Retrieving an on-map position is executed within a targeted search area that is one of search areas. Search information items are stored for retrieving. Each of the search information items is related to one of the search areas. Area-designating information items are also stored for designating one of the search areas. When a user selects, as a search item, one of address-book information items, address information included in the selected address-book information item is collated with the area-designating information items. A corresponding search area is thereby automatically designated as the updated targeted search area. Thus, based on the address-book information and area-designating information, the targeted search area is automatically switched into a search area that includes the retrieved on-map position. User's procedure in retrieving the on-map position can be thereby reduced.

A car navigation device is conventionally equipped with a map search system for retrieving an on-map position that is a position on map data with purposes such as designating a destination. Namely, when a map search system is started by user's input of a search item such as an address, a phone number, a facility name, or the like, an on-map position corresponding to the inputted search item is retrieved on map data. A map around the on-map position is then displayed on a display unit. The user thereby recognizes the on-map position on the displayed map and designates the on-map position as a destination through manipulating a switch.
For the above map search system, the car navigation device possesses search information items that are related to the respective on-map positions. The search information items include an address, a phone number, a facility name, or the like inputted as the search item.
In a car navigation device using map data that covers a wide range of region, the wide range of region is divided into a plurality of search areas. The search information items belong to the respective search areas. Namely, each of the search information items is related to one of the plurality of search areas. Here, when a search item is inputted, within a targeted search area the inputted search item is collated with search information items related to the targeted search area. The reason why a search area for retrieving the on-map position is limited to the single targeted search area is that the number of candidates of the search information items becomes too large if an area for retrieving is expanded to the entire wide range of region.
The above-mentioned targeted search area is typically designated by the user. Once the targeted search area is designated, the designated targeted search area is apt to be continuously retained. Therefore, when a certain search area including a destination is different from the targeted search area, the user needs to switch the targeted search area from the currently designated search area into the certain search area. Here, the user at first determines whether the certain search area is currently designated as the targeted search area. When the certain area is determined to be currently not designated, the user needs to switch the targeted search area from the current search area into the certain search area. This involves user's bothersome procedure for switching the targeted search area in the map search.


Compressed graphic image data files, such as Compressed ARC (Arc-second Raster Chart/map) Digitized Raster Graphics (CADRG) map files for a region of interest, are stored in blocks of memory (nodes) preferably arranged as a linked list. Portions of files containing data for an area of interest including an image of interest are decompressed before the data are sent to a frame buffer for display. Nodes that do not contain requested data are flagged as unused, but not deallocated, making the data in such nodes available for use or replacement.

Many applications require storage and retrieval of data from among vast amounts of graphic image data. To reduce storage requirements, the image data is frequently stored on media in a compressed format. Conventional systems typically decompress an entire file containing data for an image before loading it into memory. The data for the image is then sent to a frame buffer for display on a display device. While decompression prior to loading data in memory may facilitate display, it does so at the expense of memory and hardware cost. The decompressed data will occupy much more memory than its compressed counterpart, increasing hardware cost and/or leaving less memory available for storing other data and for other purposes.
Conventional systems typically do not maintain files of interest in memory for repeated use. If sufficient memory is available, a first decompressed file may occupy a significant portion, if not all, of the available memory in a conventional system. When data from a second file is needed, memory in which the first decompressed file is stored is deallocated and the second file is decompressed and loaded into memory. If data from the first file is needed later, the entire process must be performed again, swapping the first file for the second file. As the system must access a disk to decompress and load the desired file into memory each time it is needed, this process is time consuming and inefficient and reduces response time.
Conventional systems are also typically unable to efficiently isolate data for a subsequent image from a decompressed file in memory. After displaying a first image from a decompressed file loaded in memory, many systems will reload the file from disk into memory to access data for a second image. This reloading operation entails accessing the disk and decompressing the file. Other systems will read and rewrite the entire decompressed file in memory to cull out data for the image of interest, a process which is conducive to memory fragmentation.
Such use of resources compromises the performance of a conventional graphic image display system by relying heavily on redundant disk access operations to load data into memory. Memory provides storage at a higher cost per megabyte than hard disks and CD-ROMs, but typically with relatively fast access and data transfer rates. In sharp contrast, hard disks and CD-ROMs provide relatively inexpensive non-volatile storage for large amounts of data, but take substantially more time to access and transfer data (often hundreds or thousands of times longer than the time taken to access data in memory), thereby creating a bottleneck.
Delays caused by accessing and transferring data from a disk can be particularly acute in the case of a conventional geographic display system, such as a system for displaying geographic images from CADRG data. Frequently, a sequence of images is displayed, starting with a first geographic image, then one or more other images for contiguous regions. Even if a single file contains the data for these images, many conventional systems must decompress the file and reload the data into memory to access the data for successive images. Common operations, such as flipping back and forth between two images, panning and cycling through a series of images, may entail multiple disk access, loading and decompression operations, consuming substantial time.
Instead of decompressing data for only an area of interest, conventional systems typically decompress an entire file, further compromising performance. Such indiscriminate decompression wastes both time and memory.
Frequent memory allocation and deallocation operations performed by conventional systems may further compromise performance. Such operations are conducive to memory fragmentation, especially in systems running multithreaded applications and multitasking operating systems, and consume valuable time. Memory can be viewed as a continuous range of allocatable cells. Fragmentation, the occurrence of unused gaps between useful cells in memory, can both increase the requirement for memory and slow down computation due to less efficient use of the storage hierarchy and complexity of memory access.

System and method for managing compressed graphic image data


A plant for transmitting electric power having an alternating voltage network with at least one phase and at least one VSC converter is provided. The converter has at least one phase leg with two current valves connected in series. Each phase leg is connected at a point between the two current valves to a respective phase of the alternating voltage network. The plant also comprises at least one additional phase leg in the converter more than the number of phases of the alternating voltage network and a means for disconnecting a phase leg from its respective phase and for connecting the additional phase leg at a point between its two current valves to the disconnected phase.

The present invention relates to a plant for transmitting electric power comprising an alternating voltage network having at least one phase and at least one VSC-converter having at least one phase leg with two current valves connected in series, in which one point of the phase leg between the two current valves is connected to the phase of the alternating voltage network.
A plant of this type may, for example, be a plant for transmitting electric power between a direct voltage network for High Voltage Direct Current (HVDC) and an alternating voltage network. Such a plant has recently become known through the thesis "PWM and Control of Two and Three Level High Power Voltage Source Converters" by Anders Lindberg, Kungliga Tekniska Hogskolan, Stockholm, 1995. It is emphasized that the invention is not restriction to this application, but the plant may, for example, comprise a SVC (Static Var Compensator), in which the direct voltage side of the converter is not connected to any direct voltage network but to a direct voltage capacitor freely arranged. However, to illuminate, but accordingly not limit the invention, a plant of the type defined in the introduction for HVDC will hereinafter be described.
The number of phases of the alternating voltage network, and thereby the number of phase legs of the VSC-converter in such a plant, may be arbitrary, but there are usually three phases of the alternating voltage network and thereby three phase legs of the VSC-converter, and accordingly six current valves therein in total, so that the converter constitutes a six-pulse bridge. In the event of a fault in a phase leg of the converter, the entire transmission of electric power between the direct voltage network and the alternating voltage network is wiped out in the HVDC-case, and in the case of SVC. The power transmission and the stabilizing of the voltage of the alternating voltage network therethrough also fail. In the HVDC-case, the entire transmission may also be wiped out upon any fault of one of the two pole conductors of the direct voltage network connected to the VSC-converter.

SVC converter with an extra phase leg to replace a failed phase leg


An open chamber, accommodative, intraocular lens method and apparatus operable to be positioned within an evacuated capsular bag of a human eye following extracapsular extraction of a natural crystalline lens is provided having an anterior refractive lens optic, a first haptic segment having a first end and being connected at said first end to a peripheral portion of said anterior lens optic and a second end and said haptic segment extending in an elliptical curve, in longitudinal cross-section, along the the line of sight of the lens and at least a second haptic segment having a first end and being connected at said first end to a peripheral portion of said lens optic and a second end and said at least a second haptic segment extending in an elliptical curve, in longitudinal cross-section, and being operably joined with the second end of said first haptic segment to form an open chamber, elliptical shaped haptic accommodating support for the anterior lens within an evacuated capsular bag of a human eye.

This invention relates to an improved, accommodative, intraocular lens system operable to be positioned within the interior of an evacuated capsular bag of a human eye. More specifically, this invention relates to an open accommodative, intraocular lens system method and apparatus operable to be inserted within an evacuated capsular bag of a human eye following extracapsular surgery to remove and replace a dysfunctional natural crystalline lens. The invention finds particular application in restoring multi-focal vision following cataract surgery, correction of myopia, correction of presbyopia and treatment of the symptoms of retinal damage, such as, age related macular degeneration of the human eye.
In the human eye, multi-focal vision is provided by a combination of a convex-concave lens, known as the cornea, positioned in front of the iris and a bi-convex lens positioned within a clear elliptical envelope behind the iris and in front of the vitreous humor of the eye. Accommodation of vision at both infinity and near vision of 250 mm is provided by a peripheral muscular body extending about the capsular bag and connected to the equator thereof by Zonula of Zinn which are thin strands attaching the equator of the capsular bag to the ciliary muscles of a human eye system. Tension and the relaxation of the ciliary muscles causes the capsular bag to lengthen or contract which varies the focus of the eye.
In certain instances at an early age, such as trauma or heredity, or in later stages of the life cycle, the natural crystalline lens of a human becomes cloudy and hardened, somewhat like milk glass, which occludes vision and results in eventual blindness. This condition is known as a cataract and was a major source of blindness in mankind for centuries. As early as 1766 Cassanova, in his memoirs, suggested that an intraocular lens could be implanted within a human eye to replace an opaque natural crystalline lens. It was not until 1949, however, that a Dr. Harold Ridley, at the Thomas Hospital in London, inserted the first intraocular lens within the eye of a woman of about 60 years of age following cataract extraction. Early IOLs, however, tended to dislocate, cause iris atrophy and in some instances secondary glaucoma. Attempts to overcome the early disadvantages of Dr. Ridley""s solid posterior chamber lens included placement of a lens in the anterior chamber, in front of the iris. In addition Dr. Binkhorst of Holland invented an iris clip lens and Dr. Choyce an iris plane lens. However, both anterior chamber and iris fixed lenses created a risk of damages to delicate iris tissue.
An advanced in the intraocular lens art occurred when Dr. Shearing invented the first, practical, posterior chamber lens. Dr. Shearing""s design included a bi-convex polymethylmethacrylate (PMMA) lens body which was positioned behind the iris and against the ciliary muscle or within the capsular bag. The Shearing IOL was maintained in a generally central axis of vision by thin strand haptics that extended radially from the peripheral edge of the lens optic and were curved at their distal ends. The curved portions of the haptics abutted against peripheral tissue of the eye to support the lens. Although the Shearing lens haptics had small arc contact zones, the success of the lens led other pioneers to develop a variety of haptic designs, such as, a C-loop or an S-loop and other designs to relieve trauma to adjacent contact tissue. A significant limitation of all fixed focus intraocular lens designs is that the focal point is fixed at infinity. Accordingly, for all near vision tasks, conventional reading glasses became necessary. In this connection, it is believed that several million pairs of reading glasses are sold annually within the United States alone.
In addition to the incidences of cataract formation and its attendant tendency to blindness, reductions in both amplitude and speed of accommodation with age are well known. This condition is known as presbyopia. The amplitude of accommodation decreases progressively with age from some 14 diopters in a child of ten years to near zero at age fifty or so. The exact explanation for the physiological phenomena is not well documented, however, it is observed that the curvatures of excised senile lenses were considerably less than those of juvenile ones. This failure could be due to a hardening of the lens material, sclerosis, decrease in modulus of elasticity, or to a decrease in thickness of the capsule or a combination of the above. Regardless of the cause, it is a recognized fact that beginning at about age 40-45 correction for both near and far vision becomes necessary in most humans. Conventional techniques include bifocal glasses, bifocal contact lenses, contact lenses for distance and reading glasses for near vision, and mono-focus contact lens sets where one eye carries a contact lens for distance vision and the other eye carries a contact lens for reading. Still further refractive surgery for distance vision coupled with reading glasses has been used successfully to correct presbyopia. Notwithstanding the grateful relief of being able to see clearly at both near and distance, all of the above solutions are compromises, in one form or another, and are dramatically more inconvenient than the natural bifocal vision of youth.
A somewhat related visual dysfunction in youth and young adults is mild to severe myopia or the loss of an ability to clearly focus at distance. Glasses, contact lenses or refractive surgery are the most common forms of accommodation, however, with certain cases of myopia it may be necessary to correct vision up to 30 to 40 diopters. As the degree of myopia increases the use of conventional solutions becomes less attractive and it would be highly desirable to be able to reliably correct this patient concern.
Still further, as humans age, or through viral inflammations or trauma, deterioration in retinal cells, including macular degeneration, can cause a dramatic loss of perception of light and color by rods and cones of the retina. In certain instances a degree of relief for humans suffering from impairment of vision from the loss of retinal cells can be achieved by increasing the intensity or magnification of images presented to healthy cells. In certain instances of macular degeneration it would be desirable to present a patient with an option of a correction of 30 to 70 diopters. This magnitude of correction is not readily achievable with presently known techniques.
The limitations to vision outlined in the proceeding are not intended to be exhaustive but are major concerns and represent limitations placed on mankind of impaired vision occasioned from trauma, disease, and/or age. It would be highly desirable if these limitations could be addressed and minimized or eliminated and thus restore to patients at least a portion of the accommodation and clarity of the vision of their youth.
It is a general object of the invention to provide a method and apparatus to obviate or minimize limitations to accommodated bifocal vision of the type previously described.
It is another object of the invention to provide an intraocular lens system which is operable to restore a patient""s multi-focal vision following extracapsular cataract extraction.
It is a further object of the invention to provide an intraocular lens system which can be used as a replacement of a patient""s natural crystalline lens to accommodate and offset presbyopia limited vision with age.
It is a related object of the invention to provide an intraocular lens system that can be used in place of a patient""s natural crystalline lens to correct instances of mild to severe myopia.
It is yet another object of the invention to provide an intraocular lens system which can be used to improve vision in patients having retinal deterioration, such as, macular degeneration.
It is a specific object of the invention to provide an intraocular lens system that is operable to utilize the natural physiology of the human eye to restore accommodative multi-focal vision to a patient.
It is yet another object of the invention to restore a patient""s vision following cataract surgery or for correction of presbyopia without using refractive surgery, contact lenses, or glasses as a part of the corrective solution.
It is still another object of the invention to provide an intraocular lens system solution to create a vision augmentation of 70 to 90 diopters without use of thick glasses or radical refractive surgery
In at least one preferred embodiment of the invention, intended to accomplish the above, and other, objects of the invention are achieved by an open chamber, accommodative, intraocular lens system operable to be positioned within the interior of an evacuated capsular bag of a human eye. The inventive intraocular lens system includes a first anterior lens optic and a second posterior lens optic which are arranged in axial alignment visually. An open chamber, haptic system is connected between the two lenses and in a preferred form three haptics segments are fashioned in the form of elliptical segments which are connected at their ends to the peripheral rims of the lens bodies and arc outwardly away from the visual axis of the lenses.
The overall cross-sectional shape of the inventive intraocular lens system is elliptical and is designed to fit smoothly within the interior of a patient""s capsular bag. The elliptical haptic elements are flexible and as the capsular bag is peripherally pulled outwardly at its equator the bag contracts. This contraction is produced by a patient""s natural vision accommodations by the ciliary muscles of the eye. In this, the anterior lens is moved axially toward the posterior lens to provide vision at infinity. As the ciliary muscles are constricted and move radially inward, for near vision accommodation, tension on connective zonula decreases and the patient""s capsular bag thickens allowing the haptics to assume their natural memory state.
Although the use of a two optic lens system is preferred, wherein the anterior lens is bi-convex and the posterior lens is concavo-convex to provide a corrective range of accommodation of about 4 diopters following extracapsular cataract surgery, other lens embodiments are contemplated by the subject invention. In this, other lens cross-sectional configurations can be used, for example, concavo-planar or concavo-convex for either the anterior or posterior. lens. In still other instances it may be desirable to remove the posterior lens entirely or eliminate its optic function by using a biplanar lens body. Finally, the invention also envisions adding more than two lenses, such as three lenses, in instances where extreme dioptive correction is desirable.
In a preferred embodiment three elliptical haptic segments are use extending at an arc of about 40 degrees outwardly from the rims of the lens optics and are peripherally spaced around the periphery with 80 degree segments of open space. These haptic segments are elliptical in cross-section takes along a line of sight of the lens system and are fashioned in a natural state to have an elliptical ratio of 0.96. Other arrangements of the haptics are also envisioned such as two wider based haptics or four or more haptics that would be thinner in outer width. The underlying criteria is that the haptics are flexible enough to enable relatively unrestricted accommodation movement of the anterior lens toward the posterior chamber lens of about 1.9 mm or so in response to the natural movement of the ciliary muscle and zonula attached to the capsular bag while simultaneously being stiff enough to support a lens or lenses of the optic system in visual axial alignment within the capsular bag of a patient""s eye.

Open chamber, elliptical, accommodative intraocular lens system


An elliptic curve multiplication method comprises three stages. In the first stage, randomly selected point representations are stored in variables. In the second stage, a right-to-left loop is executed that modifies the variable values in dependency of a multiplier. In the last stage, the result is calculated from the modified variable values.

Implementations of elliptic curve cryptosystems may be vulnerable to side-channel attacks ([1], [2]) where adversaries can use power consumption measurements or similar observations to derive information on secret scalars e in point multiplications eP.
One distinguishes between differential side-channel attacks, which require correlated measurements from multiple point multiplications, and simple side-channel attacks, which directly interpret data obtained during a single point multiplication. Randomization can be used as a countermeasure against differential side-channel attacks.
In particular, for elliptic curve cryptography, projective randomization is a simple and effective tool ([3]):
If (X, Y, Z) represents the point whose affine coordinates are (X/Z2, Y/Z.3) another representation of the same point that cannot be predicted by the adversary is obtained by substituting (r2X, r3Y, rZ) with a randomly chosen secret non-zero field element r. (When starting from an affine representation (X,Y), this simplifies to (r2X, r3Y, r).)
Simple side-channel attacks can be easily performed because usually the attacker can tell apart point doublings from general point additions.
Thus point multiplication should be implemented using a fixed sequence of point operations that does not depend on the particular scalar.
Note that it is reasonable to assume that point addition and point subtraction are uniform to the attacker as point inversion is nearly immediate (dummy inversions can be inserted to obtain the same sequence of operations for point additions as for point subtractions).
Various point multiplication methods have been proposed that use an alternating sequence of doublings and additions:
The simplest approach uses a binary point multiplication method with dummy additions inserted to avoid dependencies on scalar bits ([3]); however as noted in [4] it may be easy for adversaries to determine which additions are dummy operations, so it is not clear that this method provides sufficient security. For odd scalars, a variant of binary point multiplication can be used where the scalar is represented in balanced binary representation (digits −1 and +1) ([5]). Also Montgomery's binary point multiplication method ([6]), which maintains an invariant Q1−Qo=P while computing eP using two variables Qo, Q1, can be adapted for implementing point multiplication with a fixed sequence of point operations ([7], [8], [9], [10], [11]).
With this approach, specific techniques can be used to speed up point arithmetic:
The doubling and addition steps can be combined; y-coordinates of points may be omitted during the computation ([6], [9], [10], [11]); and on suitable hardware, parallel execution can be conveniently used for improved efficiency ([10], [11]).
All of the above point multiplication methods are binary. Given sufficient memory, efficiency can be improved by using 2w-ary point multiplication methods. Here, the scalar e is represented in base 2w using digits bi from some digit set B:
  e  =            ∑              0        ≤        i        ≤        l                                                  b        i                          2        wi
A simple way to obtain a uniform sequence of doublings and additions (namely, one addition after w doublings in the main loop of the point multiplication algorithm) is to use 2w-ary point multiplication as usual (first compute and store bP for each bεB, then compute eP using this precomputed table), but to insert a dummy addition whenever a zero digit is encountered.
However, as noted above for the binary case, the dummy addition approach may not be secure.
This problem can be avoided (given w≧2) by using a representation of e without digit value 0, such asB={−2w, 1, 2, . . . , 2w−1}as proposed in [4], orB={−2w, ±1,±2, . . . , ±(2w−2),2w−1}for improved efficiency as proposed in [12].
A remaining problem in the method of [4] and [12] is that the use of a fixed table may allow for statistical attacks: If the same point from the table is used in a point addition whenever the same digit value occurs, this may help adversaries to find out which of the digits b1, have the same value (cf. the attacks on modular exponentiation using fixed tables in [13] and [14]).
This problem can be countered by performing, whenever the table is accessed, a projective randomization of the table value that has been used.
This will avoid a fixed table, but at the price of reduced efficiency.

This patent is subject to a terminal disclaimer.

Method for elliptic curve point multiplication


A ball transfer mechanism for a harmonic drive and linear piston motor is disclosed. The ball transfer mechanism includes a spherical ball and a cylindrical seat portion. The seat portion defines a hemispherical shaped recess with a contour for receiving the ball. The ball transfer mechanism is in an exterior wall of a housing for converting rotary motion to linear motion, driving a linear piston motor. The harmonic drive drives a rotor of the linear piston motor. The harmonic drive includes a hollow cylindrical coupler portion engaging a rotor portion for transferring torque to the rotor portion. Transfer mechanisms disposed along a housing wall of the linear piston motor engage the coupler portion. The coupler portion includes harmonic cam grooves for receiving spherical balls in the ball transfer mechanism that drives rotational motion in the rotor in response to axially linear movement of the piston assembly.

The present invention relates to the field of drilling, and specifically to a ball transfer assembly for a high temperature downhole motor.
Downhole drills are used for oil drilling, geothermal drilling, and other deep earth penetration applications. Downhole drills include rotary and percussive drills. For nearly any drilling method, rotational energy must be transferred downhole in order to promote rock reduction. The drill bit may be rotated by an electric motor or fluid/hydraulic system. The rotating action can be produced either at the surface or near the drill bit. In addition to rotational cutting, drills may also be pressurized or mechanically actuated to force the drill bit to hammer against the rock/earth. Prior art rotation systems and methods are complex, require large form factors to create sufficient torque, and require a high degree of maintenance.
The most common method of downhole energy transfer is rigid drill pipe. The drill pipe is rotated from the surface, with drilling joints added for tripping (moving in and out of the hole). For this type of system, the entire drill string rotates. Typically a rotary table system or a top drive is used to drive the drill string. Although it is well suited for vertical drilling, it has limited applications in directional drilling because the drill string curvature and thrust loads generate additional torque that the surface based motor must overcome and drill pipe survive.
Downhole techniques used to generate rotation such as positive displacement motors (PDMs) are limited in their temperature range due to the use of elastomers. Energy resources like geothermal and deep oil and gas wells lie in hot (160° C.-300° C.), and often hard rock. The high-temperatures limit the use of PDM's in those environments. In addition, PDMs generate rotation by eccentric motion of the rotor around the motor case which induces significant lateral vibration to the drilling assembly.
U.S. Pat. No. 9,447,798 discloses a motor that includes a module assembly incorporating an axially-cycled piston. The piston axial motion is torque coupled to convert the axial motion into rotary motion. The method does not require elastomers for operation and the rotor operates concentrically thereby not inducing lateral vibration. A modular fluid powered linear piston motor with harmonic coupling is described in U.S. patent application Ser. No. 15/090,282 filed Apr. 4, 2016, entitled "Modular Fluid Powered Linear Piston Motors with Harmonic Coupling", and includes a drive train to convert reciprocating motion from a piston into rotary motion in an output shaft. Rotation is accomplished with roller balls captured between an inner race and a drive liner to facilitate rotation between a rotor and a stator. These roller balls must operate with low friction to enable smooth operation of the motor. Additionally, they must operate under a high contact load as they are in the preloaded and active load path to transmit torque to the output rotor. Finally, they must potentially operate with an abrasive drilling fluid under the rigors of high ambient temperatures and high friction conditions.
What is needed is a system and/or method that satisfies one or more of these needs or provides other advantageous features. Other features and advantages will be made apparent from the present specification. The teachings disclosed extend to those embodiments that fall within the scope of the claims, regardless of whether they accomplish one or more of the aforementioned needs.

Ball transfer mechanism with polycrystalline diamond bearing support

National Technology & Engineering Solutions of Sandia, LLC


A method of estimating a state of charge of a secondary cell includes: calculating a value of (∂Eemf/∂T) in advance on the assumption that Eemf is an electromotive force of the secondary cell and T is a temperature of the secondary cell; and calculating the state of charge based on at least a value of (∂Eemf/∂T) for which a value of the state of charge is set as a variable, a temperature measurement value of the secondary cell, and a current measurement value of the secondary cell.

The present disclosure relates to a method of estimating a state of charge of a secondary cell, a state-of-charge estimation device, a cell pack including the state-of-charge estimation device, an electronic apparatus, and an electric vehicle.
In consideration of user's convenience, a state of charge (SOC) is frequently estimated and displayed in secondary cells. In most of the secondary cells, the state of charge is shown at about three to five stages from a measurement result of a terminal voltage of the secondary cell. Further, secondary cells such as lithium-ion secondary cells are often used in electronic apparatuses such as personal computers, and thus the state of charge is also calculated by current integration.
In general, a state of charge can be estimated by accurately measuring an open voltage (open circuit voltage or open terminal voltage: OCV) of a secondary cell. For example, Japanese Unexamined Patent Application Publication No. 11-204149 discloses a lithium cell remaining capacity measuring method of correcting current dependency of an electromotive force of a lithium cell according to a lithium diffusion concentration gradient in an electrode of the lithium cell based on respective sampling data of the terminal voltage and current of the lithium cell, calculating an open circuit voltage of the lithium cell based on the correction result, and measuring the remaining capacity of a lithium cell based on the open circuit voltage.

Method of estimating state of charge of secondary cell, state-of-charge estimation device, cell pack, electronic apparatus, and electric vehicle


A liquid fuel composition containing a biofuel component, produced from a fraction of one or more cracking products produced by catalytic cracking of a biomass source. The liquid fuel composition contains in the range of 0.5 to 20 vol. % of C4-C8-olefins, which C4-C8-olefins contain in the range from equal to or more than 0.02 wt % to equal to or less than 100 wt % of bio-carbon, based on the total weight of carbon present in the C4-C8-olefins.

With the diminishing supply of crude mineral oil, use of renewable energy sources, such as biomass sources, is becoming increasingly important for the production of liquid fuels. These fuels from biomass sources are often referred to as biofuels.
Although a variety of biofuels can be produced from biomass sources, such as ethanol, methanol, biodiesel, Fischer-Tropsch diesel and kerosene, and gaseous fuels, such as hydrogen and methane, these fuels may require either new distribution technologies and/or new combustion technologies appropriate for their characteristics. The production of these fuels also tends to be expensive.
It would be an advancement in the art to provide a liquid biofuel composition that can be produced and handled by the existing infrastructure and combustion technologies. In addition it would be advantageous to provide liquid fuel compositions that may be suitable for the existing vehicles tank and fuel delivery systems.
WO2010/135734 describes a method for catalytically cracking a biomass feedstock and a refinery feedstock in a refinery unit having a fluidized reactor. WO2010/135734 further describes that a liquid product or a fraction thereof can be used or sold as a final product and/or can be subject to further processing/upgrading to produce a fuel or specialty chemical. WO2010/135734, however, does not disclose fuel products which are ready to be produced and/or used in the existing infrastructure and combustion technologies.
WO 2010/062611 describes a method for converting solid biomass to hydrocarbons requiring three catalytic conversion steps. First the solid biomass is contacted with a catalyst in a first riser operated at a temperature in the range of from about 50 to about 200° C. to produce a first biomass-catalyst mixture and a first product comprising hydrocarbons (referred to as pretreatment). Hereafter the first biomass-catalyst mixture is charged to a second riser operated at a temperature in the range of from about 200° to about 400° C. to thereby produce a second biomass-catalyst mixture and a second product comprising hydrocarbons (referred to as deoxygenating and cracking); and finally the second biomass-catalyst mixture is charged to a third riser operated at a temperature greater than about 450° C. to thereby produce a spent catalyst and a third product comprising hydrocarbons. The last step is referred to as conversion to produce the fuel or specialty chemical product. WO 2010/062611 mentions the possibility of preparing the biomass for co-processing in conventional petroleum refinery units. The process of WO 2010/062611, however, is cumbersome in that three steps are needed, each step requiring its own specific catalyst. WO 2010/062611 mentions the possibility of blending the first product, the second product and the third product together to form a final product comprising components selected from the group consisting of ethane, propane, butane and hydrocarbons boiling in the range of naphtha, jetfuel, diesel, heating oil and combinations thereof. This final product formed in WO 2010/062611 is, however, not ready for use in for example a transportation vehicle. WO 2010/062611 does not disclose fuel products which are ready to be produced and/or used in the existing infrastructure and combustion technologies.
It would be an advancement in the art to provide biofuel compositions, which can be produced and handled by the existing infrastructure and/or combustion technologies and/or existing vehicles tank and/or fuel delivery systems.


A projection-type display device includes: a light source; a dust-proof case; heat-dissipating fins; a heat-dissipation fan that causes cooling air to flow into the heat-dissipating fins; a prism unit that is provided inside the dust-proof case and that separates light from the light source into a multiplicity of illumination light beams; an internal circulation fan; heat-receiving fins; and heat pipes that connect the heat-dissipating fins and the heat-receiving fins. The heat-receiving fins and the heat-dissipating fins are both formed in a substantially rectangular parallelepiped shape, each having, as cooling air inflow surfaces that are effective in heat dissipation or heat reception, a first surface and a second surface whose area is greater than the first surface. The cooling airflow inside the dust-proof case that is supplied by the internal circulation fan flows from the first and second surfaces of the heat-receiving fins.

A projection-type display device is made up of a light source, an optical engine that, after light that is emitted from the light source has undergone optical processing by optical components such as lenses and mirrors, generates an image by means of image-generating elements (liquid crystal panel or DMD (Digital Micro-mirror Device)), and projection lens that enlarges and projects the image that was generated by means of the image-generating elements.
The light source conventionally uses a xenon lamp or a high-pressure mercury lamp but in recent years uses an LED (Light Emitting Diode) or LD (Laser Diode), whereby the light source lifetime, which is defined by a drop in the optical luminance of the light source, is five to ten times or more longer. Apart from the lifetime of the light-source, causes for a drop in the luminance of a projection-type display device include decrease of transmittance of the optical components due to the adhesion of dust, dirt, or soot in the air to the optical components or to the image-generating elements. In particular, when dust adheres to components such as image-generating elements in which light creates an image, the shape of the adhering matter results in defects that show up in the projected image. Still further, the irradiation of light upon dust or dirt generates heat which results in higher temperatures, and this leads to damage of the optical components and breakdown of the projection-type display device.
Extending the life of a light source results in an increase of the occurrence of decrease in luminance that results from the dust or dirt that adheres to an optical components or image-generating elements up until the light source reaches the end of its lifetime. In addition, the higher luminance of the projection-type display devices in recent years tends to facilitate the rise in temperature that results from adhered dust or dirt, and the previously mentioned decrease in transmittance, defects, and breakdowns become more likely to occur.
In order to prevent the decrease of transmittance and the occurrence of defects and breakdowns described above, dust and dirt must be kept from adhering to optical components and image-generating elements, and constructions are therefore being investigated that, by sealing the optical components and image-generating elements within a structural part, prevent the infiltration of dust and dirt contained in the air of the environment of the projection-type display device into the surroundings of the optical components or image-generating elements. In the interior of the sealed construction, the optical energy that is absorbed by the optical components and image-generating elements and the light energy of the unnecessary light that does not reach the projection screen result in the generation of heat, and this heat must be efficiently dissipated to the exterior of the sealed construction.
In the technology of discharging heat of a sealed construction, heat exchangers that use heat pipes are widely used. For example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2010-107631) discloses a configuration in which the air intake port and air exhaust port of a projection-type display device are linked by a duct and a heat exchanger, in which fins are provided at both ends of the heat pipe, is installed inside the duct.
When the hot air that is exhausted from the air exhaust port passes through the fins inside the duct, heat is received by the fins. The heat is transferred to the fins outside the duct by means of the heat pipe and a fan sends air to the fins outside the duct to radiate the transferred heat. The temperature of the air that passes through the fins in the duct interior is decreased by radiating heart toward the outside of the duct exterior, the air then flows to the air intake port of the projection-type display device, becomes hot by cooling the parts inside the projection-type display device, and then is exhausted from the air exhaust port. The air intake port and air exhaust port of the projection-type display device and duct are sealed, and the air that is used for cooling circulates through the air intake port, the interior of the projection-type display device, the air exhaust port, and the duct, and the dust and dirt contained in the air surrounding the projection-type display device therefore do not infiltrate into the interior of the projection-type display device, and as a result, dust and dirt do not adhere to the optical components or image-generating elements.


A projector displays an image on a projection surface. The projector has a zoom adjusting module and a keystone correcting module. The zoom adjusting module adjusts zoom level of a zoom lens for enlarged projection of image light. The keystone correcting module corrects trapezoidal distortion of the image displayed on the projection surface by means of forming the effective panel image in a revised image formation area, the revised image formation area being part of the image formation area of the panel surface.

1. Field of the Invention
The present invention relates to a projector for projecting light onto a screen or other projection surface to display an image, and in particular relates to a technique for executing zoom adjustment and keystone correction.
2. Description of the Related Art
When an image is displayed on a projection surface such a screen using a projector, trapezoidal distortion sometime occurs in the image displayed on the projection surface (hereinafter termed "display image") due to the relative positions of the projector and the projection surface. In such instances, keystone correction is used to correct trapezoidal distortion of the display image.
Keystone correction is carried out by reducing the image to trapezoidal shape and forming the image on the liquid crystal panel of the projector, and thus when there is appreciable trapezoidal distortion of the display image, the image formed on the liquid crystal panel becomes small, resulting in some instances in a drop in image resolution.
In the meanwhile, projectors are equipped with a zoom lens for adjusting the size of the display image on the projection surface. By adjusting the zoom lens (hereinafter referred to as "zoom adjustment"), zoom level can be adjusted between the telephoto end (smaller display image end) and the wide angle end (larger display image end). When a display image is displayed on the projection surface using the projector, it is preferred that a display image is displayed as large as possible on the projection surface.
Various techniques have been disclosed for performing zoom adjustment and keystone correction automatically, while avoiding a drop in resolution. For example, there has been disclosed a technique in JP2000-241874A whereby a test pattern is displayed on the projection surface and captured with a monitor camera, the image so captured being used to carry out zoom adjustment such that the largest possible display image is displayed automatically on the projection surface; and keystone correction is then performed. There has also been disclosed a technique in JP8-292496A whereby a test pattern is displayed on the projection surface, and zoom adjustment is then carried out while determining whether the pattern has reached maximum size within the projection surface.
However, with the prior art mentioned above, since keystone correction is performed after zoom adjustment to display the display image at maximum size on the projection surface, the display image on the projection surface is reduced due to keystone correction, becoming smaller in size. This causes necessity of repeating zoom adjustment.
An additional problem is that conventional zoom adjustment such as that described above is executed repeatedly through process of projecting a test pattern, capturing it with a monitor camera, making a determination, and performing zoom adjustment, until the intended zoom level is determined, making the process very time consuming.


A multi-direction switch (10) includes a housing (1), first fixed contacts (23, 24, 25, 26), common fixed contacts (22), a second fixed contact (21), a first movable contact (5), a driving device (6) and a second movable contact (3). The first movable contact includes constant contact portions (51) and movable contact portions (52). The constant contact portions touch the common fixed contacts. The second movable contact lays over the second fixed contact. The driving device is disposed on the second movable contact and includes first depressing portions (63) and a second depressing portion (65). The first depressing portions depress the movable contact portions and the second depressing portion depresses a central portion (31) of the second movable contact. The housing includes anchor grooves. The driving device includes anchor arms (64) received in the anchor grooves (14).

1. Field of the Invention
The present invention relates to a switch, and in particular to a multi-direction switch employed in portable electronic devices.
2. Description of the Prior Art
One such multi-direction input apparatus is disclosed in Japanese Publication for Laid-Open Patent Application No. 2002-343195 including a casing, which has a bottom wall disposed with a common contact; a first fixed contact, which is held by the casing; a first movable contact, which can be brought into or out of contact with the first fixed contact; a handle, which can be tilted in different directions to generate different electric signals; and a second movable contact, which touches the common contact. The first movable contact has a contact portion that touches the second movable contact. When the handle is tilted, the first fixed contact touches the first movable contact such that the conduction between the first fixed contact and the common contact is established through the first movable contact, the contact portion and the second movable contact, and a first electric signal is output.
The handle is actuated by outside force, the second movable contact and a cover of the multi-direction input apparatus. However, the handle is not supported by the casing. When the handle is titled, lack of balance often occurs in the multi-direction input apparatus. The first movable contact is combined with the handle by insert molding, thus the procedure of manufacture such multi-direction input apparatus is complex and the cost of manufacture is high.
Hence, an improved multi-direction switch is desired to overcome the above-mentioned shortcomings of the existing multi-direction input apparatus.


A plurality of buses of an electrical power system are grouped into agents, family lines of agents and families of agents based on the reactive reserves depleted when the buses are loaded. Contingencies are applied and the reactive reserves are monitored to determine an exhaustion factor for one or more family lines in one or more families. A boundary case solution exists for each outage that has no solution when the outage is removed in small steps and an additional step has no solution and is used to assess where, why, and how the contingency causes voltage instability, voltage collapse and local blackout. Based on this information, the voltage rescheduling, active rescheduling, unit commitment and load shedding is determined that can be used as preventive, corrective or emergency controls in system design and planning, operation planning, reactive and voltage management, real time control, and Special Protection System Control.

A number of problems can arise when outages occur within an electrical power system. One kind of problem, called voltage collapse, is a cascading loss of stability. The loss of stability typically originates in one or more subsystems of the electrical power system (caused by an equipment outage or increased load), which in turn overloads additional power system components. Voltage collapse can also be caused by an equipment outage due to relaying actions, failure of equipment, or failure of control. Typically, voltage collapse leads to a blackout or brownout where customers are no longer provided with the power they desire. Another type of voltage problem, called loss of voltage stability, is the inability of the generation, transmission, and distribution system to supply enough power to satisfy customer demand after a disturbance, increased load, or a change in operating conditions without an uncontrollable and progressive decrease in voltage. The source of these instability problems is within and between components in the electrical power system that delivers electrical power to customers. A third problem, called local blackout, occurs when the power network is pushed to its physical limits. This phenomenon can be caused by numerous factors, some of which are 1) exhaustion or depletion of reactive supply in the voltage control or reactive supply devices serving the local region or 2) outages of equipment or 3) increased power flow into or within a local region.
In an attempt to prevent voltage instability, methods have been developed that are directed toward identifying and rectifying weaknesses in the electrical power system before those weaknesses result in voltage instability. One such method is disclosed in U.S. Pat. No. 5,594,659 ('659 patent) entitled Method for Performing a Voltage Stability Security Assessment for a Power Transmission System.
While the '659 patent does provide a method directed toward identifying weak subsystems that evidence coherent behavior for the electrical power system, some drawbacks exist in its disclosed methods. Specifically, the '659 methods are intended to solely assess proximity to voltage instability in a coherent subsystem of a high voltage portion (i.e. transmission level) of a power network. The proximity measures developed in the '659 patent are not intended to assess the vulnerability to voltage collapse or local blackout; or more importantly, to determine when the network has experienced voltage collapse and local blackout. The '659 patent does not address the structure within the transmission, sub-transmission and distribution networks responsible for producing sequential exhaustion of reactive reserves, sequential instability, voltage collapse, local blackout or inability to obtain a loadflow solution. The '659 patent does not teach a "divide and conquer" method of finding contingencies that cause sequential exhaustion of reactive reserves, cascading instability, voltage collapse, local blackout or that have no loadflow solution. The present invention was developed in light of these and other drawbacks. In a preferred embodiment of the present invention, the Voltage Collapse Diagnostic, Preventive, Corrective and Emergency Control, and Available Transfer Capability is described. The present invention defines the structure responsible for producing sequential exhaustion of reserves, sequential instability, voltage collapse, local blackout or conditions that give rise to no loadflow solution.

Voltage collapse diagnostic and ATC system


An acousto-optic tunable filter based on isotropic acousto-optic diffraction using phased array transducers. The isotropic AOTF provides the advantages of narrow optical passband, low acoustic frequencies, and insensitivity to the input optical polarization. Preferred embodiments of the isotropic AOTFs are described for optimized spectral resolution and diffraction efficiency.

1. Field of the Invention
This invention relates to the field of electronically tunable optical filters utilizing acousto-optic (AO) diffraction.
2. Description of Prior Art
Acousto-optic tunable filters (AOTFs) have been constructed so that an incident light of a first polarization is diffracted by an acoustic wave in a birefringent crystal to shift from the first to a second polarization of the light beam for a selected bandpass of optical frequencies. The center wavelength of the passband of this type of filter is electronically tunable by changing the frequency of the acoustic wave within the crystal.
The AOTFs can be divided into two broad categories: collinear and noncollinear. In the collinear filter, the incident and diffracted optical waves inside the birefringent crystal are collinear with the acoustic wave. The diffracted light beam at the selected passband is separated from the incident light beam by crossed polarizers. One significant feature of the collinear AOTF is that the narrow filter bandpass can be maintained for incident light within a large angular aperture. The collinear type of acousto-optic filter is disclosed in an article entitled "Acousto-Optic Tunable Filters," appearing on pages 744-747 in the June, 1969 issue of The Journal of the Optical Society of America (Vol. 59, No. 6), and in U.S. Pat. No. 3,679,288, entitled "Tunable Acousto-Optic Method and Apparatus."
In the noncollinear filter, the optical waves inside the birefringent crystal are noncollinear with the acoustic wave. The diffracted beam at the passband is selected from the incident light beam either by crossed polarizers or by spatial separation. One type of noncollinear AOTF was described in a paper entitled "Noncollinear Acousto-Optic Filter," presented at the 1973 IEEE/OSA conference on laser engineering and applications and in U.S. Pat. No. 3,953,107; entitled "Acousto-Optic Filter." This type of noncollinear AOTF has a small angular aperture and must be restricted to a well-collimated light source. A second type of noncollinear AOTF is disclosed in an article entitled "Noncollinear Acousto-Optic Filter with Large Angular Aperture," appearing on pages 370-372 of the Oct. 15, 1974 issue of the Applied Physics Letters (Vol. 25), and in U.S. Pat. No. 4,052,121 entitled "Noncollinear Tunable Acousto-Optic Filter." In contrast to the first type, this type of noncollinear AOTF has the important feature of large angular aperture. The large angular aperture is due to the proper choices of interaction geometry wherein the tangents to the loci of the incident and diffracted light wave vectors are "parallel," a condition known as non-critical phase matching (NPM).
All of the AOTFs are based on bireflingent diffraction that couples incident light to diffracted light with orthogonal polarizations and different refractive indices. This type of diffraction can occur only in an optical birefringent crystal.
A more comnon type of AO diffraction is the isotropic diffraction that occurs in isotropic media (e.g. crystals or glasses) or in birefringent crystals between incident and diffracted light with the same polarization. In an isotropic diffraction the refractive indices of the incident light and diffracted light are approximately equal. Up to now, isotropic diffraction has not been utilized for AOTF applications.
A different class of AO device is the AO deflector for laser beam scanning. By varying the acoustic frequency the AO deflector scans an incident laser beam into a wide range of resolvable angular positions or spots. A basic performance parameter of the AO deflector is the bandwidth, which is approximately equal to the number of resolvable spots per unit time. The realization of large bandwidth has been one of the major goals in the design of the AO deflector.
One technique of increasing the bandwidth of AO deflector is the use of acoustic beam steering with a phased array of transducers. The simplest phased array employs fixed phase difference of 180 degrees between alternate transducer elements in a planar configuration. By selecting the inter element spacing s to be approximately equal to the characteristic length L.sub.0, where EQU L.sub.0 =n.LAMBDA..sub.0.sup.2 /.lambda..sub.0 ( 1)
where n is the refractive index of the AO medium, .LAMBDA..sub.0 is the acoustic wavelength at the center frequency and .lambda..sub.0 is the optical wavelength, the acoustic beam will be scanned to maintain the phase matching condition over a larger frequency range, thereby increasing the bandwidth of the AO deflector. This technique of increased bandwidth is referred to as tangential phase matching (TPM) since the steered acoustic wavevector is tangential to the locus of the diffracted light vector. A more efficient use of the acoustic power has been demonstrated using a stepped phased array where the height of each step in the phased array is equal to .LAMBDA..sub.1 /2. The phased array is blazed so that the beam steering angle from the transducer plane is zero at the reference acoustic wavelength .LAMBDA..sub.1. Wideband AO deflectors using planar and stepped phased arrays were described in an article by Korpel et al entitled, "A Television Display Using Acoustic Deflection and Modulation of Coherent Light" appearing on pages 1667-1675 in the October 1967 issue of Applied Optics, and another article by E. I. Gordon entitled, "A Review of Acousto-Optical Deflection and Modulation of Coherent Light" appearing on pages 325-335 of the same issue of Applied Optics. The stepped array AO deflector was also disclosed inn U.S. Pat. No. 3,493,759. Since the stepped phased array transducers are difficult to implement in practice, simpler fabrication techniques have been proposed. These are disclosed in U.S. Pat. No. 4,381,887, entitled, "Simplified Acousto-Optic Deflector using Electronic Delays," and U.S. Pat. No. 4,671,620, entitled, "Phased-Array Acousto-Optic Bragg Cell".
All of the prior art have limited the discussion on the use of phased array for increasing the bandwidth of AO deflectors by operating at the tangential phase matching; i.e., the selection of the spacing of the phased array element according to Eq. (1).
It is possible to achieve tangential phase matching by combining phased array transducers and birefringent diffraction. The net effect is to shift the acoustic frequency for tangential phase matching. The phased array birefringent deflector is described in the following articles: "Birefringent Phased Array Bragg Cells," 1985 IEEE Ultrasonics Symposium Proceedings, pages 381-384 and "Generalized Phased Array Bragg Interaction in Anisotropic Crystals," 1991 Proceedings of SPIE, Vol. 1476, pages 178-179.
Recent development of AO devices has been focused on integrated optic or guided wave structure, i.e., the interaction between surface acoustic waves (SAW) and guided optical waves. The integrated optic AOTF is described in an article by Y. Ohmachi and J. Noda, entitled, "LiNbO.sub.3 TE-TM Mode Converter Using Collinear Acousto-Optic Interaction" appearing in IEEE Journal of Quantum ElecLronics, Vol. QE-13, pp. 43-46, 1977. To date, all integrated AOTF work has been restricted to LiNbO.sub.3 using collinear birefringent AO interaction. The use of phased array transducer for increasing the integrated AO deflector bandwidth has been discussed, for example, in an article entitled, "Efficient Wideband Guided-Wave Acousto-Optic Bragg Diffraction Using Phased-Surface Array in LiNbO.sub.3 Waveguide," Appl. Opt., Vol. 16, pp. 1297-1304, May, 1977.

Acousto-optic tunable filter based on isotropic acousto-optic diffraction using phased array transducers


An active-matrix substrate is provided, which suppresses the unevenness of its surface due to the height difference of the TFTs and gate and data lines from the remaining area. After TFTS, gate lines, and data lines are formed on a transparent base, a transparent dielectric layer is formed on the base to cover the TFTs, the gate lines, and the data lines. The dielectric layer is selectively etched to form transparent dielectric portions arranged in a matrix array in such a way as to form a first plurality of recesses extending along the respective gate lines and a second plurality of recesses extending along the respective data lines. Each of the portions has a thickness equal to or greater than the maximum height of the TFTs, the gate lines, or the data lines, and a distance equal to or greater than the thickness thereof from a corresponding one of the TFTs, the gate lines, or the data lines. A planarization layer is then formed to fill at least the first plurality of recesses and the second plurality of recesses. Pixel electrodes are arranged on or over the flat surfaces of the respective portions. The connection part of each pixel electrode is connected to a corresponding one of the TFTs by way of a corresponding one of holes of the planarization layer.

1. Field of the Invention
The present invention relates to an active-matrix substrate used for Liquid-Crystal Display (LCD) devices, and a method of fabricating the same. More particularly, the invention relates to an active-matrix substrate comprising a dielectric plate and switching elements such as Thin-Film Transistors (TFTs) arranged in a matrix array on the plate, and a method of fabricating the substrate.
2. Description of the Related Art
In recent years, active-matrix addressing LCD devices using TFTs as their switching elements have been developed and used practically. LCD devices of this type comprise typically an active-matrix substrate on which gate lines, drain lines and TFTs are regularly arranged; an opposite substrate on which a color filter and a black matrix are formed; and a layer of liquid crystal sandwiched by the active-matrix substrate and the opposite substrate. On operation, a proper voltage is applied across the electrodes formed on the active-matrix substrate and the corresponding electrode or electrodes formed on the opposite substrate, or across the relating electrodes formed on the active-matrix substrate. Thus, the molecules of the liquid crystal are rotated to the specific orientations at the respective pixels according to the applied voltage to thereby change the transmission/reflection characteristic of light at the pixels, thereby displaying desired images on the screen of the LCD device.
With active-matrix addressing LCD devices, it is important to strictly control the orientation of the molecules of the liquid crystal to generate desired high-resolution and high-quality images. To realize this, it is required to enhance the accuracy of substrate flatness, electrode shape, electrode intervals, and so on.
FIG. 1 shows the structure of a prior-art active-matrix substrate of the LCD device of this type, which is fabricated in the following way. Although the substrate actually comprises TFTs, gate lines, and data lines, only one of the TFTs is shown in FIG. 1 for the sake of simplification.
First, a semiconductor layer, which is typically made of amorphous silicon or polycrystalline silicon, is formed on a transparent glass plate 101 and then, it is patterned by using popular photolithography and dry-etching techniques, forming semiconductor islands 112 on the plate 101.
Next, a silicon dioxide (SiO2) layer 117a is formed on the whole surface of the plate 101 to cover the semiconductor islands 112 and patterned, thereby forming gate dielectric layers 117a on the islands 112 for the respective TFTs 102. The remaining layer 117 covers the surface of the plate 101.
A conductive layer is formed to cover the SiO2 layer 117 and the gate dielectric layers 117a over the whole plate 101 and patterned, thereby forming gate electrodes 107a and gate lines (not shown in FIG. 1). The gate lines are connected to the respective electrodes 107a. In other words, specific parts of each gate line serve as the gate electrodes 107a.
Proper dopant atoms are selectively introduced into the semiconductor islands 112 in self-alignment with respect to the corresponding gate electrodes 107a by the ion-implantation method, thereby forming a source region and a drain region in each of the islands 112. The remaining part of each island 112 between the source and drain regions, which is located below the gate electrode 107a, forms a channel region.
A silicon nitride (SiNx) layer 118 is formed on the SiO2 layer 117a to cover the gate electrodes 107a and the gate lines over the whole plate 101. The layer 118 serves as an interlayer dielectric layer. Then, the layer 118 is selectively removed by the etching method in the peripheral area of each of the islands 112, thereby forming two contact holes that expose the source and drain region 5 of each island 112 by way of the SiO2 and SiNx layers 117 and 118, respectively.
A conductive layer is formed on the interlayer dielectric layer 118 of SiNx over the whole plate 101 and patterned, thereby forming a source electrodes 108a and a drain electrode 108b for each of the TFTs 102, and data lines (not shown in FIG. 1) over the plate 101. The data lines are connected to the corresponding source electrodes 108a of the TFTs 102. Each of the source electrodes 108a is contacted with the source region of the semiconductor island 112 by way of its contact hole. Each of the drain electrodes 108b is contacted with the drain region of the island 112 by way of its contact hole.
Through the above-described process steps, the TFTs 102, the gate lines, and the data lines are formed on the plate 101.
Subsequently, a thick, transparent, dielectric planarization layer 106 is formed on the interlayer dielectric layer 118 to cover the TFTs 102 and the gate and data lines. Contact holes 116 are formed to penetrate the layer 106 at the locations just above the respective source electrodes 108a. These contact holes 116 are to expose the underlying source electrodes 108a from the layer 106.
A transparent conductive layer such as Indium Tin Oxide (ITO) is formed on the planarization layer 106 and patterned, thereby forming pixel electrodes 109 in the respective pixel regions on the layer 106. Each of the pixel electrodes 109 is contacted with a corresponding one of the source electrodes 108a of the TFT 102 by way of its contact hole 116 of the planarization layer 106.
Thus, the prior-art TFT substrate of FIG. 1 is fabricated.
On the other hand, a color filter for red (R), green (G) and blue (B) colors and a black matrix for blocking unnecessary light among the pixels are formed on a transparent glass plate. Thus, an opposing substrate is formed.
Following this, the active-matrix substrate and the opposing substrate are fixed together to keep a specific gap between them with spacers. A specific liquid crystal is filled into the gap and sealed. Thus, the active-matrix LCD device is fabricated.
With the above-described prior-art active-matrix substrate of FIG. 1, the planarization layer 106 is formed to reduce the height difference between the areas including the TFT 102 and the gate and data lines and the other area. However, there is a problem that the height difference is not sufficiently reduced as desired with the use of the layer 106.
In particular, each pixel electrode 109 is raised at its end part 109a near the corresponding TFT 102 with respect to the surface of the plate 101 corresponding to the surface inclination of the layer 106, as shown in FIG. 1. Therefore, the gap between the active-matrix substrate of FIG. 1 and the opposing substrate varies and therefore, the voltage applied across these two substrates becomes non-uniform. This results in a problem of degradation of image quality. This problem is caused by the fact that the TFTs 102 (and the gate and data lines) generate protrusions of the planarization layer 106 and at the same time, each of these protrusions is considerably wide.
To solve the above-described problem, the inventor created the following improvement and submitted it as a Japanese patent application.
Specifically, prior to the formation of the TFTs, a transparent dielectric layer is selectively formed on a transparent plate except for the areas for the TFTs and the gate and data lines. The transparent dielectric layer has a thickness equal to or greater than the height difference between the areas including the TFTs and the gate and data lines and the other area. With this technique, the area for each pixel electrode is planarized by the transparent dielectric layer and therefore, the above-identified problem can be solved.
The structure of the active-matrix substrate and a method of fabricating the same according to the above-described inventor's improvement are explained below with reference to FIGS. 2A to 2C. FIG. 2C is a plan view showing the arrangement of the pixels including the TFTs, the gate and data lines, and the pixel electrodes. FIGS. 2A and 2B are cross-sectional view along the line IIB—IIB in FIG. 2C before and after the TFTs are formed, respectively.
First, transparent dielectric layer 113 is formed on a glass plate 101. The layer 113 has a thickness greater than the height difference H of the TFTs 102 from the surface of the plate 101. Then, the layer 113 is selectively removed by using known photolithography and etching techniques in such a way as to be left on the areas that exclude the TFTs 102 and the gate and data lines. In these areas, the pixel electrodes 109 are formed in the later process steps. The layer 113 is made of, for example, SiO2. The removed parts of the layer 113 form recesses 105a and 105b on the plate 101. The recesses 105a, each of which has an approximately rectangular cross-section, are formed to extend in a horizontal direction in FIG. 2C along the respective gate lines 107. The recesses 105b, each of which has an approximately rectangular cross-section, are formed to extend in a vertical direction in FIG. 2C along the respective data lines 108. The recesses 105a and 105b form rectangular pixel regions, as clearly shown in FIG. 2C.
Thereafter, the TFTs 2 having the same structure as shown in FIG. 1 are formed near the respective intersections of the recesses 105a and 105b. The pixel electrodes 109 are formed on the remaining transparent dielectric layer 113 in the respective pixel regions. The pixel electrodes 109 are connected to the source electrodes 108a of the corresponding TFTs 102 by way of the relating connection parts 110 of the electrodes 109. The connection parts 110 are extended over the height-different portions between the TFTs 102 and the pixel regions. The TFTs 102, the gate lines 107, and the data lines 108 are all located in the recesses 105a and/or 105b.
As shown in FIG. 2C, the gate lines 107 are extended horizontally in the respective horizontal recesses 105a while the data lines 108 are extended vertically in the respective vertical recesses 105b. The TFTs 102 are located near the respective intersections of the gate and data lines 107 and 108 (or, the recesses 105a and 105b).
With the active-matrix substrate according to the inventor's improvement shown in FIGS. 2A to 2C, the recesses 105a and 105b are small in width and occupy narrow areas compared with the size of the plate 101. On the other hand, the surface of the remaining transparent dielectric layer 113 is flat and occupies a wide area of the plate 101. As a result, it may be said that almost all the surface of the active-matrix substrate is flat, which leads to the solution of the above-described problem.
With the method of fabricating the active-matrix substrate according to the inventor's improvement shown in FIGS. 2A to 2C, however, there is a disadvantage that the patterning accuracy for the formation of the TFTs 102 is difficult to be controlled, and that the transparency at the pixel regions deteriorates to darken the displayed images.
Specifically, in this method, the transparent dielectric layer 113 is formed and patterned to form the recesses 105a and 105b and thereafter, the TFTs 102 and the gate and data lines 107 and 108 are formed in the recesses 105a and 105b. Thus, because of the effect of the height difference H between the layer 113 and the bottoms of the recesses 105a and 105b, each photoresist film used therefor has unavoidably a large thickness. As a result, there is a problem that desired fine patterns for the TFTs 102 are difficult to be formed in the respective photoresist films.
Moreover, because of the same reason, dry etching processes need to be carried out for forming the holes or recesses with large aspect ratios and thus, the dimensional accuracy is difficult to be controlled in the dry etching processes. Concretely, for example, when a photoresist film to be used for forming holes or recesses with a depth of approximately 1 μm has a thickness of approximately 2 μm, a possible focal point difference will be approximately 1 μm in the exposure process for the photoresist film. As a result, the dimensional accuracy of the patterned photoresist film will deteriorate.
In addition, as shown in FIG. 3, as the fabrication process steps are carried out, a plurality of interlayer dielectric layers 114 are successively formed on the patterned transparent dielectric layer 113. These dielectric layers 114 are stacked not only on the layer 113 but also along the sidewalls. In particular, the effective thickness of the stacked layers 114 along the sidewalls with respect to the exposing light irradiated will be increased in the regions 120. Therefore, undesired reflection and/or refraction of the exposing light tend to occur in the regions 120, in other words, the regions 120 tends to be transmittance-decreased regions, resulting in quality degradation of displayed images.

Active-matrix substrate and method of fabricating same


In order to connect a stepping motor driven type camera unit to a camera control unit intended for a DC motor driven type camera apparatus, a camera system includes a lens block provided with a stepping motor for adjusting lens operation, an A/D conversion block for converting a DC control signal ranging from positive to negative polarity into a digital signal to be outputted, a shift direction/velocity calculation block which generates and outputs data on lens shift direction and velocity according to the digital signal from the A/D conversion block, and a pulse signal generation block for outputting a pulse signal according to the data from the shift direction/velocity calculation block.

1. Field of the Invention
The present invention relates to a camera apparatus and lens control interface apparatus and more particularly, to a camera apparatus and a lens control interface unit to be connected to a control unit used for a DC motor-type lens unit and capable of operating a lens mechanism provided with a pulse signal drive motor.
2. Description of the Prior Art
Conventionally, a DC motor has been used in a camera apparatus having a zoom lens mechanism such as a video camera for controlling zoom, focus, iris and the like. Such a camera apparatus has been widely used in an image pickup system for monitoring, for example, in a bank, shop, parking area, and the like. Hereinafter, an explanation will be given of an image pickup system using a conventional camera apparatus with reference to FIG. 1 and FIG. 2.
As shown in FIG. 1, a conventional image pickup system 100 includes: a camera unit 110 consisting of a zoom lens block 120 having a zoom lens (not depicted) operated by a DC motor and a pickup signal generation block 130 having an image pickup element 131 and an image processing circuit 132; and a camera control unit 140 for controlling the zoom lens block 120 of this camera unit 110. In this conventional image pickup system 100, the zoom lens of the camera unit 110 is remote controlled from the camera control unit 140 for zooming, focusing, and iris operation as well as zoom and focus preset operation.
The camera unit 110 is installed, for example, at a predetermined position for monitoring clients of a bank. In the camera unit 110, an image pickup light from the zoom lens arranged in this zoom lens block 120 is received by an image pickup element 131 such as a CCD arranged in the pickup signal generation block 130, whose output is supplied to the image processing circuit 132, which in turn generates a pickup signal.
The pickup signal is supplied via a coaxial cable or the like to the camera control unit 140. The camera control unit 140 can control the display of a monitor image on a image display unit (not depicted) and the recording of a pickup signal on a VTR apparatus.
The zoom lens block 120 of the camera unit 110 includes the aforementioned zoom lens, a zoom position adjustment mechanism (not depicted) for adjusting a zoom position, and a zoom DC motor 121 which is connected to this zoom position adjustment mechanism. The zoom DC motor 121 is connected to a zoom DC motor drive circuit 143 of the camera control unit 140, so as to be operated by a zoom DC motor drive voltage signal 140a outputted from this drive circuit 143.
Moreover, the zoom lens block 120 includes a focus position adjustment mechanism (not depicted) for adjusting a focus position of the aforementioned zoom lens and a focus DC motor 122 connected to this focus position adjustment mechanism. This focus DC motor 122 is connected to a focus DC motor drive circuit 144 of the camera control unit 140 which will be explained later, so as to be operated by a focus DC motor drive voltage signal 140b outputted from this drive circuit 144.
Furthermore, the zoom lens block 120 includes an iris position adjustment mechanism (not depicted) for adjusting an iris amount (stop amount) of the aforementioned zoom lens and an iris DC motor 123 connected to this iris position adjustment mechanism. This iris DC motor 123 is connected to an iris DC motor drive circuit 145 of the camera control unit 140, so as to be operated by an iris DC motor drive voltage signal 140c outputted from this drive circuit 145.
Still further, the zoom lens block 120 includes a zoom position detecting rheostat 124 which is interlocked to be slided with a zoom position adjustment operation of the aforementioned zoom position adjustment mechanism and a focus position detecting rheostat 125 which is interlocked to be slided with a focus position adjustment operation of the aforementioned focus position adjustment mechanism.
On the other hand, the camera control unit 140 includes, as shown in FIG. 2: an operation section 141, a control section 142, a zoom DC motor drive circuit 143, a focus DC motor drive circuit 144, an iris DC motor drive circuit 145, an A/D converter 146, 147, a position detecting power circuit 148, and a position data storage section 149. This camera control unit 140 is installed, for example, in a building manager room which is separated from the location of the aforementioned camera unit 110.
The operation section of the camera control unit 140 is provided with a zoom position adjustment knob 141a, a focus position adjustment knob 141b, an iris position adjustment knob 141c, a position store key 141d, and a preset key 141e. These adjustment knobs 141a, 141b, and 141c, and the keys 141d and 141e are respectively connected to the control section 142. The operation section 141 is formed, for example, on an operation panel arranged in the aforementioned building manager room so that the adjustment knobs and keys can be operated by the manager or the like.
The control section 142 controls the aforementioned DC motor drive circuits 143, 144, and 145 according to the operations of the aforementioned adjustment knobs 141a, 141b, and 141c of the operation section 141.
That is, when the zoom position adjustment knob 141a is operated, the control section 142 makes the zoom DC motor drive circuit 143 output a zoom DC motor drive voltage signal 140a.
Moreover, when the focus position adjustment knob 141b is operated, the control section 142 makes the focus DC motor drive circuit 144 output a focus DC motor drive voltage signal 140b.
Furthermore, when the iris control adjustment knob 141c is operated, the control section 142 makes the iris DC motor drive circuit 145 output an iris DC motor drive voltage signal 140c.
Here, the aforementioned DC motor drive voltage signals 140a, 140b, and 140c outputted from the aforementioned DC motor drive circuits 143, 144, and 145, respectively are DC currents of positive or negative polarity within a range of .+-.12 volts so that respective voltage values to be applied to the corresponding DC motors can be varied in this range of .+-.12 volts.
When the zoom position adjustment knob 141a is operated so as to request for the zoom position in the TELE direction, the control section 142 controls so that the zoom DC motor drive circuit 143 outputs a zoom DC motor drive voltage signal 140a of positive or negative polarity. On the other hand, when the zoom position adjustment knob 141a is operated so as to request for the zoom position in the WIDE direction, the control section 142 controls so that the zoom DC motor drive circuit 143 outputs a DC motor drive voltage signal 140a of negative or positive polarity.
Moreover, when the zoom position adjustment knob 141a is operated by a large value in the TELE or WIDE direction, the control section 142 controls so as to increase the voltage of the zoom DC motor drive voltage signal 140a outputted from the zoom DC motor drive circuit 143.
It should be noted that when the focus position adjustment knob 141b or the iris position adjustment knob 141c is operated for changing the focus position or the iris position, the controls section 142 similarly control the focus DC motor drive circuit 144 or the iris DC motor drive circuit 145 so as to output a focus DC motor drive voltage signal 140b or an iris DC motor drive voltage signal of positive or negative polarity.
In the camera unit 110 shown in FIG. 1, the respective DC motors 121, 122, and 123 arranged in the zoom lens block 120 are operated according to the corresponding DC motor drive voltage signals 140a, 140b, and 140c which have been outputted as described above. For example, the zoom DC motor 121 is controlled to rotate in a direction according to the polarity of the aforementioned zoom DC motor drive voltage signal 140a and to increase its rotation speed as the voltage increases.
Consequently, in the camera unit 110, a zoom operation is carried out in the TELE or WIDE direction according to the polarity of the zoom DC motor drive voltage signal 140a, whereas the zoom position shifting speed is changed according to an increase and a decrease of a voltage of the zoom DC motor drive voltage signal 140a.
Furthermore, in the conventional image pickup system 100, the position detecting power circuit 148 in the pickup camera control unit 140 outputs a position detection DC voltage V+, V- to the zoom lens block 120 of the camera unit 110. These position detection DC voltages V+, V- are supplied, as shown in FIG. 1, to both ends of the zoom position detection rheostat 124 and the focus position detecting rheostat 125 which are connected in parallel in the zoom lens block 120.
The zoom position detecting rheostat 124 outputs a voltage (voltage divided by the rheostat) corresponding to the zoom position as a zoom position voltage signal 140e to the A/D converter 146 of the camera control unit 140. This zoom position voltage signal 140e is, as shown in FIG. 2, converted from AC to DC by the A/D converter 146 and supplied as zoom position voltage data to the control section 142.
On the other hand, the focus position detecting rheostat 125 outputs a voltage (voltage divided by the rheostat) corresponding to a focus position as a focus position voltage signal 140f to the A/D converter 147 of the camera control unit 140. This focus position voltage signal 140f is converted from AC to DC by the A/D converter and supplied as focus position voltage data to the control section 142.
The control section 142 stores the aforementioned zoom position voltage data and the focus position voltage data in the position data storage section 149 according to the operation of the position store key 141d. When the preset key 141e is operated so as to request for preset which controls the zoom position adjusting mechanism and the focus position adjusting mechanism of the camera unit 110 to be positioned at the stored zoom position and the stored focus position, the control section 142 reads out the zoom position voltage data and the focus position voltage data from the position data storage section 149 and changes the voltage values of the zoom DC motor drive voltage signal 140a and the focus DC motor drive voltage signal 140b, so that zoom position voltage data and focus position voltage data are respectively identical to the zoom position voltage data and the focus position voltage data which have been read out from the position data storage section 149, thus adjusting the zoom position and the focus position to be set at the preset zoom position and the preset focus position.
Moreover, the conventional image pickup system is provided with a serial communication such as RS-232C for data communication with a system controller (not depicted). In such a conventional image pickup system, the zoom position, focus position, and iris position are controlled according to zoom position instruction data, focus position instruction data, iris position instruction data, zoom position and focus position storage request data, and preset request data which are supplied from the system controller.
In such an image pickup system, a single system controller is connected to a plurality of camera control units 140, enabling the control at a single center of a plurality of camera units 110 installed in a plurality of locations within an area to be monitored.
Recently, in contrast to the aforementioned conventional camera unit 110, there has been utilized a stepping motor driven camera apparatus in which zooming, focusing, and iris adjustment of the zoom lens is carried out by driving a stepping motor. The zoom lens used in such a camera apparatus costs less and has a smaller size than the zoom lens used in the conventional DC motor driven type camera unit 110. For example, such a lens has begun to be used as a built-in component in a monitor video camera, for example.
However, in such a stepping motor driven type camera apparatus, the aforementioned stepping motor is normally driven by a pulse signal generated by a microcomputer built in the apparatus, and has a control system different from the aforementioned DC current driven type camera unit 110. Consequently, in the conventional image pickup system 100, it is impossible to directly connect a stepping motor driven type camera apparatus to the camera control unit 140 intended for the DC motor driven type camera unit 110.
For this, in order to replace the camera unit 110 of the DC motor drive type in the existing image pickup system 100 with a stepping motor drive type camera apparatus, it is necessary to replace the camera control unit 140 and the aforementioned system controller, which brings about a problem requiring a large cost and engineering work. From the viewpoint of utilizing the existing facility, it has been desired to connect a stepping motor drive type camera apparatus to the camera control unit 140 intended for the conventional DC motor driven camera unit 110.

Camera system and camera lens control unit


Fully austenitic alloys are provided whose essential components are as follow:. ______________________________________ NICKEL 17.3-22.5% BY WEIGHT CHROMIUM 9-14% MOLYBDENUM 1.2-2.8% COPPER 2.6-3.8% MANGANESE 2.6-4.2% COLUMBIUM 0.2-0.85% IRON ESSENTIALLY BALANCE ______________________________________. Nominally these alloys of the invention will also contain carbon, up to a maximum of about 0.08% by weight, and up to about 1.5% silicon in its usual role in ordinary steel-making practice as a deoxidizer or as a portion of scraps and returns. The usual minor impurities may also be present.

For several decades in the field of corrosion resistant metals most inventive effort has been directed toward development of nickel base or low iron content alloys. While relatively little effort has been made to improve austenitic iron base alloys of low special element content, their importance may be judged by the fact that the ordinary 18% Cr--8% Ni family of stainless steels is employed more than all other corrosion resistant alloys combined. However, those steels have very limited utility in handling sulfuric acid solutions.
Because of cost, availability and metallurgical factors, alloys intended to resist sulfuric acid contain several or all of the elements from the group, iron, nickel, chromium, molybdenum, copper, manganese, silicon and columbium. The nominal compositions of commercial alloys intended for sulfuric acid service as well as for many other applications are shown in Table I. The carbon content is approximate.
TABLE I ______________________________________ Alloy Designation Ni Cr Mo Cu Cb Si Fe C ______________________________________ 20 29 20 2.5 3.5 -- 1. 47 .15 20Cb3 34 20 2.5 3.3 .6 .6 38 .06 20Mo4 36 23 4.0 1.0 .25 .4 35 .02 20Mo6 35 24 6.0 3.0 -- .2 30 .02 825 42 22 3.5 2.5 -- .6 26 .03 G-3 45 22 7.0 2.0 .8 .6 22 .01 625 63 22 9.0 - 4.0 .6 1 .06 ______________________________________
While carbon contents above about 0.08% do not reduce the sulfuric acid resistance of these alloys, at very low carbon levels, less than about 0.03%, they have been found to have good resistance to a wide spectrum of other corrosive substances.
Parson, U.S. Pat. No. 2,185,987, discloses the first notable alloy of this group, commonly referred to as Alloy 20.
To avoid intergranular attack in weld zones, columbium was added to Alloy 20. Because Alloy 20 was reported to suffer stress corrosion in certain concentrations of sulfuric acid, Scharfstein, U.S. Pat. No. 3,168,397, developed the higher nickel 20Cb3 alloy, which was claimed to overcome this problem. DeBold, et al., U.S. Pat. No. 4,487,744, discloses the still higher nickel content 20Mo4 alloy, which is claimed to provide improved resistance to many chemical substances including sulfuric acid. Later, Henthorme, et al., U.S. Pat. No. 4,201,575, developed alloy 20Mo6, which was claimed to have good general corrosion resistance as well as resistance to chloride solution pitting and crevice corrosion. Alloys 825 and G-3 have even higher nickel and lower iron contents, while Alloy 625 has virtually eliminated iron. While these high nickel alloys provide remarkable resistance to many other corrosive substances, their resistance to sulfuric acid solutions at ambient temperatures is achieved at very high cost and consumption of the nonferrous elements involved. Also, while all of these alloys are furnished in wrought or cast forms, fabricability and weldability tend to be lower as iron content drops. Other similar high nickel alloys not listed above possess even lower fabricability and weldability. Thus, there has remained a need for leaner, rather than richer, principally Ni but also Cr containing alloys for the handling of sulfuric acid at ambient temperatures which are also very ductile and weldable.


A power transmission system including a direct current power source electrically connected to a conversion device for converting direct current into alternating current, a conversion device connected to a power distribution system through a junction, an energy storage device capable of producing direct current connected to a converter, where the converter, such as an insulated gate bipolar transistor, converts direct current from an energy storage device into alternating current and supplies the current to the junction and subsequently to the power distribution system. A microprocessor controller, connected to a sampling and feedback module and the converter, determines when the current load is higher than a set threshold value, requiring triggering of the converter to supply supplemental current to the power transmission system.

The invention describes a power transmission system and, more particularly, to a distributed energy resource system enhanced to provided supplemental current when required to a power distribution.
Distributed energy resource (DER) systems consist of energy generation and storage systems placed at or near a power load center. Unlike large electric power plants, DERs are small in terms of capacity and are installed close to the consumer. Examples of DERs are fuel cells, microturbines and photovoltaic systems. These distributed resources can provide the consumer with better power quality and higher energy efficiency. A DER system also has the potential to mitigate transmission congestion, control price fluctuation, strengthen security and improve grid stability. Most DER systems are typically less than a megawatt in size. Such a limitation will degrade DER's transient roadability in case of large load switching, such as induction motor starting. Therefore, it is highly desirable to integrate a supplemental power conversion system (SPCS) into a DER system so that the over-loaded energy can be compensated by injecting supplementary current from a SPCS into the grid. A device is required which senses the DER current to detect the overload condition and triggers the SPCS inverter.
The implementation of distributed energy resource systems as a supplementary or stand-alone power source can achieve significant benefits in terms of economy and reliability, such as better power quality, higher energy efficiency and improved system stability. However, an isolated DER system will experience overload stress when transient inductive loads, such as motor starting, drawing excessive currents from the system. Such stress might cause severe voltage sag due to the over-current protection of the DER system itself. In many cases, the system protection scheme will shut down the DER system if the current is much higher than the DER system capability.
Required is a system and method for implementing a distributed energy resource system that has suitable capability to supply excess current demands and protect the integrity of the energy delivery system.

Enhanced distributed energy resource system