The present invention is a three stage water-from-air-filter system which can be used in combination with substantially any household vacuum cleaner. The system includes a main cylindrically shaped body and a hollow cylinder within the main body. The main body and cylinder form a ring-shaped chamber. The chamber has a spherical bottom partially filled with water. The hollow cylinder is made of a large pipe and a small pipe. The large pipe has an areohydrodynamic separator. An entrance nozzle may be located on either the main body or on the small pipe. Regardless of where the nozzle is located, polluted air enters the ring-shaped chamber through the nozzle. In the chamber the air mixes with the water. The air and water mixture is centrifugally separated several times through the concentric cylinders within the filter system to ensure a high quality of cleaning.

The present invention is directed toward a multi-stage water filter and, more particularly, to a system for treating polluted air by impinging the air against a liquid surface, causing the air and liquid to mix and thereafter separating the air from the liquid several times, thereby ensuring high quality cleaning.
Most portable vacuum cleaners have two main units: a fan for suctioning polluted air and some system for cleaning the air of various particles and dust, typically a filter. Portable vacuum cleaners used in households for cleaning carpets, upholstered furniture, bare floors, walls, etc., are characterized by two main features: the ability to suction, i.e., the maximum weight of particles that may be suctioned, and the ability of the filter unit to retain all of the various particles. The ability to suction depends on the velocity of air flow entering the machine. The air flow is what captures all the loose particles from a surface and suctions them into the machine. The velocity of the air flow, other than the power of the motor and the design of the fan, depends on the resistance it meets inside the machine from the entryway to the exit.
Household cleaner filters are typically bags made from paper or fabric and are the most commonly used for cleaning the contaminated air from particulate matter (Consumer Reports: Vacuum Cleaners 1995; Mody, Jakhete Dust Control Handbook Pollution Technology Review #161, Noyes Data Corporation.) Other types of filters are cyclones and liquid filter systems.
Bags, as elements for catching dust have one well known disadvantage. That is, the smaller the pores in the bag, the finer the dirt particles they are able to catch. However, this creates a greater resistance against the exiting air flow which slows it and reduces the vacuum cleaner's suction ability. Furthermore, it is impossible to catch every particle of dust with a filter bag since only a nonporous bag will catch every particle, which is what eventually becomes of the bag once it is clogged, therefore completely stopping the air flow which catches the particles. It should also be noted that all particles that are suctioned in and not retained are released back into the environment. The smaller the particles, the more dangerous they are to humans.
Cyclones are inertial collectors which transform a gas stream into a confined vortex, from which inertia moves suspended particles to the wall of the cyclone's body. Cyclones have a significantly lesser resistance than bags, but they can only capture particles larger than 5 microns (1992 ASHRAE Handbook for Heating, Ventilating, and Air Conditioning System and Equipment, SI Edition, p. 26.7.) In FANTOM vacuum cleaner machines disclosed in U.S. Pat. Nos. 4,573,236; 4,643,748; 4,826,515; 4,853,008; 5,078,761; 5,145,499; and 5,160,356, a common porous filter is used to seize particles smaller than 5 microns but these filters have the same disadvantages as filter bags, discussed above.
Wet scrubbers and water filters used for air cleaning exist in two varieties. The first has a continuous feeding of water into the stream of contaminated air and a constant removing of the sludge. The second has a periodic feeding of water and a periodic removal of the sludge. Portable household cleaners usually use the second type. Water can capture finer particles, as small as 0.3 micron. However, these particles can only be captured by passing the contaminated air through liquid (1992 ASHRAE Handbook for Heating, Ventilating, and Air Conditioning System and Equipment, SI Edition p. 26.15). Furthermore, water filtration has a lesser resistance to the air flow than bags or other filters.
The vacuum cleaner "Rainbow" (Rexair, Inc.) is described in U.S. Pat. Nos. 2,221,572; 2,228,750; 2,886,127; 2,945,553; 4,640,697; and 4,824,333. This machine basically consists of a water basin, an electrical motor which drives a system of centrifugal fans suctioning in the contaminated air into the water basin, and a spinning separator which separates clean air from the water. A spinning hollow cone-shaped cup with slits on the sides perpendicular to the direction of rotation is used as a separator. The same motor that drives the fan system functions as the drive for the spinning separator. The contaminated air enters the water basin through a nozzle directed perpendicularly to the surface of the water.
This Rainbow device, however, has a number of disadvantages. First, it results in a low quality of air cleaning due to poor mixing of the contaminated air and water since the shortest path from the nozzle to the separator is by avoiding the water surface altogether, and because the air suctioned in has a low kinetic energy and a low impulse of force. If the nozzle end is placed lower than the water surface, an evacuation of air above the water surface occurs and the whole mass of water goes into the separator which cannot possibly separate it from the air. Consequently, many of the later filed "Rainbow" patents include an above-the-surface nozzle. According to "Consumer Reports," 1995, Rainbow holds the finest dust, like household dirt, well, but cannot catch most mineral particles which are not easily wetted, and therefore emits them into the air again.
Secondly, the mechanically rotating separator requires a complicated mechanical drive and is unreliable because of the large number of parts rotating at great speeds. Other than that, wet or damp dust, and other various debris, sticks to the separator clogging its slits.
In addition, the spinning slotted separator of the Rainbow vacuum cleaner has a relatively high aerodynamic resistance lowering the suctioning ability of the vacuum cleaner.


In a semiconductor device including a semiconductor substrate, first and second external terminals, a first impurity diffusion region connected to the first external terminal, and second and third impurity diffusion regions forming a MIS transistor, one of the second and third impurity diffusion regions facing the first impurity region is connected to the second external terminal. The distance between the first diffusion region and the MIS transistor is substantially smaller than a certain value compared to conventional device.

1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly, to a semiconductor device capable of avoiding damage by electrostatic discharge (ESD) phenomena.
2. Description of the Related Art
Generally, in a semiconductor device, an input circuit includes a first external terminal and an input resistor formed by an N-type impurity diffusion region connected to the first external terminal. On the other hand, an internal circuit such as an N-channel MOS (broadly, MIS) transistor has an N-type impurity diffusion source region connected to a second external terminal, an N-type impurity diffusion drain region, and a gate electrode therebetween. In this case, the drain rather than the source of the MOS transistor faces the input resistor (see: JP-A-59-87873). This will be explained later in detail.
Therefore, when a negative electrostatic pulse with respect to the second terminal is applied to the first external terminal, electrons are injected from the input resistor into a semiconductor substrate. Accordingly, the electrons are diffused and some of them reach the source region of the MOS transistor. As a result, the electrons injected into the source region serve as an energy source due to a high electric field in the periphery of the source region, thus destroying a gate insulating layer and the like. Particularly, if the MOS transistor has a lightly-doped drain (LDD) configuraturation, some of the electrons reach an N.sup.- -type region of the source region, so that the N.sup.- -type region may be destroyed.
In the above-described prior art semiconductor device, however, in order to avoid the destruction of the gate insulating layer, the source region and the like, a distance between the input resistor and the internal circuit has to be very large, for example, about 100 .mu.m to 300 .mu.m, thus reducing the number of electrons reaching the source region. Here, a minimum value of this distance is called a critical distance. The larger this distance, the larger the amount of dead space where elements cannot be arranged occurs.
Thus, the prior art semiconductor device is disadvantageous in terms of integration.

Semiconductor device capable of avoiding damage by ESD


Solutions of image processing in a VR system is disclosed, including: obtaining a photographic image; identifying at least one object in the photographic image; generating at least one tag respectively for each of the at least one object; presenting the at least one tag of the photographic image through a VR User Interface (UI); confirming one or more of the at least one tag in response to receiving a confirmation user instruction from the VR UI; and associating the confirmed one or more tags with the photographic image.

Virtual reality (VR) typically refers to computer technologies that use software to simulate realistic images, sounds and other sensations that replicate a real environment (or create an imaginary setting), and simulate a user's physical presence in this environment, by enabling the user to interact with this space and any objects depicted therein using specialized display screens or projectors and other devices. VR has been defined as "a realistic and immersive simulation of a three-dimensional environment, created using interactive software and hardware, and experienced or controlled by movement of the body" or as an "immersive, interactive experience generated by a computer". A person using virtual reality equipment is typically able to "look around" the artificial world, move about in it and interact with features or items that are depicted on a screen or in goggles. Virtual realities artificially create sensory experiences, which can include sight, touch, hearing, and, less commonly, smell. Most 2016-era virtual realities are displayed either on a computer monitor, a projector screen, or with a virtual reality headset (also called head-mounted display or HMD). HMDs typically take the form of head-mounted goggles with a screen in front of the eyes. Virtual Reality brings the user into the digital world by cutting off outside stimuli. In this way user is solely focusing on the digital content.
Photospheres (or photo sphere) are 360-degree or 720-degree panoramic photos with a 3-dimension view provided in a VR system, which can be created by a professional or amateur VR camera.

Image processing in a virtual reality (VR) system

TENCENT TECHNOLOGY (SHENZHEN) COMPANY LIMITED


An ink stock solution contains at least a dye and a colorless planar compound having more than ten delocalization π electrons in one molecule, and an ink composition is manufactured with the same ink stock solution.

1. Field of the Invention
The present invention relates to an ink stock solution and an ink composition.
2. Background Art
With the spread of the computer in recent years, ink jet printers are widely used not only in offices but also in homes for printing on papers, films, cloths, etc.
As ink jet recording methods, a method of ejecting ink droplets by applying pressure by piezo-elements, a method of ejecting ink droplets by generating bubbles in ink composition by heat, a method of using ultrasonic waves, and a method of suction-ejecting ink droplets by electrostatic force. As the ink compositions for these ink jet recording methods, an aqueous ink, an oil ink composition and a solid ink composition (a melting type) are used. Of these ink compositions, aqueous ink composition is mainly used for easiness of manufacture and handling, odor and safety.
Colorants used in these ink compositions for ink jet recording are required to have high solubility in a solvent, to be capable of high density recording, to be good in hue, to be excellent in fastness to light, heat, air, ozone, water and chemicals, to have good fixing property to an image-receiving material and to hardly blot, to be excellent in preservation stability as ink composition, to be free of toxicity, to be high in purity, and to be available inexpensively. However, it is extremely difficult to search for colorants that satisfy these requirements on a high level.
Various dyes and pigments have been already proposed for ink jet recording and practically used but colorants that satisfy all of these requirements have not been discovered yet. It is difficult for dyes and pigments having Color Index Nos. (C.I.) to reconcile the hue and the fastness required of the ink compositions for ink jet recording.
The present inventors have proposed cyan dyes having excellent hue and fastness (refer to, e.g., JP-A-2003-321630 (The term "JP-A" as used herein refers to an "unexamined published Japanese patent application".) and JP-A-2004-75825).
In manufacturing an ink composition, e.g., an ink composition for ink jet recording, powders of dyes are generally used, but it is advantageous to manufacture an ink composition from a concentrated ink composition, that is, an ink stock solution considering handling property and solubility.
However, when a dye having a high oxidation potential is used in an ink stock solution for ink jet recording that is the feedstock of the ink composition for ink jet recording, the viscosity becomes extremely high, so that serious problems arise in handling properties at the time of feeding and filtering of the ink composition.

This patent is subject to a terminal disclaimer.


Before a WiMAX-equipped device is distributed to an end-user, the manufacturer or distributor of the WiMAX-equipped device will record in the device a set of data that describes characteristics (e.g., type, features, capabilities, and limitations) of the device. When the end-user powers on the device or otherwise brings the device within the coverage of a service provider's WiMAX base station, the device will then acquire radio connectivity, typically with the service provider authenticating the device's WiMAX chipset. Thereafter, the device will engage in a first-time activation/service-provisioning session with a system operated by the service provider, and during that session, the device will provide the system with its device-characteristics data and the service provider will use that device-characteristics data as a basis to customize provisioning of service for the device based on the device's features and capabilities.

The widespread growth in popularity of wireless communications has given rise to a commensurate growth in the number of end-user devices that are equipped with wireless communication functionality. Once limited to cellular telephones and pagers, the industry has now expanded to provide wireless communication functionality in many other types of devices as well, including, for example, notebook computers, personal digital assistants, cameras, media players, vending machines, automobiles, parking meters, factory equipment, and household appliances, among others.
The recent introduction of WiMAX technology promises to further increase the proliferation of wirelessly-equipped devices. WiMAX (Worldwide Interoperability for Microwave Access) is an Institute of Electrical and Electronics Engineers (IEEE) standard, designated 802.16, and provides a robust mechanism for wireless communication between base stations and subscriber stations. In particular, WiMAX is designed to provide fixed, portable or non-line-of-sight service with a potential range of 6 miles, a potential bandwidth on the order of 40 megabits per second, and superior quality of service and security.
Current industry plans call for a WiMAX forum to test and certify WiMAX chipsets and for chipset manufacturers to include on each chipset a digital certificate such as an X.509 certificate in accordance with International Telecommunications Union (ITU) recommendations. It is anticipated that manufacturers of such chipsets will then sell the certified chipsets to device manufacturers, who will then embed the chipsets in end-user devices so as to enable the devices to engage in wireless communication.
When a user buys a WiMAX-equipped device and first powers up the device, the WiMAX chipset will search for a signal from a service provider's WiMAX base station and, upon finding the signal, will then engage in an authentication process. In particular, the chipset will transmit its X.509 certificate to the base station and may then engage in back and forth communication with the base station to facilitate validation of the chipset. If the base station successfully authenticates the chipset, the base station will then allow the chipset to engage in higher level communication with the network.
A problem that the present inventors have discovered with this arrangement is that it does not allow the service provider to determine the type and capabilities of device in which the WiMAX chipset is embedded. The X.509 certification process merely allows the service provider to authenticate the WiMAX chipset, so as to determine that the chipset is a valid WiMAX chipset. However, the act of authenticating the WiMAX chipset does not provide the service provider with any useful information about the device in which the chipset is embedded, such as an indication of what type of device it is (e.g., an MP3 player, a camera, a notebook computer, a dishwasher, or the like) and what its features and capabilities are. Consequently, the service provider would be unable to provide the device with communication service specifically tailored to (or appropriate for) the particular device, and the service provider would similarly be unable to provision the device with application logic and other data tailored to the particular device.
One possible solution to this problem is to have the service provider, or some central authority, maintain a profile database that correlates each WiMAX chipset's X.509 certificate or other device identifier with the type/capabilities of the device in which the chipset is embedded. That way, when the service provider receives the chipset's X.509 certificate, the service provider can not only authenticate the chipset but can also query the profile database to determine the type and capabilities of the device in which the chipset is embedded.
A problem with this solution when it comes to initial service provisioning of WiMAX devices, however, is that the solution would require establishment and maintenance of the profile database in the first place, and then reference to the profile data in practice. Manufacturers of WiMAX-embedded devices would need to populate the profile database with device type/capability data at the time of manufacture, once the WiMAX chipset is embedded in a particular device. Furthermore, the data stored in such a profile database would in theory need to be maintained forever, to facilitate reference to the data whenever the device may be first distributed to an end-user and powered up (e.g., to account for possibly long shelf life before activation). Along those lines, the profile data might also need to be updated to reflect any changes to the device capabilities before the device reaches the end-user (or, in theory, after the end-user obtains the device). Unfortunately, these restrictions could hamper widespread distribution and use of WiMAX-embedded devices.
Another possible solution to the problem is to have a user manually inform the service provider of the type of device and the device capabilities. For instance, the user could call a service provider or could interact with the service provider through a web interface and could provide the service provider with a description of the device that will try to obtain WiMAX connectivity. However, requiring an end user to manually convey this sort of information to a service provider would result in a far more complex and far less seamless experience for the user and could similarly hamper widespread adoption of WiMAX technology.
These and other issues underscore the need for an improvement.

Method and system for tailoring device provisioning based on device capability information communicated to network


A method of incrementally reducing a design is disclosed. A logic verification tool receives a design and a property for verification with respect to the design, and then selects one or more of a plurality of diverse techniques for reducing the design. The logic verification tool then reduces the design to create a reduced design using the one or more techniques and attempts to generate a valid solution for the property on the reduced design. The logic verification tool determines whether a valid solution is generated, and, if not, replaces the design with the reduced design. Until a valid solution is generated, the logic verification tool iteratively performs the selecting, reducing, determining and replacing steps.

1. Technical Field
The present invention relates in general to testing and verification, and in particular to verification of digital designs. Still more particularly, the present invention relates to a system, method and computer program product for incremental reduction of a digital design through iterative overapproximation and re-encoding.
2. Description of the Related Art
With the increasing penetration of processor-based systems into every facet of human activity, demands have increased on the processor and application-specific integrated circuit (ASIC) development and production community to produce systems that are free from design flaws. Circuit products, including microprocessors, digital signal and other special-purpose processors, and ASICs, have become involved in the performance of a vast array of critical functions, and the involvement of microprocessors in the important tasks of daily life has heightened the expectation of error-free and flaw-free design. Whether the impact of errors in design would be measured in human lives or in mere dollars and cents, consumers of circuit products have lost tolerance for results polluted by design errors. Consumers will not tolerate, by way of example, miscalculations on the floor of the stock exchange, in the medical devices that support human life, or in the computers that control their automobiles. All of these activities represent areas where the need for reliable circuit results has risen to a mission-critical concern.
In response to the increasing need for reliable, error-free designs, the processor and ASIC design and development community has developed rigorous, if incredibly expensive, methods for testing and verification. Functional hardware verification has been a traditional method for verifying such complex designs as processor chips. Because the functional hardware verification time for a design grows in relation to the number of logic elements, functional hardware verification of complex systems is one of the most time-consuming computing tasks today. It is therefore important to use functional hardware verification cycles effectively, with the aim that few bugs escape and development time is reduced.
As mentioned above, functional hardware verification is a computationally expensive process; for sequential designs, functional hardware verification is a PSPACE-complete problem (by algorithmic complexity analysis) and hence generally requires resources which are exponential with respect to the size of the design under verification. Many prior art functional hardware verification proof algorithms rely upon reachability analysis, which requires enumerating the reachable states of the design under test to assess whether the design conforms to its specification, which unfortunately is a size-limited process.
Reachability analysis is a powerful verification framework; it is able to identify whether a design satisfies its specification (i.e., if all reachable states of a design satisfy the property being verified, then a correctness proof has been completed) and also whether the design does not satisfy its specification (if any of the reachable states does not satisfy the property being verified). Reachability algorithms operate by assigning R—0 to be the set of predefined initial states of the design under verification, then assigning R_{i+1} (for increasing i) to be the set of all states which may be reached in one design transition from R_i. Eventually, R_{i+1} will be a subset of all the previous states encountered in R—0 . . . R_i, after which this process will terminate; this final set of reachable states is referred to as R. To partially alleviate some of the computational overhead of the expensive process of computing the exact set of reachable states, there have been numerous proposals to "overapproximate" the set of reachable states. For example, some authors have proposed using "inductive" methods. The drawback of prior art overapproximation methods is that they are often inconclusive, resulting in "spurious failures" due to their overapproximate nature.
Despite decades of research in improving the performance of reachability analysis, such techniques are still limited in application to designs with several hundreds of state elements or less and are also hindered by other design size metrics. Because of the size limitations of reachability analysis, there has been some research in ways to overapproximate the reachable state set to enable computational shortcuts. For example, inductive proofs begin with R—0 being all states which do not themselves violate a property (after guaranteeing that the actual initial states of the design are a subset of this overapproximated R—0), and compute an overapproximated set R′ starting from this overapproximated initial state set. The benefits of this approach include a substantial decrease in the number of steps needed to complete the analysis. The main drawback of this inductive approach is that it often renders an inconclusive result. In particular, if the overapproximated set R′ contains some states S′ which violate the property being verified, one cannot immediately discern if this violation is only due to the overapproximation of the initial state set (i.e., S′ is a subset of R′-R), or if S′ contains some truly reachable states in R. The former case is a spurious failure of the property being verified.
Cut-point insertion refers to the process of replacing a gate in the netlist with a random gate. A design modified by cut-point insertion is called overapproximated because it may "simulate" the original design—the random gate may exhibit any behavior that the gate it is replacing may exhibit, but the converse is not necessarily true. Such an overapproximate technique increases the number of random gates in the design, sometimes dramatically; certain algorithms (particularly those based upon Binary Decision Diagrams) may suffer computational bottlenecks due to this increase in random gates.
Many prior art techniques exist for re-encoding a design to obtain a functionally-equivalent reduction of a design. Given a combinationally-driven cut of the design under test (i.e., the 'source' side of the cut contains no state elements), a re-encoding tool can compute the set of values that are producible at those cut gates. More generally, given a cut of the design under test which contains zero or more state elements and zero or more random gates, the re-encoding tool can compute the set of values that are producible at those cut gates as a function of values of the state elements. The re-encoding tool can then create a new piece of logic which produces exactly the same behavior as the 'source' side of the cut as a function of the state elements, and replace the cut gates with this new logic. Note that one cannot merely inject cutpoints to the cut gates, as that would generally constitute an overapproximate transformation, whereas the purpose of re-encoding is to render a property-preserving transformation.
It is often the case that the ability of the re-encoding tool to create a significantly simpler piece of logic than that being replaced relies upon the 'source' side of the cut containing a significant number of random gates in its 'combinational fanin cone'—i.e., the set of gates which may be reached by fanin traversal without traversing through a register. Because re-encoding relies on selecting cutpoints for which the 'source' side of the cut contains random gates, conventional methods for re-encoding suffer from paralyzing limitations in terms of the depth of the design to which cutpoints can be injected. In other words, re-encoding is often of no utility for logic deep from the random gates, e.g., that which is exclusively driven by state elements. This depth limitation has conventionally limited the usefulness of re-encoding techniques.
The limitations of conventional systems of re-encoding and prior art systems for overapproximation are well documented. What is needed is a more efficient method for verifying digital designs utilizing a method that obviates the known limitations of overapproximation and the depth limitation of re-encoding.

Method for incremental design reduction via iterative overapproximation and re-encoding strategies

International Business Machines Corporation


A method and system for recommending one or more tasks from a plurality of crowdsourcing tasks to a crowdworker is disclosed. The method includes identifying one or more categories for the plurality of tasks on the plurality of crowdsourcing platforms. In response to the identifying, determining, at a login time, values of one or more utility parameters of the crowdworker corresponding to the one or more categories. After identifying, the method selects the one or more tasks from the plurality of tasks by choosing one or more constraints on the determined values of the one or more utility parameters of the crowdworker. The method then recommends to the crowdworker at the login time, the one or more tasks associated with the crowdworker based on selected one or more tasks.

In an environment in which business tasks are to be outsourced or crowdsourced, its necessary to find a crowdsourcing platform that is attractive for crowdworkers. With the mushrooming of crowdsourcing platforms and overwhelming growth in number of task postings on various crowdsourcing platforms, crowdworkers face a real challenge finding which tasks are more suited to the changing and dynamic environment. Some enhanced crowdsourcing platforms give the crowdworkers an option to rank tasks by "most recent", or "most HITs (Human Intelligence Task) available". Some also post some extra HITs within the task, repost it, or repost with added payments to make the task more suited to the crowdworkers. Some other crowdsourcing platforms attempt to circumvent these problems by pushing tasks to a pool of "dedicated" crowdworkers who have a contractual binding to solve a certain number of tasks everyday within the crowdworker's area of expertise.
As a result the crowdsourced tasks may also not be very relevant and useful for the crowdworkers who view these tasks. For the crowdworker, the state of the art technology solutions may not suffice in more than one scenario. It is possible that many of the tasks posted on the crowdsourcing platforms may take longer times to complete or never getting complete. Also, these approaches may limit the needs of crowdworkers with a primary job, and looking at crowdsourcing platforms for an engaging experience that may provide secondary income. It is also necessary to factor in the changing and dynamic business needs associated with the crowdsourced tasks.
The end result is a solution where crowdworkers are unproductive or disinterested, while requesters are left struggling to find crowdworkers for completing their tasks on time. In order to provide the most suited tasks to the crowdworker it is therefore necessary to create an ecosystem that attracts crowdworkers towards an engaging business model with the crowdsourcing platforms.

Method and system for recommending tasks to crowdworker


A surface-emitting type device includes a rectification section including a substrate and a first semiconductor layer formed above the substrate, and an emission section including a second semiconductor layer of a first conductivity type formed above the rectification section, an active layer formed above the second semiconductor layer and a third semiconductor layer of a second conductivity type formed above the active layer, wherein the rectification section and the emission section are electrically connected in parallel with each other, and the rectification section has a rectification action in a reverse direction with respect to the emission section.

1. Technical Field
The present invention relates to surface-emitting type devices and methods for manufacturing the same.
2. Related Art
A surface-emitting type semiconductor laser has a smaller device volume compared to an ordinary edge-emitting type semiconductor laser, such that the electrostatic breakdown voltage of the device itself is low. For this reason, the device may be damaged by static electricity caused by a machine or an operator in a mounting process. In particular, a surface-emitting type device such as a surface-emitting type semiconductor laser has a certain tolerance to a forward bias voltage, but has a low tolerance to a reverse bias voltage, and the device may be destroyed when a reverse bias voltage is impressed. A variety of measures are usually implemented in a mounting process to remove static electricity, but these measures have limitations. For example, JP-A-2004-6548 is an example of related art.

Surface emitting type device, and method for manufacturing the same


A planar waveguide grating (PWG) sensor is described herein which exhibits a low signal drift and an enhanced sensitivity due to the use of a fully dense silicon-rich nitride surface layer. In the preferred embodiment, the silicon rich silicon nitride surface layer has a composition which includes Si and N, and optionally H, Ge and/or O, where a Si/N atomic ratio is greater than 0.75. In addition, the silicon rich nitride surface layer has a refractive index that is greater than 2.45 and less than 3.2 at a wavelength of operation. A method is also described herein for manufacturing the PWG sensor with acceptable costs and high yields by utilizing well known semiconductor processes and tools.

1. Field of the Invention
The present invention relates to a planar waveguide grating (PWG) sensor which exhibits a low signal drift and an enhanced sensitivity due to the use of a fully dense silicon rich silicon nitride surface layer. In addition, the present invention relates to a method for manufacturing the PWG sensor with acceptable costs and high yields by utilizing well known semiconductor processes and tools.
2. Description of Related Art
The following abbreviations are herewith defined, at least some of which are referred to in the ensuing description of the prior art and the preferred embodiments of the present invention.
APCVDAtmospheric Pressure Chemical Vapor DepositionCVDChemical Vapor DepositionFIBFocused Ion BeamFSGFluorine Doped Silica GlassLPCVDLow Pressure Chemical Vapor DepositionPECVDPlasma Enhanced Chemical Vapor DepositionPWGPlanar Waveguide GratingPVDPhysical Vapor DepositionRIEReactive Ion EtchingSACVDSub-Atmospheric Chemical Vapor DepositionSEMScanning Electron MicroscopySPRSurface Plasmon ResonanceUVUltraviolet
Evanescent field-based sensors are fast becoming a technology of choice for accurate label-free detection of a biological, biochemical, or chemical substance (e.g., cells, spores, biological or drug molecules, or chemical compounds). The label-free detection technology typically involves using a PWG sensor or a SPR sensor to detect a change in the refractive index of liquid or gas immediately above the sensor. For example, the change in refractive index can arise from a concentration change, surface adsorption, reaction, or the mere presence of a biological or chemical substance at the sensor's surface. Several types of known PWG sensors are described next each of which have different structures and materials of construction. And, then a description is provided about what causes a problematical signal drift which adversely affects the sensitivity of those PWG sensors. The cause of this problematical signal drift is addressed by the present invention.
In general, the PWG sensor is made from a substrate, a monomode waveguide and a sub-wavelength period diffraction grating that is formed into either the substrate or the waveguide. FIG. 1 (PRIOR ART) is a diagram which is used to help describe the basic elements and the basic functionality of one type of PWG sensor 100. As shown, the PWG sensor 100 has the following elements:                Substrate 102 (patterned with a sub-wavelength period diffraction grating 104).        Waveguide 106.        Chemically responsive surface chemistry layer 108.        Chemically bound molecules 110 (targets 110) of interest.        Solution 112 containing the substance 114 (analyte 114) to be detected.
Typically, the thickness and refractive index of the waveguide 106 along with the characteristics (pitch, depth, and duty cycle) of the diffraction grating 104 are chosen to yield the highest possible sensitivity to a refractive index change which is caused by the interaction of the analyte 114 and target 110. This sensitivity is defined as the shift in the reflected light 116 relative to the refractive index change (nm/refractive index unit). Because, the sensing principle involves the interaction of an evanescent wave emerging from the waveguide 106, the sensed volume is typically limited to the first 150–200 nm above the surface of the waveguide 106. A more detailed discussion about the structure and the functionality of this PWG sensor 100 can be found in U.S. Pat. No. 4,815,843. The contents of this patent are incorporated by reference herein.
In the past, a lot of work has been done to enhance the performance of the PWG sensor 100. For example, it has been shown that the performance of the PWG sensor 100 can be enhanced by: (1) raising the index contrast between the substrate 102 and the waveguide 106 (see U.S. Patent Application 2005/0025421 and PCT Patent Application WO0235214); (2) producing a highly uniform diffraction grating 104 (see U.S. Pat. No. 6,873,764 B2); (3) lowering unfavorable interactions between the solution 112 containing the analyte 114 (molecules 114) of interest and the waveguide 106 which can result in resonant drift and other detrimental effects (see U.S. Pat. No. 6,332,363); and (4) increasing the amount of analyte 114 binding to the target 110 (receptor 110) by improving the surface chemistry layer 108 or its application (see U.S. Patent Application No. 2004/0043508A1).
In addition, a lot of work has been done in the past to make a disposable PWG sensor 100 so that one does not have to re-use the sensor 100 after performing an assay. This is desirable because if one re-uses the PWG sensor 100 then there is a possibility of cross-contamination. However, there are problems associated with manufacturing disposable PWG sensors 100 at a high yield and a low cost. And, there are problems associated with the performance of these disposable PWG sensors 100. These problems are described next.
The prior art demonstrates that there has been a struggle to balance the cost and performance in making a disposable PWG sensor 100. For instance, the PWG sensor 100 can have a low cost polymeric substrate 102 within which the sub-wavelength gratings 104 can be easily embossed or molded. However, the PWG sensor 100 which has a polymeric substrate 102 can suffer from a problematical optical signal loss that is due to absorption in the polymeric substrate 102. To address this absorption problem, the PWG sensor 100 can be enhanced by depositing a thick oxide or organic modified oxide layer between the polymeric substrate 102 and the waveguide 106. This type of PWG sensor 200 is illustrated in FIG. 2 (PRIOR ART). As shown, the PWG sensor 200 has the following elements:                Polymeric substrate 202 (patterned with a sub-wavelength period diffraction grating 204).        Inorganic cladding layer 205.        Waveguide 206.        Chemically responsive surface chemistry layer 208.        Chemically bound molecules 210 (targets 210) of interest.        Solution 212 containing the substance 214 (analyte 214) to be detected.
For a more detailed discussion about the structure and the functionality of PWG sensor 200, reference is made to the following documents:                U.S. Pat. No. 5,369,722.        U.S. Pat. No. 6,804,445 B2.
The contents of these documents are incorporated by reference herein.
Referring back to FIG. 1, it can be difficult to manufacture the PWG sensor 100 which has a polymeric substrate 102. In particular, there is a significant manufacturing challenge in keeping the polymeric substrate 102 flat to ensure a uniform coupling angle for the light 116 that is directed into and reflected out-off the PWG sensor 100. And, there is a significant manufacturing challenge in depositing the waveguide 106 onto the polymeric substrate 102 without damaging the polymeric substrate 102. To address these problems, the PWG sensor 100 can be enhanced by using a flat glass substrate 102 (which is more costly than a polymeric substrate 102) and then forming a polymeric layer onto the glass substrate 102 so the sub-wavelength diffraction grating 104 can be formed into the polymeric layer by embossing, UV curing, or molding. This type of PWG sensor 300 is illustrated in FIG. 3 (PRIOR ART). As shown, the PWG sensor 300 has the following elements:                Flat glass substrate 302.        Polymeric cladding layer 305 (patterned with a sub-wavelength period diffraction grating 304).        Waveguide 306.        Chemically responsive surface chemistry layer 308.        Chemically bound molecules 310 (targets 310) of interest.        Solution 312 containing the substance 314 (analyte 314) to be detected.
The sensitivity of the PWG sensor 300 can be further enhanced if low index polymer layers (not shown) are used instead of the polymeric cladding layer 305. For a more detailed discussion about the structure and the functionality of these types of PWG sensors 300, reference is made to the following documents:                U.S. Patent Application No. 2003/0017580.        PCT Patent Application WO 0235214.        U.S. Patent Application No. 2005/0025421.
The contents of these documents are incorporated by reference herein.
Referring again to FIG. 1, the PWG sensor 100 can be made where the diffraction grating 104 is directly formed into a flat glass substrate 102 by a photolithographic patterning and etching process. This type of PWG sensor 100 is costly but it is desirable because it uses a glass substrate 102 which does not have the flatness problem that is associated with a polymeric substrate 102. In addition, this type of PWG sensor 100 is more durable than the PWG sensor 100 which has the polymeric substrate 102. Because, the waveguide 106 can be deposited onto the glass substrate 102 without the strict restrictions on temperature and ion bombardment that are needed when the waveguide 106 is deposited onto a polymeric substrate 102.
However, the use of a photolithography patterning and etching process to form a smooth and accurately reproduced diffraction grating 104 on the top surface of the glass substrate 102 can be challenging. For example, a PWG sensor 100 has been made where ˜0.25 to 0.5 micron linewidths which are required for a subwavelength diffraction grating 104 have been formed in a glass substrate 102 by using a holographic photolithography process (see PCT Patent Application Nos. WO9809156 and WO02082130 and U.S. Pat. No. 6,873,764 B2). Unfortunately, this type of photolithography patterning process can be costly and as such it is not be suitable to manufacture disposable PWG sensors.
Moreover, the etching process which is used to form the diffraction grating 104 within the glass substrate 102 can be a significant challenge itself. For example, silicate glass substrates 102 can be etched by wet etching in a solution containing hydrofluoric acid, or by dry etching in a fluorine containing plasma. However, only simple glass substrates 102 like fused silica may be cleanly etched in this manner. In contrast, most commercial glass substrates 102 have compositions which are complex and contain alkali metals, alkaline earths, aluminum oxide, or transition metal oxides that do not etch well. In particular, the etching of these complex glasses by either a hydrofluoric acid containing solution or a fluorine containing plasma typically produces a rough etch surface, because the fluoride salts of the alkali metals, alkaline earths, aluminum and transition metals are not removed. However, clean features (such as diffraction gratings 104) can be etched for some compositions of glasses using mixed halide gases such as CCl2F2 when all of the etch products are volatile (see U.S. Pat. No. 6,873,764 B2). And, clean features (such as diffraction gratings 104) may also be plasma etched in some glasses under conditions where sputter etching is utilized (see J. Liu, N. I. Nemchuk, D. G. Ast, and J. G. Couillard, J. Non-Crystalline Solids 342 110 (2004)). Unfortunately, these plasma etching method are not practical for manufacturing large numbers of glass PWG sensors 100.
The aforementioned problems associated with etching clean diffraction gratings 104 in glass substrates 102 can be overcome by depositing a silica layer (which can be easily etched) or a polymer layer onto the glass substrate 102 and then patterning that layer by wet or dry etching. This type of PWG sensor 400 is illustrated in FIG. 4 (PRIOR ART). As shown, the PWG sensor 400 has the following elements:                Flat glass substrate 402.        Discontinuous oxide or polymer layer 405 (which also forms a sub-wavelength period diffraction grating 405).        Waveguide 406.        Chemically responsive surface chemistry layer 408.        Chemically bound molecules 410 (targets 410) of interest.        Solution 412 containing the substance 414 (analyte 414) to be detected.
For a more detailed discussion about the structure and the functionality of PWG sensor 400, reference is made to the following document:                PCT Patent Application WO02082130.
The contents of this document are incorporated by reference herein.
In many of the above PWG sensors, a surface layer (e.g., SiO2) may be deposited on top of the waveguide (e.g., PVD deposited Nb2O5) to facilitate the formation of a chemoresponsive layer. An exemplary PWG sensor 500 which has this surface layer is illustrated in FIG. 5 (PRIOR ART). As shown, the PWG sensor 500 has the following elements:                Flat glass substrate 502.        Polymer layer 505 (patterned with a sub-wavelength period diffraction grating 504).        Waveguide 506.        Surface layer 507.        Chemically responsive surface chemistry layer 508.        Chemically bound molecules 510 (targets 510) of interest.        Solution 512 containing the substance 514 (analyte 514) to be detected.
For a more detailed discussion about the structure and the functionality of PWG sensor 500, reference is made to the following document:                U.S. Patent Application No. 2004/0043508A1.
The contents of this document are incorporated by reference herein.
In all of the above PWG sensors, a key performance attribute is signal drift. Signal drift occurs when the high index waveguide (and if present the SiO2 surface layer) is porous or cracked which allows the interaction of the solution and the waveguide material. These pores and root cracks are always present in PVD deposited metal oxide waveguides which are deposited over gratings in polymer substrates (see FIG. 1), or deposited over polymer gratings which are on top of glass substrates (see FIG. 3). The pores result from the deposition of the waveguide at a low temperature and under a low ion flux. Under such conditions, adatoms from the vapor arrive at the growth surface and stay where they fall. This produces a columnar grain growth where the packing of adatoms is not optimal, resulting in porosity (see, D. L. Smith, Thin Film Deposition: Principles and Practice, McGraw-Hill (1995) 159–161).
A coating scientist can produce a fully dense oxide coating/waveguide by PVD if they can heat the substrate (typically 250° C. or above) to provide energy for surface diffusion of the adatoms to sites of higher binding energy, and/or if they can use ion bombardment to transfer momentum and pack the adatoms more densely (see D. L. Smith, Thin Film Deposition: Principles and Practice, McGraw-Hill, New York (1995) pp 119–180). However, these methods cannot be used in applications where polymer substrates and/or polymer gratings degrade at temperatures below 200° C. and under ion bombardment. This porosity problem is solved by the present invention.
Moreover, since this PVD coating process is a line of sight process, root cracks are often caused by inadequate step coverage over the grating features. These root cracks may cause signal drift due to infiltration of water during assays. A FIB image which is shown in FIG. 6 (PRIOR ART) illustrates two root cracks 602 that are in the waveguide layer 506 of the prior art PWG sensor 500. As can be seen, this PWG sensor 500 has a UV curable polymer grating 504 formed in a UV curable polymer 505 which is located on a glass substrate 502. FIG. 7 (PRIOR ART) has several plots which illustrate the signal drift (grating resonance vs. time) for 96 PWG sensors 500 (shown in FIGS. 5–6) that are located in a 96 well microplate which contains an aqueous solution. This root problem is solved by the present invention.
An engineering solution to cancel out the effects of signal drift caused by porosity and root cracks in PWG sensors 500 (for example) would be to reference the signal from within one half of each PWG sensor 500 to the other half, or from one PWG sensor 500 to other PWG sensors 500 that are incorporated in the wells of a microplate. For example, in the former solution part of each PWG sensor 500 may be covered or its surface chemistry altered to prevent binding of the target molecules. Then, these PWG sensors 500 would be interrogated. Alternatively, in the later solution a buffer solution can be added to all wells of a microplate, and the biological molecules only to some of the wells in the microplate. Then, the PWG sensors 500 in these wells would be interrogated. However, measurements of differential signal drift may only be used if each PWG sensor 500 in the microplate exhibits a similar signal drift when exposed to the same solutions. Unfortunately, as the plots in FIG. 8 (PRIOR ART) indicate, this is not the case for PWG sensors 500. These plots illustrate the intra-well referenced signal drift (grating resonance vs. time) for 96 PWG sensors 500 located in a 96 well microplate. Accordingly, there is a need to overcome the problematical signal drift that is associated with PWG sensors. This need and other needs are addressed by the present invention.

Low drift planar waveguide grating sensor and method for manufacturing same


An electrically actuated apparatus for discouraging animals from instinctively licking their wounds including an elongated flexible substrate which is foldable upon itself to form a laminate configuration with a battery receiving pocket formed at the fold-over area. Conductive traces are provided in circuit with the battery power source to provide a field across the exposed conductive traces to deliver an electrical impulse to the animal upon contact with the tongue or other sensitive tissues surrounding the mouth. In addition, a pressure sensitive adhesive layer is provided to coat the back surface of the laminate configuration to bond the apparatus to the body of the animal in a location closely adjacent the site of the wound.

The present invention relates generally to an electrically actuated apparatus for discouraging animals from instinctively licking their wounds, and more particularly to an apparatus which is provided with a self-contained power source and has exposed conductive traces for completing a circuit through the animal's tongue whenever it comes in contact with adjacent conductive traces. The apparatus has been found to be particularly useful for use when pets such as dogs or cats suffer wounds and their instinctive licking of the wounds impairs their prompt healing. The apparatus is further adapted for use with larger domestic animals who frequently suffer wounds and also develop certain "hot spots" during continued exposure to certain skin aggravating conditions.
In the past, various devices have been proposed and/or employed for use in discouraging animals from this practice. These devices, for the most part, have been cumbersome and difficult to controllably position on the skin adjacent the wound. Furthermore, prior art devices tend to be large and cumbersome, and hence susceptible of being removed by the animal through rubbing contact with stationary objects.

Electrical apparatus for discouraging animals from instinctively licking their wounds


The present invention relates to an optical modulator capable of preventing a disconnection of an electrode and improving a discontinuity of a characteristic impedance while realizing a polarization inverting area and a ridge waveguide in a single optical modulator. In the optical modulator, a first electrode is composed of an inverting area electrode portion formed on an upper portion of one of first and second waveguides in the polarization inverting area, a non-inverting area electrode portion formed on an upper portion of the other one of the first and second waveguides in the other area, and a connection portion for making a connection between the inverting area electrode portion and the non-inverting area electrode portion at the boundary between the polarization inverting area and the other area. A supporting mechanism for supporting the connection portion of the first electrode is provided in a groove.

1) Field of the Invention
The present invention relates to an optical modulator suitable, for example, for use in the field of optical communications.
2) Description of the Related Art
An optical modulator using an electro-optical crystal such as an LiNbO3 (lithium niobate, which will hereinafter be referred to simply as LN) substrate or an LiTaO2 substrate is formed by placing electrodes in the vicinity of an optical waveguide, which is formed in a manner such that a metal film is formed at a portion of the crystal substrate and thermally diffused or proton-replaced in benzoic acid after patterning to form an optical waveguide.
Usually, as the optical waveguide of the optical modulator, there is employed a Mach-Zehnder optical waveguide comprising an incidence waveguide, two parallel waveguides and an outgoing waveguide, with a signal electrode and an earth electrode being provided on the parallel wageguide to form a coplanar electrode. In the case of the employment of a Z-cut substrate, an electrode is located just above the optical waveguide because of the utilization of a variation of refractive index due to an electric field in the Z direction. At this time, a signal electrode and an earth electrode are patterned on parallel waveguides, respectively, and for the purpose of preventing the light propagated in the parallel electrodes from being absorbed by the signal electrode and the earth electrode, a buffer layer is interposed between the LN substrate and the signal electrode/earth electrode. As the buffer layer, for example, there is employed SiO2 having a thickness of approximately 0.2 μm to 1 μm.
For driving the optical modulator at a high speed, the signal electrode and an endpoint of the earth electrode are connected to each other through a resistor to establish a traveling-wave electrode and a microwave signal is applied thereto from the input side. At this time, due to the electric field, the refractive indexes of the two parallel waveguides vary like +Δna and −Δnb and the phase difference between the two parallel waveguides varies so that a signal light intensity-modulated is outputted from the outgoing waveguide.
However, the absolute values of the electric fields applied to the two parallel waveguides differ from each other, and since Δna<Δnb, a phenomenon (chirp) occurs where the wavelength of the output light varies in the transition phase from the ON-state of the light to the OFF-state thereof. For solving this, for example, there has been proposed the employment of a substrate in which a polarization inversion is made as shown in FIG. 9. In an optical modulator 100 shown in FIG. 9, a substrate is designated at numeral 106 and is equipped with an area 106-1 and a polarization inverting area 106-2 in which the electro-optical characteristic, i.e., the phase modulation characteristic of the light propagated in an optical waveguide in conjunction with an applied voltage, is in an inverted condition with respect to the area 106-1.
In addition, in FIG. 9, an optical waveguide 102 is formed on the substrate 106 and is composed of an incidence side Y-branched waveguide 103, two parallel waveguides 104-1, 104-2 and an outgoing side Y-branched waveguide 105, and a signal electrode 101a passes on one parallel waveguide 104-1 in the non-inverting area 106-1 and passes on the other parallel waveguide 104-2 in the polarization inverting area 106-2. Moreover, numeral 101b designates an earth electrode, and 108 depicts a buffer layer interposed between the substrate 106 and the electrodes 101a, 101b.
In the optical modulator 100 shown in FIG. 9, in a case in which the overall length L1 of the non-inverting area 106-1 in an optical propagation direction is equal to the length L2 of the inverting area 106-2 in an optical propagation direction, the lights passing through the two parallel waveguides 104-1 and 104-2 respectively vary by +Δθs and −Δθg in the non-inverting area 106-1 and espectively vary +Δθg and −Δθs in the polarization inverting area 106-2.
Accordingly, the phases of the lights passing through the two parallel waveguides 104-1 and 104-2 respectively vary by +(Δθs+Δθg) and −(Δθs+Δθg) in the Y-branched waveguide 105, which provides a phase modulation so that the absolute values are equal to each other but the signs being reverse to each other. This enables the wavelength chirp to become zero with respect to the light to be outputted from the Y-branched waveguide 105. Moreover, the adjustment of the chirp quantity becomes feasible by changing the ratio between the aforesaid L1 and L2.
FIG. 10A is a cross-sectional view taken along a line A-A′ in the optical modulator 100 shown in FIG. 9, FIG. 10B is a cross-sectional view taken along a line B-B′ in the optical modulator 100 shown in FIG. 9, and FIG. 10C is a cross-sectional view taken along a line C-C′ at the boundary portion between the non-inverting area 106-1 and the polarization inverting area 106-2 in the optical modulator 100 shown in FIG. 9. The signal electrode 101a is formed on the parallel waveguide 104-2 in the non-inverting area 106-1 and on the parallel waveguide 104-1 in the polarization inverting area 106-2. Therefore, as shown in FIG. 10C, at the boundary portion between the non-inverting area 106-1 and the polarization inverting area 106-2, the signal electrode 101a makes a connection between the upper portions of the parallel waveguide 104-1 and the parallel waveguide 104-2.
In addition, in the case of such an optical modulator using a substrate having electro-optical effects, an optical waveguide having a ridge configuration (structure) is obtainable in a manner such that both external sides of an optical waveguide (in FIG. 9, the parallel waveguides 104-1 and 104-2) in an interactive area are dug through the use of etching or the like to form grooves. In comparison with an optical waveguide formed on a flat substrate without having grooves, an optical waveguide with this ridge configuration is capable of improving the electric field application efficiency to this optical waveguide when an electric field is applied through electrodes, lowering the drive voltage and enhancing the broadbandization in modulation-possible optical wavelength. Still additionally, because of a high containment of light to the waveguide, in particular, also in the case of the formation of a waveguide having a curve with a small radius, the loss is reducible.
Therefore, through the use of an optical modulator having the aforesaid polarization inverting area and having a ridge configuration, it is expectable to achieve higher light containment in a waveguide, reduction of drive voltage and the enhancement of broadbandization while advancing the aforesaid wavelength chirp suppression. In this case, for example, it is considered that an optical modulator 100A is constructed as shown in FIG. 11 or FIGS. 12A to 12C. FIG. 12A is a cross-sectional view taken along a line A-A′ in the optical modulator 100A shown in FIG. 11, FIG. 12B is a cross-sectional view taken along a line B-B′ in the optical modulator 100A shown in FIG. 11, and FIG. 12C is a cross-sectional view taken along a line C-C′ at the boundary portion between a non-inverting area 106-1 and a polarization inverting area 106-2 in the optical modulator 100A shown in FIG. 11.
In the optical modulator 100A shown in FIGS. 11 and 12A to 12C, grooves 107 are made at both external sides of parallel waveguides 104-1 and 104-2, thereby enabling the parallel waveguides 104-1 and 104-2 to provide an optical waveguide with the aforesaid ridge configuration. Additionally, a ridge configuration is formed outside the parallel waveguides 104-1 and 104-2 having the ridge configuration.
Furthermore, for the construction of the aforesaid optical modulator 100A shown in FIG. 11, in addition to the optical waveguide 102, an signal electrode 101a and an earth electrode 101b are formed on a substrate 106 in which the grooves 107 are formed at both the external sides of the parallel waveguides 104-1 and 104-2. Also in this case, the signal electrode 101a makes a connection between the upper portions of the parallel waveguide 104-1 and the parallel waveguide 104-2 in the boundary portion between a non-inverting area 106-1 and a polarization inverting area 106-2.
Incidentally, the well-known techniques connected with the present invention, there are the following patent documents 1 to 4.
[Patent Document 1]                Japanese Patent Laid-Open No. 2003-228033
[Patent Document 2]                Japanese Patent Laid-Open No. HEI 11-101962
[Patent Document 3]                Japanese Patent Laid-Open No. 2001-194637
[Patent Document 4]                Japanese Patent Laid-Open No. 2003-233047
However, in the case of realizing both the aforesaid polarization inverting area and ridge waveguide in a single optical modulator, a signal electrode comes down to the bottom of a groove at the boundary portion between the polarization inverting area and the non-inverting area and, hence, a disconnection of the electrode tends to occur at this portion. In addition, when the electrode comes into contact with a side surface of the ridge, a discontinuity of the characteristic impedance (impedance mismatch) occurs, which interferes with the enhancement of broadbandization of a modulator.
For example, for the construction of the aforesaid optical modulator shown in FIGS. 11 and 12A to 12C, in the construction, the signal electrode 101a falls to the bottom of the groove 107 at the portion D (see FIGS. 11 and 12C) forming the boundary between the non-inverting area 106-1 and the polarization inverting area 106-2 and, hence, a disconnection of the signal electrode 101a tends to occur at this portion, and when the electrode 101a comes into contact with a side wall of the ridge structure of the parallel waveguides 104-1 and 104-2, a discontinuity of the characteristic impedance can occur.
Incidentally, each of the techniques disclosed in the aforesaid patent documents 1 to 4 cannot eliminate the above-mentioned problems arising in a case in which both the polarization inverting area and ridge waveguide are realized in a single optical modulator.


A liquid ejection head includes a substrate which has an energy-generating element that generates energy to be utilized for ejecting a liquid, and a supply orifice for supplying the liquid to the energy-generating element; and an ejection orifice forming member that has a plurality of ejection orifices through which the liquid is ejected, and at least one beam-like projection which projects toward the substrate and extends along an array direction of the ejection orifices at a position corresponding to the supply orifice. A sectional area perpendicular to the array direction of the ejection orifices at the central part of the beam-like projection in the array direction of the ejection orifices is larger than a sectional area in the direction perpendicular to the array direction of the ejection orifices at both ends of the beam-like projection in the array direction.

1. Field of the Invention
The present invention relates to a liquid ejection head for ejecting a liquid such as an ink.
2. Description of the Related Art
Requests for the enhancement of a recording speed and an image quality of an ink jet printer have progressively increased, and resulting liquid ejection heads tend to have a higher density and an elongated size. As a dot density of the liquid ejection head is enhanced from a conventional 600 dpi to 1,200 dpi, a sectional area of a flow channel wall which constitutes a flow channel of an ink tends to decrease and a mechanical strength of an ejection orifice forming member tends to be lowered. For this reason, it is notably concerned that the ejection orifice forming member tends to be easily deformed by stress. In addition, rigidity against the stress is relatively lowered in a central part in an array direction of a plurality of ejection orifices, in which the volume of the ejection orifice forming member is small, compared to that in both ends in the array direction of the ejection orifices. For this reason, as the liquid ejection head is elongated, the central part in the array direction of the ejection orifices becomes easily affected by the stress, and there is concern that the ejection orifice forming member is deformed. In the case where the deformation has occurred in the ejection orifice forming member, the ejection orifice is deformed, and it becomes difficult for a droplet to be stably landed at a desired position through the ejection orifice. As a result, the record quality of a recorded article results in being lowered.
As a measure of suppressing such a deformation of the ejection orifice forming member, Japanese Patent Application Laid-Open No. 2000-158657 discloses a configuration in which a beam-like projection is provided in the ejection orifice forming member at a position which faces an ink supply orifice, thereby enhancing the rigidity of the ejection orifice forming member. When the rigidity of the ejection orifice forming member is enhanced, an effect of suppressing the deformations of the ejection orifice forming member and the ejection orifice is obtained.
In addition, Japanese Patent Application Laid-Open No. 2007-283501 discloses a configuration in which a reinforcing rib that extends from the beam-like projection toward the ejection orifice and comes in contact with the substrate is formed integrally with the beam-like projection, thereby enhancing the rigidity against an external force and suppressing the deformations of the ejection orifice forming member and the ejection orifice.
However, the configuration disclosed in Japanese Patent Application Laid-Open No. 2000-158657 has the following problem. In the central part in the array direction of the ejection orifices in the ejection orifice forming member, a volume occupied by the ejection orifice forming member is relatively small compared to that in both the ends, and it is concerned that the central part tends to be easily deformed. This concern much more remarkably appears as the ejection orifice forming member is elongated. This is because when the beam-like projection is provided in the ejection orifice forming member, the rigidity is uniformly enhanced in the whole ejection orifice forming member, and accordingly it is still concerned to originate in a difference of the rigidity between both ends and the central part in the array direction of the ejection orifices.
In addition, when the volume of the beam-like projection is sufficiently increased so as not to cause the deformation of the ejection orifice forming member, a position onto which the stress acts results in moving to a portion at which the rigidity is relatively low, in other words, to an interface between the substrate and the ejection orifice forming member. As a result, it is concerned that the ejection orifice forming member is separated from the substrate. Accordingly, it is difficult to solve a problem that the record quality of the recorded article is lowered.
In addition, the configuration disclosed in Japanese Patent Application Laid-Open No. 2007-283501 has the following problem. Even in the structure having a reinforcing rib, the ejection orifice forming member still has a smaller volume in the central part in the array direction of the ejection orifices compared to that in both the ends in the array direction, and tends to easily cause the deformation in the central part. This tendency much more remarkably appears as the ejection orifice forming member is elongated. The configuration disclosed in Japanese Patent Application Laid-Open No. 2007-283501 cannot resolve such a tendency that the central part in the array direction of the ejection orifices tends to be easily deformed, which much more remarkably appears as the length of the ejection orifice forming member increases.


A system for converting digital television signals encoded according to an MPEG standard into standardized analog video signals. The system includes means for generating graphic images and for inserting corresponding image signals in a decoded digital flow of main image signals, a digital decoding unit, and an analog coding unit. The digital decoding unit includes means for providing a flow of multiplexed image signals including a first flow of main image signals and of a second flow of image signals that contains, in addition to the main image signals, possible graphic image signals. The analog coding unit includes a demultiplexer of the flow of multiplexed image signals and two encoders. The two encoders respectively receive the first and second flows, and each respectively provide a digital flow of images encoded according to a color television standard to digital-to-analog converters respectively associated therewith, the digital-to-analog converters providing the standardized analog video signals.

1. Field of the Invention
The present invention relates to the reception of digital television signals transmitted, for example, by a cable network or a satellite. Such television signals require a conversion system to adapt the digital signals to the standardized analog input signals of a television set. The analog input signals of a television set include at least one of signals providing the intensity of each primary color (RGB), or signals providing a composite video signal (CVBS), or separate luminance signals Y and chrominance signals C, the separate luminance and chrominance signals being the signals used for some video tape recorders, particularly S-VHS video tape recorders.
2. Discussion of the Related Art
Digital television signals generally are coded, on the transmit side, according to a data compression process in order to minimize the amount of digital data to be transmitted. This compression is standardized (MPEG). On the receive side, the images are thus generally decompressed in a digital form before being coded according to a color television standard (PAL, NTSC, SECAM) and converted into analog signals. These transformations are generally performed within a conversion system.
FIG. 1 shows, in the form of a block-diagram, an example of a conventional conversion system. Digital television signals transmitted by a satellite reception antenna (not shown) or by a cable network are sent, after a first analog demodulation of the channel frequency and a second demodulation, of the QAM type (quadrature amplitude modulation) for the cable network and of the QPSK type (quadrature phase skip modulation) for the satellite, to an input E of a digital unit 1 of the conversion system. This unit 1 essentially includes a decoder (MPEG-DEC) 2 that receives the digital signals coded according to an MPEG standard and received by input E. Decoder 2 reads out a digital image data flow I.
Unit 1 further generally includes a circuit (OSD-GEN) 3 for generating graphic elements to be inserted in the image data flow. These graphic elements generally correspond to interactive menus, called by means of a remote control, that enable the user to set certain operating parameters of the television set and its receive unit. These can be, for example, settings of the receive channels, settings of the satellite reception dishpan, sound or contrast settings, etc. The signals relative to these graphic elements are generated in a digital form by circuit 3 in a format compatible with that of unit 1, that is, with digital image flow I. These signals are generally called "On screen display" signals, or OSD signals. The OSD signals are inserted in image flow I by means of a mixer (MIX) 4, an output S of which provides a digital image flow resulting from the mixing of the main images I supplied by decoder 2 and the OSD signals. Generator 3 and decoder 2 generally share a same memory (MEM) 5 associated with digital unit 1.
Digital image flow S is then sent to a unit 6 for coding the signals into analog signals which conform with the PAL, SECAM or NTSC color television standards. Unit 6 essentially includes a coding circuit 7 and digital-to-analog converters 8 which transpose flow S into analog CVBS and/or R, G, B and/or Y, C, video signals. The signals provided by unit 6 are used by the television set to display the images.
Some of these signals may also be used to record television programs, for example, on a video tape recorder. When this is the case, the presence of OSD signals inside image flow S is problematic because these OSD signals are then present on all the analog outputs of conversion unit 6 and thus are recorded on the tape of the video tape recorder. Thus, the recording of the television programs is disturbed by any calling of a menu by the user by means of the remote control. Accordingly, it is not possible to check or modify settings during a recording.
To overcome this disadvantage, it is conventionally required to use two digital decoding units and two coding units such as described with respect to FIG. 1 within the conversion system. FIG. 2 shows an example of a conventional conversion system of this type. The conversion system includes two digital units for decoding according to an MPEG standard, respectively units 10 and 20. Each unit 10 or 20 receives a same flow of digital television signals as an input, respectively signals E1 or E2. Units 10 and 20 have substantially the same structure as digital unit 1 of FIG. 1. Thus, they each include an MPEG decoder (MPEG-DEC), respectively 12 or 22, an OSD signal generator (OSD-GEN), respectively 13 or 23, a mixer (MIX), respectively 14 or 24, and a memory (MEM), respectively 15 or 25.
Each unit 10 or 20 is associated with a coding unit, respectively 16 or 26, for converting the digital image flows, respectively S1 and S2, provided by units 10 and 20 into standardized analog video signals. Units 16 and 26 are shown in FIG. 2 by a simple block; each unit 16 and 26 being identical to the unit 6 shown in FIG. 1.
Unit 10 and unit 16 generate analog video signals including, when necessary, OSD signals inserted in the flow I of main images. The operation of units 10 and 16 is identical to the operation of units 1 and 6 described with respect to FIG. 1. Units 20 and 26 generate analog video signals free of OSD signals. Generator 23 of unit 20 is thus unused. Similarly, only outputs CVBS2, Y2, and C2 of unit 26 are used since the outputs R, G, and B of a coding circuit are generally not used for the recording of video images on a video tape recorder.
Two possibilities are thus available for signals CVBS, Y, and C, a first possibility (CVBS1, Y1, C1) including, when necessary, OSD signals for the displaying of interactive menus on the television set, and the second possibility (CVBS2, Y2, and C2) including the flow of main images only. A disadvantage of the conversion system such as shown in FIG. 2 is that it requires four circuits 10, 16, 20, and 26, which are generally integrated. The cost of the system is then substantially doubled with respect to a system such as shown in FIG. 1.

System for converting digital television signals with insertion of interactive menus