sub.B)|>0.1
|(V.sub.A -V.sub.B)/(V.sub.A +V.sub.B)|>0.1
|(V.sub.A -V.sub.B)/(V.sub.A +V.sub.B)|>0.1
The present invention relates to a liquid crystal display apparatus using a ferroelectric liquid crystal composition, particularly a liquid crystal apparatus which can be driven at a particular duty ratio having a high frequency.
Hitherto, liquid crystal devices have been used as an electro-optical device in various fields. Most liquid crystal devices which have been put into practice use TN (twisted nematic) type liquid crystals, as shown in "Voltage-Dependent Optical Activity of a Twisted Nematic Liquid Crystal" by M. Schadt and W. Helfrich "Applied Physics Letters" Vol. 18, No. 4 (Feb. 15, 1971) pp. 127-128.
These devices are based on the dielectric alignment effect of a liquid crystal and utilize an effect that the average molecular axis direction is directed to a specific direction in response to an applied electric field because of the dielectric anisotropy of liquid crystal molecules. It is said that the limit of response speed is in the order of milli-seconds, which is too slow for many uses. On the other hand, a simple matrix system of driving is most promising for application to a large-area flat display in view of cost, productivity, etc., in combination. In the simple matrix system, an electrode arrangement wherein scanning electrodes and signal or data electrodes are arranged in a matrix, and for driving, a multiplex driving scheme is adopted wherein an address signal is sequentially, periodically and selectively applied to the scanning electrodes and prescribed data signals are selectively applied in parallel to the signal electrodes in synchronism with the address signal.
When the above-mentioned TN-type liquid crystal is used in a device of such a driving system, a certain electric field is applied to regions where a scanning electrode is selected and signal electrodes are not selected or regions where a scanning electrode is not selected and a signal electrode is selected (which regions are so called "half-selected points"). If the difference between a voltage applied to the selected points and a voltage applied to the half-selected points is sufficiently large, and a voltage threshold level required for allowing liquid crystal molecules to be aligned or oriented perpendicular to an electric field is set to a value therebetween, display devices normally operate. However, in fact, as the number (N) of scanning lines increases, a time (duty ratio) during which an effective electric field is applied to one selected point when a whole image area (corresponding to one frame) is scanned decreases with a ratio of 1/N. Accordingly, the larger the number of scanning lines are, the smaller is the voltage difference of an effective value applied to a selected point and non-selected points when scanning is repeatedly effected. This leads to unavoidable drawbacks of lowering of image contrast or occurrence of interference or crosstalk. These phenomena are regarded as essentially unavoidable problems appearing when a liquid crystal having no bistability (i.e. liquid crystal molecules are horizontally oriented with respect to the electrode surface as a stable state and is vertically oriented with respect to the electrode surface only when an electric field is effectively applied) is driven (i.e. repeatedly scanned) by making use of a time storage effect. To overcome these drawbacks, the voltage-averaging method, the two-frequency driving method, the multiple matrix method, etc. have been already proposed. However, none of the above-mentioned methods is sufficient to overcome the above-mentioned drawbacks. As a result, it is the present state that the development of large image area or high packaging density in respect to display elements is delayed because it is difficult to sufficiently increase the number of scanning lines (about 400 lines being considered as the upper limit).
To overcome drawbacks with such prior art liquid crystal devices, the use of liquid crystal devices having bistability has been proposed by Clark and Lagerwall (e.g. Japanese Laid-Open Patent Appln. No. 56-107216, U.S. Pat. No. 4,367,924, etc.). In this instance, as the liquid crystals having bistability, ferroelectric liquid crystals having chiral smectic C-phase (SmC*) or H-phase (SmH*) are generally used. These liquid crystals have bistable states of first and second stable states with respect to an electric field applied thereto. Accordingly, as different from optical modulation devices in which the above-mentioned TN-type liquid crystals are used, the bistable liquid crystal molecules are oriented to first and second optically stable states with respect to one and the other electric field vectors, respectively. Further, this type of liquid crystal has a property (bistability) of assuming either one of the two stable states in response to an applied electric field and retaining the resultant state in the absence of an electric field.
In addition to the above-described characteristic of showing bistability, such a ferroelectric liquid crystal (hereinafter sometimes abbreviated as "FLC") has an excellent property, i.e., a high-speed responsiveness. This is because the spontaneous polarization of the ferroelectric liquid crystal and an applied electric field directly interact with each other to induce transition of orientation states. The resultant response speed is faster than the response speed due to the interaction between dielectric anisotropy and an electric field by 3 to 4 digits.
Thus, a ferroelectric liquid crystal potentially has very excellent characteristics, and by making use of these properties, it is possible to provide essential improvements to many of the above-mentioned problems with the conventional TN-type devices. Particularly, the application to a high-speed optical shutter and a display of a high density and a large picture is expected.
However, a ferroelectric liquid crystal device has a problem that it shows a smaller drive margin on a high temperature side in a temperature range showing chiral smectic C phase than on a low temperature side. More specifically, when a device is driven at a voltage value which has been set so as to effect a drive on a high temperature side (at a constant pulse duration), it becomes difficult to effect an appropriate drive if the liquid crystal temperature is changed to a further higher temperature. Particularly, in case of a multiplex driving for writing in pixels on a selected scanning line depending on given data wherein the pixels on the scanning line are supplied with a voltage for resetting the pixels simultaneously into a black (or white) state and then only a selected pixel is supplied with a voltage for switching the pixel inversely into a white (or black) state, there is encountered a problem that a drive margin represented by the formula |(VA -VB)/(VA +VB)| becomes smaller at a higher temperature side in the chiral smectic region, wherein VA denotes a minimum amplitude (at a given pulse duration) for causing the inverse switching and VB denotes a maximum amplitude (at the given pulse duration) sufficient for holding the resultant state after the resetting, as will be defined in more detail hereinafter.
An object of the present invention is to provide a liquid crystal apparatus showing a good rewriting speed and having a response speed and a drive margin which are sufficient to provide good images even at a high temperature of 50° C. or above.
According to the present invention, there is provided a liquid crystal apparatus, comprising:
a liquid crystal cell comprising a pair of substrates having thereon a first electrode and a second electrode, respectively, disposed opposite to each other, and a chiral smectic liquid crystal showing a first and a second orientation state disposed between the first and second electrodes, and
a drive circuit for applying voltages between the first and second electrodes including voltages |VS | and |VI | which provide voltages VA and VB (VB >VA) satisfying the relationship of:
|(V.sub.A -V.sub.B)/(V.sub.A +V.sub.B)|>0.1
at 40° C., wherein
VA is a minimum peak value of a voltage |VS |+|VI | (at a constant pulse width) capable of inverting the first orientation state of the chiral smectic liquid crystal into the second orientation state when a voltage pulse is applied between the first and second electrodes to cause the first orientation state of the chiral smectic liquid crystal and then the voltage |VS |+|VI | is applied between the first and second electrodes as a combination of a voltage |VS | applied to the first electrode and a voltage -|VI | applied to the second electrode; and
VB is a value of |VS |+|VI | calculated based on a maximum peak value of a voltage |VS |-|VI | (at a constant pulse width) capable of maintaining the first orientation state of the chiral smectic liquid crystal when a voltage pulse is applied between the first and second electrodes to cause the first orientation state and then the voltage |VS |-|VI | is applied between the first and second electrodes as a combination of a voltage |VS | applied to the first electrode and a voltage |VI | applied to the second electrode.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
FIG. 1 is a schematic cross-sectional view of a liquid crystal display device using a ferroelectric liquid crystal.
FIGS. 2 and 3 are schematic perspective views of a device cell embodiment for illustrating the operation principle of a ferroelectric liquid crystal device.
FIG. 4A shows unit driving waveforms used in an embodiment of the present invention; FIG. 4B is time-serial waveforms comprising a succession of such unit waveforms.
FIG. 5 is a plan view of a ferroelectric liquid crystal panel having a matrix electrode structure.
FIG. 6 is an illustration of a display pattern obtained by an actual drive using the time-serial waveforms shown in FIG. 4B.
FIGS. 7, 8 and 12 are graphs showing changes in PS versus (TCA -T) of liquid crystal compositions used in Examples 1, 2 and Comparative Examples 1-4, respectively.
FIG. 9 is a block diagram showing an embodiment of the liquid crystal device according to the invention.
FIG. 10 is a perspective view of another embodiment of the liquid crystal device according to the invention.
FIG. 11 is a waveform diagram showing a set of drive waveforms used in Example 4.
FIG. 1 is a schematic sectional view of a liquid crystal device (cell) comprising a layer of a ferroelectric liquid crystal (chiral smectic liquid crystal) 1 disposed between a pair of glass substrates 2 each having thereon a transparent electrode 3 and an insulating alignment control layer 4. Lead wires 6 are connected to the electrodes so as to apply a driving voltage to the liquid crystal layer 1 from a power supply 7. Outside the substrates 2, a pair of polarizers 8 are disposed so as to modulate incident light I0 from a light source 9 in cooperation with the liquid crystal 1 to provide modulated light I.
Each of two glass substrates 2 is coated with a transparent electrode 3 comprising a film of In2 O3, SnO2 or ITO (indium-tin-oxide) to form an electrode plate. Further thereon, an insulating alignment control layer 4 is formed by rubbing a film of a polymer such as polyimide with gauze or acetate fiber-planted cloth so as to align the liquid crystal molecules in the rubbing direction. Further, it is also possible to compose the alignment control layer of two layers, e.g., by first forming an insulating layer of an inorganic material, such as silicon nitride, silicon nitride containing hydrogen, silicon carbide, silicon carbide containing hydrogen, silicon oxide, boron nitride, boron nitride containing hydrogen, cerium oxide, aluminum oxide, zirconium oxide, titanium oxide, or magnesium fluoride, and forming thereon an alignment control layer of an organic insulating material, such as polyvinyl alcohol, polyimide, polyamide-imide, polyester-imide, polyparaxylylene, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, polyamide, polystyrene, cellulose resin, melamine resin, urea resin, acrylic resin, or photoresist resin. Alternatively, it is also possible to use a single layer of inorganic insulating alignment control layer or organic insulating alignment control layer. An inorganic insulating alignment control layer may be formed by vapor deposition, while an organic insulating alignment control layer may be formed by applying a solution of an organic insulating material or a precursor thereof in a concentration of 0.1 to 20 wt. %, preferably 0.2-10 wt. %, by spinner coating, dip coating, screen printing, spray coating or roller coating, followed by curing or hardening under prescribed hardening condition (e.g., by heating). The insulating alignment control layer may have a thickness of ordinarily 30 Å-1 micron, preferably 30-3000 Å, further preferably 50-1000 Å. The two glass substrates 2 with transparent electrodes 3 (which may be inclusively referred to herein as "electrode plates") and further with insulating alignment control layers 4 thereof are held to have a prescribed (but arbitrary) gap with a spacer 5. For example, such a cell structure with a prescribed gap may be formed by sandwiching spacers of silica beads or alumina beads having a prescribed diameter with two glass plates, and then sealing the periphery thereof with, e.g., an epoxy adhesive. Alternatively, a polymer film or glass fiber may also be used as a spacer. Between the two glass plates, a ferroelectric liquid crystal is sealed up to provide a ferroelectric liquid crystal layer 1 in a thickness of generally 0.5 to 20 microns, preferably 1 to 5 microns.
The transparent electrodes 3 are connected to the external power supply 7 through the lead wires 6. Further, outside the glass substrates 2, polarizers 8 are applied. The device shown in FIG. 1 is of a transmission type and is provided with a light source 9.
FIG. 2 is a schematic illustration of a ferroelectric liquid crystal cell (device) for explaining operation thereof. Reference numerals 21a and 21b denote substrates (glass plates) on which a transparent electrode of, e.g., In2 O3, SnO2, ITO (indium-tin-oxide), etc., and an above-mentioned alignment control layer subjected to a uniaxial aligning treatment are disposed, respectively, so that the alignment directions applied to the substrates are parallel to each other. A liquid crystal of an SmC*-phase (chiral smectic C phase) in which liquid crystal molecular layers 22 are aligned perpendicular to surfaces of the glass plates is hermetically disposed therebetween. Full lines 23 show liquid crystal molecules. Each liquid crystal molecule 23 has a dipole moment (P⊥) 24 in a direction perpendicular to the axis thereof. The liquid crystal molecules 23 continuously form a helical structure in the direction of extension of the substrates. When a voltage higher than a certain threshold level is applied between electrodes formed on the substrates 21a and 21b, a helical structure of the liquid crystal molecule 23 is unwound or released to change the alignment direction of respective liquid crystal molecules 23 so that the dipole moments (P⊥) 24 are all directed in the direction of the electric field. The liquid crystal molecules 23 have an elongated shape and show refractive anisotropy between the long axis and the short axis thereof. Accordingly, it is easily understood that when, for instance, polarizers arranged in a cross nicol relationship, i.e., with their polarizing directions crossing each other, are disposed on the upper and the lower surfaces of the glass plates, the liquid crystal cell thus arranged functions as a liquid crystal optical modulation device of which optical characteristics vary depending upon the polarity of an applied voltage.
Further, when the liquid crystal cell is made sufficiently thin (e.g., less than about 10 microns), the helical structure of the liquid crystal molecules is unwound to provide a non-helical structure even in the absence of an electric field, whereby the dipole moment assumes either of the two states, i.e., Pa in an upper direction 34a or Pb in a lower direction 34b as shown in FIG. 3, thus providing a bistable condition. When an electric field Ea or Eb higher than a certain threshold level and different from each other in polarity as shown in FIG. 3 is applied to a cell having the above-mentioned characteristics, the dipole moment is directed either in the upper direction 34a or in the lower direction 34b depending on the vector of the electric field Ea or Eb. In correspondence with this, the liquid crystal molecules are oriented in either of a first stable state 33a and a second stable state 33b.
When the above-mentioned ferroelectric liquid crystal is used as an optical modulation element, it is possible to obtain two advantages. First is that the response speed is quite fast. Second is that the orientation of the liquid crystal shows bistability. The second advantage will be further explained, e.g., with reference to FIG. 3. When the electric field Ea is applied to the liquid crystal molecules, they are oriented in the first stable state 33a. This state is stably retained even if the electric field is removed. On the other hand, when the electric field Eb of which direction is opposite to that of the electric field Ea is applied thereto, the liquid crystal molecules are oriented to the second stable state 33b, whereby the directions of molecules are changed. This state is similarly stably retained even if the electric field is removed. Further, as long as the magnitude of the electric field Ea or Eb being applied is not above a certain threshold value, the liquid crystal molecules are placed in the respective orientation states.
When such a ferroelectric liquid crystal device comprising a ferroelectric liquid crystal composition as described above between a pair of electrode plates is constituted as a simple matrix display device, the device may be driven by a driving method as disclosed in U.S. Pat. No. 4,655,561, GB 2156131, etc.
FIGS. 4A and 4B are waveform diagrams showing driving voltage waveforms for measuring VA and VB from which the above-mentioned drive margin is derived. FIG. 5 is a plan view of such a ferroelectric liquid crystal panel 51 having a matrix electrode structure. Referring to FIG. 5, the panel 51 comprises scanning lines 52 and data lines 53 intersecting with the scanning lines. Each depending on switching characteristics of a ferroelectric liquid crystal material used.
In this embodiment, VA may be obtained by applying a voltage waveform shown at IS -SS in FIG. 4A to a pixel whereby the pixel is reset to a first optical state by application of a voltage VR and then inverted to a second optical state by application of a voltage VX (=VS +VI). VA is defined as a minimum value of the voltage VS +VI capable of causing the optical inversion while the voltages VS and VI are changed. (The voltage VS and VI are generally defined with respect to the potential level of a scanning electrode when the electrode is not supplied with a scanning selection signal.) On the other hand, VB may be obtained by applying a voltage waveform shown at IN -SS in FIG. 4A to a pixel whereby the pixel is reset to a first optical state by application of a voltage VR and held at the first optical state under application of a voltage VY (=VS -VI). VB is defined as a value |VS +VI | based on voltage values VS and VI giving a maximum voltage VY (=VS -VI) beyond which the pixel is inverted from the first optical state to a second optical state while the voltages VS and VI are changed. For example, VA and VB may be obtained by using a fixed pulse duration of Δt=50 μsec and a fixed bias ratio of VI /(VI +VS)=1/3.
The threshold characteristics of a ferroelectric liquid crystal are strongly affected by an ambient temperature. For this reason, the value of drive margin Md is affected by an ambient temperature and becomes smaller on a higher temperature side in the chiral smectic phase. In the case of a small drive margin Md, particularly the case of Md<0.1, a uniform display on a large panel (e.g., a size of JIS A4) could not be achieved according to our experimental study because a larger panel is accompanied with a larger fluctuation in cell gap for pixels over the panel which leads to a larger fluctuation in threshold characteristic of pixels.
Further, in order to achieve a high-rewriting speed display (high-frequency drive), a high-speed responsiveness is of course required.
Among a response time τ, the magnitude of spontaneous polarization PS and viscosity η, the following relationship exists: τ=η/(PS ·E), where E is an applied voltage. Accordingly, a large response speed can be obtained by (a) increasing the spontaneous polarization, (b) lowering the viscosity η, or (c) increasing the applied voltage. However, the driving voltage has a certain upper limit in view of driving with IC, etc., which may be Vpp of about 30 volts, so that the drive voltage VS +VI should also be suppressed to 30 volts or less. Accordingly, it is actually necessary to lower the viscosity or increase the spontaneous polarization.
A ferroelectric chiral smectic liquid crystal having a large spontaneous polarization generally provides a large internal electric field in a cell given by the spontaneous polarization and is liable to pose many constraints on the device construction giving bistability.
According to our study, it is necessary that a frame frequency Ff is 20 Hz or higher in order to achieve a good rewriting speed. This means a one-scanning line writing time (1H) of 125 μsec or less (Δt≦41.6 μsec in a set of driving waveforms shown in FIG. 4A) if the number of scanning lines is assumed to be 400. In order to lower the temperature range satisfying such a responsiveness at least to room temperature, it is necessary that a liquid crystal composition is provided with PS which is large to some extent. According to our extensive study, however, such an increase in PS tends to cause a failure in realization of bistability and also a decrease in drive margin Md. This tendency has also been confirmed in cell structures where bistability is less affected by an increase in PS, more specifically in a cell structure wherein a very thin polyimide film of about 50 Å is directly formed and rubbed on a transparent electrode (ITO) without forming an intermediate insulating layer and in a cell structure wherein ITO is directly rubbed.
For the above reason, in order to obtain a liquid crystal material showing an increased responsiveness, it is effective to use a large proportion of a compound showing a lowest viscosity as possible (e.g., a compound having a phenylpyrimidine skeleton) so as to provide an appropriate liquid crystal phase transition pattern (e.g., SmC*←→SmA←→Ch←→Iso; SmC*: chiral smectic phase, SmA: smectic A phase, Ch: cholesteric phase) and to add a compound having a large spontaneous polarization (e.g., a compound having an asymmetric carbon atom to which a fluorine atom is directly attached) as a PS -imparting component so as to adjust the value of PS to an upper limit capable of avoiding a remarkable decrease in drive margin by controlling the addition amount of the PS -adjusting component.
Further, if it is assumed that a display is actually used in a temperature range of about 5-45° C., the display should be actually operable at 50-55° C. or higher on the high temperature side because an additional heat is given by a drive system and a backlight.
However, the drive margin Md generally tends to decrease on the high temperature side and remarkably decrease within 10° C. from TC (upper limit of chiral smectic range). For this reason, the TCA (SmC*←→SmA transition temperature) of a liquid crystal composition should be set in consideration of the temperature range of use and particularly of the ensurement of an appropriate drive margin.
A serious problem on the low temperature side is a deterioration of responsiveness and a difference in response speed between 5-50° C. amounts to about ten times even for a chiral smectic composition having an excellent temperature characteristic (small temperature-dependence). Accordingly, it is difficult to compensate for the temperature-dependence only by adjustment of drive voltages while retaining a good rewriting speed (frame frequency Ff ≧20 Hz) for display device.
For the above reason, it has been proposed to provide a liquid crystal device with a heat application means for the purpose of compensating for a steep temperature dependence below room temperature. In this case, however, there arises a tendency that an increased temperature difference develops over the extension of the device, so that a larger drive margin is required. Especially, the drive margin on the high temperature side poses a most important problem.
On the other hand, we have also tried to increase the frame frequency of a display device by changing the drive waveform from one providing a one-line scanning time (1H) composed of 3Δt as shown in FIG. 4A or by scanning two or more scanning lines simultaneously. In most cases, however, the drive margin Md is decreased, so that it is necessary to ensure a large drive margin Md of a liquid crystal material.
Further, a ferroelectric liquid crystal material is required to provide a monodomain state showing a uniform alignment characteristic so as to obtain a good image quality. The ferroelectric liquid crystal may desirably have a phase transition series of Iso (isotropic phase)--Ch (cholesteric phase)--SmA (smectic A phase)--SmC* (chiral smectic phase).
Liquid crystal materials (compositions) usable in the present invention may include the following mesomorphic compounds:
(1) Mesomorphic compounds having a skeleton including two rings connected with a single bond as shown below, which show a low viscosity and are advantageous for a high speed drive at a low temperature: ##STR1##
(2) Optically active mesomorphic compounds having large PS (and preferably also a low viscosity) including a group as shown below, which may be added in a small proportion as a PS -imparting component to control the PS of the resultant liquid crystal composition as a whole: ##STR2## wherein Z: a bonding group with a cyclic skeleton, R: an arbitrary alkyl group, and C*: an optically active asymmetric carbon atom.
(3) Mesomorphic compounds providing an increased TCA without remarkably increasing the viscosity of the liquid crystal composition, thus being advantageous for high-temperature and high-speed drive, which may include:
mesomorphic compounds having a three-ring skeleton wherein three arbitrarily selected rings, such as: ##STR3## are respectively connected with a single bond. Examples of the three-ring skeleton may include: ##STR4## etc.;
mesomorphic compounds having a three-ring skeleton wherein a two-ring structure, such as a phenylpyrimidine ring, including two rings connected with a single bond, is connected to another ring, such as phenyl ring and cyclohexane ring with a connecting group, such as: ##STR5## Examples of the three-ring skeleton may include: ##STR6##
mesomorphic compounds having a two-ring skeleton but still providing a high SmC* phase upper limit temperature of 70° C. or higher, such as those having a skeleton as shown below: ##STR7##
(4) Mesomorphic compounds for ensuring a lower temperature side of SmC* phase (lowering the melting point) or for adjustment of a phase transition series, having a skeleton as shown below: ##STR8##
Further, it is necessary to appropriately select factors regarding the above classes (1)-(4) of mesomorphic compounds, such as the length of side chains, kinds of connecting groups with the skeletons, the presence or absence of a branch or substituent, and the presence or absence or position of a substituent in the skeletons in view of the influences thereof on the resultant ferroelectric liquid crystal composition, such as PS -imparting characteristic, increase or decrease in viscosity, phase transition pattern, temperature region of Ch phase or SmA phase, and chemical stability.
Hereinbelow, the present invention will be explained in more detail based on Examples. It is however to be understood that the present invention is not restricted to the Examples. In the Examples, in order to evaluate a drive margin characteristic of a liquid crystal material, a voltage margin ΔV (=VB -VA) was measured by using a certain driving waveform with a fixed Δt at a temperature, and the above-mentioned drive margin Md was obtained as a parameter in resistance to fluctuation in cell gap. If it is assumed that VA =10 volts and VB =15 volts were measured to provide Md=0.2, this means that the drive margin Md allows a cell gap of ±20% over the extension of the cell. In the present invention, Md>0.1 may suitably be set.
Further, a drive temperature margin Mt (±x °C.) may be measured as a temperature difference (range) allowing a drive (i.e., not causing switching failure on an entire panel) while setting drive voltages (VS and VI) so as to satisfy VS +VI =1/2 (VA +VB) and changing the drive temperature. The drive margin characteristic of an liquid crystal apparatus can be more exactly evaluated based on both Md and Mt.
According to our study, it has been found difficult to maintain a good image display over a panel of a certain size (e.g., a size of 10 inches) or larger unless the condition of Md>0.1 is satisfied.
FIG. 9 shows an apparatus equipped with a means for controlling the liquid crystal layer temperature to a temperature of (TCA -10) °C. or below.
More specifically, the apparatus shown in FIG. 9 is provided with a heating means for controlling the temperature of a ferroelectric liquid crystal 1001 at a temperature of (TCA -10) °C. or below, e.g., at 50° C. The heating means may comprise a heat-generating resistor 1002 which may be disposed as shown (with an insulating member (not shown)) or can be disposed (not shown) in contact with the ferroelectric liquid crystal 1001, and also a power supply 1003 for supplying a current to the heat-generating resistor. The heat-generating resistor may be in the form of a transparent film of a transparent metal oxide, such as indium oxide, tin oxide or titanium oxide.
In the present invention, the liquid crystal temperature is raised by heat-generation from the resistor 1002 to a temperature T.sub.α which is higher than an operation temperature T °C. but lower than (TCA -10) °C. and then lowered by natural cooling to T °C. This control may be effected by means of a thermistor 1005 as a temperature sensor, a current regulator 1004, a temperature control circuit 1007 and a microprocessor 1006.
In the apparatus shown in FIG. 9, signals are selectively supplied to electrodes 1009 and 1010 in the cell form a liquid crystal drive circuit 1017 whereby the orientation state of the ferroelectric liquid crystal 1001 is selectively controlled to open or close a light path therethrough. The modulation by the change in orientation state is detected by polarizers 1015 and 1016 disposed on both sides of the cell. The cell structure itself is similar to one shown in FIG. 1 and comprises substrates 1011 and 1012 of, e.g., glass or plastic sheets and alignment control films 1013 and 1014 formed from insulating materials, such as SiO, SiO2, polyimide, polycarbonate and polyamide.
FIG. 10 shows another embodiment of the apparatus according to the present invention. In this embodiment, a heating member 1103 comprising a heat-resistance body arranged with a resistance heating element 1101 is disposed on a side of a liquid crystal cell 1102. The current supplied to the resistance heating element 1101 may be controlled by a sequence as disclosed, e.g., in U.S. Pat. No. 4,763,992.
In the examples shown below, the spontaneous polarization of a ferroelectric liquid crystal material was measured by "Direct Method with Triangular Waves for Measuring Spontaneous Polarization in Ferroelectric Liquid Crystal", as described by K. Miyasato, et al (Jap. J. Appl. Phys. 22, No. 10, L661 (1983)).
A liquid crystal composition 1-A was prepared by mixing the following two mesomorphic compounds each having a large spontaneous polarization in an indicated ratio.
______________________________________ ##STR9## 2 wt. parts ##STR10## 1 wt. parts______________________________________
Then, the above-obtained liquid crystal composition 1-A was mixed with a liquid crystal composition CS-1014 (trade name, available from Chisso K.K.) in different ratios as shown in the following Table to obtain liquid crystal compositions 1-1 to 1-5, which showed TCA (SmC*→SmA transition temperature) also shown in the table and each of which showed a phase transition series of SmC*←→SmA←→Ch←→Iso.
______________________________________Composition CS-1014/1-A (wt. %/wt. %) T.sub.CA (°C.)______________________________________1-1 95/5 54.11-2 92/8 53.11-3 90/10 52.51-4 85/15 51.1______________________________________
The spontaneous polarizations PS of these liquid crystal composition and CS-1014 were measured at different temperatures by the above-mentioned triangular wave method. The results are shown in FIG. 7 with respect to temperatures T (°C.) expressed in terms of TCA -T (°C.). As shown in FIG. 7, the increase in PS is linear with respect to TCA -T in the temperature range of TCA -T≧15° C. and is decreased somewhat sharply on the higher temperature side. (The PS of CS-1014 does not substantially increase in a lower temperature region. It can be concluded that no material shows an abrupt increase in PS in a low temperature region unless it is accompanied with a phase transition.) The values of |PS | of the respective liquid crystal compositions may be expressed as a function of (TCA -T), i.e., by an equation of |PS |=α+β(TCA -T) [nC/cm2 ]. The values of α and β for the liquid crystal compositions 1-1 to 1-5 and CS-1014 taken from FIG. 7 are shown below.
______________________________________ α β______________________________________1-1 4.8 0.141-2 4.6 0.231-3 5.8 0.251-4 7.5 0.34CS-1014 3.8 0.05______________________________________
Ferroelectric crystal devices (cells) were prepared by using the above-mentioned liquid crystal compositions and a blank cell prepared in the following manner, and then subjected to observation of the optical response.
Two 1.1 mm-thick glass plates were provided and respectively coated with an ITO film to form stripe electrodes for voltage application, which was further coated with a 400 Å-thick insulating layer of vapor-deposited SiO2.
Further, each glass plate provided with ITO electrodes and an insulating layer was coated with 1.0%-solution of polyimide resin precursor (SP-510, available from Toray K.K.) in dimethylacetoamide by a spinner coater rotating at 3000 rpm for 15 seconds. Thereafter, the coating film was subjected to heat curing at 300° C. for 60 min. to obtain about 120 Å-thick film. The coating film was rubbed with acetate fiber-planted cloth. The thus treated two glass plates were washed with isopropyl alcohol. After silica beads with an average particle size of 1.5 microns were dispersed on one of the glass plates, the two glass plates were applied to each other with a bonding sealing agent (Lixon Bond available from Chisso K.K.) so that their rubbed directions were parallel to each other and heated at 100° C. for 60 min. to form a blank cell. Thus, five liquid crystal devices were prepared. The cell gap of each cell was found to be about 1.5 microns as measured by a Berek compensator.
Then, one of the above-prepared liquid crystal Compositions 1-1 to 1-4 and CS-1014 was heated into an isotropic liquid, and injected into the above prepared cell under vacuum and, after sealing, was gradually cooled to 25° C. at a rate of 20° C./hour to prepare a ferroelectric liquid crystal device.
Thus, five liquid crystal devices were prepared.
Each of the ferroelectric liquid crystal devices thus prepared was driven by using a set of driving waveforms (1/3 bias) as shown in FIGS. 4A and 4B while fixing Δt to 40 μsec, whereby the drive voltage margin Md was measured. The results are shown below.
______________________________________ 25° C. 40° C. V.sub.A /V.sub.B (Md) V.sub.A /V.sub.B (Md)______________________________________CS-1014 >45 V/--*.sup.1 *.sup.2 19.2 V/28.8 V (0.200)1-1 32.5 V/>45 V *.sup.2 14.5 V/21.4 V (0.192)1-2 22.6 V/30.5 V (0.149) 10.1 V/13.1 V (0.130)1-3 18.8 V/20.3 V (0.038) 8.8 V/8.9 V (0.005)1-4 switching failure switching failure______________________________________ *.sup.1 Not measured (>50 volts) *.sup.2 Not obtained
As is understood from the above Table, the device using the composition 1-2 alone could be driven below 30 V even at 25° C. and showed an Md exceeding 0.1.
As for the liquid crystal compositions having a PS not satisfying (exceeding) the relationship of |PS |<5+0.25 (TCA -T), Composition 1-3 provided a remarkably small Md, and Composition 1-4 caused switching failure due to loss of bistability, thus providing no Md.
Further, the devices containing Compositions 1-1 and 1-2 were subjected to the same measurement at 45° C., whereby Composition 1-1 provided an Md value of 0.08 and Composition 1-2 provided an Md value of 0.03, which cannot be recognized as sufficient. This is presumably because T=45° C. falled within a temperature region of TCA -T<10° C.
Then, a liquid crystal composition 1-B was prepared by mixing the following two mesomorphic compounds in an indicated ratio for the purpose of providing an increased TCA :
__________________________________________________________________________ ##STR11## 1 wt. part ##STR12## 1 wt. part__________________________________________________________________________
The improvement of the above compositions 1-1 and 1-2 was tried by mixing the compositions CS-1014, 1-A and 1-B as follows:
______________________________________Composition CS-1014 (wt. %) 1-A (wt. %) 1-B (wt. %)______________________________________1-5 80 5 151-6 77 8 15______________________________________
The resultant compositions 1-5 and 1-6 respectively showed a phase transition series of SmC*←→SmA←→Ch←→Iso. and TCA values of 61.8° C. (1-5) and 61.3° C. (1-6). The temperature-dependence of PS for these compositions is also shown in FIG. 7.
Two ferroelectric liquid crystal devices were prepared in the same manner as above except for using the compositions 1-5 and 1-6, respectively, and measurement of drive margins Md (Δt being fixed at 40 μsec), whereby the following results were obtained:
______________________________________25° C. 40° C. 45° C.V.sub.A /V.sub.B (Md) V.sub.A /V.sub.B (Md) V.sub.A /V.sub.B (Md)______________________________________1-5 33.4 V/>45 V 15.8 V/24.0 V 12.0 V/17.6 V (--) (0.206) (0.194)1-6 23.1 V/32.4 V 11.6 V/15.5 V 8.7 V/11.4 V (0.166) (0.144) (0.134)______________________________________
When the results obtained by Compositions 1-5 and 1-6 are compared with those obtained by Compositions 1-1 and 1-2, respectively, the values of VA (as a measure of a switching speed) at 25° C. were not changed substantially but the drive margins Md at 45° C. were remarkably increased. Further, the drive temperature margins Mt of Compositions 1-2 and 1-6 were ±2.5° C. and ±3.3° C., respectively, and thus Composition 1-6 provided an improved value.
Liquid crystal compositions 2-A, 2-B, 2-C and 2-D as shown below were prepared by mixing the following mesomorphic compounds in respectively indicated proportions:
__________________________________________________________________________(2-A) ##STR13## 4 wt. parts ##STR14## 2 ##STR15## 1(2-B) ##STR16## 1 ##STR17## 1(2-C) ##STR18## 1 ##STR19## 1 ##STR20## 1(2-D) ##STR21## 1 ##STR22## 1__________________________________________________________________________
These liquid crystal compositions and other mesomorphic compounds were mixed with each other in respectively indicated weight parts to prepare liquid crystal compositions 2-1 to 2-5 as shown below:
These liquid crystal compositions 2-1 to 2-5 all showed a phase transition series of SmC*←→SmA←→Ch←→Iso and TCA values of 57.8° C., 63.2° C., 71.4° C., 70.6° C. and 69.6° C., respectively, in the order indicated. The changes in PS dependent on temperature change are shown in FIG. 8.
Five ferroelectric liquid crystal devices were prepared in the same manner as above except for using the compositions 2-1 to 2-5, respectively, and subjected to measurement of drive margins Md in the same manner as above except for using a fixed Δt of 30 μsec., whereby the following results were obtained.
______________________________________30° C. 40° C. 55° C.V.sub.A /V.sub.B (Md) V.sub.A /V.sub.B (Md) V.sub.A /V.sub.B (Md)______________________________________2-1 22.7 V/32.9 V 13.9 V/18.7 V No margin* (0.184) (0.147)2-2 24.5 V/36.7 V 16.3 V/23.5 V 8.9 V/10.1 V (0.199) (0.183) (0.063)2-3 25.8 V/40.8 V 17.2 V/26.0 V 10.1 V/14.7 V (0.225) (0.204) (0.185)2-4 19.5 V/26.0 V 13.1 V/17.2 V 7.7 V/9.8 V (0.143) (0.135) (0.120)2-5 13.1 V/13.5 V 8.8 V/8.9 V No margin (0.015) (0.005)______________________________________ *V.sub.A > V.sub.B
Composition 2-5 showing PS not satisfying the relationship of |PS |<5+0.25 (TCA -T) provided an extremely low drive margin or failed to show a drive margin. Further, Compositions 2-1 and 2-2 not having a TCA which is higher than 55° C. by 10° C. or larger showed a small drive margin Md or failed to show a drive margin, so that they provided a problem with respect to its upper limit temperature in the operation temperature range.
Compositions 2-3 and 2-4 having PS satisfying the relationship of |PS |<5+0.25 (TCA -T) and having TCA higher than 65° C. (=55°+10° C.) showed sufficient drive margins at 55° C. and also could be driven below 30 V at 30° C., thus being highly practical.
Ferroelectric liquid crystal devices were prepared by using the liquid crystal compositions CS-1014, 1-1, 1-2, 1-3, 1-4, 1-5 and 1-6, respectively, in the same manner as in Example 1 except that each cell was prepared by omitting the SiO2 insulating layer to use the alignment control film of polyimide resin alone. The devices were subjected to measurement of drive margins Md in the same manner as in Example 1, whereby the device using Composition 1-4 was free from switching failure but only the devices using Compositions 1-5 and 1-6 were ensured with a drive margin Md even at a high temperature. The other tendencies were also similar to those observed in Example 1.
The ferroelectric liquid crystal devices prepared in Example 2 were driven and subjected to measurement of drive margins Md by using a set of driving waveforms shown in FIG. 11 (whereby two scanning lines were scanned simultaneously for a period of 1/3.1H so that the frame frequency of the device could be increased to 1.5 times as compared with a case without such simultaneous scanning). As a result, only the devices using Compositions 2-3 and 2-4 could be driven at a temperature of 50° C. or higher. The other tendencies were similar to those observed in Example 2.
Four ferroelectric liquid crystal devices of Comparative Examples 1-4 were prepared in the same manner as in Example 1 except that ferroelectric liquid crystal compositions CS-1017 (TCA =53° C.), CS-1019 (TCA =67.2° C.) [available from Chisso K.K.], and ZLI-4000 (TCA =63.8° C.), ZLI-4003 (TCA =62.0° C.) [available from Merck Japan K.K.] were used respectively instead of those used in Example 1. These devices were subjected to measurement of drive margins Md in the same manner as in Example 1 with a fixed Δt of 30 μsec. The results are shown below. Incidentally, these compositions all show a phase transition series of SmC*←→SmA←→Ch←→Iso, and the measured spontaneous polarization data thereof are shown in FIG. 12.
______________________________________25° C. 40° C. 55° C.V.sub.A /V.sub.B (Md) V.sub.A /V.sub.B (Md) V.sub.A /V.sub.B (Md)______________________________________CS-1017 40.0 V/>45 V 17.0 V/20.9 V -- (--) (0.103)ZLI-4000 35.2 V/>45 V 16.2 V/20.3 V 8.5 V/0.3 V (--) (0.112) (0.019)______________________________________
The devices using the compositions CS-1019 and ZLI-4003 failed to provide any drive margin Md.
The above data show that also the compositions CS-1017 and ZLI-4000 poses a serious problem in drive margin Md at a high temperature.
A liquid crystal composition 5-1 was prepared by mixing the following mesomorphic compounds (1)-(17) in respectively indicated proportions:
__________________________________________________________________________(1) ##STR25## 6 wt. parts(2) ##STR26## 3(3) ##STR27## 9(4) ##STR28## 4(5) ##STR29## 4(6) ##STR30## 4(7) ##STR31## 8(8) ##STR32## 6(9) ##STR33## 6(10) ##STR34## 7.5(11) ##STR35## 7.5(12) ##STR36## 10(13) ##STR37## 7(14) ##STR38## 3(15) ##STR39## 6(16) ##STR40## 6(17) ##STR41## 4__________________________________________________________________________
The liquid crystal composition 5-1 showed a phase transition series of SmC*←→SmA←→Ch←→Iso and TCA of 68.1° C. The composition also showed the following values of PS at various temperatures (T °C.) in terms of TCA -T:
______________________________________|P.sub.S | (nC/cm.sup.2)(T.sub.CA -T =) (10° C.) (20° C.) (30° C.) (40° C.)______________________________________ 3.9 6.2 8.5 11.0______________________________________
A ferroelectric liquid crystal device was prepared by using the above composition 5-1 otherwise in the same manner as in Example 1 and subjected to measurement of drive margins Md in the same manner as in Example 1 with a fixed Δt=30 μsec. The results are shown below:
______________________________________25° C. 40° C. 55° C.V.sub.A /V.sub.B (Md) V.sub.A /V.sub.B (Md) V.sub.A /V.sub.B (Md)______________________________________29.4 V/45.5 V 17.3 V/26.3 V 9.8 V/13.2 V(0.215) (0.206) (0.148)______________________________________
The ferroelectric liquid crystal device could display good images even at 50° C. or higher.
A liquid crystal composition 6-1 was prepared in the same manner as the liquid crystal composition 5-1 prepared in Example 5 except that the mesomorphic compounds (13) and (14) were replaced by the following mesomorphic compounds, respectively, in the same amounts.
__________________________________________________________________________ ##STR42## 7 wt. parts ##STR43## 3 wt. parts__________________________________________________________________________
The composition 6-1 showed a phase transition series of SmC*←→SmA←→Ch←→Iso and TCA of 68.9° C. The PS values of the composition at different temperatures in terms of TCA -T (°C.) are shown below.
______________________________________|P.sub.S | (nC/cm.sup.2)(T.sub.CA -T =) (10° C.) (20° C.) (30° C.) (40° C.)______________________________________ 4.1 6.3 8.9 11.2______________________________________
A ferroelectric liquid crystal device was prepared by using the above composition 6-1 otherwise in the same manner as in Example 1 and subjected to measurement of drive margins Md in the same manner as in Example 1 with a fixed Δt=30 μsec. The results are shown below:
______________________________________25° C. 40° C. 55° C.V.sub.A /V.sub.B (Md) V.sub.A /V.sub.B (Md) V.sub.A /V.sub.B (Md)______________________________________32.1 V/48.1 V 18.1 V/26.3 V 10.3 V/13.6 V(0.199) (0.185) (0.138)______________________________________
The ferroelectric liquid crystal device could display good images even at 50° C. or higher.
As is clear from the above description, the ferroelectric liquid crystal apparatus using the ferroelectric liquid crystal composition according to the present invention can provide a display device with a large display area which shows a good rewriting speed and provides uniform and good images over a wide temperature range from approximately room temperature to a high temperature of 50° C. or higher.
As another effect of the present invention, there is provided a larger latitude with respect to fluctuation in electrode gap and temperature distribution while providing uniformly good images at a good rewriting speed.
|Cited Patent
|Filing date
|Publication date
|8 Jan 1980
|11 Jan 1983
|Clark Noel A
|Chiral smectic C or H liquid crystal electro-optical device
|10 Apr 1984
|7 Apr 1987
|Canon Kabushiki Kaisha
|Method of driving optical modulation device using ferroelectric liquid crystal
|28 Apr 1987
|16 Aug 1988
|Canon Kabushiki Kaisha
|Smectic liquid crystal device with temperature control system
|21 Jul 1987
|23 Aug 1988
|Canon Kabushiki Kaisha
|Method and apparatus for driving ferroelectric liquid crystal, optical modulation device to achieve gradation
|6 Jan 1987
|13 Sep 1988
|Hitachi, Ltd.
|Ferroelectric liquid crystal matrix driving apparatus and method
|15 Apr 1986
|18 Oct 1988
|Canon Kabushiki Kaisha
|Method and apparatus for driving optical modulation device
|3 Nov 1987
|22 May 1990
|Canon Kabushiki Kaisha
|Method and apparatus for driving optical modulation device
|23 Dec 1986
|12 Jun 1990
|Canon Kabushiki Kaisha
|Driving method for optical modulation device
|13 Feb 1989
|25 Sep 1990
|Canon Kabushiki Kaisha
|Liquid crystal apparatus having light quantity of the backlight in synchronism with writing signals
|Title not available
|Title not available
|Applied Physics Letters, vol. 18, No. 4, Feb. 15, 1971, pp. 127 128, Schadt, M., et al., Voltage Dependent Optical Activity of a Twisted Nematic Liquid Crystal .
|Applied Physics Letters, vol. 18, No. 4, Feb. 15, 1971, pp. 127-128, Schadt, M., et al., "Voltage-Dependent Optical Activity of a Twisted Nematic Liquid Crystal".
|Journal of Applied Physics, vol. 22, No. 10, Oct. 1983, pp. 661 663, Miyasato, K., et al., Direct Method With Triangular Waves for Measuring Spontaneous Polarization in Ferroelectric Liquid Crystals .
|Journal of Applied Physics, vol. 22, No. 10, Oct. 1983, pp. 661-663, Miyasato, K., et al., "Direct Method With Triangular Waves for Measuring Spontaneous Polarization in Ferroelectric Liquid Crystals".
|Citing Patent
|Filing date
|Publication date
|21 Apr 1994
|29 Aug 1995
|Canon Kabushiki Kaisha
|Liquid crystal display with projecting portions on the electrodes
|3 Jun 1994
|3 Dec 1996
|Canon Kabushiki Kaisha
|LCD electrode projections of variable widths and spacings
|26 Apr 1994
|7 Jan 1997
|Canon Kabushiki Kaisha
|Liquid crystal display apparatus and drive method
|22 Mar 1994
|4 Mar 1997
|Canon Kabushiki Kaisha
|Liquid crystal display apparatus
|29 Jul 1996
|8 Jul 1997
|Canon Kabushiki Kaisha
|Method and apparatus for ferroelectric liquid crystal display having gradational display
|26 May 1995
|12 Aug 1997
|Samsung Display Devices Co., Ltd.
|Method for driving a matrix liquid crystal display panel with reduced cross-talk and improved brightness ratio
|3 May 1995
|18 Nov 1997
|Canon Kabushiki Kaisha
|Liquid crystal display apparatus having a film layer including polyaniline
|17 Nov 1994
|14 Apr 1998
|Central Research Laboratories Limited
|Analogue greyscale addressing in a ferroelectric liquid crystal display with sub-electrode structure
|22 Dec 1994
|21 Apr 1998
|Canon Kabushiki Kaisha
|Method of aligning liquid crystals by applying an alternating electric field under periodically changing temperature
|11 Oct 1996
|28 Jul 1998
|Canon Kabushiki Kaisha
|Liquid crystal composition, liquid crystal device, and liquid crystal display apparatus using same
|28 May 1998
|24 Oct 2000
|Sharp Kabushiki Kaisha
|Liquid crystal device and method of addressing a liquid crystal device
|14 Sep 1998
|9 Apr 2002
|Citizen Watch Co., Ltd.
|Antiferroelectric liquid crystal display with liquid crystal layer structure control
|26 Oct 1998
|18 Nov 2003
|Canon Kabushiki Kaisha
|Control of video signal inversion frequency independently of frame or field frequency
|10 May 2010
|12 Mar 2013
|Samsung Display Co., Ltd.
|Liquid crystal display device including sensing element
|10 Apr 2007
|9 Aug 2007
|International Business Machines Corporation
|Clearing Selected Storage Translation Buffer Entries Based on Table Origin Address
|10 May 2010
|26 Aug 2010
|Samsung Electronics Co., Ltd.
|Liquid crystal display device including sensing element
|U.S. Classification
|349/37, 349/72, 345/97, 349/161, 349/34, 349/184, 349/172
|International Classification
|Cooperative Classification
|European Classification
|26 Jun 1990
Owner name: CANON KABUSHIKI KAISHA, 3-30-2 SHIMOMARUKO, OHTA-K
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Effective date: 19900620
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text:
A laidback clubhouse for nerds to talk about the things they like (anime, video games, culture, memes or nothing).
movies, anime, video, games, #otaku, entertainment, culture, books, comics
Welcome to the board!
If you wish for a more unique forum with a twist then here is where to go, We have many ideas so if ya love anime, games, manga, reading etc. then come along to heaven where Goddesses of all types can assist you in any wish you desire. A friendly
manga, #otaku, games, downloading, anime, fans, alike, gaming, imaginations, hang, creative
Le petit Atelier des Garage Kitters!
garage, wonder, festival, figurine, japanimation, hobby, japan, maquette
A2 is an anime (OTAKU) fan base community - (Members have more fun)
anime, acces, anime(otaku)fan, base, organization, manga, animation, #otaku, cosplay

subset: commoncrawl


text: Human Rights Observatory Boko Haram Attacks Army Base in Niger Suspected Boko Haram militants attacked a Niger army base on an island in Lake Chad, leaving many soldiers dead. Niger military sources said hundreds of armed militants riding on motorized canoes attacked the island of Karamga early Saturday, their second attempt to capture it since February, army and government sources told Reuters. A second army source told Reuters a counter-attack to clear the island of militants was ongoing Sunday. The number of casualties was not release, but...Read complete article© Voice of America - Sunday, April 26, 2015


text:
Cruise on board P&O Cruises's Azura
The Azura is one of the larger ships in the P&O Cruises fleet and offers a huge range of family-friendly entertainment, dining options, bars and pampering opportunities to make sure that everyone has a great time.
Throughout the day, you can explore the cafes, art gallery, bookshop, library and shops of the Atrium, the three-storey heart of Azura. Then at night, the Playhouse Theatre comes alive with magnificent shows and musicals while the New York-themed Manhattan Lounge and Malabar heat up with music, cabaret, comedians and classic entertainment.
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Cruisers will be whisked away to incredible destinations on-board the Azura, including Scandinavia and the Norwegian Fjords, Greece, Iberia, Western Europe, the Canary Islands, the Baltic Islands and across the Mediterranean.
For more information about booking a blissful cruise aboard the Azura, or for information on other ships and journeys from P&O Cruises, give our expert cruse consultants a call on 1300 769 228 or email us using the form below.
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Food and Drink Aqua Bar, Blue Bar, Breakers Bar, Chic Restaurant, Epicurean, Glass House, Java Cafe, Malabar, Manhattan, Meridian Restaurant, Oriental Restaurant, Peninsular Restaurant, Pizzeria, Poolside Grill, Poolside Pizzeria, Sabatini's Italian Trattoria, Sindhu Restaurant, Terrace Bar, The Atrium, The Blue Bar, The Manhattan Room, The Planet Bar, The Playhouse, Venezia, Verona,
Entertainment Coral Bar,
Recreational Deck Quoits, Golf Nets, Shuffle Board,
Fitness Gym, Ocean View Gymnasium, Sports Court,
Relaxation Health Club, Oasis Spa, Sauna, Swimming Pool, The Retreat, Thermal Suite, Treatment Rooms, Whirlpool,
Other Karmala Room, Photo Gallery, Reception,
Cabin type: balcony (HA)
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Cabin type: suite (A1)
Cabin type: suite (B2)


text: for? I have a volt meter. There are no obvious signs of burn marks or broken parts. Previously I checked for power on the external connectors. I put one lead on the power and one on the ground and I got 14volts. I put one on the ground and one on the remote turn on lead and got 13 volts. Fuses are all good and I put all new ones in just for shits and giggles. On the circuit board where is an obvious place to check for resistance? I know little about circuit boards. Where are the vulnerable areas? I'm looking at the circuit board and it looks fine, I don't know what to check. Any other thoughts?


text:
"Leadership, like Motorcycling is not, of itself, inherently dangerous. The difference is motorcycling is extremely unforgiving of inattention, ignorance and incompetence."
Steven G. Foster, CMP
Managing Partner, Foster+Fathom
Steven G. Foster, CMP
Managing Partner, Foster+Fathom
A good rider has balance, judgment, and good timing. So does a good leader.
Everyone crashes. Some get back on. Some don't. Some can't.
Routine team maintenance should never be neglected.
Riding faster than everyone else only guarantees you'll ride alone.
Never mistake horsepower for staying power.
When you're riding lead don't spit.
You don't wait for the storms to pass; You learn to ride in the rain!
Full-Throttle Leadership
Keynotes – Facilitation – Consulting
"If I have to explain it, you wouldn't understand!"
This popular saying in the Biker Community expresses perfectly the challenge we have conveying our passion for motorcycles with those who don't ride. Every Biker instinctively knows that the choices we make and the roads we take affect everyone on the ride. We ALL have to "GET IT." The Road, the Rules, the Route.
Unfortunately, the same can't be said when it comes to leadership.
One Team, One Ride
Connect – Engage – Inspire
"What makes leadership so elusive isn't what we KNOW, it's how we ROLL."
There is a huge gap between what we know about leadership and what we do as leaders. What should be a clear leadership choice; getting a team of people focused on a common purpose, managing change, fueling success and maintaining balance, often ends up in a heap of twisted perspectives and ruined expectation.
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Latest Road Stories
Fueling Your Ride with "Passion-Power & Purpose" to Give-Back and Change the World
I have been riding motorcycles for about 45 years; it is what I do for pure enjoyment. There are few things better than getting out on the open road, seeing new places and meeting interesting [...]
Leadership: Get REAL!
Seems like I've been asked to discuss "TEAM" a lot this year; how to build a great team, determine why some teams fail so completely and provide some helpful insights into behaviors (good and bad) [...]
Full-Throttle Leadership: Capability, Responsibility & Influence
There is a popular saying in the Harley-Davidson motorcycle community; "If I have to explain it, you wouldn't understand." Bikers have a hard time explaining "IT" – our deep appreciation for the freedom we feel [...]
Team-building: Is the JUICE worth the SQUEEZE?
Organizations do strange things in the name of "team building." Most of it fails spectacularly! For too long team building has been nothing more than simple games poorly executed and resulting in a false sense [...]


text:
The Japanese were looking to make it through to the last eight of a World Cup for the first time in their history in Pretoria, but it ended up being the South Americans achieving that same goal.
After a largely uninspiring 120 minutes of action which produced no goals and only a handful of goalmouth incidents, Paraguay claimed their maiden appearance in the quarter-finals with a 5-3 win in the penalty shoot-out.
After the match in Pretoria, Okada shouldered the blame for Japan's exit, saying: "In terms of how we played, I have no regrets at all.
"The players were really wonderful and they've been truly proud of being Japanese and also representing Asia as a whole. They played until the end and I'm proud of them.
"I was not able to make them win - that's my responsibility. I didn't make them eager enough. It wasn't sufficient on my part."


text:
France backs the idea of an emergency summit of eurozone countries to prevent Greece's debt crisis infecting Italy and Spain, government spokeswoman Valerie Pecresse said on Wednesday.
President Nicolas Sarkozy told a cabinet meeting that "France has always supported the holding of eurogroup meetings in case of need" and backs the summit now proposed by EU president Herman Van Rompuy, she told reporters.
Asked whether that Brussels summit would go ahead, she replied: "Nothing is definitively settled but there is a clear will by all the eurogroup partners to reach the most effective solution as quickly as possible."
Germany on Wednesday played down the prospects for such an emergency gathering, saying finance ministers should continue their work on the issue.
Eurozone finance ministers on Monday agreed to take new measures to support Greece and strengthen the zone against crises, but this did not calm markets which plunged along with the euro before recovering slightly on Wednesday.
Countries still cannot agree on the role of private lenders, which some see as essential to keep Greece afloat and stabilise the eurozone.
"The question of how to involve the private sector in the rescue plan for Greece remains to be settled," said Pecresse, who is also France's budget minister. "That is what the ongoing work is focussing on."


text:
Half Borad in Sassi di Matera
The collaborates with some local restaurants and we can offer you different hollday packages with half board included. These restaurant offer traditional local food and they will satisfyyour every request. Beverage is not included.
- Soul Kitchen
- Trattoria del Caveoso
- Dalla Padella alla Brace


text: Search Results Studies Variables Publications (1) Your query returned 1 citations. Sort by: Pub Date (newest) Title Recent Additions Author Clear All Pub. Year Citation 1. 1997 Ratcliffe, Caroline E. Effect of Mother's AFDC Receipt on Daughter's Teenage Childbearing?. Population Association of America Annual Meetings. . Export Options: RIS EndNote XML Results 1 - 1


text:
Jim Barbey Automotive
Review for Jim Barbey Automotive
Tianbo L. on 10/16/2013
Tianbo said the service is good at this business and it is done on time. The price is a little expensive, but overall he is satisfied with the service.
Vehicle: Toyota Corolla
Category: Service
Service Date: 10/08/2013
Review Created: 10/16/2013
This review was collected via phone interview by Customer Research Inc.


text:
Public Access
New Constellations
The New Constellations sound combines Ethiopian + North African melodies, soulful Afro-Cuban rhythms, psychedelic + ambient textures, and American roots music. Memorable hooks and melodies are balanced with a flair for improvisation. Ideal music for either a party atmosphere, or as chill background music. Members of New Constellations play or have played with Chicago Afrobeat Project, Ted Sirota's Heavyweight Dub, The Interiors, Joe Pug, Van Ghost, Fire Show, Frank Catalano, and Rebel Roots.
Robert J. Zimmer?
Robert J. Zimmer? is dedicated to exploring the fundamentals of universal mechanics through a multidimensional musical approach that blends the study of macroscopic acoustic environments with quantum interactions of sound waves. In essence, it is "that one band that I saw at that one place that one time that played some [good] stuff." This, and other proclamations of ecstatic enjoyment, represent the general response of those fortunate enough to encounter the tunes of RJZ. Thrown into the public eye and forced to face a world of harsh criticism and rejection, Robert J. Zimmer? has emerged a hardened power and decorated name in the Hyde Park community. Hailed as a "musician's musician's musician's musician's musician's band" it is far ahead of its time while still managing to touch the minds of simpletons via a synergy of intricate complexities that results in a sound of such emotional power it touches the roots of man's most fundamental sentiments.


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Health insurance premiums for New Jersey families covered by employer plans rose about 80 percent over the past six years and grew a whopping 5.5 times faster than their income, according to a Families USA study.
From 2000 to 2006, median income in New Jersey rose 14.4 percent, from $31,923 to $36,511. Average annual health care premiums rose from $7,592 to $13,620 for families, and from $2,911 to $4,360 for individuals.
On the bright side, Wal-Mart recently expanded its new low-cost generic drug program to New Jersey. The retailer offers $4 generic prescriptions at more than 49 Wal-Mart and Sam's Club pharmacies throughout the state. Target and some other retail pharmacies are promising to match the deal.
Advice: Now's a good time to educate your employees about generic drugs and suggest they take advantage of the low-cost program. While maybe not a cure, it might take the edge off the headache of rising health care costs for your organization and your employees.


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Ask the Experts
Educating my kids about STD'sHey there everyone, I am one of those Dad's who actually talks to my older (14+ years of age!) about STD's pregnancies etc. I was recently called on the carpet by my middle son (18), after a discussion about condom use and what it protects from...
Response from Robert J. Frascino, M.D.
The Robert James Frascino AIDS Foundation...Hello,The kudos belong to you dad and all the parents who actually provide their kids with age-appropriate, science-based sex education! (I'll bet Sarah Palin wishes she had had a birds and bees and condoms talk Read more »
DonateI have found this website and Dr. Bob to be simply fabulous. How do I donate? Read more »
CAN I GIVE MYSELF AN STD (QTND: CAN YOU GIVE YOURSELF AN STD BY MASTURBATION, 2008)I am 22 years old. I have been masturbating since the age of 13. I never had sex with anyone.... Read more »
Parents' Disapproval of Sex May Cut Kids' STD Risk...Hill and colleagues found that teenage girls who think their parents disapprove of their having sex may have a lower risk of STDs as young adults. Compared with their peers, girls who believed their parents would not want them to have sex were 16... Read more »
Sexually Transmitted Diseases and HIV-Related Risks:...HIV Impacts Specific STDs Do STD Programs Influence HIV Rates? STD-HIV Recommendations Resources Selected Sources Sexually transmitted diseases (STDs), formerly known as venereal diseases, are diseases that are spread from... Read more »
Cook County, Ill., Ranks High in Sexually Transmitted Disease: STD Treatment Costs U.S. Health Care System $16.4 Billion a Year...than half the people who should be screened receive the recommended STD tests, CDC said. If left undiagnosed and untreated, STDs raise the risk of HIV infection. The report found large racial disparities in STD rates, reflecting a range of... Read more »
Chlamydia's Quick Cure...Anna Lange (not her real name) had no symptoms when she went to a Wake County, N.C., sexually transmitted diseases clinic earlier this year to pick up her birth control pills. But a routine test revealed that the 20-year-old Lange had chlamydia. Read more »
Connect With Others
sister of my fiance has aids, need advice
Posted by knut_hamsun, 4 Replies...tested. The sister has been sick for 10y. I am in a bit of shock here, and need some advice. the sister has daily care for 2 kids. i presume this is ok, but how often should the kids be tested? and what precautions can we easily make to avoid... Read more »
Girl on girl rubbing
Posted by Anonymous, 4 RepliesHi, I'm 16 years old and think i made a big mistake. I had sex with another girl 3 months ago. She's 25 and I don't know much about her sexual history. She's my Dad's neighbor and one weekend while I was visiting him I went to her apartment. One... Read more »
6 weeks test
Posted by Anonymous, 2 Replies...1977. You have used street drugs by injection since 1977, especially when sharing needles and/or other equipment. You have a sexually transmitted disease (STD), including pelvic inflammatory disease (PID). You are a health care worker with... Read more »
any babies infected by breast milk?
Posted by Anonymous, 3 RepliesWould someone know how many if any babies hiv infected by breast milk? Read more »
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Holidays don't have to result in the dreaded 'all inclusive belly' when you get back! LighterLife makes it easy for you to stay on track with your weight loss and still have fun while you're away. Here's what you need to know…
LighterLife makes weight loss easy with just a few simple rules to follow while you're on the plan – if you're on Total, you'll eat four Foodpacks a day, and when you're on Lite it's three Foodpacks a day, plus a meal. If you've planned a holiday this summer, you can continue to follow your plan while you're away – meaning you can spend less time worrying about food and more time enjoying your well-earned break!
Hold luggage
Most airlines accept you carrying Foodpacks in your hold luggage without any issues. Do check with your individual airline just to make sure it's fine to do so for the destination you are travelling to.
Hand luggage
Carrying LighterLife Foodpacks in your hand luggage shouldn't be a problem, but make sure your packs are unopened and undamaged. It's worth bearing in mind that individual airlines may operate different policies on hand luggage, so if you are concerned, do give them a quick call in advance to check on this.
Travelling to the US
For US trips, we wouldn't recommend taking Mousse Mix, as current import regulations don't permit entry – although other Foodpacks (including shakes, meals, bars and soups) should be fine.
Border-entry controls in some countries may require information regarding the use and content of Foodpacks, so we've produced a letter about them that you can present if requested, along with a list of ingredients. Contact your LighterLife Centre for more information.
Keep up to date
Since countries outside the EU have widely differing regulation on food imports, it's always a good idea to check ahead of time. One of the best sources of information is the British Foreign & Commonwealth Office's travel advice section here, where you can search for advice and links by country, or you could contact the embassy of the country you're visiting directly.
If you have any other questions, drop us a message on Facebook or Twitter or ring us on 0800 2 988 988.
Have a great holiday, and keep up the good work with your LighterLife plan!


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Dogs of 9-11
Today marks the 10 year anniversary of the horrific attacks on America. Today, I honour all of those who have lost their lives and the families who grieve those losses; all of the First Responders who have succumbed to disease or are mamed from the aftermath they heroically responded to; or our soldiers lost in the wars which have followed it. This is the sadness of mankind of all nations: radical extremism.
Today, I also honour the Dogs of 9/11 — I was honoured to have worked with 5 of them and their stories are below. Just click their names to read more.
- Biscuit — a dog rescued from a top of the rubble, with his story of trying to find his man after they were separated when the first plane hit the first tower of WTC.
- Dui —a Bernise Mountain Dog who saw the attacks coming in the weeks before they happened.
- Gitander —a First Responder Search and Rescue Dog who was killed in the line of duty back in his home town after he had returned from NYC.
- Louise —who leapt out of her people's car in Manhattan in fear just after the attacks and found her way to the docks where she rode the ferry back and forth to NJ, comforting traumatized people while being comforted herself.
- Sirius —the only working K9 to die during the attacks when the first tower fell while he was in his kennel in the basement.


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Heat use big third quarter to down HornetsJan 31, 2012 - 5:30 AM Miami, FL (Sports Network) - Every so often, a poor team can catch an elite team looking past it and steal a win.
Monday was not one of those occasions at American Airlines Arena.
LeBron James finished two assists shy of a triple-double with 22 points, 11 rebounds and eight helpers, and Dwyane Wade netted 22 points to go with five assists as the Miami Heat took care of business against a struggling New Orleans Hornets team with a 109-95 win.
Mike Miller finished with 14 points of 6-of-8 shooting, while Norris Cole and Chris Bosh had 12 points each for the Heat, who have won five straight and eight of their last nine.
Jarrett Jack and Carl Landry led the Hornets with 14 points apiece and Emeka Okafor added 13 in defeat. Greivis Vasquez netted 11 for New Orleans, which has now lost 11 of its last 12 games.
New Orleans got off to an incredibly hot start, knocking down 10 of their first 11 shots to lead 23-15 with 4:25 to play in the opening 12 minutes.
The Hornets led by as many as eight in the frame, but Miami stayed close and a layup by Cole with 0.6 seconds remaining cut the deficit to 29-27.
New Orleans opened the second quarter with an 16-6 burst to go ahead 45-33 with 5:46 to play before halftime.
But Miami answered with a 15-2 run to take a 48-47 lead with 2:41 to play before halftime. Wade netted 13 points during the run and capped it with a pair of free throws.
"It was good to have that energy burst. We were down 12 and we kind of needed it," Bosh said of Wade's quarter.
The Heat shot 56 percent in the quarter and led 51-49 at the break.
Miami kept the pressure on in the third quarter, scoring the first nine points of the frame to extend its lead to 60-49 early in the quarter.
James finished with 14 of his 22 points in the quarter and the Heat took a comfortable 87-68 margin into the fourth.
With Wade and James both on the bench for the duration of the fourth quarter, New Orleans played hard and outscored the Heat, 27-22, but the deficit was too large for it to make a full comeback.
"Tough game," Hornets head coach Monty Williams said. "In one sense we played really hard, in the other sense, we just didn't have the third quarter energy to match what they brought to the table."
Game Notes
Monday marked the first meeting of the season between the teams. They split two games last season, with each team holding home court...Hornets center Chris Kaman was not with the team because the Hornets are looking to trade him...Wade netted 15 points in the second quarter, his highest total for one quarter this season...New Orleans has not won a game this season when trailing at halftime...The Heat shot 55 percent from the floor and 6-of-15 from three- point range, while the Hornets shot 53 percent from the field and 4-of-13 from beyond the arc...Miami got the better of the play on the glass, outrebounding New Orleans, 39-25.
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Talstar P (Talstar One)
Buy Now
Jen from Baltimore, Md writes,
How long does it take from when a bug comes into contact with Talstar until it dies? 1 hour? one day?
does that timeline vary from bug to bug?
How long it takes an insect to die after coming into contact with an area that has been sprayed with Talstar P will depend on several factors. How long has the Talstar P application been in place (the longer it has been there the more degraded it is and the longer it will take an insect to die), age and size of the insect, What species is the insect (insects with piercing sucking mouth parts such as spiders and scorpions take longer to succumb) and How long has the insect sat on the dry deposits of Talstar P. Generally speaking you can expect most insects to die within 24-48 hours of contact.
Answer last updated on: 07/02/2012
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