An indoor or quasi-indoor aviary for soft-bill and small hook-bill birds designed so as to permit the creation of both a miniature natural habitat and the illusion of an unenclosed space. The aviary features a lower frame that rests on a floor. Four removable corner supports extend vertically from each corner and provide support for an upper frame. Detachable netting connects to both the upper and lower frame and to a flexible lean-in, walk-in entryway. The top of the upper frame supports a removable upper cover. The sides of the upper frame support a built-in perch, an entry guide, vertical snap-on nesting poles and a horizontal brace extending across the top. The lower frame contains a feeding stand accommodating both peg-style and hanging-style feed and water containers. It also contains a plant rack with built-in holders for dried plant materials. Four legs lift the lower frame off the floor. A decorative upper band wraps around the upper frame. A decorative lower band that raises and lowers to allow removal of a litter tray wraps around the lower frame. The litter tray inserts into a disposable litter bag and slides under the lower frame. For those wishing to eliminate the removable corner supports, suspension cords attach to the upper frame and allow the aviary to be suspended from a structure above and external to the aviary.

People who wish to enclose pet birds in their living or working areas face a difficult task providing a suitable flight environment. It is widely recognized that the preferred flight environment is one that complements the decor of the area in which it is placed, simulates a natural habitat, is safe and relatively large, provides a high degree of visibility, and creates an illusion of birds perching, flying and nesting in an unenclosed space. Consumer access to this "preferred flight environment" is limited due to five design factors found in current aviaries: visibility, safety, cost, space and aesthetics.


A plastic pipe coupler is provided having a plurality of sections connected to one another but with at least one gap between the ends of two sections which are adjacent to one another. Each of the coupler sections has an exterior surface and an interior surface, and is fabricated so that when taken together, the sections cooperatively circumvent a section of plastic pipe. Each bracket is secured to the exterior surface of one of the aforesaid sections of the coupler and has a base plate, a pair of sidewall plates attached to each base plate, and a crosspiece having a first end and a second end, the first end of which is in contacting relationship with one of the pair of sidewall plates, while the second end is in contacting relationship with the other of the pair of sidewall plates.

1. Field of the Invention
This invention relates generally to couplers, and more particularly, to a coupler that can mechanically join together a plastic pipe and a concrete pipe, and still more particularly a plastic pipe that is corrugated.
2. Description of the Related Art
This invention is directed to the providing of a coupler for use with plastic and concrete pipe. Over the years, there have been many couplers for joining one plastic pipe with another pipe also made from plastic. Similarly, there have been couplers that have been made to join together two pipes fabricated from concrete. However, there has never been a coupler that can mechanically join together a concrete pipe having a smooth-walled exterior and a plastic pipe, especially one that is corrugated.
Historically, concrete and plastic pipes have not been used together in the field due to the absence of mechanical connectors. Attempts at using the screw-type of coupler used with concrete pipe on plastic pipe as well could result in the tearing of the plastic pipe if the juncture of the two pipes was subjected to stress. Additionally, many job applications only permitted the use of one type of pipe, however, recently there has been some willingness on the part of some organizations charged with overseeing transportation related pipe installations to permit concrete and plastic pipe to be used in the same job installation.
For example, one place historically where only concrete pipe has been used is in culvert applications beneath roadways. Cylindrical, smooth-walled concrete pipe typically 8′ in length is laid well beneath the road surface, extending from one side of the road to the other. Penultimate sections of concrete pipe are laid at opposing ends of the concrete pipe(s), with concrete culvert openings attached to the opposite free ends of the concrete conduit. Each of the concrete structures is coupled to the structure adjacent thereto using couplers well known in the concrete pipe industry. The installation process is time consuming and requires the use of manpower and equipment sufficient to move such heavy structures. By using HDPE (high density polyethylene) or other types of plastic pipe with similar characteristics to HDPE, the manpower and equipment requirements could possibly be lessened. Additionally, a longer plastic pipe (greater than 12′ and normally 20′ in length) could be utilized in place of several shorter concrete sections due to the weight factor. This could further reduce installation time and decrease the number of joints, thereby decreasing the number of joint leaks, as well as being cheaper due to the relative costs of the pipes involved.
It is thus apparent that the need exists for a coupler for mechanically joining concrete and plastic pipe which effectuates a watertight seal so as to be useful in culvert construction, which coupler is relatively easy to fabricate and cost effective to use.

Coupler for joining plastic and concrete pipe


A communication session support infrastructure comprises a networked packet based connection unit or gateway. The gateway includes a packet data interfacing unit for converting between protocols used by a plurality of current connecting devices in a session and a packet-based protocol so that different kinds of communication devices can connect to the session although internal session management is carried out using IP type protocols. The connection unit includes a one-to-many packet routing unit which receives packets through the interfacing unit from one of the current connecting devices in a session and routes the packets back to the interfacing unit for forwarding to each of the other current connecting devices in the session.

Multiple user sessions are well known in the telephony field in the form of what are known as conference calls. In a conference call, all users are connected to a given location, often an advanced telephone of a call originator but alternatively a location belonging to the telephone service provider. The location receives all signals and mixes them for sending to each user. Mixing of the signals has a particular disadvantage in that specific hardware is needed, thereby increasing cost. Conference calls generally require specialized telephones in order to provide the support necessary for setup of such a conference call, and therefore, it is generally more difficult to arrange a conference call from a standard telephone. The specialized telephone may require support from office private branch exchange (PBX) hardware. If office PBX hardware is being used to set up the conference call, then it may be necessary for all participants to be called from the setup location in order to activate the conference call. In any of the above cases, there is often a limit on the number of participants to the conference call. As an alternative, the hardware needed for the conference call can be provided at the exchange. In such a case, an advanced telephone is not needed for call setup, but it may be necessary for each participant in the conference to call a central location. Usually in such circumstances, the conference call is arranged in advance and the users are notified of the time and the number to call.
Another kind of multi-party communication session is that provided by standard radio connections involving a base station and mobile units, such as commonly used by taxi companies, the police, and military for example. In these cases, a single channel is reserved for the group. Each member of the group is able to speak to each other member of the group via the base station. At any given time, only a single user is allowed to speak, and all the other users are limited to listening.
Numerous variations of the above radio system allow, for example, for dispensing with the base station in favor of one of the mobile units being set as master, or in favor of a circular connection system.
Disadvantages of the mobile radio system include limited range, although the range can be extended with the use of repeaters, and a closed group of users. The base station may be limited in capacity, and in any case, each user must be supplied with a mobile unit. These disadvantages do not apply to the conference call, in which anyone who is able to connect to the central telephone number is able to participate in the call. It is further noted that dial-in conference facilities also have limits on the number of simultaneous callers.
However, the mobile radio system has a number of advantages over the conference call. The multi-party session does not have to be arranged in advance. As long as the base station is operational, any mobile unit can connect. Upon doing so, the connecting unit will be connected to any of the mobile units which are currently switched on to the appropriate channel.
A service that offers a combination of the advantages of group radio and telephone conferencing is provided by telephone networks that use the Integrated Dispatch Enhanced Network (iDEN) system of cellular technologies. The iDEN solution is not applicable to the currently widespread cellular technologies, such as GSM, because it is restricted to iDEN supporting networks only. The iDEN solution cannot support devices on any other kind of network and certainly cannot support groups that encompass more than one network.
The iDEN service is thus unable to provide cross-network functionality, meaning that participation is limited to users of the iDEN service.

Apparatus and method for multiple party communication session


According to an aspect, there is provided a method comprising controlling a structural light source of a modelling arrangement to produce a diffraction pattern of a known geometry on a surface to be modeled, the diffraction pattern accurately complying with a mathematical-physical model and wherein beam output angles of the diffraction pattern are accurately known based on the mathematical-physical model; recording a first image of the surface comprising the diffraction pattern with a first camera and a second image of the surface comprising the diffraction pattern with a second camera substantially simultaneously; determining a point cloud comprising primary points from the diffraction pattern visible in the first image; identifying the corresponding primary points from the second image; and using each primary point of the point cloud in the first and second images as an initial point for search spaces for secondary points in the first and second images.

Photogrammetry makes use of mapping or modeling based on photographs taken of an object of interest. There are numerous applications in which, for example, three-dimensional imaging conducted by means of machine vision is very useful. In general, these systems may include, for example, a camera, a lighting device and a control system managing the equipment. In stereophotogrammetry, a three-dimensional object is modeled by taking two or more photographs of an object from different camera positions and identifying the common points in each photograph.
The challenge in photogrammetry and stereophotogrammetry is to be able to model a three-dimensional object quickly, for example, in real-time or near real-time, and do this very accurately.

Modeling the topography of a three-dimensional surface


A weapon grip assembly for attachment to a forward portion of a weapon is provided. The invention includes a base assembly supported for operative engagement by a handle. The base assembly includes clamps adapted to be secured to a forward portion of the weapon and further includes a post having a clamp end adapted to retain the clamps for pivot motion with respect thereto. The post of the base assembly is received within a bore of the handle, a mandrel being interposed between the handle and the clamps of the base assembly. As the base assembly is drawn into the handle, by rotation of the handle about the post of the base assembly, the mandrel receives the clamp end of the post, with an upper free surface thereof engaging the clamps for pivoted closure about a portion of the weapon in furtherance of securing the weapon grip assembly thereto.

Weapons having barrels for discharging munitions are primarily adapted to be griped in the vicinity of the trigger, more particularly via a "pistol grip." A wide variety of styles and configurations are know for pistol grips, key considerations being functionality, ergonomics, and aesthetics.
For "long" barreled weapons, rifles for instance, forward support of same is accomplished via hand placement upon the forend, e.g., a barrel handguard or the like (i.e., a lower portion of the forward portion of the weapon). With the advent and advancement of weapon systems, for instance tactical weapons, the functionality of the "weapon" has become quite diverse, a challenge being to maintain an ease of use of the variety of features thereof, and avoidance of a cumbersome, inflexible and heavy weapon system.
Many members of the armed services and law enforcement officers, are issued, and carry a tactical weapon system which includes a "host weapon" (e.g., a rifle) which is equipped with, or may be equipped with, a variety of "supplemental devices," for instance a 40 mm grenade launcher. Such host weapons, sometimes referred to as modular weapon systems, are further configurable or adaptable to receive a variety of rails, interbars, or rail systems, upper/lower receiver and/or handguard components, buttstocks, or other accessories (e.g., sites, illumination devices, sling attachments or anchors, etc.). Traditionally, weapon system accessories have been manufacturer specific, each manufacturer of modular weapon systems providing items for integration with their rail, rail system etc. Although forward pistol grips are known and commercially available for integration with a forend assembly of a weapon, more particularly a rail or rail system, the variety of forend configurations available for a weapon have precluded a more versatile, "one size fits all" solution for forwardly supporting a weapon system in its variety of configurations.
For instance, in a weapon system comprising a host weapon (e.g., rifle) and a supplemental device (e.g., grenade launcher), the launcher mounts to the rifle in a position which places the launcher in the front half of the rifle, and below the rifle barrel. This location has been the standard of armed forces worldwide since the introduction of the rifle mounted grenade launcher about 40 years ago.
While the above described attachment method of the launcher to the host rifle may be the most practical solution for the integration of these separate devices, it does not provide the user with the best solution for carrying or operating the rifle or the launcher when the two devices are combined.
Carrying or operating the rifle/launcher combined weapon system requires that one of the operator's hands be placed on the pistol grip of the rifle, near the rifle trigger, while the other hand is placed near the forward end of the weapon system, beneath the grenade launcher, to support the system in a position chosen by the operator for carrying and/or operation of either device. The right hand, typically used to support the rear end of the rifle at the pistol grip, and to operate the rifle trigger, is partially wrapped around the pistol grip which allows the operator to close their fingers around same, and use their index finger to fire the rifle. The left hand, typically used to support the forward end of the rifle (i.e., the end away from the user) is placed below the grenade launcher, in a palm-up cup or cradle position, with the fingers and thumb wrapped partially around the launcher handguard to both support the weight of the rifle/launcher combination and control its orientation in all axes.
The palm-up position required of the operator's left hand is necessary because of the ribbed handguard of the 40 mm launcher barrel cannot be gripped by the operator's hand in any other way. Because the barrel is located below the launcher receiver, the handguard does not and cannot fully encircle the barrel, making it thereby impossible for the operator to wrap their hand around the barrel to establish a strong grasp on the barrel. This results in weak control of the weapon system and increased operator fatigue due to the necessitated hand position and orientation with respect to the weapon system, more particularly, the launcher thereof.
The diameter along the launcher handguard is over 2.25 inches, which is more than 50% larger than the optimal grip diameter for an operator with average sized hands to grip an object by wrapping their fingers around it, and having at least one finger wrap back to their thumb. The launcher barrel handguard is not sized to provide the best gripping surface, it is sized to accommodate the 40 mm barrel within it.
With the knowledge that this rifle/launcher combination is now front-heavy because of the shift in the rifle's center of gravity with the addition of the launcher, and that the handguard's diameter and orientation are controlled by the functional characteristics of the launcher, both a user and non-user understands why this weapon system combination, while highly desirable for its capabilities, is hard to control and is fatiguing to carry and operate, primarily because of the hand position and orientation required. The only solution to relieving the fatigue and adding additional control over the system for the operator is to change the way in which the operator holds the launcher.
There are many obstacles to developing a better way to grip the launcher. To provide maximum comfort, leverage and efficiency to the operator, the area in which the launcher is handled should not be changed, only the operator's hand position. The only way to change the hand position as required to grip the launcher is to add a gripping device. Adding any component, assembly or device to a 40 mm grenade launcher barrel presents a variety of challenges, some of which are discussed herein below.
First, the M203 40 mm barrel handguard is made of a thin plastic material which is designed primarily to serve as a location for the operator to place their hand. As there is very little heat produced when firing through an M203 barrel, the handguard is not specifically required to perform an insulating function.
Second, the M203 40 mm handguard surface is interrupted by two cartridge retainer rivets and a handguard locator rivet. Such structures may interfere with attachment solutions, and therefore require consideration.
Third, the M203 40 mm barrel is a thin wall design which precludes using fasteners which only partially penetrate the barrel wall. As a matter of fact, the barrel handguard is adhesively adhered to the barrel because the barrel walls prohibit the use of fasteners. Furthermore, weapon barrels are generally not pierced by fasteners because of their prime function to contain exploding gases. Any solution requiring a fastener which breaches the barrel wall is not possible. Further still, the thin wall of the barrel prevents any attachment solution which could distort the barrel by applying pressure unevenly, such a barrel being incapable of proper performance.
Fourth, the barrel assembly of the M203 is designed for removal from the receiver without tools. This allows for easy cleaning by the operator as the barrel is the component most dirtied by firing. Being able to clean the barrel as a separate component keeps the rest of the receiver, and the rifle to which it is attached, uncontaminated by the cleaning process. Any grip attachment solution which prevents or inhibits this barrel removal process is undesirable. Furthermore, cleaning the barrel can be a messy affair using solvents to remove barrel reside and then repeatedly rinsing the barrel to remove the solvent residue. The barrel and handguard get contaminated on the outside during the process and must also be cleaned. A dry handguard is essential for the operator to maintain a grip. Any grip attachment solution that remains on the barrel during the cleaning process becomes another area to clean and is therefore undesirable.
Fifth, the barrel is also removable from the receiver to allow an armorer to perform repairs. Without removal it would be impossible to re-stake or change the barrel extension, repair or replace the cartridge locator or the cartridge locator spring. To perform these repairs the barrel is placed in a vise or other holder which positions and supports the barrel assembly along the sides and on the bottom during repairs. Any grip attachment solution that remains in place in any of these areas would inhibit maintenance activities and is likewise undesirable.
Finally, the handguard can be removed from the barrel for the repair of the cartridge retaining springs or for replacement of the handguard itself. Any grip attachment solution which is permanently affixed to the handguard would either inhibit or make this activity or exchange impossible.
Thus, it is highly desirable and advantageous to provide a weapon grip assembly for supporting a forend of a weapon or weapon system, more particularly a versatile weapon grip assembly for select integration with a 40 mm grenade launcher which:                is commercially available "off-the-shelf" and requires no developmental effort;        can be fitted to any M203 launcher now in service, with no modifications of same required;        is small, lightweight and rugged;        is not permanently mounted onto the launcher barrel assembly;        can be quickly attached and detached from the launcher handguard by the operator without tools;        conforms tightly to barrel surfaces;        does not pierce the barrel or handguard;        can be adjustably positioned on the launcher to suit operator size preferences and comfort;        can aid and/or improve the firing accuracy of the weapon system (e.g., rifle and launcher) by allowing the operator to have improved control on the weapons because of a better grip;        does not hamper or prolong maintenance activities of the launcher or rifle;        does not implicate nor involve additional launcher or rifle operational considerations or limitations;        requires no additional operator training for use thereof;        improves operator weapon control, and thus, its safety;        reduces operator fatigue by improving the method by which the launcher and rifle are operated and carried;        allows the operator to easily focus all energy into motions associated with opening/closing the launcher barrel by reducing the effort required to grip the barrel while in motion;        enhances the loading and re-loading operations of the M203, making them faster and more controllable, thereby allowing faster aimpoint acquisition by the operator for firing the next round;        provides improved firing speed and accuracy which makes the operator safer and more effective;        allows the operator to easily maintain or re-establish a firm grip on the launcher and rifle in humid, wet or snowy conditions or in the presence of any other contaminants which now make these actions difficult with the current hand position required to grip the launcher handguard; and,        allows the operator to easily maintain or re-establish a firm grip on the launcher and rifle while using the weapons while walking, running or after a fall or other unexpected activity. This improvement in control makes the operator more effective and safer to others around them.
With weapon adaptability being an important consideration or factor for a weapon user, a "Rail Adaptor System" (RAS) has become a popular accessory for/on combat rifles and the like. There exists many versions of such systems, made by many manufacturers, see for example those produced by Knight's Armament Co.
Typically, a RAS is installed in place of the weapon hand guard (i.e., substituted therefore), and is intended to provide a universal structure (i.e., a rail) for mating attachment (i.e., receipt) of accessories, e.g., a flashlight, a thermal scope, a laser, etc., to the rifle at 3, 6, 9, and 12-O'clock positions about the weapon barrel. Known systems incorporate different rail lengths and integration techniques for attachment to the weapon. Some RAS consist of a two-piece assembly, namely, a first portion providing rails at the 3, 9, and 12-O'clock positions, a second portion providing a rail at/for the 6-O'clock position. It is advantageous that the rail of the 6-O'clock position be separately removable so as to permit grenade launcher installation (i.e., in lieu thereof, as each structure competes for the same physical space, and generally uses the same attachment points on the weapon).
The RAS system was originally proposed by the United States Army in 1998 so as to provide to all vendors a common style of attachment point to the M-16 rifle. While specifying the beveled lateral edge of the rail (i.e., its profile), the circumferential clock positions for the rails about the weapon barrel, and the call outs of the spacing between the crossbars of the rail and their marking (e.g., B22, B28, etc. for "bottom," with "T" designated for "top"), implementation of the solution (i.e., weapon integration strategies) was left to those in the marketplace.
In addition to the aforementioned accessories (i.e., flashlights, scopes, aiming aids, etc.), rail mount grips (e.g., vertical forend grips), are available for affixation to the rail, with heretofore know rail mount grips characterized by a female mounting flange which is slidingly received upon a rail of the RAS, and is thereafter selectively bound against a portion of the rail via, for example, a threaded fastener which is tightened to engage or press against the rail so as to secure the grip thereto.
In a rail mount grip offered by Knight's Armament Co., a binding stud is threadingly received within an axial bore of a hand grip having a rail receiving flange. The binding stud includes a base or cap end which defines a lower-most extremity for the device, and a free end opposite thereof having a nub (e.g., a centrally located projection) on a top surface thereof. Upon sliding the grip, via the flange, longitudinally along and upon the rail, the binding stud is upwardly extended, relative to the grip, such that the nub on the top surface of the free end thereof locates one of the many slots or spaced apart channels in the rail (i.e., the knob is dimensioned to be received within any one of said slots or spaced apart channels). Thereafter, the binding stud is further tightened into pressing engagement with a portion of the rail.
The subject design has proved problematic, with the nub being susceptible to breakage and or deformation, and requiring further operator attention to appropriately position the grip upon the rail such that the nub will in fact fall into one of the many locating slots. Since the slot and the raised portions between the slots of the rail are the same width, the operator has a 50-50 chance of getting it right the first time. Miss the location, and the grip will not tighten up.
A further drawback of presently known rail mount grips is the requirement that they be slid on, more particularly, they be slid onto the rail of the RAS from the weapon front (i.e., the muzzle end) toward the weapon back (i.e. the butt stock end). Known grips cannot be slid onto the rear end of the rail because there is not enough clearance between the rail end and rifle receiver to allow access for alignment of the flange with the rail. This is a critical consideration should any other accessory be mounted on the rail forward of the grip. Should a user wish to remove the grip from the weapon, or move it to a different rail to improve handling, a lot of busy time is had configuring or reconfiguring the weapon. Thus, it remains advantageous to provide a weapon grip which is versatilely mountable to the rail of a RAS, further still, to provide a rail mount grip which has an easily operable secure fastening or affixation mechanism, namely one which abandons heretofore known sliding engagements and/or binding studs.
Further desirable and advantageous is a forend grip for a weapon or weapon system which is versatile in its securement methodology. For instance, and as alluded to herein, a weapon grip having an adaptability or convertibility for receipt by a variety of known weapon or weapon system structures is particularly desirable, more particularly, a weapon grip characterized by grasping jaws. For instance, a weapon grip having replaceable or substitutable jaws for grasping a grenade launcher barrel on the one hand, or a rail of a RAS on the other hand is especially advantageous.
More specific features and advantages obtained in view of those features will become apparent with reference to the drawing figures and DETAILED DESCRIPTION OF THE INVENTION.


A system and method for management of communications for components in a global accelerator system is provided. The global accelerator system includes client devices communicating with a global access point via a public network to access various endpoints that can host services. In turn, a global access point communicates to various endpoints, which are organized into different data centers, via a private network. To facilitate exchanges on behalf of different client devices, the global access points can characterize groupings of endpoints into subgroups or braids. Individual braid communications can be encapsulated and are routed at the data center by a networking equipment using 5-tuple information in packets. The components within individual braids can broadcast or multi-cast state information via management messages to ensure failover or mitigate duplicative processing.

Generally described, computing devices utilize a communication network, or a series of communication networks, to exchange data. Companies and organizations operate computer networks that interconnect a number of computing devices to support operations or provide services to third parties. The computing systems can be located in a single geographic location or located in multiple, distinct geographic locations (e.g., interconnected via private or public communication networks). Specifically, data centers or data processing centers, herein generally referred to as "data centers," may include a number of interconnected computing systems to provide computing resources to users of the data center. The data centers may be private data centers operated on behalf of an organization or public data centers operated on behalf, or for the benefit of, the general public.
Because the resources of any individual computing device are limited, a variety of techniques are known to attempt to balance resource usage among devices. For example, a "load balancer" device may be placed between client devices requesting use of computing resources and servers providing such resources. The load balancer may attempt to distribute the requests among the servers, thus allowing the servers to work in conjunction to provide such resources. A significant drawback of use of such a load balancer is that it may create a single point of failure, such that if the load balancer fails, requests to the servers fail, and resources are made unavailable.
Another type of load balancing known in the art is domain name system (DNS) load balancing. DNS generally refers to a network of devices that operate to translate human-recognizable domain names into network address on a network, such as the Internet. To load balance using DNS, a DNS server is populated with network addresses of multiple computing devices offering a given resource. When responding to requests to resolve a domain name associated with that resource, the DNS server alternates which addresses are provided, thus causing requests for the resources to be divided among the provided addresses. Because the DNS server does not act as a conduit for traffic to the resources, and because DNS generally provides highly redundant operation, DNS load balancing generally avoids having a single point of failure. However, a significant drawback of DNS load balancing is the delay required to alter a load balancing scheme. DNS requests generally flow through a series of DNS resolvers, each of which may cache prior DNS results for a period. Thus, changes made at a DNS server in an attempt to alter how load is balanced among servers can take significant time to propagate. Particularly in instances where a server has failed, these delays can cause significant errors in network communications. Moreover, maintaining up-to-date DNS records can be difficult, as they generally must be modified as new devices are added to or removed from a load balancing scheme.
Yet another type of load balancing known in the art is the use of "anycast" network addresses. In a network, such as the Internet, different autonomous systems ("AS") provide devices with different network addresses. Each AS notifies its neighboring AS's of addresses available within its network, by "advertising" the addresses. Most typically, each address is associated with a single location (e.g., a single device or group of devices). In an anycast configuration, multiple devices, often in multiple AS's, advertise the same network address. Depending on the configuration of neighboring AS's, client requests to access the address can then be routed to any of the multiple device, distributing load among the devices. A significant drawback of the use of anycast to attempt to load balance is that routing to the anycasted address is generally controlled by neighboring networks. These networks are often under control of other entities. Thus, it is difficult or impossible to completely control how requests are distributed among devices with an anycasted network address. Moreover, when the configuration of neighboring networks changes, the distribution of requests may also change, leading to volatility in the load balancing scheme.


This invention relates to an isotonic energy composition including the carbohydrates, fructose and maltodextrin, the electrolytes, zinc, chromium, calcium, potassium, magnesium, sodium, and the nutrients vitamin C, citric acid and beta carotene. The electrolytes zinc and chromium are delivered in the form of an organic complex. The invention also relates to a method to use the composition.

1. Field of the Invention
This invention relates to a multi-electrolyte composition with nutrients and a method to use this composition to provide electrolytes, nutrients and energy lost during physical exertion.
2. Description of Prior Work in the Field
Many fluid replacement and energy drinks are currently being sold. In particular, EXCEED (Ross laboratories) provides the following electrolytes: calcium, magnesium, sodium, potassium and chloride. Similarly, GATORADE (Quaker Oats Co.) contains the following electrolytes: potassium and sodium. Other fluid replacement beverages include: 10K, ERG, ULTRA FUEL, CARBOFORCE and RECHARGE. These drinks offer a variety of electrolyte combinations. None of these drinks, however, provide the electrolytes chromium or zinc. The present invention provides a multi-electrolyte composition including both zinc monomethionine and chromium polynicotinate to provide a better balance of electrolytes. This isotonic energy drink also includes vitamin C and beta carotene as important nutrients for optimum performance.

Isotonic energy composition and method to use same


A liquid crystal (LC) cell having LC phase gratings is disclosed. The LC cell includes alternating strips of a first single domain LC material having a twist angle with a magnitude and a positive sign, and a second single domain LC material having a twist angle with the same magnitude and a negative sign. The magnitude of the twist angle is approximately from 45 to 70 degrees. The first and second LC materials are twisted nematic LC materials or ferro-electric LC materials. The liquid crystal phase gratings operate preferably in a normally-black condition with low operating voltages of below 3 V and high optical diffraction efficiencies. The LC cell is used in reflective or transmissive spatial light modulators of displays.

1. Field of the Invention
The present invention is directed to a polarization independent liquid crystal display using reflective spatial light modulators, and more particularly, to a display having reflective spatial light modulators with liquid crystal phase gratings that exhibit polarization independent diffraction of incident light.
2. Discussion of the Prior Art
Increasingly, cathode ray tube (CRT) displays are being replaced with liquid crystal displays (LCDs). LCDs use spatial light modulators (SLMs) to form images. One type of an LCD is an active-matrix-driven liquid crystal display (AMLCD) that uses SLMs. The SLMs may be either transmissive or reflective.
FIG. 1 shows a basic structure of a display 100 having conventional active-matrix-driven liquid crystal transmissive spatial light modulators (AM LC SLMs). The display 100 has a back polarizer 110 and a front polarizer 115 which faces a viewer. Front and back glass substrates 120, 125 are located between, and next to, the back and front polarizers 110, 115, respectively. The AM LC SLMs, whether transmissive or reflective, typically have repetitive unit cells or picture elements (pixels) 130. FIG. 1 shows 9 pixels in a 3.times.3 pixel array.
An array of transistors 135, such as field effect transistors (FETs), is formed on the back glass substrates 125. Each FET 135 in the array has its own transparent conductive electrode 140, referred to as a pixel electrode 140. Each FET 135 and pixel electrode 140 are part of one pixel (or subpixel) of an image formed on a screen (not shown) located between a viewer (not shown) and the front polarizer 115 of the display 100. Collectively, the pixel electrodes 140 form an array of pixel electrodes.
On the front substrate 120, a transparent conductive front electrode 145 is formed, which is common to all the FETs 135 in the transistor array. The front electrode 145 is referred to as a counter-electrode. Optional color filters 150 arranged in an array may be formed between the front substrate 120 and the common counter-electrode 145. The color filters include red, green and blue filters, where each pixel has its own filter.
A liquid crystal (LC) medium 155 is sandwiched between the transparent conductive pixel and common counter-electrodes 140, 145. Two alignment layers, i.e., front and back alignment layers (not shown), such as rubbed polyimide films, are formed between the LC medium 155 and the pixel and common electrodes 140, 145, respectively. A back-light source 160 illuminates the back of the display panel 100, where light rays 165 from the back-light source 160 are incident on the back polarizer 110.
Each FET 135 is an on/off transistor switch that supplies a voltage to the pixel electrode 140 in the ON condition. This in turn generates an electric field between the pixel electrode 140 and the common counter-electrode 145. The electric field aligns molecules of the LC medium 155. This alignment causes light passing through the LC medium 155, from the back-light source 160, to form an image a screen (not shown) located between the front polarizer 115 and a viewer (not shown).
Instead of transmissive SLMs, where the pixel electrodes 140 are transparent, reflective SLMs may be used having reflective pixel electrodes. For reflective AM LC SLMs having reflective pixel electrodes, the transparent conductive pixel electrode 140 is replaced with a reflective metal electrode. Each metal pixel electrode of a reflective SLM typically occupies a larger area than a corresponding transparent pixel electrode 140 of a transmissive SLM.
The additional area of the reflective metal pixel electrode covers the FET 135.
For reflective AM LC SLMs, there is no need for the back-light source 160 used with transmissive SLMs. Instead, ambient light or another light source illuminates the display panel from the front of the panel, e.g., from the top or front polarizer 115 shown in FIG. 1. A more detailed description of a display having reflective AM LC SLMs is given in connection with FIG. 8.
FIG. 2 shows an equivalent circuit 200 of one of the pixels 130 shown in FIG. 1. Although FIG. 1 is a display using transmissive SLMs, FIG. 2 is an equivalent circuit 200 for both transmissive and reflective SLMs. A display using reflective SLMs is shown in FIGS. 3 and 4.
As shown in FIG. 2, the gate 205 of the FET 135 is connected to a gate bus line 210, while the FET drain 215 is connected to a data bus line 220. The source 225 of the FET 135 is connected to the pixel electrode 140, which is shown in FIG. 1 as the transparent pixel electrode, and is also shown in FIGS. 3, 4 as a reflective pixel electrode 140'. The LC medium 155 of FIG. 1 is equivalent to a capacitor 230, which has one terminal connected to the pixel electrode 140 and another terminal connected to the common transparent counter-electrode 145.
A storage capacitor 240 provides parallel capacitance to the LC capacitor 230. The storage capacitor 240 is terminated on a common line 260, which is common to all the storage capacitors 240 in the display. Another alternate design for a storage capacitor is to replace the storage capacitor 240 with a storage capacitor 250, which is connected from the pixel electrode 140 to the gate bus line 210.
When a voltage below a threshold voltage is applied on the gate bus line 210, the FET 135 is in an OFF condition (OFF state). The OFF FET 135 acts as an open switch and separates the data bus line 220 from the pixel electrode 140. This isolates the potentials on data bus line 220 and the pixel electrode 140 from each other.
When a voltage larger than the threshold voltage is applied to the gate bus line 210, the FET 135 is turned ON (ON state) and has a low impedance between its source 225 and drain 215. The ON FET 135 acts as a closed switch and connects the data bus line 220 to the pixel electrode 140. This transfers the data voltage on the data bus line 220 to the pixel electrode 140.
In the ON state, varying the data voltage on the data bus line 220 varies the voltage applied to the pixel electrode 140. The different voltages applied to the pixel electrode 140 variably turn on the liquid crystal cell 230. Varying the pixel voltage (on the pixel electrode 140) varies the intensity of light as it passes through the liquid crystal cell 155 shown in FIGS. 1, 3, 4, and represented as the LC capacitor 230 in FIG. 2. This results in displaying different scales of gray color on a screen (not shown) located between a viewer (not shown) and the front polarizer 115 shown in FIG. 1.
FIGS. 3 and 4 show cross sectional and perspective views of a conventional reflective display 300 using an array of reflective liquid crystal spatial light modulators (LC SLMs). The array of FETS 135 are formed on the substrate 125, which is a silicon (Si) wafer, for example. Each FET 135 drives one of the reflective SLMs in the SLM array as described below.
FIG. 3 is a cross sectional view of a single reflective liquid crystal light valve or SLM of the conventional reflection liquid crystal (LC) display 300. The FET 135 is formed between field oxide regions 305 on the semiconductor Si substrate 125. The field oxide regions 305 separate the FET 135 from other FETs or devices formed on the substrate 125. The FET 135 has source and drain regions 225, 215 which are formed in the substrate 125. The source and drain regions 225, 215 are separated by a channel region 310.
Over the channel region 310, a gate insulating film 315 is formed. Illustratively, the gate insulating film 315 is an SiO.sub.2 layer having a thickness which is approximately from 150 to 500 angstroms (.ANG.). A polysilicon gate electrode 205, e.g., having a thickness of approximately 0.44 micron (.mu.), is formed over the gate insulating film 315.
A layer of dielectric or insulator material, such as an SiO.sub.2 layer 320, is formed over the FET 135 and field oxide regions 310. The storage capacity line 260, also shown in FIG. 2, is formed over a portion of the SiO.sub.2 layer 320 so that the storage capacity line 260 extends over portions of the source 225 and the field oxide regions 305 adjacent thereto. A second SiO.sub.2 layer 325 is formed over the storage capacity line 260 and exposed portions of the first SiO.sub.2 layer 320. The two SiO.sub.2 layers 320, 325 act as inter-layer insulating films.
First and second via holes are formed extending through both SiO.sub.2 layers 320, 325 to expose portions of the source and drain regions 225, 215, respectively. A conductive source line 330 and the conductive data bus line 220, which is also shown in FIG. 2, are formed in the first and second via holes, respectively. The conductive source and data lines 330, 220 extend over portions of the second SiO.sub.2 layer 325 and are electrically connected to the source and drain regions 225, 215, respectively. Illustratively, the source and data lines 330, 220 are aluminum (Al) and have a thickness 335 of approximately 0.7 microns.
A third silicon oxide SiO.sub.2 film 340, acting as an inter-layer insulating film, is formed over the source and data lines 330, 220 and exposed portions of the second silicon oxide SiO.sub.2 layer 325. Over the third oxide Sio.sub.2 layer 340, an optical absorbing layer 345 is formed. The optical absorbing layer 345, which has a thickness of approximately 160 nano-meters (nm), is formed of three layers that are laminated over each other in the following order: A titanium (Ti) layer having a thickness of approximately 100 .ANG.; an aluminum (Al) layer having a thickness of approximately 1000 .ANG.; and a titanium nitride (TiN) layer having a thickness of approximately 500 .ANG..
Laminating these three layers so as to form the optical absorbing layer 345 with a thickness of approximately 160 nm, reduces reflection of light, e.g., having a wavelength from 345 to 700 .ANG., that enters the optical absorbing layer 345 to result in a reflection factor of approximately 25%. The light that enters the optical absorbing layer 345 is shown as arrow 350 in FIG. 3.
In addition, the optical absorbing layer 345 prevents the light 350 from being transmitted to the FET 135 to result in a transmission factor of approximately 0%. The optical absorbing layer 345 improves contrast of images and prevents leakage currents in the FET 135.
A silicon nitride film 355, having a thickness of approximately from 400 to 500 nm, is formed on the optical absorbing layer 345. Next, an Al light reflecting film 140' having a thickness of approximately 150 nm, also shown in FIG. 2 as reference numeral 140 and referred to as the pixel electrode, is formed over the silicon nitride film 355.
A via hole is formed to expose a portion of the source line or electrode 330 of the FET 135. The via hole penetrates through the light reflecting film or pixel electrode 140', the silicon nitride film 355, the optical absorbing layer 345, and the third silicon oxide SiO.sub.2 film 340.
A conducting stud, 360, such as a tungsten (W) stud is formed in the via by a chemical vapor deposition CVD method, for example. The tungsten stud 360 electrically connects the source line or electrode 330 to the light reflecting film or pixel electrode 140'. To prevent electrical connection to the tungsten stud 360, the optical absorbing layer 345 is removed from around the tungsten stud 360.
As more clearly shown in the perspective view of the display 300 in FIG. 4, the light reflecting film or pixel electrode 140' is separated from adjacent pixel electrode 140'. Illustratively, the reflective pixel electrode 140' are spaced apart from each other at a specified interval of about 0.5 to 1.7 microns. Each reflective pixel electrode 140', along with its associated FET 135, form a subpixel. For example, three subpixels for red, green and blue components of light form a pixel.
At selected locations of the array of subpixels, pillar-shaped spacers 365 are formed in the space that separates the reflective pixel electrodes 140' from each other. Illustratively, the pillar-shaped spacers 365 are SiO.sub.2 spacers having a width 370 of approximately 1 to 5 microns. The height 375 of each spacer 365 is determined according to the desired cell gap, which is filled with the liquid crystal (LC) 155. The spacers 365 are provided throughout the substrate at specified intervals in order to retain the desired cell gap or thickness d of the LC material 155.
Note, the width 370 of each spacer 365, which is about 1-5.mu., is the same order as the distance of about 0.5-1.7.mu. that separates the reflective pixel electrode 140'. This provides minimum overlap of the spacers 365 with the reflective pixel electrode 140', which in turn minimizes any reduction of the numerical aperture of each subpixel resulting from the pillar-shaped spacer 365.
The counter-electrode 145, which is formed on the glass protect substrate 120, is attached over the spacers 365. The counter-electrode 145 and glass substrate 120 are also shown in FIG. 1. The glass protect substrate 120 is the front portion of the display 300, i.e., the portion facing a viewer. As described in connection with FIG. 1, the counter-electrode 145 is transparent and common to all the pixels. Illustratively, the counter-electrode 145 is an indium titanium oxide (ITO) transparent electrode.
Attaching the counter-electrode 145 over the pillar-shaped spacers 365 forms the cell gap. The liquid crystal (LC) layer 155, in which a liquid crystal material is sealed, is formed in the cell gap between the light reflecting film or pixel electrode 140' and the counter-electrode 145. Orienting films (not shown) are also formed over the pixel electrode 140' and the counter-electrode 145 to orient the liquid crystal molecules.
Illustratively, as shown in FIG. 4, each pixel electrode 140', which defines a subpixel, has a square shape with a side of approximately 17 microns. To form the display 300, the subpixels are arranged in a matrix or array of 1280 rows and 1600 columns, for example.
In the reflective liquid crystal light valve or SLM, comprising the LC material 155 sandwiched between the common transparent ITO counter-electrode 145 and the reflective pixel electrode 140', light 350 entering from the glass protect substrate 120 reflects from the reflective pixel electrode 140'. The pixel electrode 140' also functions as a display electrode for applying a voltage to the liquid crystal layer 155. The FET 135 functions as a switching element for providing a signal voltage from the data line 220 to the pixel electrode 140', when a control voltage on the gate 205 turns on the FET 135, as described in connection with FIG. 2.
An image is projected, from the front glass substrate 120, onto a screen (not shown) located between a viewer (not shown) and the front glass substrate 120, when the light 350 that enters the front glass protect substrate 120 travels through LC material 155 and reflects back to the front glass substrate 120. This light is reflected from the reflective pixel electrode 140'. Depending on the voltage of the pixel electrode 140', which voltage affects alignment of the LC material 155, the light reflected from the reflective pixel electrode 140' either exits the front glass protect substrate 120, e.g., to form an image on the screen, or is blocked by an analyzer (not shown) from reaching the screen.
The light polarization rotating properties of the LC material 155 results from varying the direction of the liquid crystal molecules (not shown) in accordance to a voltage applied between the reflective pixel electrode 140' and the transparent ITO common counter-electrode 145. As described in connection with FIG. 2, this voltage is supplied from the data bus line 220 to the pixel electrode 140' when the FET 135 is turned on in response to a control signal on the gate bus line 210 (FIG. 2), which is connected to the gate 205 of the FET 135.
Depending on the voltage applied to the pixel electrode 140', the directors' orientation of the LC material 155 changes. This varies the state of the polarization of light that is incident on the pixel electrode 140', that reflects therefrom, and that exits the front glass protect substrate 120. Based on this variation of the state of light polarization, an image is formed on a screen located between the front glass protect substrate 120 and a viewer, as further described in connection with FIG. 8.
According to the prior art, the LC medium 155 used in reflective spatial light modulators (SLMs) requires either a linearly-polarized or randomly polarized incident light 350. The requirement of a polarized incident light results in a poor optical through-put, because more than half of the incident light is absorbed or rejected by the polarizer 110 (FIG. 1), which is located over the front glass protect substrate 120. That is, only one of the vertical or horizontal polarizations of light is used thus limiting the display efficiency to a theoretical maximum of 50%.
To increase the display or SLM efficiency, both vertical or horizontal polarizations of light are used. In this case, the LC medium 155 has been used in polarization independent LC devices based on scattering or diffraction. This allows the entire input intensity of both orthogonal horizontal and vertical polarizations to be used.
One typical example of scattering LC SLMs or light valves used in displays is referred to as a polymer-dispersed liquid crystal. However, polymer-dispersed liquid crystal light valves cannot operated below 4 volts (V). In addition, the polymer-dispersed liquid crystal has a large hysteresis as seen from plots of transmission or reflection versus voltage. Thus, a full-color display cannot be realized by using polymer-dispersed liquid crystal.
Instead of scattering LC SLMs, the other approach to achieve a polarization independent light valve having LC material uses light diffraction effect of LC phase gratings.
Diffractive light valves using LC material have been previously proposed. These proposed prior art SLMs use nematic LC mixtures with positive dielectric anisotropy. In addition, the LC molecules adjacent to the cell substrates are in homogeneous, i.e., parallel, alignment.
One such proposal of an LC grating design, based on field-induced tunable birefringence, is described in Y. Hori, K. Asai, "Field Controllable Liquid-Crystal Phase Grating", IEEE Trans. Elec. Dev. Vol. 26, pp. 1734-1737 (1979), hereinafter referred to as Hori. However, the Hori configuration requires the use of polarizers which lower the transmission of light.
The LC light valve proposed by Hori uses an untwisted LC material which has polarization dependent performance and requires high voltage to achieve high contrast. In addition, the Hori proposed LC light valve also requires interdigitated electrodes within each pixel, resulting in increased possibility of shorts and undesired interconnections across electrodes.
Other proposals have investigated polarization independent LC gratings. One such proposal is disclosed by M. Fritsch, H. Wohler, G. Haas, D. Mlynski, "Liquid Crystal Phase Modulator for Large Screen Projection", IEEE Trans. Elec. Dev. Vol. 36, pp. 1882-1887 (1989), hereinafter referred to as Fritsch. Fritsch proposed an LC light valve using a 90.degree. and a 180.degree. twisted LC material. However, the Fritsch light valve demonstrated only about a 0.5 .pi. (i.e., 90.degree.) phase difference between ON and OFF states. The result is a reflective light valve based on field-controlled birefringence difference between alternating strips inside each pixel.
All the above approaches have the further disadvantage that electrodes are required to be patterned with high resolution.
To avoid the use of the interdigitated electrodes, the use of pattern alignment to generate phase gratings has been suggested in W. Gibbons, P. Shannon, S. Sun, B. Swetlin, "Surface-Mediated Alignment of Nematic Liquid Crystals with Polarized Laser Light", Nature Vol. 351, pp. 49-501991), hereinafter referred to as Gibbons. Because the differently patterned domains of the LC material requires no separation, diffraction efficiency is increased and the risk of shorts between electrodes is reduced.
Other proposals have demonstrated the use of pattern alignment with an optically active device for transmissive SLMs. One such proposal is disclosed in P. Bos, J. Chen, J. Doane, "An Optical Active Diffractive Device for a High Efficient Light Valve", SID 95 DIGEST, pp. 601-604 (1995), hereinafter referred to as Bos. Bos proposed several schemes. The first scheme is an LC diffractive light valve based on a two domain tunable birefringence (TD-TBD) light valve.
FIG. 5 shows a top view of the LC material of one pixel of the Bos TD-TBD light valve 400. The Bos TD-TBD light valve has alternating strips 410, 420 of tunable birefringence LC material. The projections of the LC material's optical axes or directors 430 of one strip 410 are orthogonal to the directors 430 of adjacent strips 420. The alternating strips 410, 420 are formed by patterning the alignment layer of the LC medium, which alignment or orienting layer is formed on the pixel electrode 140, for example.
The TD-TBD LC phase gratings that have alternating strips, which are also referred to as Freedericksz domains, are "No-Twist" gratings. Within each Freedericksz domain, the LC directors are aligned uniformly across the cell substrates. For example, in the strip referenced by numeral 410 in FIG. 5, all the LC directors 430 are vertical, while all the LC directors 430 in the strip referenced by numeral 420, which is adjacent to the first strip 410, are horizontal.
When the devices have a voltage applied such that the effective value of d.DELTA.n/.lambda. is a multiple of a 1/2, then all polarizations of light is diffracted. However, if d.DELTA.n/.lambda. is 0 or a multiple of 1, then no diffraction occurs. Note that d, which is shown in FIG. 3, is the cell gap or the thickness of the LC material 155; .lambda. is the wavelength of incident light 350; and .DELTA.n is optical refractive index anisotropy or birefringence of the LC material 155. In particular, .DELTA.n is the difference in the refractive indices of the LC material 155 for extraordinary light n.sub.e (e.g., horizontal polarization) and ordinary light n.sub.o (e.g., vertical polarization) ; .DELTA.n=n.sub.e -n.sub.o. When .DELTA.n is positive, then the LC material is referred to as having positive birefringence. Similarly, when .DELTA.n is negative, then the LC material is referred to as having negative birefringence.
A problem with the Bos TD-TBD no-twist grating light valve is that when the LC material has positive dielectric anisotropy and the device is switched between 0 and 1/2 wave, the voltage required to get to zero retardation is undesirably high, such as above 5 volts.
The second light valve described by Bos is a two-domain 90.degree. twisted nematic (TDTN) phase grating, with adjacent domains being twisted opposite to each other. That is, adjacent domains alternate between a positive and a negative twist angle. However, the magnitude of the twist angle of each domain, excluding the direction or sign of the twist angle, is 90.degree..
FIG. 6 shows a liquid crystal (LC) configuration 500 of LC directors 510 in two adjacent strips 520, 530 of a conceptual device described in Bos. The magnitude of the twist angle of each strip 520, 530, is 90.degree.. One strip 520 has a left handed twist, e.g, having a positive sign, for a twist angle of +90.degree. shown as arrow 540, arid the other strip 530 has a right handed twist, e.g, having a negative sign, for a twist angle of -90.degree. shown as arrow 550. A reference axis 560 along the cell gap thickness d is shown in FIG. 6.
FIG. 7 shows light waves 610, 620 propagating through the two strips 520, 530 of the conceptual device 500 of FIG. 6. As shown in FIG. 7, both the polarization and the phase of the light waves 610, 620 change as they propagate through the LC of the device 500. The polarization of the incident light waves 610, 620 changes from vertical to horizontal polarization.
Because the two strips 520, 530 are twisted 90.degree., the light waves 610, 620 exit the strips 520, 530 each rotated by 90.degree.. However, since the 90.degree. twist of the two strips 520, 530 are in opposite directions, i.e., +90.degree. for one strip 520 and -90.degree. for the other strip 530, the light waves 610, 620 exit the strips 520, 530 with opposite polarizations. This results in two light waves 610, 620 being 180.degree. out of phase as they exit the strips 520, 530 of the LC conceptual device 500.
In TDTN phase gratings, if d.DELTA.n/.lambda. is chosen to satisfy the condition that d.DELTA.n/.lambda.=.sqroot.n.sup.2 -0.25, where n is an integer, then all polarizations of light passing through the LC material is diffracted.
Using TDTN phase gratings, a transmissive light valve with high contrast and relatively low-operating voltage has been demonstrated. However, while the optical diffraction efficiency for transmissive TDTN phase grating can be high, approaching 100%, nevertheless the diffraction efficiency is below 35% when used as a reflective (instead of transmissive) LC phase grating. It is desirable to lower the operating voltage of reflective LC phase gratings to around 3 volts or lower. However, a reflective TDTN LC phase grating cannot operate at 3 volts or lower.
The third light valve described by Bos is an orthogonal-twist two-domain TN (OTTDTN) having alternating TN domain strips. The alternating TN domain strips within each pixel have identical twist direction. The rub direction to align the LC medium in one domain is perpendicular to that of the other domain at the front and back surfaces of the LC cell. For example, one strip has a twist angle from 0.degree. to +90.degree., while the other strip has a twist angle from +90.degree. to +180.degree.. In comparison, in the second light valve described by Bos having the two-domain 90.degree. twisted nematic (TDTN) phase grating, one strip has a 0.degree. to +90.degree. twist angle, while the other strip has a 0.degree. to -90.degree. twist angle.
Although reflective OTTDTN LC phase gratings have a better optical diffraction efficiency than that of reflective TDTN phase gratings, the operating voltage of the OTTDTN is similar to the operating voltage of the TDTN and is unlikely to be lower than about 3.4 volts.
In using polarization-independent LC phase gratings, except for rare cases where the incident light is monochromatic and the LC cell gap is uniform with negligible deviation from a design value, it is difficult to make the non-diffracted light vanishingly small. If the non-diffracted light is collected as a signal to form the image, it is important to make the non-diffracted light vanishingly small because one of the ON or OFF states of the SLM has to be a dark state of the display. Therefore, collecting the non-diffracted light to represent a signal results in poor contrast. Accordingly, for illustrative purposes, the following description of the present invention concerns only the case of collecting diffracted light as a signal that forms an image. However, it is understood that non-diffracted light may also be collected as a signal to form an image.
Both the second and third type of light valves described by Bos, i.e., the TDTN and OTTDTN gratings, are diffractive at zero volt and less diffractive at higher voltages. Such devices are called normally-white diffractive (NWD) gratings in the case where the diffracted light is collected to represent a signal. There are other types of LC phase gratings, typically referred to as normally-black diffractive (NBD) gratings, that do not diffract light at zero volt and becomes more diffractive as the applied voltage increases.
Bos only proposed NWD LC phase gratings without any mention of the NBD LC phase gratings. The Bos proposed NWD gratings are either unsuitable for reflective SLMs or have an operating voltage which is higher than about 3 volts. That is, the Bos proposed NWD gratings cannot operate at voltages below about 3 volts.
Reflective SLMs have been used for projection displays. FIG. 8 shows a typical optical system 700 having three reflective SLMs 705, 710, 715 which use LC phase gratings to render the reflective SLMs 705, 710, 715 into polarization independent devices.
Light is emitted from a lamp 720 having a reflector 725. The emitted light passes through a relay lens 730, and is reflected by a mirrored bar (louvers) system 735 toward crossed dichroic filters 740, 745. Red, green, and blue components of the light are separated by the crossed dichroic filters 740, 745, and are directed toward the reflective SLMs 705, 710, 715, respectively. Schlerien lenses 750, 755, 760 are located between the SLMs 705, 710, 715, and the dichroic filters 740, 745, respectively. The Schlieren lenses 750, 755, 760 image each color components of the incident light onto and out of the corresponding SLMs 705, 710, 715.
For the case of NBD modes, if the LC phase grating of each reflective SLM 705, 710, 715 is not activated, the incident red, green, and blue lights are not diffracted by the LC material of the SLM 705, 710, 715. After being reflected back from the corresponding SLM 705, 710, 715, the red, green, and blue component of light are imaged by the corresponding Schlieren lenses 750, 755, 760 and are recombined by the crossed dichroic filters 740, 745. The recombined light from the dichroic filters 740, 745 are reflected by the mirrored bar system 735 back toward the relay lens 730.
Because the LC phase grating of each reflective SLM 705, 710, 715 is not activated, almost no light reflected from the SLMs 705, 710, 715 passes through the mirrored bar system 735. Thus, this light reflected from the SLMs 705, 710, 715 is not directed to a projection lens 765 located between the mirror bar 735 and a screen 770. This inactivated state of the SLM 705, 710, 715 represents the dark state of the display 700.
The bright state of the display occurs when the LC phase grating in each reflective SLM 705, 710, 715 is activated. In this bright state, light incident on the reflective SLMs 705, 710, 715 from the lamp 720 is diffracted. Most of the light reflected from the reflective SLMs 705, 710, 715 passes through the mirrored bar system 735 and is projected by the projection lens 765 onto the display screen 770 to illuminate a pixel 775 thereon.
For the NWD modes, the fully activated state of the SLMs 705, 710, 715 of FIG. 8 represents the nondiffractive state, so that the screen 770 appears dark. The fully diffractive state occurs in the quiescent state, where the SLMs are not activated, i.e., the FETs are not turned ON. In this quiescent or fully diffractive state, the screen 770 appears bright.
The present invention relates to polarization independent LC phase gratings that are fabricated into reflective SLMs e.g., for projection displays, such as the display 700 shown in FIG. 8.

Polarization independent liquid crystal phase gratings for reflective spatial light modulators

International Business Machines Corporation


Systems and methods for predicting a software build error are described herein. In one example, a method includes detecting a plurality of changes in software. The method also includes identifying a plurality of change lists, wherein a change list is identified for each of the plurality of changes in the software. Additionally, the method includes identifying a characteristic for each change list in the plurality of change lists. Furthermore, the method includes calculating a plurality of probabilities based at least in part on the characteristic of each of the plurality of change lists, wherein each of the probabilities indicates the likelihood of one of the plurality of change lists creating the software build error. The method also includes reporting the plurality of probabilities of the software build error.

Software development can involve developing software code that is to be translated into machine executable code. The translation of software code written by developers into machine executable code can be referred to as a software build. During software development, errors encountered during the software build can increase the amount of time to develop software. For example, some organizations develop software with teams of developers. In some instances, one team of developers may wait to build a portion of a software application until a second team has built a separate portion of the software application. If the second team of developers encounters a software build error, the first team of developers may be delayed in building a portion of the software application. Therefore, minimizing software build errors can prevent a delay in the software development process.


The resistance of an oxygen sensor heating element is estimated by modeling the effects of physical and electrical heating on the resistance of the heating element lead-in conductors, and subtracting the lead-in conductor resistance from a measure of the heating circuit resistance. The lead-in conductor resistance model is based on the temperature of the oxygen sensor boss and the current carried by the lead-in conductors. The heating element temperature is calculated from the determined heating element resistance and initial (cold-start) parameters of the heating circuit.

Exhaust-gas oxygen sensors are commonly equipped with an integral resistive heating element that is electrically activated following engine starting to quickly bring the oxygen sensor to a desired operating temperature. The control objective during the warm-up interval is to maintain the heating element at a target temperature such as 700° C. Since the actual temperature of the heating element cannot be conveniently measured, it is typically estimated based on a measurement of electrical resistance. However, heating element resistance varies not only with temperature, but also from sensor-to-sensor due to manufacturing tolerances. One way of addressing this problem is disclosed in the U.S. Pat. No. 6,586,711 to Whitney et al., where the resistance of the heating element is measured at a known starting temperature and a resistance offset is calculated based on the deviation of the measured resistance from a nominal value. Unfortunately, the resistance of the heating element cannot be directly measured with many oxygen sensors, and any resistance measurement will also include the resistance of the wiring harness and terminals, lead-in conductors, and so forth. While the resistance of the wiring harness and terminals may be neglected, many planar oxygen sensors include printed lead-in conductors whose resistance can be similar to that of the heating element. Accordingly, what is needed is a way of determining the resistance of the lead-in conductors to enable reliable estimation of the heater element resistance and temperature.

This patent is subject to a terminal disclaimer.

Method of estimating the temperature of an oxygen sensor heating element


A method and an apparatus of measuring a state of an IC lead frame are disclosed. The method has the steps of detecting a first projective position of an upper edge of a lead terminal of the IC lead frame on a reference surface and a second projective position of the upper edge, the second projective position of the upper edge having a projective angle different from that of the first projective position of the upper edge, detecting a first projective position of a lower edge of the lead terminal on the reference surface and a second projective position of the lower edge, the second projective position of the lower edge having a projective angle different from that of the first projective position of the lower edge, and computing the state of the lead terminal from the detections of the projective positions. The apparatus has a sensor transmitting beams of light at least at two different angles so as to sense an edge of a lead terminal of the IC lead frame at the angles, a mechanism moving the sensor along the IC lead frame transversely to the longitudinal axis of the lead terminal, a detector for a position of the sensor, and a computer computing a state of the lead terminal from an edge detection by the sensor and a detection of the position of the sensor by the position detector.

1. Field of the Invention
The present invention relates to a method and an apparatus of measuring a state of an IC lead frame.
2. Description of the Related Art
Recently, ICs have been used widely in various fields. A lead frame of an IC comprises many lead terminals in the form of thin strip. Inserting the lead terminals into a socket or directly into a printed circuit board connects the IC with a circuit connected to the socket or a circuit on the printed circuit board. All of the lead terminals must be horizontally arranged at a predetermined pitch and vertically even with one another. However, since the lead terminals often have an irregularity in the horizontal pitch and a vertical irregularity or a relief, the irregularities must be checked before the IC is actually mounted.
Heretofore, a measurement of a state of an IC lead frame employs a prior-art method of monitoring a reflected light from the lead frame using a CCD or ITV camera, and a prior-art method of monitoring a reflected light from the lead frame using laser beam. However, since the prior-art methods of measuring the state of the IC lead frame separately measures pitches and reliefs of the lead terminals, an apparatus of measuring the state of the IC lead frame is complicated and the measurement of the pitches and the reliefs of the lead terminals is time-consuming.

Method and apparatus of measuring state of IC lead frame


An ophthalmic photographic apparatus includes an illumination optical system for illuminating an eye fundus and a photographing optical system for photographing an image of the illuminated eye fundus. The ophthalmic photographic apparatus includes a first aperture stop, a second aperture stop having an outside diameter that is smaller than that of the first aperture stop, a third aperture stop that transmits more light than the first aperture stop, and means for selectively inserting the first to third aperture stops into the optical path of the illumination optical system. The ophthalmic photographic apparatus does not have a complicated structure, but can be readily used in the various photographing modes.

1. Field of the Invention
The present invention relates to an ophthalmic photographic apparatus, and more particularly to an ophthalmic photographic apparatus that includes an illumination optical system for projecting illuminating light onto a subject eye fundus via an aperture stop such as a ring slit or the like, and a photographing optical system that photographs the fundus thus illuminated.
2. Description of the Prior Art
There are various ways of photographing the eye fundus in color using an ophthalmic photographic apparatus such as a fundus camera. In mydriatic photography, a mydriatic agent is administered to the eye, which is taxing for the patient. There is also non-mydriatic photography in which a mydriatic agent is not used. In non-mydriatic photography, infrared light is projected onto the fundus and the fundus is photographed after the alignment is completed. There is also fluorescent photography, which includes fluorescein angiography for photographing visible fluorescent images, and ICG (indocyanine green) fluorophotography (ICG angiography) for photographing infrared fluorescent images. Each photography mode uses different illumination and photographing filters, and the optical characteristics also differ. It is, therefore, preferable to use a specialized fundus camera for each mode. However, from the standpoint of cost-performance, fundus cameras are being developed that can be used for various modes. For example, Japanese Laid open Patent Publication No. Hei9-140672 describes a fundus camera that can be used for mydriatic and non-mydriatic photography and fluorescein angiography; Japanese Laid open Patent Publication No. Hei 8-150120 describes a fundus camera that can be used for mydriatic photography (color), fluorescein angiography and ICG fluorophotography; Japanese Laid open Patent Publication No. Hei 1-300926 also describes a fundus camera that can be used for mydriatic photography (color), fluorescein angiography and ICG fluorophotography; and Japanese Patent No. 2894359 describes mechanisms for interlocking variable power lenses, fluorescent filters and ring slits depending upon the photographing modes.
However, for a fundus camera to be able to handle mydriatic, non-mydriatic, fluorescein angiographic and ICG fluorophotographic modes, it has to be able to insert complex combinations of filters into the optical path and retract the filters from the optical path when the system is switched among the four modes. This increases the complexity of the apparatus and of the various setting operations, increasing the misoperations. For these reasons, there is no fundus camera that can handle the above four photographing modes.


This invention refers to a MEASURING APPARATUS FOR THE PROGRAMMING AND WELDING OF ADJUSTABLE BRACKETS permitting the electrical spot welding with a great accuracy of the elements of an adjustable bracket, in this manner being able to adjust or to program the information that the orthodontist wants to incorporate in the bracket in regard to inclination, angulation and rotation. In order to achieve this aim I developed two attachments: THE POSITION MEASURING ACCESSORY and the WELDING ACCESSORY.

Nowadays, the welding machines used by orthodontists allow to perform the electrical spot welding of the attachments used in orthodontic treatments, for instance lingual attachments to bands or brackets to bands. The electrical spot welding performed chair-side presently lacks the precision required to weld an adjustable bracket providing accurate programming or prescription information.
With the aim of solving these and other drawbacks, I thought of developing the present appliance I am seeking to protect by means of this request, since it is an invention which allows the orthodontist to record the dental position in the three space planes on dental casts; and to be able to weld adjustable brackets incorporating the desired programming of inclination, angulation and rotation, thus having individualization for each treatment.
THE MEASURING APPARATUS FOR THE PROGRAMMING AND WELDING OF ADJUSTABLE BRACKETS includes two main sections:
1. Position Measuring Accessory
It is an innovative precision system for measuring in dental casts the accurate dental position of the teeth in regard to inclination, angulation and rotation.
2. Welding Accessory
It belongs to the electrical welding or electrical spot welding section; it has the innovation of including three graduating systems (in the three space planes) for the accurate electrical spot welding of the two elements of the adjustable bracket, according to the information of inclination, angulation and rotation that the orthodontist wants to program.

Measuring apparatus for the programming and welding of adjustable brackets

Abstract: THE POSITION MEASURING ACCESSORY has the function of recording or measuring accurately the dental position as for inclination, angulation and rotation on dental casts. This measurement is performed by means of a template system that allows the recording a tooth position in relation to its osseous basis and the occlusal plane.

Abstract: THE WELDING ACCESSORY has the innovation of allowing the accurate welding of the adjustable bracket elements (base and body), being able to adjust or program (in the three space planes) the information of inclination, angulation and rotation that the orthodontist wants to incorporate in the bracket by means of three fine graduation systems.


A toothpaste dispenser is in the form of a hollow container having a chamber with toothpaste therein. A dispensing spout communicates with the chamber and includes a cap detachably mounted over the dispensing spout for selectively closing the spout. The container includes externally mounted structure simulating a portion of the human mouth anatomy to function as an indicator for making readily apparent to the user that the dispenser is for the dispensing of toothpaste and to encourage its use particularly by children. The simulated anatomy could be a tooth such as a molar or could be lips or a tongue.

An important part of dental hygiene is in the use of a regular program of brushing the teeth. This is particularly important with young children who sometimes find tooth brushing to be a chore. In order to teach a child to adopt tooth brushing habits it would be desirable if brushing the teeth became more pleasant.


An LED drive circuit includes: a rectifier circuit that outputs a full-wave rectification waveform voltage; a primary LED row that includes a first partial LED row and a second partial LED row; an auxiliary LED row; a bypass circuit that is connected to part connecting the first partial LED row and the second partial LED row and that returns current from the first partial LED row to the rectifier circuit; and a current limiting circuit that limits the current flowing through the auxiliary LED row wherein the primary LED row and the auxiliary LED row are connected in parallel to the rectifier circuit; and the bypass circuit blocks the current passing through the bypass circuit in accordance with the current flowing through the primary LED row, and controls and blocks the current flowing through the auxiliary LED row.

An LED drive circuit is known which drives LEDs to emit light by applying a full-wave rectified waveform obtained from an AC commercial power supply directly to an LED array. The LED array here is a series connection of a plurality of LED arrays and is constructed to be able to withstand a high voltage. Compared with other types of LED drive circuits that drive LEDs to emit light by generating a constant voltage from an AC commercial power supply, the above LED drive circuit has the advantage that the circuit configuration is simple and compact.
However, if a full-wave rectified waveform is simply applied to an LED array, a problem occurs in which the LEDs light only during the periods when the full-wave rectified waveform exceeds the threshold value of the LED array. For example, when the forward voltage Vf of each LED is 3 V, and the LED array is constructed by connecting 40 such LEDs in series, the threshold value of the LED array is 120 V. Suppose that the rms value of the AC commercial power supply is 100 V; then, with the above LED drive circuit, the LEDs light only during short periods when the full-wave rectified waveform exceeds 120 V. As a result, with the above LED drive circuit, not only do the LEDs become dim or produce perceivable flicker, but the power factor and distortion factor also decrease.
To address this, it is known to provide methods for extending the LED ON period; in one known method, the LED array is divided into a number of LED sub-arrays, and provisions are made to turn on only some of the LED sub-arrays during the low voltage period of the full-wave rectified waveform and to increase the number of LED sub-arrays to be turned on as the voltage increases (refer to patent document 1).
FIG. 4 is a circuit diagram showing one example of an LED drive circuit; the diagram is redrawn from FIG. 26 given in patent document 1 without departing from the purpose thereof. In the diagram, the current-limiting resistor is replaced by a current-limiting circuit. Therefore, it should be noted that the LED drive circuit shown in FIG. 4 is given only for illustrative purposes and does not directly represent the LED drive circuit known in the art.
In the example of FIG. 4, a bypass circuit which turns on (conducts) during the low voltage period of the full-wave rectified waveform and turns off (does not conduct) during the high voltage period is connected to a connection node between each LED sub-array. The bypass circuit is controlled on and off according to the voltage value of the full-wave rectified waveform or the value of the current that flows through the LED array.
The LED drive circuit 400 shown in FIG. 4 comprises a diode bridge circuit 405, LED sub-arrays 410 and 430, a bypass circuit 420, and a current-limiting resistor 440. A commercial power supply 406 is connected to input terminals of the diode bridge circuit 405.
The bridge rectifier circuit 405 is constructed from four diodes 401, 402, 403, and 404, and has a terminal A as an output terminal for outputting a full-wave rectified waveform and a terminal B as a terminal for providing a reference voltage. The LED sub-array 410 is constructed from a series connection of a large number of LEDs including LEDs 411 and 412. Similarly, the LED sub-array 430 is constructed from a series connection of a large number of LEDs including LEDs 431 and 432. The bypass circuit 420 includes a pull-up resistor 421, a current-sensing resistor 424, a field-effect transistor (FET) 422, a bipolar transistor (hereinafter simply "transistor") 423, a first current input terminal 427, a second current input terminal 428, and a current output terminal 429. Similarly to the bypass circuit 420, the current-limiting circuit 440 includes a pull-up resistor 441, a current-sensing resistor 444, an FET 442, a transistor 443, a current input terminal 447, and a current output terminal 449. The FETs 422 and 442 are enhancement-mode n-type MOS-FETs.
FIG. 5(a) is a waveform diagram depicting a full-wave rectified waveform, and FIG. 5(b) is a waveform diagram depicting a circuit current I in the LED drive circuit 400. The same time axis is used for both FIGS. 5 (a) and 5(b).
In FIG. 5, no circuit current I flows during the period t1 because the voltage value of the full-wave rectified waveform is smaller than the threshold value of the LED sub-array 410.
In the period t2, the voltage value of the full-wave rectified waveform exceeds the threshold value of the LED sub-array 410 but is smaller than the sum of the threshold value of the LED sub-array 410 and the threshold value of the LED sub-array 430. In this case, the circuit current I passes through the bypass circuit 420 and returns to the bridge rectifier circuit 405. During the period t2, feedback is applied so as to maintain the base-emitter voltage of the transistor 423 at 0.6 V, and the bypass circuit 420 thus operates in a constant current mode. Actually, in the last short portion of the period t2, the voltage value of the full-wave rectified waveform becomes slightly larger than the sum of the threshold value of the LED sub-array 410 and the threshold value of the LED sub-array 430, and a current flows in from the LED sub-array 430 via the current input terminal 428.
In the period t3, the voltage value of the full-wave rectified waveform exceeds the sum of the threshold value of the LED sub-array 410 and the threshold value of the LED sub-array 430, and the current flows to the current input terminal 428 by passing through the LED sub-array 430. At this time, the transistor 423 saturates, and the gate voltage of the FET 422 becomes equal to the reference voltage (the voltage at the terminal B), so that the FET 422 is cut off. As a result, the current flowing into the bypass circuit 420 via the current input terminal 427 rapidly drops. On the other hand, in the current-limiting circuit 440, feedback is applied so as to maintain the base-emitter voltage of the transistor 443 at 0.6 V, and the current-limiting circuit 440 thus operates in a constant current mode. The process that takes place during the period that the voltage of the full-wave rectified waveform falls is the reverse of the process that takes place during the period that the voltage of the full-wave rectified waveform rises.


A liquid crystal display includes a liquid crystal display panel having a plurality of pixels on a display line. A set of drivers drives a set of pixels, the set of drivers receiving display data and providing video signals to the set of pixels. A clock provides a clock signal to the set of drivers to latch the display data based on a frequency of the clock signal, and receives a feedback signal from the set of drivers prior to an end of the display data received by the set of drivers. A delay circuit stops the clock signal to the set of drivers, based on the feedback signal, after delaying for a first time period, that is no less than a predetermined time period between the feedback signal and the end of the display data received by the set of drivers.

A liquid crystal display ("LCD") device forms images by passing polarized light through small cells that vary their light-transmission characteristics according to electrical charges applied to the cells. Comparing with conventional cathode ray tube ("CRT") display devices, LCDs provide superior display quality, require lower operation voltage, consume less power, and occupy less space. As a result, liquid crystal display has become one of the major display technologies today. In fact, liquid crystal displays have been employed in various types of systems, such as laptop and desktop computers, personal digital assistants (PDAs), car navigation systems, projectors, and cellular phones.
A liquid crystal display panel generally includes an array of active pixel elements, such as transistors. Color filters accompanying individual displaying pixels enable a color display. As an example, a display array may include scanning lines formed horizontally along rows of pixels, and signal or data lines formed FINNEGAN vertically along columns of pixels. Individual transistors, such as thin-film transistors (TFTs), are formed at or near the intersections of the scanning lines and data lines. The transistors operate according to video signals supplied through the scanning and data lines to control how images are displayed by pixels.
In general, the major components of a liquid crystal display include an interface integrated circuit ("IC") for communicating with a source of video signals, a timing application-specific-integrated-circuit ("ASIC") controller, data drivers, scan drivers, a display panel with passive devices thereon, and a backlight unit. The interface IC communicates with and receives data from a data source, such as a motherboard in a desktop or laptop computer. The timing ASIC controller receives data from the interface IC and sends display data to the scan and data drivers. The data drivers generate video signals and deliver the video signals to the pixels in the display panel to drive the pixels to display video images. In some designs, the timing ASIC controller also provides a scaling function to enable switching among two or more different resolutions.
FIG. 1 illustrates the operation of a single data driver 10. Data driver 10 has a clock input, load input, and RGB (red-green-blue) data input. Data driver 10 has two cascade terminals that can be coupled to other data drivers or devices. Data driver 10 samples RGB data according to the clock input and generates signals, such as analog video signals for controlling the pixels. Taking a liquid crystal display for a laptop computer as an example, the size of the liquid crystal display may vary from 12 to 15 inches; the resolution may vary from 640×480 to 1600×1200; and the pixel clock for scanning lines may vary from 50 to 100 MHz.
Generally, a driver drives a certain number of channels or pixels but does not handle all the pixels on one display line. The number of pixels each driver drives is usually far smaller than the number of pixels that a liquid crystal display has in a single display line or scan line. Therefore, most liquid crystal displays employ a design of pooling together multiple data drivers and jointly operate the multiple data drivers to receive and process data. Generally, the multiple data drivers drive all of the pixels in the liquid crystal display in a line-by-line manner.
In driving a line of pixels, drivers usually operate jointly in a cascaded configuration. FIG. 2 illustrates conventional cascaded data drivers. The structure consists of "n" data drivers that are cascaded through their cascading terminals to drive all of the pixels of a liquid crystal display. Here, each data driver receives data to drive M channels or pixels, with each pixel acting as a complete RGB display unit. The total number of pixels in a display line is, therefore, the total number of pixels driven by all of the data drivers, namely n×M.
Under the cascaded configuration, driver #0 receives a first group of display data at the beginning of a display line. When driver #0 is full, it sends out a signal to the next driver, driver #1. Driver #1 then starts to receive the next set of display data. When driver #1 is full, it sends out a signal to a subsequent driver, driver #2. All the subsequent drivers, drivers #2 to #n−1, then conduct the same operation until the data for a full display line are received by the cascaded data drivers.
More specifically, driver 10 in FIG. 1 is triggered to operate by a clock signal through the clock-in terminal, by a triggering pulse through a cascade-in terminal, or by both. Based on this configuration, driver #0 in FIG. 2 latches a unit of display data, such as RGB image data, at each rising edge of the clock signal. After a number of clock cycles, the register array of driver #0 becomes full and driver #0 then sends a signal to the next driver, driver #1, through the cascade-out terminal of driver #0. Once driver #1 receives the signal through its cascade-in terminal, it starts to receive the next group of data until the register array of driver #1 becomes full.
Referring to FIG. 3, a conventional design of a liquid crystal display employs a single clock in a timing ASIC controller 12 to provide a clock signal to all of the data drivers, drivers #0 to #n−1. The conventional design requires a single clock to have the capability to drive several cascaded data drivers, such as eight, ten, twelve, or fourteen cascaded data drivers. The clock also has to deliver signals of sufficient level and strength to the clock input pin of each data driver. Due to the total amount of load imposed by the input load of all input pins, the clock source must have a high output load driving capability, a term known as "fan-out."
A clock with a higher fan-out, however, generates significant electromagnetic radiation that causes electromagnetic interference (EMI) with other devices or circuits. An excessive level of electromagnetic radiation may significantly interfere with the operation of other electronic devices to result in deteriorated performance of electronic devices within the proximity of the LCD. In addition, high EMI may also prevent the liquid crystal display from meeting certain safety and operational standards, such as the EMI standards established by the U.S. Federal Communications Commission (FCC).
To solve these problems, a dual or multiple clock design is developed and implemented in some liquid crystal displays. FIG. 4 provides an example of a dual clock design for a liquid crystal display. Data drivers #0 to #2n−1, which are used to be driven by a single clock in the conventional single-clock design, are now divided into two groups of equal numbers. Each group has "n" data drivers and is driven by a different clock. The illustrated system provides two clocks of smaller fan-out, pixel clocks 1 and 2, in the timing ASIC controller 14. These two clocks replace the single clock of a high fan-out illustrated in FIG. 3. The two clocks may provide continuous and synchronous clock signals to each group of data drivers. In general, the two clocks may operate to deliver synchronous signals and have overlapping signals near the center of the active "high" region of a valid display, as shown in FIG. 4B. Consequently, the two groups of drivers may alternate smoothly at a transitional point of data with the overlapping and synchronized clock signals.
The dual clock liquid crystal display system, however, requires each group of data drivers to drive an equal number of pixels, with each driver group being driven by one clock. The traditional dual clock system provides little flexibility in the design of the liquid crystal display, especially in the driving circuits. Also, the requirement of the traditional system considerably limits the possible implementations of data driver arrangements and creates significant obstacles for developing future generations of LCD systems. For example, current LCD system provides 800×600 pixels under the VGA mode, 1024×768 pixels under the SVGA mode, and 1280×1024 pixels under the SXGA mode. And future generations of LCD would provide an even larger number of pixels. The increased pixel dimension would make the traditional system less feasible.

Liquid crystal display and method for operating the same