An array substrate for an FFS mode LCD device includes a gate line and a gate pad electrode on a substrate; a common line parallel to the gate line; a data line extending along a second direction in a display area and a data pad electrode disposing in a non-display area; a thin film transistor electrically connected to the gate and data lines; a first passivation layer covering the thin film transistor and the data line; a second passivation layer on the first passivation layer and having a first thickness in the display area and a second thickness in the non-display area; a common electrode on the second passivation layer and connected to the common line; a third passivation layer on the common electrode; and a pixel electrode, a gate auxiliary pad electrode and a data auxiliary pad electrode on the third passivation layer.

1. Field of the Disclosure
The disclosure relates to a liquid crystal display device, and more particularly, to an array substrate for a fringe field switching (FFS) mode liquid crystal display (LCD) device and a method of manufacturing the same.
2. Discussion of the Related Art
Liquid crystal display (LCD) devices are driven based on optical anisotropy and polarization characteristics of a liquid crystal material. The LCD devices have been widely used for display units of portable electronic devices, monitors of personal computers, or televisions.
Liquid crystal molecules have a long and thin shape, and the liquid crystal molecules are regularly arranged along in an alignment direction. Light passes through the LCD device along the long and thin shape of the liquid crystal molecules. The alignment of the liquid crystal molecules depends on the intensity or the direction of an electric field applied to the liquid crystal molecules. By controlling the intensity or the direction of the electric field, the alignment of the liquid crystal molecules is controlled to display images.
Generally, an LCD device includes two substrates, which are spaced apart and facing each other, and a liquid crystal layer is interposed between the two substrates. Each of the substrates includes an electrode. The electrodes from respective substrates face one another. An electric field is induced between the electrodes by applying a voltage to each electrode. An alignment direction of liquid crystal molecules changes in accordance with a variation in the intensity or the direction of the electric field.
However, since the LCD device uses a vertical electric field that is perpendicular to the substrates, the LCD device has poor viewing angles.
To resolve the poor viewing angles, an in-plane switching (IPS) mode liquid crystal display (LCD) device has been suggested.
In an IPS mode LCD device, a pixel electrode and a common electrode are alternately disposed on the same substrate, and a horizontal electric field that is parallel to the substrate is induced between the pixel electrode and the common electrode. Liquid crystal molecules are driven by the horizontal electric field and move parallel to the substrate. Accordingly, the IPS mode LCD device has the improved viewing angles.
However, the IPS mode LCD device has disadvantages of low aperture ratio and transmittance. To solve the disadvantages of the IPS mode LCD device, a fringe field switching (FFS) mode LCD device has been suggested.
FIG. 1 is a cross-sectional view of illustrating a pixel region of an array substrate for a related art FFS mode LCD device, FIG. 2 is a cross-sectional view of illustrating a region for a common contact hole of the array substrate of the related art, and FIG. 3 is a cross-sectional view of illustrating a pad area for a data pad electrode of the array substrate of the related art.
In FIG. 1, FIG. 2 and FIG. 3, a gate line (not shown), a gate electrode 5 and a common line 7 are formed on a transparent insulating substrate 1. As not shown in the figures, a gate pad electrode is connected to one end of the gate line.
A gate insulating layer 10 is formed on the gate line, the gate electrode 5, the common line 7, and the gate pad electrode all over the substrate 1.
A semiconductor layer 20 including an active layer 20a and ohmic contact layers 20b is formed over the gate insulating layer 10 corresponding to the gate electrode 5, and source and drain electrodes 33 and 36 spaced apart from each other are formed over the semiconductor layer 20. A data line (not shown) is formed over the gate insulating layer 10. The data line crosses the gate line to define a pixel region P. A data pad electrode 31 is formed in a pad area PA and is connected to one end of the data line. A semiconductor dummy pattern 21 including a first pattern 21a and a second pattern 21b is formed under the data pad electrode 31.
The gate electrode 5, the semiconductor layer 20, the source electrode 33 and the drain electrode 36 constitute a thin film transistor Tr.
A first passivation layer 40 of an inorganic insulating material is formed on the data line, the data pad electrode 31, and the source and drain electrodes 33 and 36. A second passivation layer 50 of an organic insulating material is formed on the first passivation layer 40 and has a flat top surface. The second passivation layer 50 is removed in the pad area PA.
A common contact hole 55 is formed in the first and second passivation layers 40 and 50 and the gate insulating layer 10 and exposes the common line 7.
A common electrode 60 is formed on the second passivation layer 50 and is connected to the common line 7 through the common contact hole 55. The common electrode 60 has a first opening op1 corresponding to a switching area TrA in the pixel region P.
A third passivation layer 63 of an inorganic insulating material is formed on the common electrode 60. Since the second passivation layer 63 is removed in the pad area PA, the third passivation layer 63 is formed directly on the first passivation layer 40 in the pad area PA.
A drain contact hole 68 is formed in the first, second and third passivation layers 40, 50 and 63 and exposes the drain electrode 36 of the thin film transistor Tr.
A pixel electrode 70 of a transparent conductive material is formed on the third passivation layer 63 in the pixel region P and is connected to the drain electrode 36 through the drain contact hole 68. The pixel electrode 70 includes a plurality of second openings op2, which each have a bar shape and are spaced apart from each other.
The array substrate for a related art FFS mod LCD device is manufactured by seven mask processes. A method of manufacturing the array substrate will be briefly explained.
FIGS. 4A to 4C are cross-sectional views of illustrating a pixel region of an array substrate for a related art FFS mode LCD device in steps of manufacturing the same, FIGS. 5A to 5C are cross-sectional views of illustrating a region for a common contact hole of the array substrate in steps of manufacturing the same, and FIGS. 6A to 6C are cross-sectional views of illustrating a pad area for a data pad electrode of the array substrate in steps of manufacturing the same. FIGS. 4A to 4C, FIGS. 5A to 5C, and FIGS. 6A to 6C show steps of forming first and second passivation layers on a substrate.
In FIG. 4A, FIG. 5A and FIG. 6A, a gate line (not shown), a gate pad electrode (not shown), a common line 7 and a gate electrode 5 are formed on a first substrate in a first mask process. A gate insulating layer 10 is formed on the gate line, the gate pad electrode, the common line 7 and the gate electrode 5 all over the substrate 1. A data line (not shown), a data pad electrode 31, source and drain electrodes 33 and 36, and a semiconductor layer 20 are formed over the gate insulating layer 10 in a second mask process. The data line and the data pad electrode 31 are disposed directly on the gate insulating layer 10. The semiconductor layer 20 and the source and drain electrodes 33 and 35 are sequentially on the gate insulating layer 10 corresponding to the gate electrode 5.
Next, a first passivation layer 40 of an inorganic insulating material is formed on the data line, the data pad electrode 31, and the source and drain electrodes 33 and 36 all over the substrate 1.
Then, a second passivation layer 50 of an organic insulating material is formed on the first passivation layer 40 and has a flat top surface. The second passivation layer 50 is patterned in a third mask process, thereby forming a first hole hl1 and a second hole hl2 exposing the first passivation layer 40 corresponding to the drain electrode 36 and the common line 7, respectively, and exposing the first passivation layer 40 in a pad area PA where the data pad electrode 31 is formed and in a gate pad area (not shown) where the gate pad electrode is formed.
If the second passivation layer 50 remains in the gate pad area and the pad area PA, gate and data auxiliary pad electrodes, which are formed later, should be formed too deeply due to the second passivation layer 50, or diameters of pad contact holes exposing the gate and data pad electrodes increase because of a thickness of the second passivation layer 50. In this case, when a printed circuit board is connected to the gate and data auxiliary pad electrodes, conductivity is lowered because conductive balls in an anisotropic conductive film (ACF) used as an adhesive do not break, or stability in electrical connection between the array substrate and the printed circuit board declines because the conductive balls go into the pad contact holes. Thus, to prevent the problems, the second passivation layer 50 is removed in the pad area PA and the gate pad area.
In FIG. 4B, FIG. 5B and FIG. 6B, a photoresist layer (not shown) is formed on the second passivation layer by applying photoresist and is patterned in a fourth mask process, thereby forming a photoresist pattern 81 that exposes the first passivation layer 40 corresponding to the second hole hl2.
Then, a common contact hole 55 exposing the common line 7 is formed by removing the first passivation layer 40 and the gate insulating layer 10 corresponding to the second hole hl2.
Next, in FIG. 4C, FIG. 5C and FIG. 6C, the photoresist pattern 81 of FIG. 4B, FIG. 5B and FIG. 6B on the first passivation layer 40 in the pad area PA and the second passivation layer 50 is removed to there expose the first passivation layer 40 in the pad area PA and the second passivation layer 50.
In the array substrate according to the related art, the second passivation layer 50 is substantially formed through 2 mask processes.
Next, referring to FIG. 1, FIG. 2 and FIG. 3, a common electrode 60 is formed on the second passivation layer 50 in a fifth mask process and is connected to the common line 7 through a common contact hole 55. The common electrode 60 includes a first opening op1.
A third passivation layer 65 is formed on the common electrode 60, and the third passivation layer 65 and the first passivation layer 40 corresponding to the first hole hl1 of FIG. 4C are removed in a sixth mask process to thereby form a drain contact hole 68 exposing the drain electrode 36.
Next, a pixel electrode 70 is formed on the third passivation layer 65 in the pixel region P in a seventh mask process and is connected to the drain electrode 36 through the drain contact hole 68. The pixel electrode 70 includes second openings op2 each having a bar shape and spaced apart from each other.
Therefore, the array substrate of the related art is completed by performing seven mask processes. By the way, since each mask process includes several steps of deposition, light-exposure, development, etch, and so on, the more mask processes are performed, the lower productivity decreases and the more manufacturing costs increase.

Array substrate for fringe field switching mode liquid crystal display device and method of fabricating the same


Relates to writing an array of optical elements which are each switched between two states according to input data sets. In a first method, data is written in two steps in which different selected elements are respectively driven to one binary state and the other binary state. The selected elements of the two sets may be complementary, but are preferably only those which are required to change from their existing state. The latter criterion may be used in an alternative method using a single addressing of the array to turn elements in either direction as required. In a further method, as shown, selected elements only of a blank array are written in a first WRITE step so as to correspond with a set of data, and in a subsequent second ERASE step the selected elements are selectively erased to restore a blank array prior to writing and erasing another set of data. The methods have particular utility for maintaining a dc balance at pixels of a liquid crystal array.

This application in the U.S. national phase of International Application No. PCT/GB99/04275, filed Dec. 16, 1999, the entire content of which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to methods of driving a array of optical elements. It has particular but not exclusive relevance to the driving of a spatial light modulator.
2. Discussion of Prior Art
The spatial light modulator to be described in relation to a preferred embodiment in this specification is a in the form of a smectic liquid crystal layer disposed between an active semiconductor backplane and a common front electrode. It was developed in response to a requirement for a fast and, if possible, inexpensive, spatial light modulator comprising a relatively large number of pixels with potential application not only as a display device, but also for other forms of optical processing such as correlation and holographic switching. Other aspects of this device are dealt with in our copending International Patent Applications of even filing and priority dates (PCT/GB99/04285, U.S. Ser. No. 09/868,219, priority GB9827952.4; PCT/GB99/04286 and PCT/GB99/04276, U.S. Ser. No. 09/868,230 and U.S. Ser. No. 09/868,220, both priority GB9827965.6; PCT/GB99/04282, U.S. Ser. Nos. 09/446,325 and 10/084,652, priority GB9827900.3; PCT/GB99/04279, U.S. Ser. No. 10/085,140, priority GB9827901.1; PCT/GB99/04274, U.S. Ser. Nos. 09/868,218 and 10/094,958, priority GB9827964.9; and PCT/GB99/04260 and PCT/GB99/04277, U.S. Ser. No. 09/868,242, both priority GB 9827944.1).
During the course of development of this spatial light modulator, a series of problems were encountered and dealt with, and the solutions to these problems (whether in the form of construction, function or method) are not necessarily restricted in application to the embodiment, but will find other uses. Thus not all of the aspects of the present invention are necessarily limited to liquid crystal devices, nor to spatial light modulators. Nevertheless, it is useful to commence with a discussion of the problems encountered in developing the embodiment to be described later.
The liquid crystal phase has been recognised since the last century, and there were a few early attempts to utilise liquid crystal materials in light modulators, none of which gave rise to any significant successful commercial use. However, towards the end of the 1960""s and in the 1970""s, there was a renewed interest in the use of liquid crystal materials in light modulating, with increasing success as more materials, and purer materials became available, and as technology in general progressed.
Generally speaking, this latter period commenced with the use of nematic and cholesteric liquid crystal materials. Cholesteric liquid crystal materials found use as sensors, principally for measuring temperature or indicating a temperature change, but also for responding to, for example, the presence of impurities. In such cases, the pitch of the cholesteric helix is sensitive to the parameter to be sensed and correspondingly alters the wavelength at which there is selective reflection of one hand of circularly polarised light by the helix.
Attempts were also made to use cholesteric materials in electro-optic modulators, but during this period the main thrust of research in this area involved nematic materials. Initial devices used such effects as the nematic dynamic scattering effect, and increasingly sophisticated devices employing such properties as surface induced alignment, the effect on polarised light, and the co-orientation of elongate dye molecules or other elongate molecules/particles, came into being.
Some such devices used cells in which the nematic phase adopted a twisted structure, either by suitably arranging surface alignments or by incorporating optically active materials in the liquid crystal phase. There is a sense in which such materials resemble cholesteric materials, which are often regarded as a special form of the nematic phase.
Initially, liquid crystal light modulators were in the form of a single cell comprising a layer of liquid crystal material sandwiched between opposed electrode bearing plates, at least one of the plates being transparent. Such cells were slow to operate and tended to have a short life due to degradation of the liquid crystal material. Quite early on it was recognised that the application of an average dc voltage to the liquid crystal cell was not beneficial, and at least in some cases produced degradation by electrolysis of the liquid crystal material itself, and schemes were evolved to render the average dc voltage to zero (dc balance).
It is now appreciated that other effects are also at work when a dc voltage is applied. When driving liquid crystal electro-optic devices for any length of time, a phenomenon known as image sticking may occur. Although the precise cause of this effect is unknown, there are theories that ions are trapped or a space charge is induced within the material in response to an overall dc field, and this results in a residual field even when the external dc field is removed. Whether to avoid electrolytic breakdown, or to avoid image sticking, it is evidently desirable that the time averaged voltage (that is, the average over the time that the voltage is actually being applied from an external source to the liquid crystal) applied to a liquid crystal material is zero.
The thickness of the liquid crystal layer in nematic cells is commonly around 20 to 100 microns, and there is a correspondingly small unit capacitance associated with a nematic liquid crystal cell. Furthermore, the switching time from a wholly xe2x80x9cOFFxe2x80x9d state to a wholly xe2x80x9cONxe2x80x9d state tends to be rather long, commonly around a millisecond. Relaxation back to the xe2x80x9cOFFxe2x80x9d state can be somewhat longer, unless positively driven, but the xe2x80x9cOFFxe2x80x9d state is the only stable one.
At the same time, electro-optic nematic devices comprising a plurality of pixels were being devised. Initially, these had the form of a common electrode on one side of a cell and a plurality of individually addressable passive electrodes on the other side of the cell (e.g. as in a seven-segment display), or, for higher numbers of pixels, intersecting passive electrode arrays on either side of the cell, for example row and column electrodes which were scanned. While the latter arrangements provided considerable versatility, there were problems associated with cross-talk between pixels.
The situation was exacerbated when analogue (grey scale) displays were required by analogue modulation of the applied voltage, since the optical response is non-linearly related to applied voltage. Addressing schemes became relatively complicated, particularly if dc balance was also required. Such considerations, in association with the relative slowness of switching of nematic cells, have made is difficult to provide real-time video images having a reasonable resolution.
Subsequently, active back-plane devices were produced. These comprise a layer of liquid crystal material disposed between a back plane and a spaced opposed substrate. The backplane comprises a plurality of active elements, such as transistors, for energising corresponding pixels. Energisation normally involves cooperation with one or more counterelectrodes disposed on the opposed substrate, although it would be possible to provide counterelectrodes in the backplane itself for fields generally parallel to the plane of the liquid crystal layer.
Two common forms of backplane are thin film transistor on silica/glass backplanes, and semiconductor backplanes. The active elements can be arranged to exercise some form of memory function, in which case addressing of the active element can be accelerated compared to the time needed to address and switch the pixel, easing the problem of displaying at video frame rates.
Active backplanes are commonly provided in an arrangement very similar to a dynamic random access memory (DRAM) or a static random access memory (SRAM). At each one of a distributed array of addressable locations, a SRAM type active backplane comprises a memory cell including at least two coupled transistors arranged to have two stable states, so that the cell (and therefore the associated liquid crystal pixel) remains in the last switched state until a later addressing step alters its state. Each location electrically drives its associated liquid crystal pixel, and is bistable per se, i.e. without the pixel capacitance. Power to drive the pixel to maintain the existing switched state is obtained from busbars which also supply the array of SRAM locations. Addressing is again normally performed from peripheral logic and column and row addressing lines.
In a DRAM type active backplane, a single active element (transistor) is provided at each location, and forms, together with the capacitance of the associated liquid crystal pixel, a charge storage cell. Thus in this case, and unlike a SRAM backplane, the liquid crystal pixels are an integral part of the DRAM of the backplane. There is no bistability associated with the location unless the liquid crystal pixel itself is bistable, and this is not the case so far as nematic pixels are concerned. Instead, reliance is placed on the active element providing a high impedance when it is not being addressed to prevent leakage of charge from the capacitance, and on periodic refreshing of the DRAM location.
In contrast to the type of RAM associated with computing, the pixel circuits, and more significantly the pixel transistors, are often at least partially exposed to light. This can lead to problems, especially with DRAM type backplanes where the pixels are part of the DRAM circuit, including photo-induced conductivity and charge leakage. This aspect is dealt with in greater detail in our copending application PCT/GB99/04279, U.S. Ser. No. 10/085,140.
Thin film transistor (TFT) backplanes comprise an array of thin film transistors distributed on a substrate (commonly transparent) over what can be a considerable area, with peripheral logic circuits for addressing the transistors, thereby facilitating the provision of large area pixellated devices which can be directly viewed. Nevertheless, there are problems associated with the yields of the backplanes during manufacture, and the length of the addressing conductors has a slowing effect on the scanning. When provided on a transparent substrate, such as of glass, TFT arrays can actually be located on the front or rear surface of a liquid crystal display device.
In view of their overall size, the area of the TFT array occupied by the transistors, associated conductors and other electrical elements, e.g. capacitors is relatively insignificant. There is therefore no significant disadvantage in employing the SRAM configuration as opposed to the DRAM configuration. This sort of backplane thus overcomes many of the problems associated with slow switching times of liquid crystal pixels.
Generally, the active elements in TFT backplanes are diffusion transistors and the like as opposed to FETS, so that the associated impedances are relatively low and associated charge leakage relatively high in the xe2x80x9cOFFxe2x80x9d state.
Semiconductor active backplanes are limited in size to the size of semiconductor substrate available, and are not suited for direct viewing with no intervening optics. Nevertheless their very smallness aids speed of addressing of the active elements. This type of backplane commonly comprises FETs, for example MOSFETs or CMOS circuitry, with associated relatively high impedances in the xe2x80x9cOFFxe2x80x9d state.
However, the smallness also means that the area of the overall light modulation (array) area occupied by the transistors, associated conductors and other electrical elements, e.g. capacitors can be relatively significant, particularly in the SRAM type which requires many more elements than the DRAM type. Being opaque to visible light, a semiconductor backplane would provide the rear substrate of a light modulator or display device.
At a later period still, substantial development occurred in the use of smectic liquid crystals. These have potential advantages over nematic phases insofar as their switching speed is markedly greater, and with appropriate surface stabilisation the ferroelectric smectic C phases should provide devices having two stable alignment states, i.e. a memory function.
The thickness of the layer of liquid crystal material in such devices is commonly much smaller than in the corresponding nematic devices, normally being of the order of a few microns at most. In addition to altering the potential switching speed, this increases the unit capacitance of a pixel, easing the function of a DRAM active backplane in retaining a switched state at a pixel until the next address occurs.
However, as the liquid crystal thickness approaches the thicknesses associated with the underlying structure of the backplane, and any possible deformation of the liquid crystal cell structure by flexing or other movement of the substrates, problems arise, for example as to the uniformity of response across the pixel area, and the capability for short circuiting across the cell thickness. These factors are dealt with in more detail in our copending applications PCT/GB99/04285, U.S. Ser. No. 09/868,219; and PCT/GB99/04282, U.S. Ser. Nos. 09/446,325 and 10/084,652.
The possibility of long relaxation times, or even of bistability, of the liquid crystal cell or pixel, facilitates the introduction of a relatively new digital technique when a grey scale image is required, in which pixels are turned xe2x80x9cONxe2x80x9d for a fraction of the viewing period according to the grey level. Essentially, the image is computationally decomposed to a series of bit planes in which each pixel is either xe2x80x9cONxe2x80x9d or xe2x80x9cOFFxe2x80x9d, the bit planes being sequentially displayed. In a preferred form, the (normally binary) weighted bit plane technique, the durations of the bit planes are weighted thereby reducing the number of bit planes required to synthesise an image, and reducing addressing requirements somewhat.
Pixel Structurexe2x80x94Switching and Address Times When using a SRAM type backplane to switch a capacitive element the time necessary to address the location on the backplane can be as small as is necessary to switch that location, regardless of whether the capacitive element has responded. The location is always coupled to the power supply, and can continue to supply power (current/voltage) to the capacitive element after the addressing pulse has ceased.
By contrast, power is supplied to a capacitive element from a DRAM location only while addressing is taking place, after which the active element (transistor) is turned off. If the addressing pulse is insufficiently long for transfer of the requisite amount of charge, the capacitive element is incompletely switched. This is likely to occur, for example, when the capacitive element includes ferroelectric material, as in some smectic liquid crystal cells, and the addressing time is short, for example in a large scale array.
One solution is to provide an additional xe2x80x9cslugxe2x80x9d capacitance which is rapidly charged during the addressing pulse and so can provide a reservoir of charge while the capacitive element switches over a longer time period. This aspect is dealt with in more detail in our copending application PCT/GB99/04279, U.S. Ser. No. 10/085,140, which relates to the provision of a semiconductor active backplane including an array of addressable active elements on a semiconductor substrate for energising respective first electrodes, wherein at least part of the region beneath a said electrode is adapted to act as a capacitor. In particular said part may be formed as a depletion region whereby in use it acts as a reverse biassed diode, or individual capacitor plates may be formed beneath the electrode, one coupled to the substrate and the other coupled to the electrode.
Smectic Liquid Crystal Electro-Optic Cells In the smectic liquid crystal phase, the molecules exhibit positional order (xe2x80x9clayersxe2x80x9d) in addition to the orientational order exhibited by the cholesteric and nematic phases. There are a number of different smectic sub-phases which differ in the orientational order within the overall structure of the smectic layers, the most common being the smectic A phase (SmA) and the smectic C phase (SmC).
The common alignment for smectic materials is planar (molecules generally parallel to the major cell surfaces) with the smectic layers normal to the plane of the cell, as this permits the field to be applied across the cell thickness. It is possible to obtain homeotropic alignment with the smectic layers in the cell plane, and such a device could provide a fast refractive index modulator. However, in order to apply appropriate electric fields for switching, very small electrode gaps are required and therefore such devices tend to have very small active areas, and as a consequence this type of device is relatively uncommon.
In the smectic A phase the director is normal to the plane of the layers. Application of an electric field perpendicular to the director causes the latter to tilt about an axis parallel to the applied field by an amount approximately linearly dependent of field strength, making it possible to achieve analogue grey scale modulation. Polarisation of the light is affected, so that intensity or phase modulation may be achieved, and since the rotation of the director is in the plane of the cell, normally incident light is always perpendicular to the optic axis of the material. Coupled with the thinness of the cell, this leads to improved viewing angles for such devices. This effect, called the electroclinic effect, is extremely fast, switching times down to around 100 nanoseconds having been observed.
In the smectic C phase, the director forms a constant (xe2x80x9ctiltxe2x80x9d) angle with the plane of the smectic layers. The tilt angle depends on the material and the temperature, and defines a cone with its tip on the smectic layer and its axis normal to the layer, all possible positions of the director lying on the cone surface. In the bulk of a chiral smectic C phase (SmC*) the director precesses from layer to layer as in a helix.
In the chiral smectic C phase, liquid crystal materials are ferro-electric, having a permanent dipole, sometimes termed spontaneous polarisation (Ps). In the bulk material, P, rotates in the plane of the layer as the director precesses, so no net effect is observable. Bulk ferro-electricity can be observed if the precession is suppressed, either by surface stabilisation of the director positions such that only the two orientations of director which lie in the plane of the device are possible, and/or by back-doping with a chiral material of the opposite hand.
Smectic C* materials can be broadly divided into two classes known as high and low tilt materials respectively. Class I materials have the phase sequence isotropic-nematic-smectic A*-smectic C*, and tend be low tilt materials, having tilt angles generally grouped up to around 22.5xc2x0 (cone angle of 45xc2x0); class II materials have the phase sequence isotropic-nematic-smectic C*, and tend to be high tilt materials with greater tilt angles. Materials with a cone angle greater than 75xc2x0 are rare, although for holographic applications, which require phase modulation, a cone angle of 90xc2x0 would be ideal.
With low tilt materials, the smectic layers are inclined relative to the cell surface rather than at right angles, such that the director cone has a tilted axis and its surface is tangential to the cell surface. For high tilt materials the cone axis is normal to the cell surface.
When the structure is surface stabilised, then in theory, at least for Class I materials there is no preference between the two states of a low tilt material and a bistable structure should result. Surface stabilisation can be achieved simply by making the layer in the cell thin. The two states will have different effects on polarised light, and so can provide intensity or phase modulation. In practice, it is very difficult or impossible to obtain true bistability, especially on silicon backplanes and there will a slight preference for one state over the other. Nevertheless, this should give rise to relatively long relaxation times.
For high tilt materials, the two states are not equal, and one state is preferred over the other, so that there is monostability in the absence of any other factor. The two states are such that phase modulation of light may be obtained, and, indirectly, intensity modulation, e.g. in holographic applications. Both high and low tilt materials may be used in the spatial light modulator of the invention.
Stability/Relaxation The presence of the spontaneous polarisation, and its realignment as the liquid crystal molecules realign under the influence of an electric field, leads to a significant additional current or charge flow during realignment, e.g. between electrodes either side of a smectic layer. A pixel of area A will consume a charge of 2APs during switching. This factor is particularly important when pixel switching is controlled by a DRAM type of active backplane, when pixel capacitance and Ps become important design parameters. It should also be noted that charge consumption reduces the field across the electrodes in such devices if the addressing pulse is insufficiently long to accommodate pixel switching, as in the present preferred embodiment.
As has already been noted, the use of the backplanes described herein is not limited to liquid crystal devices. However, these backplanes are particularly suited for use in the manufacture of liquid crystal devices. Again, although it is possible to employ nematic or cholesteric materials in such devices, it is preferred to employ smectic materials because of their faster switching action.
Other reasons for preferring smectic materials are the fast switching times; and, in the case of using a DRAM type active backplane (this does not apply when the backplane is the SRAM type since power/current can be continuously applied to each pixel), the ability to extend the relaxation time, or even to obtain a bistable effect, once the pixel has been placed in the desired state. One advantage of having a fast switching time in the case where relaxation occurs lies in the increase of the fraction of the pixel repeat address period usable for viewing time. Another advantage, particularly where optical processing is concerned is the increase in data throughput.
Electrostatic Stabilisation The charge consumption which occurs when a pixel is switched in one direction gives rise to a corresponding generation of charge when the pixel switches in the other direction. Therefore, if a switched pixel is completely electrically isolated, charge cannot flow and the pixel cannot relax. In operation of a DRAM type array, this may be effected by turning off all the transistors of the array, and in the preferred embodiment this is made possible by applying a global reset signal NRAR to the row scanners. Also, in some embodiments of addressing scheme, all the transistors are left in the off state once all the rows in the frame have been scanned, until the start of the next frame scan. (Other embodiments of addressing scheme, including those with ac stabilisation, do require transistors to be left on).
In practice, charge leakage cannot be completely eliminated, and so relaxation will occur, but over an extended period. A common cause of charge leakage is photoconductivity associated with the slug capacitance mentioned earlier and/or photoconductive or other leakage currents in the associated switching transistor of the DRAM array.
Electrical isolation is thus a useful but imperfect tool for prolonging relaxation times. It will be appreciated that whether a long relaxation time is achieved through an appropriate choice of material and cell design, or by electrical isolation, the important factor is that sufficient time can be allowed between successive addressings of any pixel for it to be maintained essentially in its desired state.
AC Stabilisation During relaxation, the director rotates out of the plane of the device to the alternative position. If an electric field is applied to a material, the field itself induces a polarisation of the material, and the polarisation reacts to the field, resulting in a torque that is proportional to the square of the field and so independent of field polarity. With a material having negative dielectric anisotropy this torque acts to maintain the molecule in the plane of the pixel, thereby xe2x80x9clockingxe2x80x9d the liquid crystal director orientation in either of its switched states. Thus the continuous application of an alternating electrical field between successive addressings (which at least in some cases is of low amplitude relative to the switching voltage) prevents relaxation of the director to the alternative orientation. Any tendency for the director to rotate from either of the two preferred orientations is effectively immediately counteracted by the ac field which returns the director to the orientation that it should have. The effect should obtain for as long as the ac field is present, so that the device behaves as if it were bistable.
In a DRAM array device this effect can be obtained by globally turning on all of the DRAM switching transistors, applying the same dc signal (e.g. zero or V volts) to all of the column electrodes, and by applying an ac voltage to the common front electrode with dc level corresponding to that applied to the column electrodes.
This endless prolongation of the switched pixel states is particularly important in certain types of optical processing where the same optical state may need to be maintained for days, months or even years.
It is therefore clear that during operation of the array it would be desirable to be able simultaneously to enable a plurality of the rows, and more preferably all the rows, so that all of the enabled pixels down each column may be brought simultaneously to the same state. This has already been mentioned in connection with the provision of blanking and ac stabilisation for prolonging the switched state of a pixel, and it is also desirable insofar as it permits the length of time that a dc pulse of potential is applied to be clearly and precisely defined, which is desirable when considering dc balancing. Following such enabling, and where as stabilisation is not used, it is also desirable to disable the enabled transistors, preferably a global disable over the entire array, to prevent relaxation due to short circuiting of a liquid crystal cell, for example.
In the embodiment to be described hereafter, where the parallel data fed to the columns is identical, and all of the rows are enabled, the whole array can be brought to zero or one, thereby blanking the array. If the parallel data along the columns is varied, a vertically striped image is produced.
If the potential difference between the front electrode and the columns during blanking is zero, the pixels will be short circuited, thereby permitting relaxation to take place. Alternatively, the potential difference may be a positive or negative dc, thus driving all of the pixels relatively rapidly on or off. If the dc potential difference is zero but a small ac voltage is present, preferably on the common front electrode for ease of application, in certain circumstances the pixels can be maintained in their existing states, as described in more detail elsewhere in this specification (ac stabilisation).
Our copending application PCT/GB99/04274, U.S. Ser. Nos. 09/868,218 and 10/094,958 relates to the provision of an array of electrically addressable elements, said array comprising a plurality of mutually exclusive sets of said elements, means arranged to address said sets one at a time, and means for addressing more than one (and preferably all) of said plurality of sets (the xe2x80x9cselected setsxe2x80x9d) simultaneously. While the most common form of array is arranged as addressable rows (the sets) and columns, other arrangements are possible, for example based on polar co-ordinates (distance and angle). However, modern computing methods and standards converters have tended to make other formats redundant in the majority of cases.
Although, as will be seen, the facility of being able to address all pixels of the array simultaneous is highly desirable in practising the methods of the present invention, it is not essential, and there are cases where the simultaneous addressing step could be replaced by a further writing operation.
The present invention is intended to facilitate the achievement of dc balance while driving an array of binary elements.
In a first aspect, the present invention provides a method of writing an array of optical elements in a succession of cycles to alter their states according to respective ones of a series of input data sets, each cycle comprising a first step wherein selected elements only of an optically blank of uniform array are written as determined by a respective data set, and a second step wherein the selected elements are selectively erased to restore a blank array prior to another cycle.
In a second aspect, the invention provides an electro-optic arrangement comprising an array of electro-optic elements and control means responsive to a series of input data sets, the control means being arranged to respond to each data set so that starting with an optically blank or uniform array of elements in a first step selected elements are written as determined by the data set, and in a second step the selected elements are selectively erased to revert to a blank array prior to writing elements as determined by a successive data set.
The array of optical/electro-optic elements may comprise a corresponding array of addressable active elements (e.g. pixel electrodes for example formed on an active backplane, preferably a semiconductor backplane), and an electrode spaced from said corresponding array, each optical/electro-optic element being defined between said electrode and a corresponding active element. The spaced electrode may be common to all elements of the array.
In one preferred form of the method, during the first step the active elements and the spaced electrode are operated to apply a first potential difference across the selected optical/electro-optic elements, and during the second step the active elements and the spaced electrode are operated to apply a second potential difference across the selected elements, the first and second potential differences having opposite signs, and, preferably, equal amplitudes.
More preferably, the potential applied to the spaced electrode may be switched between first and second values, with the output of the whole array of addressable active elements also being similarly switched between said first and second values of potential substantially synchronously with the switching of the front electrode. The potential applied to said first electrode may have the second value only during said second step.
The optical/electro-optic elements may comprise liquid crystal material located between the array and the spaced electrode, and they may be bistable or monostable.
It is desirable that between the first and second steps all the elements of the array are simultaneously addressed to impose zero potential difference thereacross. This serves effectively to provide a defined period for each individual element during which dc has been applied across it, and so enables dc balance to be more precisely determined.
In the preferred embodiment, the array comprises a plurality of mutually exclusive sets of the optical/electro-optic elements, means arranged to address the sets one at a time, and means for addressing more than one (and preferably all) of said plurality of sets (the xe2x80x9cselected setsxe2x80x9d) simultaneously. In such a case, a preferred method of producing a binary image includes the step of simultaneously addressing all the elements of the array once they have been written. During this step the elements are subjected to a common signal such that they receive (a) an ac signal, for ac stabilisation; or, for electrostatic stabilisation or for other purposes (for example providing a clearly defined time during which a dc signal is applied for dc balancing purposes) either (b) zero volts; or (c) a finite dc voltage. Where dc or zero volts is applied, this may be subsequently terminated by application of an ac stabilising signal, or by turning the elements off, i.e. open circuit, for electrostatic stabilisation.
UK Patent Application Serial No GB2247974A is directed to refreshing an existing image in a manner designed to avoid dc imbalance, effectively involving image reversal. It is not directed to writing of a new image or images, nor is there any teaching concerning the writing of a succession of (different) images so as to maintain dc balance. In a first embodiment all elements of the array are addressed by a positive or negative voltage during each array scan. In cases where there is a fixed front electrode voltage, it is understood that all the column electrodes are addressed with positive or negative voltages so as to write a full (inverted or negative) array of pixels in the normal way during a single scan, followed by rewriting of the non-inverted image. In cases where there is an alternating front electrode voltage, after driving all pixels to the same optical state (blanking), the state of a selected set pixels is reversed to give a fully written array. The array is subsequently blanked to the opposite optical state and the state of the complementary set of pixels is reversed to give the same optical written array. This type of blanking is unnecessary in the present invention.
UK Patent Application Serial No. GB2173336A is also concerned with dc balancing of liquid crystals which switch only above a threshold voltage. A row, or set of rows is blanked, followed by the application of column data in the form of dc balanced bipolar data pulses together with a dc strobe pulse on the row. The latter pulse coacts with one of the bipolar data pulses but not with the other, to change the state of a pixel. The overall polarity of the set-up, including the polarity of the strobe and blanking pulses, is periodically inverted (regularly or randomly) to maintain overall dc balance. The methods of present invention do not necessitate blanking, but rather they could be regarded as requiring selective alteration of pixels as needed.
International Patent Application No. WO 92/04710 disclosed a scheme in which any liquid crystal element is only driven on or off when a change of state therein is required, otherwise it remains unaddressed. Each pixel can therefore be subjected only to alternate turn-on and turn-off pixel pulses of well-defined and equal lengths, thus automatically affording dc balance in the long term.
The use of intervening uniformly blank images in the manner required by the present invention is not disclosed in this prior art.

Methods of driving an array of optical elements


Techniques for determining a clock offset between monitoring devices in a network. Such techniques include: obtaining, by a first monitoring device, a first set of network traffic data units sent between a first endpoint and a second endpoint via a first tap on a network link between the first endpoint and second endpoint; obtaining, by a second monitoring device, a second set of network traffic data units sent between the first endpoint and the second endpoint via a second tap on the network link; calculating the clock offset between the first monitoring device and the second monitoring device using the first set of network traffic data units and the second set of network traffic data units; and performing an offset action based on the clock offset.

Devices within and/or operatively connected to a network often transmit and receive network traffic data units (e.g., packets). It is often useful to understand information about the time that such transmissions and receipts occur. For example, it may be useful to synchronize the clocks of sending and receiving devices, or time monitoring devices attached to sending/receiving devices, in order to understand the order in which events in a network happened. Various schemes exist for clock synchronization (e.g., Precision Time Protocol (PTP), Network Time Protocol (NTP), etc.). However, such protocols may be limited to time synchronization that is insufficient for certain situations. Additionally, such protocols use in-band exchanges of information, which may negatively impact bandwidth available for other network traffic not related to clock synchronization.


A method for producing a porous thin film with variable transmittance, includes placing a polymer into an oven for an drying process to remove water vapor from the polymer and obtain a dry polymer; mixing the dry polymer, a salt and a solvent in accordance with a mixing ratio so as to obtain a first mixed solution; placing the first mixed solution into an ultrasonic vibrator, dissolving the salt to form a second mixed solution; coating the second mixed solution on a glass plate to form a solution thin film; placing solution thin film into an exhaust cabinet to obtain a composite thin film; and washing the composite thin film to remove the salt from the composite thin film to obtain a porous thin film wherein the polymer is a polyacrylonitrile, the salt is a lithium chloride, the porous thin film changes its transmittance via dry and wet state.

1. Field of the Invention
This invention is related to a method for producing a porous thin film with variable transmittance, and more particular to a porous thin film produced by means of water absorption characteristic of salt which can change the light transmittance of the porous thin film under a dry state and a hydrous state.
2. Description of Related Art
The conventional optical transmittance and reflectance control technology is to add an electric field to a general liquid crystal layer made of a liquid crystal material in the liquid crystal display, which twists the liquid crystal molecules and changes the polarization direction of a light propagation, and then the polarization direction of a light propagation is filtered by the polarizer, so as to control the transmittance.
For example, photochromic lenses are plated a compound thin film via a glass lens. The compound thin film produces a chemical reaction by ultraviolet radiation, and thereby the chemical structure is changed, resulting in the corresponding change of the optical transmittance, reflectance or absorption rate.
In another example, the electrochromic technology uses an added electric field to allow the ions to be injected into a photochromic material, which changes the color of the photochromic material, and further changes light transmittance, reflectance and absorption rate of the photochromic material. The electrochromic technology can be applied in the areas of green energy industry and electronic goods, such as the electrochromic glasses used in construction materials, which are used to regulate the light transmittance between outdoors and indoors; and the electrochromic technology can be also applied to the flexible electronic paper.
However, in order to advocate the green energy technology, the above mentioned control technology of the liquid crystal polarization and the electrochromic technology need external power to work, which needs more which needs more power while in use, and the manufacturing costs of both technologies are also high.
The transmittance change in the compound thin film on the photochromic lenses is only a change in color, the compound thin film still belongs to a transparent film, so that its application range is limited. Therefore, how to develop a thin film with low usage cost, low manufacturing cost and more than 50% transmittance change are the lessons the industry needs to resolve.

Method for producing porous thin film with variable transmittance


In one aspect, a movable barrier operator enhancement device is provided that includes communication circuitry configured to transmit a radio frequency control signal to a movable barrier operator and a memory configured to store a first transmitter identification (ID) and a changing code for the radio frequency control signal. The device includes a processor configured to change the first transmitter ID to a second transmitter ID in response to a determination of a transmitter ID change event. The communication circuitry is configured to receive a state change request for the movable barrier operator from a remote computing device. The processor is configured to cause the communication circuitry to transmit a radio frequency control signal including the second transmitter ID to the movable barrier operator in response to the communication circuitry receiving the state change request.

Many movable barrier operators, such as garage door openers, are not internet-enabled and are instead operated by transmitters such as portable transmitters that may be carried by a user on a keychain, for example, or clipped to a visor of a vehicle. A user may desire to control the user's garage door over the internet, for example, using a remote computing device such as the user's smartphone. To address this user desire without the inconvenience and/or cost of replacing the user's previously installed movable barrier operator, the user may install a movable barrier operator enhancement device or an operator enhancement device to control the user's previously installed movable barrier operator. One example operator enhancement device is the myQ® smart garage hub sold by the Chamberlain Group, Inc. The user sets up a user account and associates the operator enhancement device with the user's movable barrier operator. The user may then communicate with the operator enhancement device via a network (e.g. the internet) and a user device, such as a smartphone.
The operator enhancement device operates as a transmitter and controls the movable barrier operator in a manner similar to other transmitters. When the operator enhancement device receives a state change request from a user over the internet, the operator enhancement device transmits a radio frequency control command to the movable barrier operator and causes the movable barrier operator to carry out the requested state change. Like the radio frequency control command of other transmitters, the radio frequency control command transmitted by the operator enhancement device includes a transmitter identifier (ID), a button ID (which corresponds to a button of a portable transmitter), and a payload. The payload includes a changing code value such as a rolling code that changes with each transmission of a radio frequency control command by the operator enhancement device. The transmitter IDs for conventional operator enhancement devices and transmitters are fixed and do not change for the life of the operator enhancement device or transmitter.
A user may cause a movable barrier operator to learn multiple transmitters including a keypad transmitter, a visor-mounted transmitter in the user's car, and an operator enhancement device. When a movable barrier operator learns a transmitter, the movable barrier operator stores the transmitter ID of the transmitter in a whitelist, table, or data structure maintained in a memory of the movable barrier operator. In many situations, the only way to remove a transmitter ID from the movable barrier operator whitelist is to erase the entire whitelist and relearn the transmitters to the operator that the user still desires to control the movable barrier operator.
A problem may arise when the user sells the user's operator enhancement device or simply wishes to decommission or remove an operator enhancement device from being able to control the user's movable barrier operator. A user may mistakenly believe that using a client application executing on the user's smartphone to delete the operator enhancement device from the user's user account prevents the operator enhancement device from being able to control the user's movable barrier operator. However, because the movable barrier operator stores the transmitter ID of the operator enhancement device in the movable barrier operator whitelist, the movable barrier operator may still respond to a command from an operator enhancement device having a transmitter ID in the whitelist even if the operator enhancement device is no longer associated with the user account.
For example, Alice may give her operator enhancement device to a neighbor, Bob. Even if Bob's movable barrier operator learns the operator enhancement device, Alice's movable barrier operator may still respond to the operator enhancement device transmitter's commands if Bob's operator enhancement device (formerly Alice's) is within range of Alice's movable barrier operator. That is, Alice's movable barrier operator recognizes the transmitter ID of the operator enhancement device and may respond to control commands originating from Bob's use of a client application executing on Bob's smartphone as if the operator enhancement device were still in Alice's garage.
As another example, a user may have two or more movable barrier operators (e.g. installed in a garage with multiple doors for controlling opening/closing of the doors separately) and change the movable barrier operator associated with the operator enhancement device via the user account. Once the user has caused the new movable barrier operator to learn the operator enhancement device, both movable barrier operators will respond to a single command from the operator enhancement device.
To address these situations, a user currently erases the memory of the movable barrier operator originally paired with the operator enhancement device. However, this is inconvenient for the user because the entire whitelist of the movable barrier operator is deleted. The balance of the user's transmitters would again need to be learned by the movable barrier operator. If a user has many transmitters, this could be a difficult and time-consuming process.

Movable barrier operator enhancement device and method


The invention relates to a method of cutting an aperture in a device (1) by means of a laser beam (9), said device comprising a wall (2) having first (5) and second (6) opposing surfaces, and a third surface (7) separated from said wall (2) along the path (11) of said laser beam (9), said method comprising the steps of:. (a) causing said laser beam (9) to be incident upon said first surface (10) so as to cut through said wall (2) and form said aperture, and PA0 (b) introducing fluid between said second (6) and third (7) surfaces in the path (11) of said laser beam (9) so as to thereby prevent damage to said third surface (7) when said laser beam has cut through said wall.. The invention may be used to cut aperture in devices such as injector nozzles syringe needles, medical stents and fluid/air control valves.

1. Field of the Invention
This invention relates generally to a method for cutting an aperture in a device, and more particularly to a method for cutting an aperture in a device comprising a wall having first and second opposing surfaces, and a third surface separated from said wall. The method is suitable for cutting apertures in a wall of narrow pieces of tubing, and it will be convenient to hereinafter disclose the invention in relation to that exemplary application. It is to be appreciated, however, that the invention is not limited to that application.
2Description of the Prior Art
Many devices manufactured today require the cutting of an aperture in a wall thereof. Devices such as injector nozzles, syringe needles, medical stents, fluid/air control valves and small collets all have bores or openings running therethrough which define at least one wall surrounding the bore or opening. In each of these devices, at least one aperture is required to be cut through the wall, so as to thereby enable, for example, the communication of a fluid with the bore in the device, or so as to alter the flexibility or other mechanical properties of the device. Moreover, many of these devices are small and require the aperture to be cut with a high degree of precision.
One existing method of accurately cutting such an aperture uses a process called Electrical Discharge Machining (EDM). The EDM process uses spark erosion to cut the aperture in the device, which, using this process, must be metallic. The device acts as a cathode, whilst the anode is provided by an electrode maintained very close to the surface of the device. Both the anode and the cathode are submerged in a dielectric liquid. High local temperatures are produced by passing a current through the gap between the device and the electrode, thus detaching and repelling particles from the device.
The EDM process can be classified according to two related techniques: a wire cutting technique and a sinker technique. In the wire cutting technique, a starting hole has to be firstly drilled in the wall of the device at the location where the cutting of the aperture is to commence. A wire, typically between 0.1-0.2 mm in diameter, is used as the anode and must be passed through the drilled hole. Current is then passed between the wire and the device so that particles from the device are detached. The wire is moved through the thickness of the wall, at a speed limited by the rate of particle detachment, so as to define the form of the aperture.
In the sinker technique, a copper or graphite electrode is placed close to the exterior surface of the wall through which the aperture is to be cut. Current is passed between the device and the electrode so that particles from the wall of the device are detached, the resulting aperture having the same form as that of the electrode. While this technique does not require the preliminary drilling of a hole, the electrode must however be precisely shaped to that of the desired aperture.
It can thus be understood that both EDM techniques are time and labour intensive in their preparation and in addition are limited in their cutting speed.
It is also known to cut apertures through the walls in such devices by the process of chemical etching. According to this process, a mask is placed on the exterior surface of the device, which mask has an opening defining the form of the aperture to be cut. When placed in a chemical bath, the aperture is etched though the device in the region of the opening of the mask. A separate mask must be produced for each device to be treated. Additionally, while chemical etching is often used in the treatment of flat, thin surfaces, the difficulty in the production and location of appropriate masks means that this process is not well suited to the cutting of apertures in walled-devices.
Milling is another process which is sometimes used to cut apertures in the walls of such devices. However the use of this process requires the removal of material by force from the wall of a device. Such force can cause the deformation of the device, particular in small, delicate devices such as syringe needles and injection nozzles.

Method of cutting an aperture in a device by means of a laser beam


A composite amplifier comprises several Chireix pairs (PA11, PA12; PA21, PA22) of power amplifiers connected to a common load. Means (21) are provided for driving each Chireix pair by drive signals having amplitude dependent phase over at least a part of the dynamic range of the composite amplifier . These parts are preferably different for different pairs.

In radio transmitters for broadcast, cellular, and satellite systems, the power amplifier (PA) in the transmitter has to be very linear, in addition to being able to simultaneously amplify many radio channels (frequencies) or independent user data channels, spread across a fairly wide bandwidth. It also has to do this efficiently, to reduce power consumption, need for cooling, and to increase its longevity. High linearity is required since nonlinear amplifiers would cause leakage of interfering signal energy between channels and distortion within each channel.
The amplitude probability density of a mix of sufficiently many independent radio frequency (RF) channels, or of a multi-user CDMA (Code Division Multiple Access) signal, tends to be close to a Rayleigh distribution having a large peak-to-average power ratio. Since a conventional linear radio frequency power amplifier generally has an efficiency proportional to its output amplitude, its average efficiency is very low for such signals.
In response to the low efficiency of conventional linear power amplifiers for wide bandwidth signals with large peak-to-average power ratio, the Chireix outphasing method [1] has been suggested. The term "outphasing", which is the key method in Chireix and LINC amplifiers (LINC=Linear Amplification using Nonlinear Components), generally means the method of obtaining amplitude modulation by combining phase-modulated constant-amplitude signals from two transistors.
Furthermore, a three-transistor amplifier (or more generally an odd number of transistors) using the outphasing principle is described in [2].
There is often a need for higher efficiency than what is obtainable with two-amplifier Chireix amplifiers. The maximum efficiency for these amplifiers is limited to a certain value, which depends on the signal amplitude distribution. Adding more amplifiers to the Chireix amplifier, as suggested in [2], has so far been unsuccessful in increasing the efficiency. In fact, the amplifier described in [2] is less efficient than a conventional Chireix amplifier with modified drive signals, as described in [6].


An approach is provided for using a passenger-based driving profile. The approach involves detecting an identity of a user of a vehicle. The approach also involves retrieving a passenger profile of the user based on the identity. The passenger profile is generated based on sensor data indicating a reaction of the user to at least one vehicle driving behavior previously experienced by the user as a vehicle passenger. The approach further involves configuring the vehicle based on the passenger profile.

There is increasing interest in the development of vehicles (e.g., autonomous vehicles, highly-assisted vehicles (HAD), etc.) that are able to at least partially drive or otherwise operate themselves without input from vehicle users or occupants. One area of development has been with respect to providing a "humanized" driving experience for such vehicles. For example, a humanized driving experience refers to configuring autonomous or HAD vehicles to operate in a way that is comfortable for their passengers or users. In particular, one source of potential discomfort is when there are differences in the driving style or behavior preferred by a user when the user is driving versus when the user is a passenger. Accordingly, service providers and manufacturers for such vehicles face significant technical challenges to enabling a more comfortable user experience by reconciling the differences between a user's personal driving style and the driving style that the user likes when the user is a passenger to configure the operation of autonomous or HAD vehicles.

Method and apparatus for using a passenger-based driving profile


There is provided an electronic voting and counting system including an electoral register check system, an electronic voting system, an electronic counting system, and an electronic examination system. The electronic voting system operated by interworking with a voter DB online or offline stores image files of candidate information of nationwide election district inputted via an external storage medium in the electronic voting apparatus, displays an image file of candidate information of an election district to which the voter belongs according to information stored in the electronic voting card, automatically guides a voting procedure to the voter when the electronic voting card is deposited, encodes a voting result to doubly store in a storage medium, and prints the voting result.

1. Field of the Invention
The present invention relates to an electronic voting, counting, and examination system, and more particularly, to an electronic voting, counting, and examination system which employs an electoral register identification system shared on network, an electronic voting system managed online or offline, an electronic counting system counting votes online or offline in real time, and an electronic examination system examining votes by safely keeping vote recording paper as a cartridge, thereby effectively coping with hacking outside or error occurrence such that the system can be stably operated.
2. Description of the Related Art
Usually, in the election of the President or the Member of the National Assembly, a voter goes to a polling place, selects a candidate in a ballot paper, and puts the ballot paper into a ballot box. The ballots are counted and the total of the ballots are computed by hand. Accordingly, there are a lot of time and effort used, and an error may occur in the counting and computing.
An electronic voting apparatus and electronic voting system are provided in order to solve the problem of the voting and counting by hand and rapidly and accurately manage voting and totalization by applying high-tech information technology in election field to accelerate the efficiency of the voting management.
For example, an electronic voting system disclosed in Korean Patent No. 0133954 is described as following.
That is, one or a plurality of voting terminal apparatus are installed at each polling place. Data of the number of votes obtained of each candidate accumulated in a buffer counting the number of votes obtained of each election terminal apparatus is wired or wirelessly transmitted to a terminal control apparatus via a communication interface. The terminal control apparatus is installed, for example, for each area. The terminal control apparatus receives data of the number of votes obtained, which is accumulated in each election terminal apparatus and computes the total of the number of votes obtained for each candidate. Also, data of the number of votes obtained totalized by the terminal control apparatus is wired or wirelessly transmitted to a main computer. The main computer totalizes the data of the number of votes obtained, which is transmitted from the terminal control apparatus or election terminal apparatus.
For another example of prior art related to an electronic voting system, an electronic voting system is disclosed in Korean Patent No. 407076.
In the prior art, an electronic voting controller having data and application programs required for operating the system, built-in and an electronic voting system including an electronic voting apparatus connected to the electronic voting controller via cable are included. In this case, the electronic voting controller and electronic voting apparatus embody a network in thin-client environment, and windows based terminal (WBT) technology is employed in the electronic voting apparatus. Therefore, convenience of usage of voters is increased, centralized network management is possible, and system construction cost is minimized.
However, since the electronic voting system according to the prior art, whose entire components are connected via network, when a backing is attempted outside or an operation error occurs, the system administration is going to suffer.

System for electronically voting, counting, and examining ballots


A planar positioning system having a rigid base, and first and second linear actuator means mounted to the rigid base, the first and second linear actuator means being arranged orthogonal to one another. A rigid reference surface (2A, 2B) is mounted to the base, (1) and a moveable platform (17) for holding a workpiece is supported for movement on the rigid reference surface (2A, 2B). First and second guiding means are coupled to moveable portions of the respective first and second actuator means, the first and second guiding means being arranged to bear on the moveable platform for transmission of forces thereto from the respective first and second actuator means to effect movement of the platform (17) on said rigid reference surface (2A, 2B). The first actuator means may comprise two linear actuators (4A, 4B) parallel to one another and spaced apart with the second linear actuator means (8) orthogonal thereto and arranged in an H-shaped configuration. The first and second guiding means and/or the components of the moveable platform (17) against which they bear are preferably constructed for low frictional movement in the direction orthogonal to the transmission of forces therefrom, such as by the use of non-contact aerostatic bearings (16A, 16B, 16C) or the like. Similarly, low friction bearings are utilised between the moveable platform (17) and the reference surface (2A, 2B).

A conventional XY planar positioning system stacks an X-actuator assembly onto a Y-actuator assembly to form the two orthogonal axes. One significant drawback of this stacking approach is that the positioning accuracy is substantially affected by the errors in each of the individual actuator assemblies. Since the actuator assemblies are coupled together, the errors of an actuator in every direction will all contribute to the overall positioning errors of the system.
Another disadvantage of stacked stages is the poor efficiency of the actuator power used for moving the payload. In such a system an actuator is required to move not only the payload but also the mass of the other actuator stacked on top of it. This necessitates the use of higher capacity actuators to overcome the problem, thereby increasing the cost of the system. Furthermore, the stacking approach reduces the overall rigidity of the system.
Whilst the conventional approach of stacking actuators has intrinsic problems of inaccuracy and low power efficiency, some prior art systems attempt to address the problems of stacking X and Y-actuator assemblies. For example, U.S. Pat. No. 5,648,690 to Hinds reveals a design wherein the actuators are not stacked but are fixed in the same plane in which the payload platform moves. However, this design has the problem of a very poor ratio of platform moving area versus the overall size of the stage footprint. This ratio is referred to herein as the footprint efficiency. Another approach, as disclosed in U.S. Pat. No. 4,676,492 to Shamir, has a similar configuration in that all the actuator assemblies are fixed on the same plane as the moving platform. Instead of using actuators to push and pull the platform at the planes perpendicular to the moving directions of the platform as presented by Hinds, the Shamir configuration realises platform motion with a pair of screw-driven actuators arranged at two sides of the platform in each of the two X-Y directions. The fact that both actuator pairs are located outside of the dimensions of the moving platform still result in a poor footprint efficiency, however.
One approach to resolving the problem of low footprint efficiency is described in U.S. Pat. No. 5,523,941 to Burton et al. In this design, two sets of actuator assemblies are mounted orthogonally below the moving platform with one set positioned on top of the other. However, in order to achieve an improved ratio of moving range versus total footprint as well as suitable platform rigidity, the platform has to be supported by at least four points on the base. As a result, the positioning accuracy of the system is negatively affected. Furthermore, as the vertical distance between the moving platform and the lower actuator assembly is long, the large offset required for the force transmission reduces the stiffness of the system, which is undesirable.

Agency for Science, Technology and Research


A LED display screen includes a case, a LED display module and a front assembling system. The case has a front opening. The LED display module is received in the case via the front opening, including a supporting base, a LED display unit mounting in front of the supporting base, and a LED shade shading in front of the LED display unit. The front assembling system has a base channel, a display unit channel and a shade channel. The front assembling system includes a still member, a supporting member and a supporting member. The still member mounts behind the supporting base. The supporting member is provided on the case. The supporting member includes a body and a head. The body is inserted through the mounting hole to engage with the supporting member. The head is hidden inside the base channel to combine the LED display unit with the supporting base.

1. Field of Invention
The present invention relates to a LED display screen, and more particularly to a LED display screen which is conveniently assembled from the front.
2. Description of Related Arts
It is a time of information and attention. As an efficient medium to transfer information and idea to people, LED display screens are widely used in many circumstances. We can see LED display screen in streets, on buses, in stadium, and even in toilet. Accordingly, assembling LED display screens becomes a usual and important task.
A LED display screen comprises a LED display module and a case. To avoid shading the LED display module, the LED display module is ordinarily connected with the case with its back, and the connecting means is hidden behind. Traditionally, The LED display module has its back attached with the case, and the case has a back opening for operating. The LED display module and the case is then assembled by fastening a screw from the back of the LED display module via the back opening of the case. Finally, the back opening of the case is closed, and the LED display screen is mounted in a display position.
However, the LED display screen may be damaged or needs to be disassembled. In this case, people must take the whole LED display screen down, expose the back opening of the case and then loose the screw to detach the LED display module from the case. Besides, when assembling, the display effect of the LED display module can not be seen, so that it takes much time to adjust the LED display module.
LED display screens can be assembled and disassembled from the front are desirable. The major problem is that the connecting means will shade the LED display module to affect display effect. Frequently, the LED display screen is large and has a certain weight, if fastening it with screw, the screw will be thick and shade a rather big area of the LED display screen. When the LED display screen needs a plurality of screws, affection to the display effect is more serious. On another hand, if simply adhering the LED display module on the case, due to the weight of the LED display module, and the adhesive may go bad, it is not stable. Especially, in many situations, the LED display screen is placed high above, e.g., evenings and matches, so it is troublesome to take the whole LED display screen down to disassemble. The better way is to disassemble the LED display screen piece by piece and then take down.

LED display screen assembled from the front


The present invention provides an adjustable venturi device designed for efficient use with blowers of various different capacities. The venturi device of the present invention includes a blower feedable positive air passage and a negative pressure air inlet exposed to and operated by air draw from the positive air passage. The venturi device is adjustable for varying exposure of the air inlet to the positive air passage with resultant varying of the air draw according to capacity of the particular blower used with the venturi device.

There are many different types of systems which use venturi devices. The purpose of the venturi device is to provide an air draw or suction to draw in different types of products passed through a pneumatic feed system.
According to conventional construction, a venturi device has a fixed configuration and therefore is not adjustable according to the capacity of the particular blower used in the pneumatic feed system. In addition, the conventional venturi is not designed for adjustment for variable air draws which may be selected according to the product drawn into the pneumatic feed system.

Inline venturi for pneumatic conveying systems


A steerable, self-propelled vehicle includes a rotatable steering column that is connected to control the steering angle of one or more ground-engaging members of the vehicle. The vehicle includes between the steering column and the ground-engaging member a first steering servomechanism having at least a first steering assistance characteristic; a second steering servomechanism having a second steering assistance characteristic also being connected to act on the steering column. A controller is provided for causing the first and second steering assistance characteristics to influence the steering of the vehicle in dependence on one or more one or more control commands generated in the controller.

It is well known to provide power assistance to the steering sub-systems of driver-operated vehicles.
In various types of vehicle it has for many years been commonplace, especially in the case of relatively large vehicles in which the required steering effort may be significant, to provide power assistance in the form of a hydraulic servomechanism. This includes a pump for pressurizing a fluid such as hydraulic oil in a circuit that includes a servo valve. The degree of opening of the servo valve is determined by turning of the steering column, of the vehicle, that is coupled to an input shaft of the valve by way of a mechanical linkage.
The valve pilots the hydraulic fluid pressure, in dependence on the resulting valve setting, to an assist motor that in some applications is a linear hydraulic cylinder having at each end an extensible arm and in some other applications may be e.g. a hydrostatic motor.
The cylinder when fitted interconnects by way of the ends of the arms the steerable wheels of the vehicle in replacement of conventional, solid steering linkage members. The cylinder may act in the same manner as the rigid linkages or, when extension of the arms occurs as a result of operation of the servomechanism, to reduce the effort needed to turn the steering wheel against the resistance provided by the mass of the vehicle acting through the steerable wheels.
Power assistance of this general kind renders the feeling of the steering "light" (i.e. relatively effortless) as experienced by the driver of a vehicle equipped with it. Moreover if the servomechanism fails for any reason the cylinder becomes rigid and behaves in the same manner as a conventional linkage member. In consequence it remains possible to steer the vehicle, albeit through the application of considerably more effort on the part of the driver, in the event of a servomechanism fault developing.
One characteristic of hydraulic servomechanisms of the general kind described above however is that they do not on their own provide a "self-centering" characteristic. This is of course important in most self-propelled, driver-controlled vehicles since it is strongly desirable that the steerable wheels return to a "straight ahead" setting in the event of the driver releasing a steering input member (that in a passenger car and the majority of the vehicle types listed is a steering wheel).
Passenger vehicle steering is normally designed to incorporate a positive caster angle that gives rise to a mechanical self-centering effect. This tends to provide directional stability when the vehicle is driven on relatively smooth, metalled roads as is normally the case for such a vehicle.
A self-centering steering effect is of limited benefit in the case of agricultural vehicles when they are operating in off-road situations such as when driving in fields.
This is partly because furrows or other features of e.g. a ploughed field tend to override any self-centering effect brought about through design features including positive camber angles. The forces induced by the furrows on the steerable wheels (or other ground-engaging members of the tractor, if fitted) exceed any self-centering forces induced by the steering geometry.
Moreover under many circumstances when operating in a field a tractor operator may find a self-centering effect to be inconvenient. Examples arise when turning at a headland, or when following a curved margin of a field, when driving on lateral slopes (in a so-called "crab-like motion"), or when ploughing with two wheels in a furrow.
At such times it may be desirable in effect to "set" a steering angle for an extended period of operation. The tractor driver therefore may find it bothersome to have to adjust the steering input member continuously in order to overcome a self-centering effect and assure constancy of the steering angle.
In any event a modern tractor is a complicated multi-purpose vehicle that may be fitted with or coupled to numerous sub-systems (such as harvesters, spraying equipment and tilling implements) that require operation from within the operator's cab. When operating such sub-systems the driver may find it very difficult simultaneously to make steering input adjustments.
On the other hand when moving in a straight line on a relatively flat field, or when driving on roads, a tractor operator may find it desirable for the tractor to behave in ways that are similar to other road vehicles, and thereby exhibit a self-centering steering effect or other effects that are useful from the standpoints of safety, stability and/or convenience.
Another known type of power steering assistance mechanism is an electric type, in which rotations of the steering column are converted (e.g. using a Hall effect device, or another kind of sensor) into electrical signals. These in turn may be used to generate commands for an electric motor that is connected to provide rotational assistance forces to the steering column. Indeed in some arrangements the shaft of the steering column itself is constituted over part of its length as the rotor of the motor.
It would be desirable to be able to adjust the characteristics of the steering of a large, heavy vehicle that operates under varying circumstances, to take account of the prevailing type of use. The presence or absence of a self-centering steering effect is exemplary of the kind of characteristic it could be desirable to adjust, although there exist others such as but not limited to the degree of damping of the steering (i.e. the extent to which the steering deviates from a set steering angle); the extent to which power assistance applies to assist the vehicle operator; assistance in turning from one lock to the opposite lock as quickly as possible; and more general transitions of characteristics that take account of changes from rough off-road to on-road or smooth field driving.

This patent is subject to a terminal disclaimer.


Provided is a method of manufacturing a battery having an electrode module including: a positive plate having a cathode collector portion formed by attaching a lead member to a cathode substrate made of a foamed metal plate; and a cathode collector plate welded to the cathode collector portion. The method includes: a pre-welding positive plate forming process of forming a pre-welding positive plate, which is the positive plate before welding, such that the pre-welding positive plate has a projection projecting from a pre-welding cathode collector portion, which is the cathode collector portion before welding; and a welding process of melting a pre-welding cathode collector plate to weld it to the projection. In the pre-welding positive plate forming process, the projection is formed into such a shape that the condition that S≦1.3W is satisfied, where W and S represent the width and the circumferential length of the projection, respectively.

1. Field of the Invention
The invention relates to a battery manufacturing method, a battery, a pre-welding positive plate manufacturing method, and a pre-welding positive plate.
2. Description of Related Art
In related art, various secondary batteries, such as nickel-hydrogen secondary batteries, have been used as drive power sources for vehicles such as hybrid vehicles and electric vehicles and drive power sources for portable electronic devices such as laptop computers and video camcorders.
As one of such secondary batteries, for example, Japanese Patent Application Publication No. 2006-351376 (JP 2006-351376 A) describes a stack-type secondary battery, more specifically, a secondary battery having a battery case, and an electrode module that is disposed in the battery case and that is constructed of positive plates and negative plates alternately stacked on top of each other via separators. In this secondary battery, a lead portion (cathode collector portion) of each positive plate is welded to a cathode collector plate and a lead portion (anode collector portion) of each negative plate is welded to an anode collector plate.
Further, JP 2006-351376 A describes forming each positive plate by impregnating a foamed metal plate with an active material, and forming a lead portion (cathode collector portion) of the positive plate by compressing a portion of the foamed metal plate, which has not been impregnated with the active material, and then welding a nickel lead plate on one side of the compressed portion. Further, JP 2006-351376 A describes that, in order to connect the negative plates to the anode collector plate, triangular projections are formed at an end of each negative plate, the negative plate is arranged such that the projections are fitted in grooves formed in the anode collector plate, and the projections of the negative plate are joined to the grooves of the anode collector plate by delivering an electron beam from the outer side of the anode collector plate (see FIG. 4 of JP 2006-351376 A). Further, JP 2006-351376 A describes connecting each positive plate to the cathode collector plate in the same manner as described above, that is, forming triangular projections at an end of the lead portion (cathode collector portion) of the positive plate, arranging the positive plate such that the projections are fitted in grooves formed in the cathode collector plate, and then joining the projections of the positive plate to the grooves of the cathode collector plate by delivering an electron beam from the outer side of the cathode collector plate.
In the battery described in JP 2006-351376 A, as mentioned above, the lead portion (cathode collector portion) of each positive plate is formed by compressing a portion of the foamed metal plate (foamed nickel plate), which has not been impregnated with the active material, and then welding the lead plate (metal lead plate), which is made of nickel, etc., to one side of the compressed portion. Further, the negative and positive plates of the battery described in JP 2006-351376 A are manufactured by pressing. Therefore, when manufacturing each positive plate of this battery, a base board is prepared by impregnating the foamed metal plate with the active material, compressing a portion of the foamed metal plate, which has not been impregnated with the active material, and welding a nickel lead plate on one side of the compressed portion, and then the prepared base board is pressed (punch-pressed) into the shape of the positive plate.

Battery manufacturing method, battery, pre-welding positive plate manufacturing method, and pre-welding positive plate


The present invention 10 discloses an interactive sports season team-tracking poster for a sports fan's favorite team. The invention is a calendar-like chart for a sports season displaying a predetermined time period by day 20 having a postable element 30 that is completed by the user containing user selected sporting event statistics. As an example, a baseball season chart would be printed for the months of April through October with the favored team schedule imprinted thereon. The fan would be able to record game statistics on an attachable preprinted statistics form 30 for each sporting event related to their chosen team and attach the event statistics form onto the season chart for that event by removing a peel-off backing 32 on its back to expose a glue surface 34 for attachment to the poster of the present invention 10.

1. Field of the Invention
The present invention relates generally to a display board assembly and, more specifically, to sports game history, scoring, scheduling and announcing systems.
The present invention is an interactive sports season team-tracking poster for a sports fan's favorite team. The invention is a calendar-like chart for a sports season displaying a predetermined time period by day having a postable element that is completed by the user containing user selected sporting event statistics.
As an example, a baseball season chart would be printed for the months of April through October with the favored team schedule imprinted thereon. The fan is able to record game statistics on an attachable preprinted statistics form for each sporting event related to their chosen team and attach the event statistics form onto the season chart for that event.
2. Description of the Prior Art
There are other scoring, scheduling and announcing devices designed for sports games. Typical of these is U.S. Pat. No. 546,959 issued to J. S. Larzelere on Sep. 24, 1895.
Another patent was issued to E. Bach on May 3, 1904 as U.S. Pat. No. 758,808. Yet another U.S. Pat. No. 1,167,715 was issued to J. L. Preo on Jan. 11, 1916 and still yet another was issued on Oct. 10, 1922 to F. W. Feihl as U.S. Pat. No. 1,431,577.
Another patent was issued to H. Beebe, Jr. on Oct. 17, 1972 as U.S. Pat. No. 3,698,741. Yet another U.S. Pat. No. 4,164,910 was issued to R. Feiler on Aug. 21, 1979. Another was issued to A. B. Todd on Feb. 24, 1987 as U.S. Pat. No. 4,645,206 and still yet another was issued on Feb. 25, 1992 to Meaney, et al. as U.S. Pat. No. 5,090,735.
Another patent was issued to E. Creech on Oct. 12, 1993 as U.S. Pat. No. 5,251,570. Yet another U.S. Pat. No. 5,694,881 was issued to E. Creech on Dec. 9, 1997. Another was issued to Huemoeller et al. on Dec. 29, 1998 as U.S. Pat. No. 5,855,006 and still yet another was issued on Apr. 3, 2001 to W. J. Gabriel as U.S. Pat. No. 6,210,296.