In an integrated circuit supporting complementary metal oxide semiconductor (CMOS) integrated circuits, latch-up immunity is supported by surrounding a hot n-well with an n-well strap spaced from the hot n-well by a specified distance in accordance with design rules. The n-well strap is positioned between the hot n-well and other n-well or n-type diffusion structures.

Latch-up is an operating condition within an integrated circuit where a low impedance path is formed between a power supply node and a ground node, and a large current may flow through this low impedance path causing damage to the integrated circuit. A trigger event (such as a current injection or an over-voltage condition) causes the low impedance path to form. Once formed, feedback causes the low impedance path to remain in place notwithstanding dissipation of the triggering event itself. A cycling of the power supply is typically required to eliminate the low impedance path.
Integrated circuits of the complementary metal oxide semiconductor (CMOS) type use n-channel transistors (nMOS) and p-channel transistors (pMOS) to form circuit functions. It is the proximity of the PN junctions of those nMOS and pMOS transistors that create inherent parasitic transistors and diodes. These parasitic circuit structures can form PNPN thyristors (i.e., silicon controlled rectifiers—SCRs) triggered by a current or voltage impulse applied to any of an input node, an output node or a supply node. The trigger event, such as with an overshoot or undershoot outside of normal operating voltage and/or current levels, turns on the thyristor and permits current flow through the low impedance path between the power supply and ground nodes.
FIG. 1 shows a cross-section of a CMOS inverter circuit 10. A semiconductor well 12 (for example, doped with n-type dopant) is formed within a semiconductor substrate 14 (for example, doped with p-type dopant). The pMOS transistor 20 of the CMOS inverter circuit 10 is formed in and on the well 12, and includes source and drain regions 22 and 24, respectively, doped with p-type dopant and an insulated gate electrode 26 positioned over a channel region between the source region 22 and drain region 24. The nMOS transistor 30 of the CMOS inverter circuit 10 is formed in and on the substrate 14, and includes source and drain regions 32 and 34, respectively, doped with n-type dopant and an insulated gate electrode 36 positioned over a channel region between the source region 32 and drain region 34. The source region 22 is connected to the power supply node 40 and the source region 32 is connected to the ground node 42. The gate electrodes 26 and 36 are electrically connected together to form an input node 44 of the CMOS inverter circuit 10. The drain regions 24 and 34 are electrically connected together to form an output node 46 of the CMOS inverter circuit 10.
The pMOS transistor 20 forms a parasitic vertical PNP bipolar transistor 50 having an emitter at the p-type doped source and drain regions 22 and 24, a base at the n-type doped well 12 and a collector at the p-type doped substrate 14. The nMOS transistor 30 forms a parasitic lateral NPN bipolar transistor 52 having an emitter at the n-type doped source and drain regions 32 and 34, a base at the p-type doped substrate 14 and a collector at the n-type doped well 12. An equivalent circuit schematic of these parasitic structures is shown in FIG. 2, which also shows the resistance Rwell provided by the n-type doped well 12 between the supply node 40 and the base of the PNP 50, and resistance Rsub provided by the p-type doped substrate 14 between the ground node 42 and the base of the NPN 52.
The latch-up phenomenon, for example, may be triggered by current impulse at the drain 24 of the pMOS transistor 20 which causes the PN junction between drain 24 and well 12 to become forward biased. If this current impulse is high enough (for example, sustained for a sufficient length of time), the carriers injected into the substrate 14 cause a voltage drop across the substrate resistance Rsub. The bias across the PN junction between the substrate 14 and drain 34 of the nMOS transistor 30 may then become high enough to turn on the NPN transistor 52. Collector current in NPN transistor 52 then flows into the base of PNP transistor 50 causing PNP transistor 50 to further turn on. At this point, the latch-up becomes self-sustaining due to positive feedback. The only way to release the latch-up is to remove power from the supply node 40.
As the number of nMOS and pMOS devices within an integrated circuit increase, the danger of latch-up increases due the creation of more parasitic bipolar transistors and the associated PNPN thyristors. Immunizing an integrated circuit against latch-up is a critical design goal. Known latch-up immunization techniques include: spacing of circuit elements, addition of guard rings around certain circuit points, use of substrate ties and well taps, and controlling substrate doping.

Latch-up immunization techniques for integrated circuits


An apparatus implementable on a pistol includes a compensator and a guide rod. The guide rod has a front distal end and a rear distal end opposite the front distal end. The compensator includes a muzzle brake having a recoil-reduction device, a first through hole and a second through hole. When the compensator is implemented on the pistol: (a) the recoil-reduction device redirects propellant gases to counter a recoil force upon firing of a round of ammunition by the pistol; (b) the first through hole is aligned with a barrel of the pistol to allow firing of the round of ammunition, and (c) the second through hole receives the front distal end of the guide rod therein such that an interface between the guide rod, the muzzle brake and a slide of the pistol is keyed to prevent rotation of the guide rod.

Unless otherwise indicated herein, approaches described in this section are not prior art to the claims listed below and are not admitted as prior art by inclusion in this section.
A muzzle brake or recoil compensator is a muzzle device mounted on, threaded on or otherwise connected to a muzzle of a firearm. One main function of a muzzle device is to redirect propellant gases to counter recoil and muzzle rise so as to allow better or quicker follow-up shots. However, many existing muzzle devices on the market tend to require significant modification and/or replacement of parts, or are otherwise integral to a proprietary system not allowing flexibility in customization.


For thermal compensation for an intrinsic element in a system, a circuit and method are proposed to predict the temperature variation caused by power loss of the intrinsic element, in addition to sense the external environment temperature variation of the intrinsic element, and thus sense the operational temperature of the intrinsic element more precisely.

Sensing an electric parameter such as current and voltage is necessary in most of systems. For example, referring to FIG. 1, a buck power converter 10 uses a pulse width modulation (PWM) controller 12 to switch power MOSFETs M1 and M2 to provide a voltage V0 and a current Io for a load 14, and for regulating the output voltage V0, the buck power converter 10 needs to sense the inductor current IL. An intrinsic lossless current sensing method is popularly used to sense the inductor current IL, which employs the winding resistance of the inductor L or the on-resistance of the power MOSFET M1 or M2 as the current sensor. However, both the winding resistance of an inductor and the on-resistance of a power MOSFET are temperature dependent, and thus the sensed current signal will not be linearly proportional to the inductor current IL, resulting in poor performance at active voltage positioning (AVP) and over current protection (OCP). Since the intrinsic element value, i.e. the winding resistance of the inductor L and the on-resistance of the power MOSFET M1 or M2, varies with temperature, thermal compensation for the intrinsic element is typically employed to improve the accuracy of the sensed current signal. Therefore, it is required an accurate and low-cost method for sensing the temperature of a power component, such as the power MOSFET M1 and M2 and the inductor L shown in FIG. 1.
Generally, a negative temperature coefficient (NTC) thermistor is used to sense the temperature of a power component for thermal compensation. For example, as shown in FIG. 2, an NTC thermistor 16 is placed nearby the inductor L to sense the temperature of the inductor L, and for precise thermal compensation, the NTC thermistor 16 is required to be as close to the inductor L as possible. According to NTC thermal compensation, U.S. Pat. Nos. 6,833,690 and 6,998,827 disclosed two different thermal compensation methods to compensate the environment temperature variation to improve the accuracy of the intrinsic current sensing method and AVP. However, as a system is operating, the intrinsic element value is varied with its operational temperature, mainly caused by the environment temperature and the power loss of the intrinsic element, and unfortunately, the NTC thermistor can not exactly sense the temperature variation caused by the power loss of the intrinsic element. For example, FIG. 3 shows the temperature measurement at the inductor L and the NTC thermistor 16 versus the output current Io in a system as shown in FIG. 1, in which the curve 18 represents the temperature of the inductor L, and the curve 20 represents the temperature of the NTC thermistor 16. As clearly shown in FIG. 3, the NTC thermistor 16 does not exactly sense the operational temperature of the inductor L. While the NTC thermistor 16 can sense the environment temperature outside the inductor L, the power loss of the inductor L can increase the internal temperature of the inductor L and thus makes the internal temperature of the inductor L higher than the external environment temperature. The NTC thermistor 16 only senses the external environment temperature of the inductor L and part of the internal operational temperature of the inductor L. Therefore, the temperature variation caused by the power loss of the intrinsic element is not precisely sensed and compensated by conventional methods.
The inductor L and the power MOSFETs M1 and M2 are all power components, whose power loss causes considerable temperature variation. Therefore, it is desired an improved intrinsic current sensing method.

Adaptive thermal compensation circuit and method


Provided is a summary management method including: a step for receiving a program signal providing a program, a step for acquiring a summary of a web content associated with the program together with the summary management information, and a step for managing the acquired summary according to the management information.

Web pages which are related to broadcasted programs for television are provided to the public, and web pages set up by organizations and corporations who provide commercial messages can be found. Television viewers who are interested in the broadcasted programs and the commercial messages can search through the internet based on names of the programs and the corporations to find the web pages related to the programs and the commercials. Alternately, the viewers can record URLs (uniform Resource Locators) which are presented in the broadcasted programs to enter in browsers and browse the web pages related to the programs and the commercials.
A technique to easily access the web pages related to TV programs is disclosed in Japanese Patent Provisional Publication No. 2005-586748. In the publication, a television receiver capable of receiving internet address information of a web page superimposed on broadcasting signals and storing the address information in a storing means is disclosed. Further, Japanese Patent Provisional Publication No. 2004-104640 discloses a digital television receiver capable of obtaining data representing program names and internet addresses which are included in digitally-broadcasted television data and storing pairs of the name and the internet address in a storage.
According to the television receiver disclosed in the former publication, the viewers are required to judge as to whether the web contents represented by the internet address should be browsed based solely on the internet address. According to the television receiver disclosed in the latter publication, the name of the program and the internet address are presented as a pair, and the viewers are required to judge as to whether the web contents represented by the program name should be browsed based on the program name.
However, it is considered to be less likely that the viewers choose to browse the web contents without further knowledge concerning the web contents; thus, the stored addresses may have been underused.

Broadcasting system and program contents delivery system


A method for stereoscopic image printing according to one aspect of the presently disclosed subject matter includes acquiring information on distribution of parallax of a multi-viewpoint image with two or more viewpoints; determining, based on the information on the distribution of parallax, a number of viewpoints of a stereoscopic image which is printed on a lenticular lens sheet; generating, if the number of viewpoints of the multi-viewpoint image is smaller than the determined number of viewpoints, a shortfall viewpoint image based on the inputted multi-viewpoint image; and printing a stereoscopic image which is made of the multi-viewpoint image and the generated viewpoint image.

1. Field of the Invention
The presently disclosed subject matter relates to a device and method for stereoscopic image printing which can form a stereoscopic image, which is adaptable to parallax between inputted images, on a lenticular lens sheet.
2. Description of the Related Art
A technology is known to stereoscopically display images which are picked up from a plurality of viewpoints via a lens-shaped sheet.
Japanese Patent Application Laid-Open No. 2007-098830 discloses types of lenticular sheets being selected by a user or based on lens resolution.
Japanese Patent Application Laid-Open No. 2001-346226 discloses a technology to convert a stereo image to a multi-viewpoint image based on a parallax map.

This patent is subject to a terminal disclaimer.

Device and method for stereoscopic image printing


A petroleum desalting process is improved by introducing the an alkaline compound such as sodium carbonate into the water phase, preferably in the vicinity of the water/oil interface which forms between the oil and water layers. This makes the rapid and effective separation of the oil and water phases from the emulsion layer possible.

Crude petroleum normally contains salts that may corrode refinery units; salt is removed from the crude oil by a process known as "desalting", in which hot crude oil is mixed with water and a suitable demulsifying agent to form a water-in-oil emulsion which provides intimate contact between the oil and water, transferring salt into the water. The salty emulsion is then passed into a high voltage electric field inside a closed separator vessel. The electric field forces water droplets to coalesce, forming larger water droplets. As the water droplet volumes increase, they settle to the bottom of the tank under gravitation. The desalted oil forms at the upper layer in the desalter from where it is continuously drawn off for distillation. The salty water is withdrawn from the bottom of the desalter.
During operation of desalter units, a stable emulsion phase (also known as a "rag layer") of variable composition and thickness forms above the interface between the oil- and the separated bulk water phase at the bottom of the desalter. This interface will be referred to here as "oil/bulk-resolved-water interface". The formation of a rag layer is mostly due to stability of the oil/bulk-resolved-water interface caused by natural surfactants (e.g. asphaltene, naphthenic acid) and/or solids. Particularly, solids can reside at the interface generating a physical barrier against the immersion of water droplets into the bulk water phase at the bottom of the desalter. Rag layer formation is especially problematic for crude with high amount of natural surfactants and/or solids. The growth of rag layer reduces workable volume and may short the electric circuit and force unplanned and costly desalter shut down.
Additionally, processing crudes with high rag layer formation tendencies in rent desalter configurations may cause poor desalting (salt removal) efficiency due to solids build up at the bottom of the vessel, and/or a solids-stabilized rag layer leading to erratic level control and insufficient residence time for proper water/oil separation. Formation of the rag layer has become a major desalter operating concern, generating desalter upsets, increased preheat train fouling, and deteriorating quality of the brine effluent and disruption of the operation of the downstream wastewater treatment facilities.
The water content of the rag layer may range from 20 to 95% water with the balance being hydrocarbon (normally full range crude oil) and up to 5 weight percent inorganic solids. Precipitated asphaltenes, waxes, and paraffins may also be found at elevated levels in the rag layer (compared to the incoming crude oil) which combine with particulates (solids), to bind the mixture together to form a complex structure that is highly stable. Intractable emulsions of this kind comprising oil, water and solids make adequate separation and oil recovery difficult. Often, these stable emulsions arising from the desalter are periodically discarded as slop streams. This results in expensive treating or handling procedures or pollution problems as well as the fact that crude oil is also lost with these emulsions and slop streams.
Refinery sites which process high solids-content crudes have the most pervasive problems with emulsion formation, Heavy crude oils and bitumens from Western Canada which contain elevated levels of small clay fines and other small solids are particularly prone to forming large volumes of highly stable emulsion and with such feeds, growth of the rag layer is more prevalent. These feeds are, however, being introduced to refineries in greater quantities despite two main disadvantages related to the efficacy of desalting. First, the viscosity of these crudes can be quite high, so transport of water through the feed is slower than in high API gravity crude. Second, the density mismatch between water and oil is lower, so the gravitational energy gradient is reduced compared to higher API gravity crudes. Growth of the rag layer in the desalter requires either the amount of crude passed through the desalter is reduced or removal of the rag layer from the desalting vessel for external treatment.
Attempts to mitigate the effects of rag layer formation are normally carried out by withdrawal of the emulsion from the unit or by the addition of chemical demulsifiers upstream of a desalter. The use of the demulsifier has proven to be effective in reducing emulsion stability between electrodes in a desalter, but may not be effective in reducing the rag layer build-up which is mainly due to stability of the oil/bulk-resolved-water interface. The common practice for application of demulsifiers has been to add the chemical demulsifiers to the water, oil, or the emulsion before introducing the oil/water mixture to the electric field, as shown by the following references.
U.S. Pat. No. 5,746,908 (Mitchell/Phillips Petroleum), discloses the use of steam to make emulsion and adding demulsifier to the mixture.
U.S. Pat. No. 7,867,382 (Droughton) discloses the use of demulsifier and mesoporous materials for reducing water-in-oil emulsion stability.
U.S. Pat. No. 7,923,418 (Becker/Baker Hughes) discloses the use of acrylate polymer emulsion breakers for reducing stability of a water-in-oil emulsion.
U.S. Pat. No. 7,981,979 (Flatt/Nalco) discloses the use of siloxane cross-linked demulsifiers for reducing water-in-oil emulsion stability.
The above-listed patents disclose the addition of chemical demulsifiers to water, oil, or emulsion before introducing an electric field. This is a common practice in the application of demulsifiers for several decades. A shortcoming of the current practice is due, in part, to the inability of chemical demulsifiers to reach high enough concentrations at the oil/bulk-resolved-water interface, particularly at the beginning of the desalter operation. In our co-pending application Ser. No. 14/556,398, however, we disclosed an improved desalting method in which a demulsifier is injected into the emulsion layer or into the water phase in the region of the emulsion layer to promote separation of the oil and water phases from the emulsion layer. Among the demulsifiers contemplated for use were the polyethyleneimines, polyamines, polyols, ethoxylated alcohol sulfates, long chain alcohol ethoxylates, long chain alkyl sulfate salts, e.g. sodium salts of lauryl sulfates, epoxies, di-epoxides (which may be ethoxylated and/or propoxylated) and the succinated polyamines prepared by the succination of polyamines/polyamine/imines with a long chain alkyl substituted maleic anhydride.

ExxonMobil Research and Engineering Company


A spiral coil conductor defining its winding central section as a conductor opening section is formed on a flexible substrate. The flexible substrate has a U shaped bend along a line passing through the conductor opening section so as to envelop a magnetic material core. The magnetic material core is arranged in a state where its end face faces the bend of the flexible substrate, and the magnetic material core includes cut shapes provided at a portion of the end face. The portion at the end face faces coil conductor sections at the bend of the flexible substrate, and the cut shapes separate the portion apart from the coil conductor sections.

In RFID systems widely employed in recent years, both a mobile electronic apparatus and a reader/writer in a mobile phone, or other equipment, incorporate an antenna for information communication in which data is exchanged between them. In particular, it is strongly desired that an antenna incorporated in a mobile electronic apparatus achieve high performance, be inexpensive, and be small. Japanese Patent No. 3772778 (Patent Document 1) discloses a magnetic material antenna including a magnetic material core as one example that attempts to meet these requirements.
FIG. 1 is a perspective view of a magnetic material antenna illustrated in Patent Document 1. This antenna 10 includes a core member (magnetic material core) 12 and a single electrical insulating film (flexible substrate) 14 having a first principal surface on which a spiral section 13a is formed by a continuous first conductor (coil conductor) 13. A second conductor 15 is formed on a second principal surface of the electrical insulating film 14, and an end of this second conductor 15 and an end of the first conductors 13 are connected to an IC chip 16.
However, with the configuration illustrated in FIG. 1, the coil conductor formed at a bend of the flexible substrate 14 is adjacent to the end face of the magnetic material core 12, so the effect of magnetic flux closed in the vicinity of the coil conductor tends to cause an excess of self-inductance. Because of this, when an antenna is realized under the constraint of a constant self-inductance value, the problem arises of a reduced number of turns of the coil and a decreased sensitivity of the antenna. Additionally, because blocking part of a magnetic-flux transmitting surface of the magnetic material with part of the coil conductor reduces the size of an opening of the antenna, the problem arises of a reduction in the distance in which communications are possible.

Magnetic material antenna and antenna device


An optical head device includes a focusing optical system for focusing a laser beam emitted from a semiconductor laser light source on an optical information medium with an objective lens. A chromatic aberration correction element for correcting chromatic aberration occurring in the objective lens is provided between the semiconductor laser light source and the optical information medium. A light distribution correction element in which the transmittance increases with the distance from the center of the aperture surface of the objective lens is provided so as to correct a reduction of the intensity of the light incident on the aperture surface of the objective lens with the distance from the center of the aperture surface.

1. Field of the Invention
The present invention relates to an optical head device for use in recording information on an optical information medium and reproducing information recorded on the optical information medium, an optical information apparatus (including recording/reproducing apparatuses and read-only apparatuses) using the same and a system in which they are used.
2. Description of the Related Art
In recent years, in-depth research has been conducted to achieve higher density for optical disk systems by increasing the numerical aperture (NA) of an objective lens to decrease the diameter of a focus spot on an optical disk. For example, the NA of an objective lens of a CD system is 0.4, and the NA of an objective lens of a DVD system is 0.6, whereas the NA of an objective lens of a next generation disk system will be as large as 0.85. In this case, the in-plane distribution of the light incident on the aperture of the objective lens is an issue.
This can be explained as follows. If the in-plane distribution of the light incident on the aperture of the objective lens is constant, the diameter of a focus spot that is focused on an optical disk by the objective lens is represented by λ/NA, where λ is a wavelength of a light source. In addition, the relationship of NA=r/f is satisfied, where r is the aperture radius of the objective lens, and f is the focal distance of the objective lens.
The aperture radius r and the focal distance f are generally determined by the physical size of the objective lens, but it is easily inferred that, for example, the effective aperture radius when the light amount is 0 at the periphery of the aperture is smaller than the physical aperture radius of the objective lens. Therefore, even if efforts are made to achieve higher density of optical disk systems by increasing the NA of the objective lens, that is, even if efforts are made to decrease the diameter of the focus spot on the optical disk, higher density cannot be achieved without the in-plane distribution of the light incident on the aperture of the objective lens being as uniform as possible.
The non-uniform in-plane distribution of the light incident on the aperture of the objective lens conventionally has been a problem. This is caused by the fact that the light intensity of the laser beam emitted from a semiconductor laser light source is not uniform in the light flux.
This problem will be described with reference to FIGS. 16 and 17. FIG. 16 is a view showing the relationship between a laser beam emitted from a semiconductor laser light source and the amount of light captured by a collimator lens, and FIG. 17 is a diagram showing light intensity distribution with respect to an angle at which a laser beam emitted from the semiconductor laser light source diverges (hereinafter, referred to as "diverging angle"). As seen from FIG. 17, the light intensity of a laser beam emitted from the semiconductor laser light source 10 decreases in the manner of a Gaussian function as the light flux radius from the center of the collimator lens 9 increases. Therefore, in prior art, in order to make the intensity distribution in the collimated light flux 8 entering the aperture radius of the objective lens as uniform as possible, the radius rc and the focal distance fc of the collimator lens 9 are adjusted (i.e., the relationship: the capturing NA of the collimator lens 9=rc/fc is adjusted). Thus, only the laser beam within the angle θd of the laser beam emitted from the semiconductor laser light source 10 is captured by the aperture of the objective lens.
Naturally, the smaller the capturing NA of the collimator lens 9 is, the less the intensity distribution in the collimated light flux 8 is, but the utilization efficiency of the laser beam emitted from the semiconductor laser light source is reduced. Therefore, the capturing NA of the collimator lens 9 is determined in view of the balance between the intensity distribution in the collimated light flux 8 and the utilization efficiency of the laser beam. In general, this value is set to about 0.2. As described above, in the next generation optical disk systems, the numerical aperture NA of the objective lens is as large as 0.85 to achieve a higher density than that of DVD systems, and a semiconductor laser light source in a wavelength of 405 nm is used.
On the other hand, for glass material for lens production, as the wavelength of a light source becomes shorter, a change in refractive index with respect to a change in wavelength becomes larger. In general, a change in refractive index of the glass material used for a lens when a wavelength of a light source is changed 1 nm in the vicinity of 405 nm is about three to four times larger than that at a wavelength in the vicinity of 650 nm for DVD reproduction.
When the temperature of a semiconductor laser light source having a wavelength of 405 nm is changed, the emission wavelength is varied, so that the refractive index of an objective lens is changed. Thus, the refractive index of the objective lens is displaced from the refractive index at the time of design, so that the shift amount of the focus spot from the surface of the optical disk by the objective lens is about three to four times larger than that for DVD (chromatic aberration of the objective lens). Furthermore, the lens refracts beams more strongly in a portion closer to the perimeter, so that the beams that pass through the portion closer to the perimeter of the objective lens are affected more by the change in the refractive index. Therefore, a larger focus shift due to the chromatic aberration of the objective lens occurs for the beams that pass through the portion closer to the perimeter of the objective lens, and substantially no focus shift occurs for paraxial beams.
On the other hand, when the NA of the objective lens is increased for higher density, the depth of focus is reduced in inverse proportion to the square of the NA. Therefore, the depth of focus of a system having an NA of 0.85 is only ½ of the focus depth of a system having an NA of 0.6.
Therefore, the focus shift due to chromatic aberration in a next generation disk system (NA of 0.85, a wavelength of a light source of 405 nm) is eight times more demanding than that of a DVD system. Therefore, in the next generation optical disk system, it is necessary to pay attention to the shift of the focus position due to a variation of the wavelength of the light source. When it takes 10 msec or more for the focus position to shift, the focus shift is detected by a focus error detection method, and the objective lens is moved accordingly so as to cancel this focus shift. Therefore, the shift of the focus position due to variations in the wavelength of the light source is not a problem. However, when it takes 10 msec or less for the focus position to shift, for example, the focus is displaced at the time of switching of recording/reproduction of the semiconductor laser light source, which results in poor recording/reproduction and causes a large problem.
As shown in FIG. 18, in order to reduce the chromatic aberration, the objective lens 1 includes three lenses 1c, 1f and 1e that form two groups. The lens 1c is a convex lens and the lens 1f is a concave lens, so that when the emission wavelength of the semiconductor laser light source is shorter than a central wavelength of 405 nm, the refractive index of the glass material constituting the convex lens is slightly increased. Therefore, the convex lenses 2b, 1c and 1e refract beams strongly, so that a focus spot 4 that is focused on a signal surface of an optical disk 3 is shifted to the side of the lens 1e. On the other hand, when the emission wavelength of the semiconductor laser light source is longer than a central wavelength of 405 nm, the refractive index of the glass material constituting the convex lens is decreased. Therefore, the refraction of beams by the convex lenses 2b, 1c and 1e becomes weak, so that the focus spot 4 that is focused on a signal surface of the optical disk 3 is shifted to the side opposite to the lens 1e.
On the other hand, concave lenses 2a and 1f act on the beams in the opposite manner to the convex lenses 2b, 1c and 1e. Therefore, when the emission wavelength of the semiconductor laser light source is varied, a change of the beams by the convex lenses 2b, 1c and 1e is cancelled by the change by the concave lenses 2a and 1f, so that the shift of the focus spot 4 can be suppressed. The shift amount of the focus spot 4 due to variations of the emission wavelength of this semiconductor laser light source is larger as the curvature of the spherical surface of the lens is larger. Therefore, the shift of the focus spot 4 by the convex lenses 2b, 1c and 1e is mostly cancelled by the concave lens 1f that has a large curvature. Thus, when the objective lens 1 is constituted by three lenses 1c, 1f and 1e forming two groups in this manner, even 1f the emission wavelength of the semiconductor laser light source is changed 1 nm from 405 nm, the shift amount of the focus spot 4 from the signal surface of the optical disk 3 can be restricted to be about 0.001 μm. However, in the case of this lens arrangement, two more lenses are required than when a single lens is used as the objective lens 1 for CD systems and DVD systems, so that an adjusting process becomes complicated. Furthermore, when the objective lens 1 is constituted by a single lens as shown in FIG. 17, simplification of an assembly process and a reduction of the number of lenses reduce costs. However, the shift amount of the focus spot 4 due to the chromatic aberration is as much as 0.5 μm. Therefore, it is necessary to add some element to reduce the chromatic aberration in this case.
In the optical head device shown in FIG. 20, an objective lens 1 constituted by two lenses is used to reduce costs. In this arrangement, not only are the costs reduced, but also the chromatic aberration can be reduced more than in the case of the objective lens 1 constituted by a single lens. Nevertheless, the shift amount of the focus spot 4 due to the chromatic aberration is about 0.35 μm, and it is necessary to add some element to reduce the chromatic aberration in this case as well.
When the objective lens 1 as shown in FIGS. 19 and 20 is used, a chromatic aberration correction element 7 constituted by a diffraction grating is inserted in order to reduce the chromatic aberration that occurs at the time of a variation of the emission wavelength of a semiconductor laser light source. In this case, compared to the objective lens 1 having three lenses in two groups shown in FIG. 18, one or two lenses are eliminated and the chromatic aberration correction element 7 is added. However, since this chromatic aberration correction element 7 can be formed in a simple manner by utilizing one surface of the convex lens 2b constituting a beam expander 2 when the convex lens 2b is formed with resin, the costs can be reduced significantly, compared to the case where the objective lens 1 having three lenses in two groups shown in FIG. 18 is used.
This approach of reducing the chromatic aberration has been well-known for a long time (e.g., JP 2001-60336A, which is referred to as "first conventional example"), but when the amount of the chromatic aberration of the objective lens 1 increases, the grating pitch of the chromatic aberration correction element 7 decreases.
This chromatic aberration correction element 7 can reduce the chromatic aberration for the following reasons. As described above, for example, when the emission wavelength of the semiconductor leaser light source is shorter than a central wavelength of 405 nm, the refractive index of the glass material constituting the convex lens increases and the power of the convex lens increases. Therefore, beams are refracted strongly and the focal distance becomes shorter. On the other hand, the relationship between the wavelength λ and the angle of diffraction θh at the diffraction grating constituting the chromatic aberration correction element 7 is θh=λ/p, where p is the grating pitch of the diffraction grating, and therefore when the wavelength becomes shorter, the angle of diffraction becomes smaller. Therefore, the chromatic aberration correction element 7 acts on beams in the opposite manner to the convex lens. Thus, it is possible to cancel the focus shift caused by the objective lens 1 due to wavelength variation by inserting such a chromatic aberration correction element 7. In this case, since the dependence of the diffraction angle on the wavelength is utilized, the larger the amount of chromatic aberration to be corrected is, the larger the angle of diffraction θh with respect to the wavelength variation has to be. Therefore, when the chromatic aberration of the objective lens 1 becomes larger, the grating pitch of the chromatic aberration correction element 7 becomes narrower, and the grating pitch of the chromatic aberration correction element 7 becomes rougher in a portion closer to the paraxial at the inner circumference.
As described above, the shift amount of the focus spot 4 due to the chromatic aberration in the case where the objective lens 1 having two lenses is about 0.35 μm, and the grating pitch of the collimator lens 9 to cancel this chromatic aberration is about 6 μm at the outermost portion of the effective diameter, and about 150 μm at the central portion. Thus, when the grating pitch is changed significantly, the diffraction efficiency in each radius position of the chromatic aberration correction element 7 is changed as shown by the solid line in FIG. 2A. Therefore, beams in the vicinity of the center of the objective lens 1 are achromatized by the diffraction grating having a pitch of 150 μm, and therefore the diffraction efficiency in this portion is 99%. On the other hand, beams in the outermost portion of the effective diameter of the objective lens 1 are achromatized by the diffraction grating having a pitch of 6.5 μm, and therefore the diffraction efficiency in this portion is about 92% (the diffraction efficiency with respect to the pitch is a value as a result of taking an estimated reduction amount due to processing error that can occur in practical use into account, based on the theoretical value).
Next, as a second conventional example, an arrangement disclosed in JP7-262594A will be described with reference to FIG. 21. In FIG. 21, reference numeral 41 denotes an optical disk, and reference numeral 42 denotes a semiconductor laser light source. Reference numeral 43 denotes a hologram that splits diffracted light 431 in a direction oblique to the optical axis of the incident beam in such a manner that the diffracted light does not enter other optical elements. The laser beam that is emitted from the semiconductor laser light source 42 and enters the hologram 43 is diffracted so as to be converted to light beams having a constant light intensity in the vicinity of the center and passes through the hologram 43 (zero-order diffraction). The upper surface of the grating constituting the surface of the hologram forms a smooth curve. Reference numeral 45 denotes an objective lens for focusing the light beam having a constant light intensity in the vicinity of the center that has passed through the hologram 43 on the optical disk 41 to form a focus spot. Since the light beams are made to have a constant light intensity in the vicinity of the center by the diffraction of the hologram 43, the light beams are focused by the objective lens 45 such that the diameter of the focus spot formed on the optical disk 41 can be a small spot in which the 1/e2 width is substantially equal to 0.96λ/NA.
In the chromatic aberration correction element 7 for correcting the chromatic aberration occurring in the objective lens 1, the grating pitch becomes smaller toward the perimeter, and the diffraction efficiency is reduced toward the perimeter. Therefore, the light intensity in the vicinity of the perimeter of the objective lens 1 is reduced significantly, corresponding to a reduction in the manner of a Gaussian function of the intensity of the semiconductor laser light source with respect to the radius distance of the light flux.
When the light intensity in the vicinity of the perimeter of the objective lens is reduced significantly, the effective NA of the objective lens is reduced. As a result, light cannot be focused sufficiently on the optical disk, and the recording density on the optical disk cannot be increased in proportion to the NA.
Furthermore, in the second conventional example, the angle of diffraction should be large so that the diffracted light 431 is split in a direction oblique to the optical axis of the incident beam in such a manner that the diffracted light does not enter other optical elements. As a result, the grating pitch of the hologram 43 is as small as 2 μm or less, and this is difficult to produce. In addition, the light intensity in the vicinity of the center is constant. Furthermore, the light beams 421 emitted from the semiconductor laser light source 42 constitute a so-called Gaussian distribution in which the intensity in the center is strongest, and the light amount decreases gradually as approaching the perimeter. Therefore, the diffraction efficiency of the hologram 43 should be highest in the center, that is, the zero-order transmittance should be low, and the diffraction efficiency should become lower gradually, that is, the zero-order transmittance should become higher, as approaching the perimeter. Thus, the diffraction efficiency of the hologram 43 is changed depending on the portion, so that if there is a displacement with the center of the light intensity of the light beams 421, the light amount distribution of zero-order transmitted light is changed significantly, which makes it difficult to form a small focus spot as desired on the optical disk.

Optical head device and optical information apparatus using the same


An innovative multi-dimensional, low frequency, impedance measurement probe array, measurement system, and method are disclosed for detecting flaws in conductive articles. The device and method provide for contacting a conductive article with an multi-probe array of current and voltage probes, injecting current sequentially through a plurality of current probe pairs and measuring absolute or relative voltages with a plurality of voltage probes and voltage probe pairs across the surface of an article for each current flow condition. The device and method further provide for constructing a voltage profile across the surface of an article where disruptions in the voltage profile enable detection of the presence, location and orientation of flaws for flaw sizes as low as 20 um. The innovative probe array and method provide for rapidly detecting cracks, inclusions, defects and other flaws in conductive articles and can be adapted and deployed as either a two-dimensional, planar array or three-dimensional shaped array for a variety of sample configurations and surfaces. By utilizing a plurality of current and voltage probes in an array format, the device and method overcomes existing limitations of conventional linear probes and traditional methods by enabling flaw detection over larger areas in a single probe placement while achieving a high degree of sensitivity and precision in determining flaw location and orientation.

Electrical methods for non-destructive testing and measuring the resistivity of metals are well known. For example, the four point probe method, also known as the potential drop method, and the eddy current method are two widely-practiced techniques for measuring the resistivity of magnetic or non-magnetic metals, respectively.
Eddy current methods and instruments have been widely used for measurements of resistivity on non-magnetic steels and nonferrous alloys, such as aluminum. These measurements have also been used for detecting flaws and cracks in non-magnetic alloys. With this technique, no electrical contact with the sample is required. However, due to the significant influence of geometrical effects, this technique requires careful calibration for articles having complex shapes. In addition, the eddy current technique requires substantial corrections for samples having high relative magnetic permeability and therefore have limited applications for measurements of ferrous alloys or ferromagnetic materials.
The four point probe impedance method is widely used for measurements of resistivity on metal samples. A typical four point probe configuration and circuit schematic are shown in FIG. 1. Both direct current ("DC") and alternating current ("AC") embodiments of this method are known in the art. The four-point probe apparatus typically comprises two pairs of probes arranged in a straight line which make electrical contact with the sample to be measured. Two current probes are positioned at either end of the linear array and two voltage probes are placed between the current probes in a collinear arrangement. A current source, either AC or DC, is connected to the current probes to supply a predetermined flow of current through the sample article and the voltage differential between the voltage probe locations is measured and recorded. The resistivity can be determined from the apparent resistance of the sample region located between the voltage probes is determined by applying the familiar Ohm's Law relation, V=IR, where V is the measured voltage, I is the applied current and R is sample resistance. The resultant measured resistivity value is thus a derived absolute value which is significantly influenced by the specific measurement conditions and specific characteristics of the sample being measured.
The apparent resistivity of the sample which is measured by the four point technique is dependent on sample composition, bulk resistivity of the material, geometry and shape of the part and the presence of physical defects, such as voids, cracks and inclusions within the sample volume which is measured. Thus, the method may be used for quality control of sample lots for checking uniformity of the lot composition by measurement of variations of resistivity between samples. Due to the large changes in resistivity produced by annealing treatments or work hardening of complex alloys, the method has been used to determine the extent of alloy phase transformation, such as the austenitic-martensitic transition in ferrous alloys. In addition, the method has been utilized to test the quality of semiconductor materials, magnetic steels and alloys, transformer steels, electroplated coatings, spot welds to gauge uniformity in sheet steel roll stock.
If a sample part has a standard geometry and the sample composition and microstructure is uniform, the effects of composition, microstructure and shape on a four point probe resistivity measurement can be factored into an apparent baseline measurement values for the specific part and deviations from the baseline value can be used to determine the presence of unacceptable defects within the article. However, for detecting such defects, the four point technique requires careful calibration by measuring the resistivity of an acceptable flaw-free sample which is free of any defects. The voltage value thus measured with a defect-free part is then utilized for comparison with a defective part.
Due to the inherent limitations of typical four point measurement probe configurations, the area and effective volume which is sampled in a four point method measurement is limited by the use of a single or dual two voltage probe pairs of fixed spacing. In establishing an apparent baseline resistivity value, a single four point measurement is typically insufficient for detecting flaws in most articles due to the intrinsic heterogeneity of the sample and limited area sampled by the four point probe. Thus, the four point method requires repeated measurements at numerous points on the sample for calculation of an average baseline value.
An additional limitation in the method is that the measurement of absolute resistivity by this method necessarily assumes a fixed geometrical relationship for the derivation of a resistivity value for a specific probe spacing and sample thickness. Typically, when the actual sample part thickness and probe spacing values do not satisfy such geometric assumptions, the four point method requires application of significant correction factors which lead to further error and lack of precision in determining a sample's resistivity distribution. Such errors will typically mask deviations from baseline measurements due to the presence of flaws in the sample.
Due to the need for measuring and establishing a baseline resistivity value for an unflawed part, the four point probe method has significant additional limitations when used to determine the presence of defects in heterogeneous materials. Due to resistivity variations typically observed in flaw-free materials caused by lot to lot variations in manufacturing methods, annealing treatments, work hardening, grain size, multiple phases, localized compositional inhomogeniety and complex geometry, as routinely encountered in practical applications, such factors tend to mask variations from the baseline resistivity measurement which would enable the detection of flaws in samples. Thus, it is difficult to establish a baseline resistivity measurement with acceptable precision to enable the detection of defects and flaws in such parts. Thus, the calibration required for the four point probe method leads to imprecision and significantly limits the capability of the technique for detecting flaws in conductive articles.
A further limitation of the four point method is that the volume of material sampled in a typical measurement is limited to the material between the narrowly spaced voltage probes. Thus, measurements made by this method are frequently subject to a lack of reproducibility when measurements are made over a large sample surface area on heterogeneous, multi-phase, or porous samples, or where variations in composition or grain size are present. Measurements made by this method on such materials can lead to considerable uncertainty as to what the appropriate baseline resistivity distributors is for an unflawed part. Thus, such variations in measured values preclude the detection of flaws where the perturbation in the measured voltage distribution for a defective part is masked by the scatter and uncertainty in measured values for a flaw-free part.

Multi-probe impedance measurement system and method for detection of flaws in conductive articles


A method for reducing plated pole height loss in the formation of a write pole for a magnetic write head is disclosed. The method includes forming a conductive layer on a thin film substrate, forming a photoresist layer on the conductive layer and forming a trench in the photoresist layer. A thick seed layer is then placed on the trench and on the photoresist layer surface using a collimator. Moreover, the process includes plating while applying a voltage to the thin film substrate where the electrically isolated seed layer is removed and the trench is filled with plating material, removing the photoresist layer, and removing the exposed portions of the conductive layer on the thin film substrate.

Conventional magnetic data recording devices employ magnetic disk drives that include a magnetic storage media and a magnetic transducer referred to as a read/write head. The head is usually formed from a plurality of ferromagnetic structures that comprise materials such as nickel iron (NiFe) alloys for instance. The read/write head utilizes poles that are formed on opposite sides of the read/write head. In conventional read/write head arrangements, the poles are joined at one end of the read/write head that is referred to as the "yoke," and are separated by a gap at an opposite end of the read/write head that is referred to as the "tip". A wire coil that is wrapped around the poles near the magnetic disk provides a mechanism for driving magnetic flux from the read/write head.
In a conventional magnetic disk drive, data is written and read by a read/write head that is positioned adjacent to a magnetic platter or disk while the magnetic disk is rotated at high speed. The magnetic read/write head is mounted on a slider that positions the read/write head over a track on the surface of the magnetic disk where it is supported by an air cushion generated by the magnetic disk's high rotational speed. In order to increase the amount of data stored per unit of disk surface area more data must be written in narrower tracks on the disk surface.
Conventional read/write heads include a write pole that is employed to drive magnetic flux from the read/write head when data is written to a magnetic disk. In the fabrication of the write pole, a seed layer is employed. Optimal performance of the write pole in effecting the transfer of data to a magnetic disk is related in part to the thickness of the seed layer that is employed in the fabrication of the write pole.
With reference to FIG. 1 and FIG. 2, a current methodology used for forming a write pole includes: (1) the deposition of a seed layer 10 on a wafer 20; (2) the printing of a photoresist pattern 30 on the seed layer; (3) the cutting of a write pole trench into the photoresist; and (4) the plating of a write pole 40 in the trench. Subsequently, (5) the seed layer is removed everywhere but under the pole. FIGS. 1 and 2 respectively show cross sectional views of a wafer undergoing this process after the plating and seed layer removal steps. During the seed layer removal step, a portion 50 of the plated pole height is generally lost (see FIG. 2). The loss in pole height during the seed layer removal step may be about 1600 angstroms for an 800 angstrom seed layer. This level of pole height loss negatively impacts the performance capacity of the read/write head thus fabricated.
One possible solution to the above noted problem is to increase the thickness of the seed layer that is employed in the fabrication of the write pole since the high-moment seed used can improve read/write head performance. However, increasing the seed thickness means reducing the final pole height (because more seed thickness needs to be removed in the area that is not under the pole) or increasing the as plated pole height. Both of these conventional solutions would prove inadequate. Accordingly, a need exists for a method or process that facilitates the fabrication of a write pole of a desired height with an optimal seed layer thickness.

Method for reducing pole height loss in the formation of a write pole for a magnetic write head


A method for allocating wireless resources for a number of user equipment in a wireless communication system is applied in an apparatus. The apparatus collects the traffic demands of all the user equipment and then selects a beam based on the traffic demands of all the user equipment in every time slot to make better utilization of resource blocks.

In an Orthogonal Frequency Division Multiple Access (OFDMA) system, a resource block (RB) is the smallest unit of resources. Each time slot consists of multiple RBs operating over different subcarriers, which can be allocated to multiple user equipment (UEs). However, only one fixed set of beams can be configured in a time slot. If a fixed beam combination is configured, the OFDMA system may support a high data rate for UEs in some RBs, but leave the remaining RBs underutilized in the same time slot, thus lowering the overall spectrum utilization.
Thus, there is room for improvement within the art.

Method and apparatus for allocation of resources in a wireless communication system