An optical displacement detecting apparatus is provided for detecting information on a relative displacement with respect to an object having a diffraction grating. The apparatus includes a light-emitting element for emitting a diverging light beam, a ball lens for converting the diverging light beam from the light-emitting element into a nearly collimated beam, a grating interference optical system for using the light beam from the ball lens to finally form interference light in such a form that two diffracted light beams from the diffraction grating are coupled, and a light detecting element for detecting the interference light from the grating interference optical system, wherein the relative displacement information with respect to the object is attained from a periodic signal from the light detecting element.

1. Field of the Invention
The present invention relates to an optical displacement measuring apparatus, and more particularly to an optical displacement measuring apparatus applicable to encoders for measuring a displacement or a velocity of an object, velocity sensors, acceleration sensors, length measuring apparatus, etc., utilizing the fact that when light impinging on a moving object is diffracted and scattered, the thus diffracted and scattered light is subject to phase modulation according to a displacement or a moving velocity of the object.
2. Related Background Art
As conventional apparatus for obtaining an amount of movement or displacement of an object at high accuracy there have been used, for example, optical encoders, laser Doppler velocimeters, laser interferometers, etc., utilizing interference of diffracted or scattered light beams from the object illuminated with light.
A specific feature of these apparatus utilizing the light is the feasibility of easily achieving high accuracy and high resolution of the wavelength order of light, but there is a demand for miniaturization (into the size of the millimeter order), to enhance the stability, "easiness to handle," and durability of the interference optical system, etc. in order to be applied in further wider fields.
The applicant proposed in the bulletin of Japanese Laid-open Patent Application No. 5-340719 a high-accuracy optical linear encoder utilizing interference based on diffracted light phase-modulated by a moving object. The same bulletin discloses an optical encoder that is simple in arrangement of the optical system, stable in interference between diffracted light, easy in handling, and suitable for miniaturization.
FIGS. 1 to 3 are schematic diagrams to show the major part of the optical encoder proposed in the same bulletin. Among them, FIG. 1 is a perspective view of the major part, and FIGS. 2A and 2B are schematic diagrams of the major part. In FIG. 1, 1a designates a light-emitting element such as a laser diode, CL a cylindrical lens, and ASP an aspherical lens, on a flat surface side of which a beam splitting diffraction grating G1, as detailed below, is disposed. The cylindrical lens CL and aspherical lens ASP compose an anamorphic optical system. Further, 4a denotes a transparent substrate, on which a beam superimposing diffraction grating G3 as described below is disposed. Reference numeral 20 represents a scale attached to a detected object relatively moving, on which a diffraction grating G2, as detailed below is disposed. Here, G1 is the beam splitting diffraction grating (for example of grating pitch P1=1.6 .mu.m), G2 the diffraction grating (for example of grating pitch P2=1.6 .mu.m) disposed on the scale 20, and G3 the beam superimposing diffraction grating (for example of grating pitch P3=1.6 .mu.m).
The beam superimposing diffraction grating G3 is placed on the same plane as the beam splitting diffraction grating G1. The beam superimposing diffracting grating G3 includes four parts G3a, G3b, G3c, G3d, which are formed at grating positions shifted from each other as shown in FIG. 3, thereby providing light beams incident to the respective parts with relative phase deviation .pi./2 between them. PD denotes a quartered photoelectric element (light-receiving element) composed of photocells PDa-PDd.
As constructed in the above structure, the optical displacement measuring apparatus operates as follows. A diverging light beam R emitted from the light-emitting element la is converted into a linearly converging light beam R' by the cylindrical lens CL. The beam next enters the aspherical lens ASP, and thereby the beam R' becomes emergent from the rear plane of the aspherical lens ASP so as to be condensed near the diffraction grating G2 in the direction of grating lines and nearly is collimated with the direction along the arrangement of grating lines. On this occasion the light is split by the beam splitting diffraction grating G1 into two light beams, i.e., zeroth-order diffracted light beam R0 advancing straight and +first-order diffracted light beam R+1, which are incident on the scale 20 relatively moving. In this event, the center rays of the respective light beams are incident at points P1, P2 on the diffraction grating G2 on the scale. Among the light beam R0 linearly illuminating the point P1, a light beam R0+1+first-order-diffracted by the diffraction grating G2 is diffracted by the diffraction grating G3. Among diffracted beams a light beam R0+1-1-first-order-diffracted there is emergent nearly normally from the diffraction grating G3.
Among the light beam R+1, a light beam R+1-1-first-order-reflection-diffracted by the diffraction grating G2 is incident to the diffraction grating G3. Among those diffracted a light beam R+1-10 traveling straight through the diffraction grating G3 is emergent nearly normally from the diffraction grating G3. The two beams R0+1-1, R+1-10 are superimposed on the beam superimposing diffraction grating G3 to interfere with each other with their wavefronts overlapping, then entering the quartered photoelectric device PD.
Employment of such an arrangement of the optical system enables the encoder to achieve high accuracy and being easy to handle, because the interference state is stable even with the occurrence of relative positional deviation (angular deviation such as azimuth, tilt, etc.) between the "diffraction grating G2 on the scale" and the "detecting head portion consisting of the beam splitting diffraction grating G1, beam superimposing diffraction grating G3, light-emitting element, photoelectric element, etc."

Optical displacement measuring apparatus including a light-emitting element and an adjacent ball lens


The present invention provides a SiGe-based bulk integration scheme for generating FinFET devices on a bulk Si substrate in which a simple etch, mask, ion implant set of sequences have been added to accomplish good junction isolation while maintaining the low capacitance benefits of FinFETs. The method of the present invention includes providing a structure including a bottom Si layer and a patterned stack comprising a SiGe layer and a top Si layer on the bottom Si layer; forming a well region and isolation regions via implantation within the bottom Si layer; forming an undercut region beneath the top Si layer by etching back the SiGe layer; and filling the undercut with a dielectric to provide device isolation, wherein the dielectric has an outer vertical edge that is aligned to an outer vertical edge of the top Si layer.

The dimensions of semiconductor field effect transistors (FETs) have been steadily shrinking over the last thirty 30 years or so, as scaling to smaller dimensions leads to continuing device performance improvements. Planar FET devices have a conducting gate electrode positioned above a semiconducting channel, and electrically isolated from the channel by a thin layer of gate oxide. Current through the channel is controlled by applying voltage to the conducting gate.
For a given device length, the amount of current drive for an FET is defined by the device width (w). Current drive scales proportionally to device width, with wider devices carrying more current than narrower devices. Different parts of integrated circuits (ICs) require the FETs to drive different amounts of current, i.e., with different device widths, which is particularly easy to accommodate in planar FET devices by merely changing the device gate width (via lithography).
With conventional planar FET scaling reaching fundamental limits, the semiconductor industry is looking at more unconventional geometries that will facilitate continued device performance improvements. One such class of devices is a FinFET.
A FinFET is a double gate FET in which the channel is a semiconducting "Fin" of width w and height h, where typically w<h. The gate dielectric and gate are positioned around the fin such that current flows down the channel on the two sides of the Fin (generally, FinFETs do not use the fin top surface as part of the conducting channel).
FinFET devices typically include a fully depleted body in the Fin that provides several advantages over a conventional FET. These advantages include nearly ideal turn off in sub-threshold voltages, giving lower off-currents and/or allowing lower threshold voltages, no loss to drain currents from body effects, no 'floating' body effects (often associated with some silicon-on-insulator (SOI) FETs), higher current density, lower voltage operation, and reduced short channel degradation of threshold voltage and off current. Furthermore, FinFETs are more easily scaled to smaller physical dimensions and lower operating voltages than conventional and SOI FETs.
Bulk FinFET integration schemes have been introduced in the prior art, but these prior art methods require expensive source/drain isolation schemes such as recessed shallow trench isolation (STI). In view of the foregoing, there is a need for providing a simple isolation scheme for a structure including a FinFET which is low cost, yet provides good n-to-n, p-to-p and n-to-p isolation.

Low capacitance junction-isolation for bulk FinFET technology

International Business Machines Corporation


In a drive circuit for a piezoelectric transformer that comprises an inverter circuit for supplying first and second primary electrodes of a piezoelectric transformer with a main drive voltage, a frequency control circuit having a normal frequency sweeping range, and a drive voltage control circuit for controlling input power of an input DC voltage supplied to the inverter circuit, an overvoltage protection circuit detects overvoltage in an output AC voltage from the piezoelectric transformer. On detection of the overvoltage in the output AC voltage, the overvoltage protection circuit supplies the frequency control circuit with an additional reset signal and a switching signal, thereby making the frequency control circuit switch the normal frequency sweeping range to a provisional frequency sweeping range included in the normal frequency sweeping range. The switching signal may be supplied to the drive voltage control circuit to make the drive voltage control circuit decrease the input power of the input DC voltage.

This invention relates to a drive circuit for driving a piezoelectric transformer which generates an AC voltage using a piezoelectric material and, in particular, to a drive method in an open state of a load or a state where a cold-cathode tube serving as the load does not light up because the cold-cathode tube has a high impedance.
In general, the piezoelectric transformer is an element which comprises a piezoelectric material having first and second primary electrodes and a secondary electrode. The piezoelectric transformer has a resonance frequency. The piezoelectric transformer is resonated by applying an AC voltage having the resonance frequency to the first and the second primary electrodes and the piezoelectric transformer takes a generation voltage due to mechanical vibration out of the secondary electrode. Inasmuch as the piezoelectric transformer is miniaturized and thinned in comparison with an electromagnetic transformer, the piezoelectric transformer is used as a main transformer for use in a back light electric source for a liquid crystal display.
A conventional drive circuit for the piezoelectric transformer is proposed in Japanese Patent Application No. Hei 7-69,207 which is published as Japanese Unexamined Patent Publication of Tokkai No. Hei 8-275,553 or JP-A 8-275,553 of Oct. 18, 1996 after making an application for the instant Japanese Patent Application No. Hei 8-203,579 of Aug. 1, 1996.
According to JP-A 8-275,553, the drive circuit comprises an inverter circuit and a frequency control circuit. The frequency control circuit is supplied with, as a feedback current, a load current from a load. The load may be a cold-cathode tube. Response to the feedback current, the frequency control circuit supplies the inverter circuit with a frequency control signal indicative of a drive frequency for the piezoelectric transformer. The inverter circuit is supplied with a DC power source voltage as an input DC voltage directly. Response to the frequency control signal, the inverter circuit converts the input DC voltage into a main drive voltage. The main drive voltage is supplied to the first and the second primary electrodes of the piezoelectric transformer as an input AC voltage. Responsive to the input AC voltage, the piezoelectric transformer carries out resonance operation to produce an output AC voltage from a secondary electrode thereof. The output AC voltage is supplied to the load.
The frequency control circuit has a normal frequency sweeping range which is defined between a normal upper limit frequency and a normal lower limit frequency. The normal frequency sweeping range includes the resonance frequency of the piezoelectric transformer. The frequency control circuit sweeps the drive frequency within the normal frequency sweep range. Responsive to a reset signal, the frequency control circuit is reset to shift the drive frequency from the normal lower limit frequency to the normal upper limit frequency.
Another conventional drive circuit for the piezoelectric transformer is proposed in Japanese Patent Application No. Hei 6-241,049 which is published as Japanese Unexamined Patent Publication of Tokkai No. Hei 8-107,678 or JP-A 8-107,678 of Apr. 23, 1996 prior to making the application for the instant Japanese Patent Application No. Hei 8-203,579 of Aug. 1, 1996.
According to JP-A 8-107,678, the drive circuit prevents destruction of the piezoelectric transformer when the output AC voltage of the piezoelectric transformer is to high. The drive circuit comprises a driving circuit, a load-current comparing circuit, an output-voltage comparing circuit, and a frequency sweeping oscillator. The load-current comparing circuit converts load current into a DC voltage and then compares the DC voltage with a load-current reference voltage which corresponds to a desired load-current value. The load-current comparing circuit produces a load-current comparison result signal which is supplied to the frequency sweeping oscillator. On the basis of the load-current comparison result signal, the frequency sweeping oscillator determines a direction in a frequency sweeping of the drive frequency. The frequency sweeping oscillator has upper and lower limit frequencies for the frequency sweeping. The output-voltage comparing circuit divides and rectifies the output AC voltage from the piezoelectric transformer to produce a divided-rectified voltage and then compares the divided-rectified voltage with an output-voltage reference voltage which corresponds to a desired output AC voltage. The output-voltage comparing circuit produces an output-voltage comparison result signal which is supplied to the frequency sweeping oscillator. On the basis of the output-voltage comparison result signal, the frequency sweeping oscillator determines the direction in the frequency sweeping of the drive frequency. The driving circuit is connected to the first and the second primary electrodes of the piezoelectric transformer. Responsive to a frequency control signal indicative of the drive frequency, the driving circuit drives the piezoelectric transformer.
Still another conventional drive circuit for the piezoelectric transformer is proposed in Japanese Patent Application No. Hei 7-264,081 which is published as Japanese Unexamined Patent Publication of Tokkai No. Hei 9-107,684 or JP-A 9-107,684 of Apr. 22, 1997 after making the application for the instant Japanese Patent Application No. Hei 8-203,579 of Aug. 1, 1996.
According to JP-A 9-107,684, the drive circuit is operable at a high efficiency in a wide input DC voltage range. The drive circuit comprises not only the inverter circuit and the frequency control circuit but also a drive voltage control circuit and a dimmer circuit. The DC power source voltage is supplied to the inverter circuit via the drive voltage control circuit. In other words, the drive voltage control circuit supplies the inverter circuit with an input DC voltage having controllable input power. The inverter circuit includes first and second subsidiary transformers supplied with first and second subsidiary drive voltages, respectively. The first subsidiary drive voltage is supplied to the drive voltage control circuit. The frequency control circuit includes a voltage controlled oscillator which oscillates a chopping wave signal as well as the frequency control signal. The chopping wave signal is supplied to the drive voltage control circuit. Responsive to the chopping wave signal and the first subsidiary drive voltage, the drive voltage control circuit controls the input power of the input DC voltage. Responsive to a dimmer voltage, the dimmer circuit produces a dimmer control signal which is supplied to the drive voltage control circuit.
However, the above-mentioned conventional drive circuits have two problems as follows. A first problem is that electronic parts composing the inverter circuit develop heat in a case where the piezoelectric transformer is put into an abnormal state or has high impedance. A second problem is that it is in design difficult to make the normal upper limit frequency of the voltage controlled oscillator shift downward. This is because the drive frequency must be laid in a frequency sweeping range of the frequency control circuit under all conditions. To resolve the first problem must shift the normal upper limit frequency to a lower frequency. On the contrary, to resolve the second problem must shift the normal upper limit frequency to a higher frequency. Accordingly, the first and the second problems conflict with each other and it result in difficult to design the drive circuit for the piezoelectric transformer. That is, the above-mentioned conventional drive circuits do not take into account in the case where the piezoelectric transformer is put into the abnormal state.

Drive circuit for driving a piezoelectric transformer capable of decreasing heat developed from electronic parts composing an inverter circuit


A beam confinement subsystem for an optical scanning system of a laser beam machine having a laser beam transfer path includes an expandable light path sealing and protecting member surrounding a portion of the laser beam transfer path, and a pressure adjusting buffer directly coupled to the expandable light path sealing and protecting member. Preferably, the pressure adjusting buffer including an expandable, airtight thin-film material. Additionally, the beam confinement can include a pressurized purge gas supply tank directly connected to the expandable light path sealing and protecting member to thereby provide greater protection from contamination to the laser beam transfer path.

Conventional laser beam machines are disclosed, for example, in Japanese Patent Publication No. SHO 62-11953. FIG. 8 shows configuration of the conventional type of laser beam machine including an optical scanning system, while FIG. 9 shows part of the laser beam machine partially modified. In FIGS. 8 and 9, the reference numeral 1 indicates a laser oscillator for outputting a laser beam 2, which laser beam 2 is deflected by a bend mirror 3 to be lead to a machining lens 4. The laser beam 2 is converged by the machining lens 4 and applied to a workpiece 5, whereby laser machining is performed.
FIG. 8, i.e., the figure showing the conventional type of device, illustrates a one-axis laser beam machine including an optical scanning system. This machine has a configuration in which a machining head section 6 holding the bend mirror 3 and machining lens 4 is driven and moved for scanning in the X direction using well-known ball screws, a linear guide, and a servo motor or the like each not shown herein to execute machining such as cutting.
In the conventional type of device, an expandable light path sealing protector, i.e., a light path bellows 7, is provided for protecting a portion of a transfer path transferring the laser beam 2; a opposite light path bellows 8 is symmetrically connected to the side opposite to the light path via a communicating box 9.
Designated by the reference numeral 10 in FIG. 8 is an inspection hole cover of an inspection hole for adjusting the bend mirror 3 and inspecting for maintenance thereof in the communicating box 9. It will be appreciated that guide rollers 11, each of which is attached at an appropriate position to the light path bellows 7 and the opposite light path bellows 8, ride along a guide rail 12, i.e., a mechanism for guiding the guide rollers 11. FIG. 9 shows an alternative configuration in which an opening edge of the opposite light path bellows 8 is attached to the side face of the machining head section 6.
Next description is made of the operations associated with the conventional laser beam machines illustrated in FIGS. 8 and 9. In particular, it will be noted that the transfer path of the laser beam 2 from the laser oscillator 1 to the machining lens 4 comprises the light path bellows 7, communicating box 9 or bend mirror 3, opposite light path bellows 8 and machining head section 6, which elements cooperatively form a sealed room. The inside of this sealed room is filled with a clean gas (normally, clean air or dry air) which gas does not interfere with transfer of the laser beam 2 and does not contaminate the bend mirror 3 and machining lens 4. Thus, the sealed room protects the laser beam transfer path from the entrance of contaminated gas from outside of the transfer path. It will be appreciated that the presence of contaminated gas, e.g., a volatile gas, is well known to be a laser interfering gas for a carbon dioxide laser. It should be mentioned that the term "contaminated gas" indicates either a gas mixed with the volatile gas or dust, either of which will interfere with laser operation.
When the machining head section 6 is driven, for instance, in the + X direction, the light path bellows 7, the moving direction of which is restricted by the guide rollers 11 and the guide rail 12, expands while the opposite light path bellows 8 shrinks, and vice versa. The machining head section 6 is operated during movement thereof so that the pressure of the clean gas in the sealed room will always be kept at a substantially constant level to move the clean gas between the bellows 7 and 8 via either the communicating box 9 or the cylinder of the machining head section 6. For this reason, contaminated gas and dust cannot enter the laser beam transfer path from the outside.
The conventional type of laser beam machine including an optical scanning systems illustrated in FIGS. 8 or 9 requires a communicating box 9, which makes the device complicated and high priced. It will also be appreciated that the access to the bend mirror 3 for maintenance is not optimal. Moreover, as shown in FIG. 9, i.e., in the configuration in which the opposite light path bellows 8 is asymmetrically attached to the machining head section 6, the guide rail 12 for the light path bellows 7 cannot be shared with that of the opposite light path bellows 8. Thus, a guide rail is required specifically for support of the opposite light path bellows 8, which makes the device more complicated and more expensive. Furthermore, an opposite light path bellows 8 is required in addition to a light path bellows 7, which makes the device basically complicated and expensive. The problems with conventional laser beam machines of this type is increased in a multi-axis moving type machines. In particular, the opposite light path bellows 8 is rather an obstacle, which causes other performance characteristics of the machine, for instance, operability or the like, to suffer.
Furthermore, although a device using a pressure adjusting buffer tank is disclosed in Japanese Patent Publication No. SHO 62-11953, there have recently been pointed out several problems with the device. For example, the configuration of the laser beam machine becomes more complicated, particularly with respect to the enlargement of the area required for installation. This is due to the fact that the external dimensions of the pressure adjusting buffer tank included in the device are required to be much larger, i.e., in proportion to the drivable range of the device. Moreover, for the case wherein the laser beam transfer path is constructed with a member such as a bellows having a comparatively low degree of sealing performance, the path has been known to gradually permit contaminated gas to migrate from the outside of the laser beam transfer path to the inside, mostly in portions of the sealed room relatively far away from the pressure adjusting buffer tank. For this reason, it is necessary to maintain a high degree of sealing by using components in the light path, a combination including a duct fitted with an O ring, which makes the configuration even more complicated and expensive.

Laser beam machine based on optically scanning system


A multi-axis plane mirror interferometer uses shared measurement and reference beams that respectively reflect from measurement and reference reflectors before that shared beams are split into individual beams corresponding to the measurement axes of the interferometer. An N-axis interferometer thus requires only N+1 measurement beam paths, one for the shared measurement beam and N for individual measurement beams, to provide for each measurement axis the two reflections that cancel angular misalignment between the measurement and reference reflectors.

Interferometers are precision tools that can accurately measure the position and/or the velocity of a target device. For such measurements, a measurement mirror is generally mounted on the target device. In semiconductor device manufacturing equipment, for example, the measurement mirror can be mounted on a precision stage to permit an interferometer to precisely measure the movement of the stage while the stage positions a wafer for processing.
The measurement mirror of an interferometer generally needs to be aligned with the interferometer optics that direct a measurement beam at the measurement mirror. Plane mirror interferometers use a planar measurement mirror, which provides a uniform target area so that alignment of the position of the measurement mirror is less critical than in some other types of interferometers. Alignment tolerances for the orientation of the measurement mirror in a plane mirror interferometer can also be relaxed through use of interferometer optics having a measurement beam path that includes two reflections from the measurement mirror. With two reflections, an angular error that the first reflection causes can cancel an equal but opposite angular error that the second reflection causes.
FIG. 1 illustrates an example of a known single axis plane mirror interferometer 100 having a measurement beam path including two reflections from a measurement mirror 140. Interferometer 100 includes a beam source 110, a polarizing beam splitter 120, quarter-wave plates 130 and 170, measurement mirror 140, a retroreflector 150, a reference mirror 180, and a sensor 160.
Beam source 110 produces an input beam IN that is either a monochromatic or heterodyne beam depending on the type of interferometer. Input beam IN contains two polarization components having orthogonal linear polarizations with directions respectively corresponding to beams reflected and transmitted through a beam splitter coating in polarizing beam splitter 120. FIG. 1 distinguishes the two component beams respectively using separated dashed and solid lines, but the two component beams are collinear in an actual interferometer. When input beam IN is a heterodyne beam, one polarization component beam has a first frequency f1, and the other polarization component beam has a second frequency f2, where frequencies f1 and f2 differ slightly (e.g., by a few MHz).
Input beam IN enters polarizing beam splitter 120 where a polarizing beam splitter coating reflects one component and transmits the other component. In FIG. 1, the transmitted beam is a measurement beam, but the reflected beam could alternatively be used as the measurement beam if the components of interferometer 100 are properly rearranged. The transmitted measurement beam follows a path MA through quarter-wave plate 130 to measurement mirror 140 and is reflected back along a path MA′. (Paths MA and MA′ will be collinear if measurement mirror 140 has its ideal alignment.) Passing twice through quarter-wave plate 130 effectively rotates the polarization of the measurement beam by 90°, so that the measurement beam upon reentering polarizing beam splitter 120 reflects from the beam-splitter coating. The measurement beam then enters retroreflector 150 and is reflected back into polarizing beam splitter 120 along an offset path that is parallel to the entry path.
The offset measurement beam reflects from the beam splitter coating in polarizing beam splitter 120 and follows path MB to measurement mirror 140. The measurement beam then reflects from measurement mirror 140 and returns along path MB′. The two trips through quarter-wave plate 130 along paths MB and MB′ return the measurement beam to its original linear polarization, so that the measurement beam heading along path MB′ passes through polarizing beam splitter 120 and forms part of an output beam OUT.
The component of input beam IN that is originally reflected in polarizing beam splitter 120 forms a reference beam that follows paths RA and RA′ through quarter-wave plate 170 to and from measurement mirror 180. The reference beam has its polarization changed by two passes through quarter-wave plate 170 and passes through polarizing beam splitter 120 to retroreflector 150. The reference beam returns from retroreflector 150 along an offset path RB and passes through polarizing beam splitter 120 and quarter wave plate 170 before again reflecting from reference mirror 180 to return along path RB′. The returning reference beam on path RB′ reflects from the beam splitter coating in polarizing beam splitter 120 to merge with the measurement beam and form output beam OUT.
The reference and measurement beams differ in that the measurement beam reflects twice from measurement mirror 140, which moves with the target device. The reference beam in contrast reflects twice from a fixed reference mirror 180. Movement of the target device (and therefore the measurement mirror on the target device) causes a Doppler shift in the frequency of the measurement beam at each reflection. Measurement electronics 160 measures the frequency difference between the reference and measurement beams and compares the difference to the nominal frequency difference with no Doppler shifts, e.g., to 0 Hz for a monochromatic input beam or to a few MHz for a typical heterodyne input beam. The comparison indicates the amount of Doppler shift and therefore indicates the velocity of measurement mirror 140. The measured velocity can be integrated over time to measure the movement of the target device.
Interferometer 100 is a single axis interferometer that measures the velocity or movement of measurement mirror 140 at a point halfway between the reflections of the measurement beam from measurement mirror 140. Measuring an angular movement of measurement mirror 140 requires at least one additional measurement. The additional measurement could be performed using another single axis interferometer, but a multi-axis interferometer provides a more compact implementation by using some of the same optical elements for more than one measurement.
FIG. 2 illustrates a known two-axis interferometer 200 including a polarizing beam splitter 120, quarter-wave plates 130 and 170, measurement mirror 140, and reference mirror 180, which are used for two measurement axes. Interferometer 200 also includes a beam source 210 that generates a pair of input beams IN1 and IN2, each having the same properties as described above for input beam IN in FIG. 1. Such input beams can be generated using a beam source 110, such as described above, with beam splitter optics 212.
Polarizing beam splitter 120 splits input beam IN1 according to polarization into measurement and reference beams for a first measurement axis. The measurement beam split from input beam IN1 follows a path including paths M1A and M1A′, an offset reflection from a retroreflector 251, and paths M1B and M1B′ to form part of an output beam OUT1. Similarly, the reference beam split from input beam IN1 follows a path including paths R1A and R1A′, an offset reflection from retroreflector 251, and paths R1B and R1B′ before forming a part of output beam OUT1. Measurement electronics 261 then determines the velocity or movement of a point between the reflections where paths M1A and M1B hit measurement mirror 140.
In a similar manner, polarizing beam splitter 120 splits input beam IN2 according to polarization into measurement and reference beams for a second measurement axis. The measurement beam split from input beam IN2 follows a path including paths M2A and M2A′, an offset reflection from a retroreflector 252, and paths M2B and M2B′ to form a part of an output beam OUT2. The reference beam split from input beam IN2 follows a path including paths R2A and R2A′, an offset reflection from retroreflector 252, and paths R2B and R2B′ before forming a part of output beam OUT2. Measurement electronics 262 then determines the velocity or movement of a point between reflection points where paths M2A and M2B hit measurement mirror 140.
The two measurements obtained permit a determination of the angular motion (e.g., a pitch or yaw) of measurement mirror 140. A third measurement axis could be used to determine an angular motion (e.g., a yaw or pitch) in a different plane, and in complex systems, multi-axis interferometers having three or more measurement axes are common. A concern in these interferometers is the required size of elements such as the measurement mirror 140 and polarizing beam splitter 120. Each of the measurement beams has a finite cross-section and a required separation for separate measurement of the output beams. Measurement mirror 140 is thus large enough to accommodate the area of the measurement beam at each reflection point and the required separation between the reflection points. However, a large measurement mirror is difficult to accommodate in confined spaces such as may be found in semiconductor manufacturing equipment. Polarizing beam splitter 120 must similarly be large enough to contain all of the measurement and reference paths. The fabrication of such large optical-quality elements can be expensive and difficult. Accordingly, compact architectures for multi-axis interferometers are sought.


An optical metrology device is capable of detection of any combination of photoluminescence light, specular reflection of broadband light, and scattered light from a line across the width of a sample. The metrology device includes a first light source that produces a first illumination line on the sample. A scanning system may be used to scan an illumination spot across the sample to form the illumination line. A detector spectrally images the photoluminescence light emitted along the illumination line. Additionally, a broadband illumination source may be used to produce a second illumination line on the sample, where the detector spectrally images specular reflection of the broadband illumination along the second illumination line. The detector may also image scattered light from the first illumination line. The illumination lines may be scanned across the sample so that all positions on the sample may be measured.

Photoluminescence imaging and spectroscopy is a contactless, nondestructive method of probing the electronic structure of materials, such as silicon semiconductor wafers, solar cells, as well as other workpieces and materials. In a typical photoluminescence process, light is directed onto a wafer or other workpiece (hereinafter collectively referred to as a "sample"), where at least some of the light is absorbed. The absorbed light imparts excess energy into the material via a process of "photo-excitation." The excess energy is dissipated by the sample through a series of pathways; one such pathway is the emission of light, or photoluminescence. The intensity and spectral content of the photoluminescence is directly related to various material properties of the sample and, thus, can be used to determine certain characteristics of the sample, including defects, as discussed in U.S. Pat. No. 7,113,276B1, which is incorporated herein by reference.
Reflectance or reflectivity imaging is a contactless, nondestructive method of probing the surface with a broadband illumination source and analyzing the intensity and spectral content of the signal bounced back from the surface. The surfaces typically can be classified into specular or diffuse surfaces and real objects typically exhibit a mixture of both properties.
It is sometimes desirable, e.g., for semiconductor wafer inspection applications, to measure intensity and spectral content of the photoluminescence and reflectance of the semiconductor wafer-size workpiece for the purpose of quality inspection in the same apparatus either concurrently or in a short sequence, with single wafer load, while achieving a high measurement throughput combined with high measurement spatial and spectral resolution.
Conventionally, spectral photoluminescence or combined spectral photoluminescence and reflectance are measured using a single point-by-point inspection solution. In a point-by-point solution, the sample is placed on an X-Y motion (or R-Θ) system and is illuminated and measured at a single excitation point. The sample is moved to another measurement point and again illuminated and measured. By repeating the translation of the sample in the X-Y directions, a photoluminescence and reflectance maps could be constructed from the point-by-point measurements. This solution, however, is inherently slow and therefore impractical in the full wafer inspection systems, especially at large specimen sizes, close to and above 100 mm in diameter, due to the low throughput.

Optical metrology system for spectral imaging of a sample


The driving device of a solid-state imaging device comprises a driving unit for driving the solid-state imaging device in either an addition driving mode in which a plurality of pixels are added and read as a single pixel or a non-addition driving mode, and a substrate bias voltage supply for applying a bias voltage to the substrate of the solid-state imaging device according to the driving mode. The substrate bias voltage is set according to the number of pixels added in the addition driving mode so that the overflow level of the charge accumulating portion may be lower in the addition driving mode than in the normal driving mode. This suppresses the input of excess charges to the horizontal transfer path even in the addition driving mode, thereby preventing the generation of horizontal streak noise.

The present invention relates to an image pickup device using solid-state imaging elements, such as charge-coupled devices (CCDs), and more particularly to a driving method and driving device which perform pixel addition by special driving.
In recent years, various digital cameras using solid-state imaging elements, such as CCDs, have been developed. In a digital camera, the photoelectric conversion portion converts an image of the subject photoelectrically, thereby producing a pixel signal (charge). The pixel signal is transferred over a transfer path including CCDs and then outputted. To read the pixel signal from the image pickup device, a driving method of reading the charge in each pixel line by line is generally used. In addition, other special types of driving have been used.
One known typical special driving is n-times-speed vertical-addition driving (hereinafter, just referred to as n-addition driving), a driving method for high-speed, high-sensitivity reading. In "n-addition driving," the number of pixels (the number of transfer clocks) transferred from the vertical transfer path to the horizontal transfer path in each horizontal (H) blanking interval is set to an integer "n" equal to or larger than 2, not to 1 as is usual, which enables charges of n pixels (or n lines) to be transferred sequentially to the horizontal transfer path and then the charges of n pixels (or n lines) added in the horizontal transfer path to be read as a single pixel of one line.
This reduces the number of lines (horizontal lines) on one screen to 1/n, with the result that the reading time of one screen decreases to 1/n, enabling high-speed reading. Since the charges of n pixels are read as the charge of one pixel, the amount of charge of one pixel increases n times as much and accordingly the sensitivity is increased.
When a high-luminance subject is imaged, however, n-addition driving may cause a white-striped pseudo signal (a phenomenon similar to blooming or a smear, in this specification, referred to as horizontal streak noise) in the horizontal direction, which will possibly deteriorate the picture quality.
The phenomenon will be explained below.
If the saturated level (or the maximum amount of charge transmittable) of the horizontal transfer path in which the charges of a plurality of pixels are added were infinite, there would be no problem. Actually, however, the saturated level is finite. Let the saturated level be expressed as SatH. Normally, SatH is designed to correspond to the saturated level of the photoelectric conversion portion (for one pixel) in the normal driving state, non-addition driving. The saturated level of the photoelectric conversion unit, in other words, is the overflow level OFL of the charge accumulating portion. Even when charges exceeding the level are produced, they are discharged to the overflow drain and not accumulated. The overflow level OFL can be varied according to the set value of the substrate bias voltage VSUB explained later. Since setting the overflow level OFL too high makes blooming liable to occur, setting is done so that the overflow level OFL may be as high as possible in the range of the tolerance limit in the blooming characteristic.
Specifically, the saturated level SatH of the horizontal transfer path generally takes such a value as gives some design margins or adjustment margins to the standard setting of the overflow level OFL of the charge accumulating portion, and does not exceed that value:SatH=k×OFL  (1)where k=about 1.1 to 1.5 (theoretical lower limit is 1.0).
When n-addition driving is performed, the pixel signal is made n times as large by addition, thereby inputting the charges exceeding the saturated level SatH to the horizontal transfer path. Specifically, even when the amount of charge per pixel is equal to or below the overflow level OFL of the charge accumulating portion, if imaging is done with such a high luminance as exceeds SatH/n, n-addition will permit charges exceeding the saturated level SatH to be transferred to the horizontal transfer path. If satisfactory excess charge measures (for example, setting an overflow drain) have been taken for the horizontal transfer path, the input of such excess charges to the horizontal transfer path will just cause the signal charge to be clipped at the saturated level SatH, causing no problem. In some actual CCDs, unsatisfactory excess charge measures have been taken for the horizontal transfer path, permitting the excess charges to overflow into the regions adjacent to the horizontal transfer path, which causes horizontal streak noise along the horizontal lines.

Image pickup device capable of adjusting the overflow level of the sensor based on the read out mode


A slim optical disc drive which includes a tray having a spindle motor to rotate an optical disc and an optical pickup which slides across the optical disc mounted on the tray, a lower case where the tray is slidably installed, and a main control board installed on the lower case to control operation of the optical disc drive. The lower case includes a first frame which supports one side of the tray, a second frame which supports the other side of the tray, and a third frame formed of a plate member narrower than the first frame and the second frame to connect the first frame and the second frame and disposed under the tray and a main control board.

1. Field of the Invention
The present invention relates to an optical disc drive, and more particularly, to a slim optical disc drive installed in portable terminals such as notebook computers.
2. Description of the Related Art
In general, optical disc drives record or read information with respect to an optical disc such as a CD or DVD. Slim optical disc drives are manufactured to be very thin for use in portable terminals such as notebook computers.
FIG. 1 shows a conventional slim optical disc drive. Referring to FIG. 1, a tray 20 is slidably installed in a lower case 10. The tray 20 includes a spindle motor 30 to rotate an optical disc D and an optical pickup 50 to read or write information by accessing the optical disc D while sliding across the optical disc D . A main control board 60 to control the operation of the optical disc drive is installed in the lower case 10 and connected to the optical pickup 50 and the spindle motor 30 installed on the tray 20 by a flexible printed circuit (FPC) 70. The FPC 70 is flexibly folded or unfolded in a space between the tray 20 and the lower case 10 as the tray 20 slides in and out of the lower case 10. Therefore, the FPC 70 is partially attached to the lower case 10.
To make notebook computers thin, the thickness of the slim optical disc drive included in the notebook computers must be reduced. In the slim optical disc drive shown in FIG. 1, the tray 20 is slidably installed with a minimum interval not to interfere with the lower case 10.
Some major factors which affect the thickness of the slim optical disc drive are the sizes of the optical pickup 50 mounted on the tray 20, a motor 40 to slide the optical pickup 50, and the spindle motor 30. If the sizes of these components are large, the slim optical disc drive is made thick accordingly.
Furthermore, the slim optical disc drive is recently developed to have a recording/reproducing function of a CD-RW and/or a DVD reproduction function, in addition to a CD-ROM reproduction function. To accommodate the above various functions, the optical pickup 50 is made larger. Also, since electrical components having various thicknesses are installed on the main control board 60, the thickness of the slim optical disc drive increases.


The present disclosure relates to methods of preparing personalized blood vessels, useful for transplantation with improved host compatibility and reduced susceptibility to thrombosis. Also provided are personalized blood vessels produced by the methods and use thereof in surgery.

Vascular diseases constitute a serious and constantly growing health issue on a global scale. The options for replacement of damaged blood vessels are limited today. Autologous transplantation requires suitable vessel in the patient and leads to donor site morbidity. Synthetic vessel replacements are available, but these lack biological integration in the host tissue and long-term patency. There is a need for fully-biological patient-individualized grafts.
International publication number WO/2013/136184 discloses "methods for recellurization of blood vessels;" for example "for producing an allogeneic vein, wherein a donor vein is decellularized and then recellularized using whole blood or bone marrow stem cells."
International publication number WO/2015/181245 discloses "methods for recellularization of valves in valve-bearing veins;" for example "for producing an allogeneic venous valve, wherein a donor valve-bearing vein is decellularized and then recellularized using whole blood or bone marrow stem cells."

This patent is subject to a terminal disclaimer.

Methods of preparing personalized blood vessels


An apple tree of the McIntosh variety, producing an apple of the best quality having an excellent sweet, juicy taste with a pronounced aroma and firm, fine and crisp white flesh possessing a green tint. The color is a bright red blush with small, pale green yellow dots fairly uniform thereon. It has a few-branching, spur-habit and semi-dwarfing growth habit being somewhat smaller than standard McIntosh.

This invention relates to apple trees and, more specifically, to those of the McIntosh variety. As will be understood by those skilled in the art, trees of this variety grown in this climate are hardy and produce a good keeping and tasting apple.
I discovered the tree of this application as a limb sport of the McIntosh variety in orchards under my control near Kentville, Nova Scotia, Canada. It was selected because of its compact spurry growth habit which is proven stable over repropagations and the superior fruit color, size, uniformity and storability along with the excellent sweet taste, qualities which are very distinctive and attractive from a commercial standpoint over other McIntosh.
I have caused the tree, which I name `NS219`, to be repoduced asexually by cuttings, at the Agriculture Canada Research Station in Kentville, Nova Scotia, Canada, and find that its characteristics are constant and stable through successive generations.

McIntosh apple tree named `Hartenmac NS 219`


Structural ribs for providing structural support for a structure, such as the pressure cabin of a blended-wing body aircraft. In a first embodiment, the ribs are generally "Y-shaped", being comprised of a vertical web and a pair of inclined webs attached to the vertical web to extend upwardly and outwardly from the vertical web in different directions, with only the upper edges of the inclined webs being attached to a structural element. In a second embodiment, the ribs are generally "trident-shaped", whereby the vertical web extends upwardly beyond the intersection of the inclined webs with the vertical web, with the upper edge of the vertical web as well as the upper edges of the inclined webs being attached to the same structural element.

The present invention relates generally to a structural support and, more particularly, to a rib for buttressing the enclosing sections and upper deck floor of an aircraft pressure cabin.
There are primarily two types of aircraft configurations: the more common (conventional) configuration which includes a tail section comprised of vertical and horizontal stabilizers located at the aft end of a tubular fuselage; and the tailless configuration. As to the latter, there are two sub-types: a first type which has no central body, commonly known as a "flying wing," and a second type having a central body which is blended into laterally extending wings.
FIG. 1 is a schematic drawing of aircraft 20, a generic example of a conventional aircraft having a tubular fuselage and tail section. Aircraft 20 includes tubular fuselage 21, wing 23, horizontal stabilizer 25, and vertical stabilizer 27. When loaded, aircraft 20 has center of gravity 29. Horizontal stabilizer 25 controls the rotation of aircraft 20 about the pitch axis passing through center of gravity 29.
The vector L represents the lift generated by wing 23. The additional lift generated by fuselage 21 is small in comparison to L, and will be ignored for the limited purpose of this brief discussion. The vector l represents the lift generated by horizontal stabilizer 25. Generally, in normal flight, L acts in the upward, or positive direction, while l acts in the opposite, or negative direction. L has a magnitude much larger that that of l. The angle of attack of aircraft 20 is controlled and stabilized by the pitch moments about center of gravity 29 generated by L and l.
The presence of horizontal stabilizer 25 causes a significant increase in the drag for aircraft 20 in comparison to what the drag would be in the absence of the two aforementioned control elements.
Another drawback inherent to aircraft 20 is the weight of fuselage 21, which serves to provide a pitch moment arm of sufficient length to allow the pitch rotation of aircraft 20 to be controlled by the lift l generated by horizontal stabilizer 25.
Also, in order to sustain flight, L must have a magnitude sufficient to lift the weight of the entire aircraft, including wing 23, fuselage 21, horizontal stabilizer 25 and vertical stabilizer 27. L must thus exceed the weight of wing 23. As a consequence, wing 23 will be subjected to a resultant upward force equal to L minus the weight of wing 23. This resultant force subjects wing 23 to a distributed bending moment, with the maximum moment occurring at the wing root where wing 23 joins fuselage 21.
Wing 23 must be designed to withstand the bending moments induced by the distributed wing lift and weight forces, for the whole prescribed range of flight and ground load conditions. The strengthening of wing 23 also typically takes up additional volume that might otherwise be utilized to carry fuel. Both of the foregoing factors reduce the range of aircraft 20.
The foregoing drawbacks inherent to the conventional aircraft configuration exemplified by aircraft 20 have caused aeronautical engineers to consider tailless designs. A perspective view of tailless aircraft 30, a generic example of a tailless aircraft, is shown in FIG. 2. Aircraft 30 includes main wing section 31, deflectable reflexes 33, deflectable flaps 35, wing tip 37, and center of gravity 39.
FIG. 3 provides a side view of wing tip 37, and shows reflex 33 with particularity. Generally, in normal flight, main wing section 31 generates upward, or positive, lift vector L, whereas each reflex 33 generates a lift vector l acting in the opposite, or negative, direction. The flight of tailless aircraft 30 is controlled and stabilized by the appropriate deflections of reflexes 33 and flaps 35.
As may be discerned by cursory inspection of FIG. 3, tailless aircraft 30 has no horizontal stabilizer projecting into the ambient airstream. Moreover, since the flight of aircraft 30 is controlled and stabilized without a horizontal stabilizer, it does not require the moment arm to this stabilizer otherwise provided by a fuselage. The absence of a horizontal stabilizer and a fuselage lowers the drag coefficient and weight of tailless aircraft 30 in comparison to aircraft 20. Wing section 31 also weighs less than wing 23 of aircraft 20 because it need not be designed to withstand the moment generated by having to lift a fuselage in addition to its own weight.
Although the foregoing advantages inherent to tailless aircraft are widely recognized, modern commercial airliners nonetheless have continued to be developed and produced using designs which incorporate tubular fuselages and tail sections. The reason apparently derives not from comparative performance analyses, but rather from commercial realities confronting airlines and the designers and builders of commercial airliners.
More particularly, modern commercial airliners are typically designed and built as one model in a family of derivative configurations. For conventional aircraft exemplified by aircraft 20, each model varies primarily in the length of its tubular fuselage, with the various family members sharing a similar wing and avionics. By using different members of a manufacturer's family of airliners, the airline company's pilots, mechanics, and other support personnel need only acquire detailed knowledge of one model in the family. They are subsequently able to fly, maintain and repair another model in the same family with substantially less instruction and training than would be required to acquire proficiency with a completely new and unfamiliar aircraft.
The primary means of creating a new model from an existing aircraft is by inserting a hollow axial plug having the identical diameter of the original fuselage, into the fuselage. This increases the length and thus the size of the original aircraft, and avoids the significant investment necessary to develop a completely new model. An airline company will select a model based on the predicted passenger load and the length of the route the aircraft is to service.
Despite offering excellent aerodynamic efficiency, no manufacturer has ventured to produce a tailless base model because of the difficulty and expense which would be entailed to develop variants to satisfy the desires of the airline companies. More particularly, as the "flying wing" type of tailless aircraft obviously does not have a fuselage whose length can be readily changed, this design cannot be easily modified to alter its load carrying capacity. The blended wing-body type of tailless aircraft has a central body which could be modified, but this design has a drawback which has impeded its commercial viability.
More particularly, the pressure cabin enclosed by the body of a blended wing-body aircraft is not cylindrical like that formed by fuselage 21 of conventional aircraft 20, but rather has top and bottom body sections which are flat or gently curved. At altitude, the pressure cabin is subjected to a force caused by the pressure differential between the pressure cabin and the ambient atmosphere, as well as dynamic forces caused by aircraft maneuvers. In a conventional cylindrical pressure cabin, this pressure force is directed radially outwards and creates a tensile force in the cabin's cylindrical shell. In the non-cylindrical body sections of the blended wing-body pressure cabin, the pressure forces are reacted largely by bending of the shell between rib supports.
As a consequence, the pressure cabin body sections for a blended wing-body aircraft would have an increased weight compared with that for a conventional cylindrical shell. The shell would suffer lateral deflections that would increase drag and, with such cyclic deflection occurring on every flight, deleteriously affect the structural integrity of the aircraft body.
To provide an attractive interior layout with adequate space for passengers and their carry-on luggage, it is necessary to space the supporting ribs widely apart. This increases the weight of the pressurized shell and the deformations of the structure.
The foregoing characteristics inherent to the configuration of tailless aircraft have impeded the development of an airliner having a tailless design in spite of its having an aerodynamic efficiency greater than conventional designs having a tubular fuselage and tail section.
Based on the foregoing, it can be appreciated that there presently exists a need for a supporting rib which overcomes the above described disadvantages and shortcomings of the structural supports of the prior art. The present invention constitutes a rib which fulfills this need in the art and, in so doing, facilitates the design of a commercially viable blended wing-body aircraft.


A sensor (10) for sensing stress applied to an object (12), wherein the sensor includes a first core member (e.g., 100) aligned substantially parallel to the direction of applied stress and a second core member (e.g., 200) aligned substantially perpendicular to the direction of applied stress. A central core portion (18) connects the first and second core members (e.g., 100 and 200). An excitation coil (20) is operatively associated around the central core portion (18). The excitation coil (20) produces magnetic flux within the object (12) and the first and-second core members (e.g., 100 and 200). A first detection coil (e.g., 104) is operatively associated around the first core member (e.g., 100). A second detection coil (e.g., 204) is operatively associated around the second core member (e.g., 200). The first and second detection coils (e.g., 104 and 204) detect changes in the magnetic flux as affected by applied stress.

The present invention is related to a sensor for sensing stress and more particularly to a sensor that utilizes magnetostrictive properties of material to sense stress caused by torque.
Magnetostrictive sensors for sensing stress are relatively well known. Further, magnetostrictive sensors for sensing torque via stress sensing are known. In general, magnetostrictive sensors utilize the magnetostrictive properties associated with ferromagnetic materials to sense stress, from torque or the like, applied to an object.
Ferromagnetic materials have magnetostrictive properties that have an interaction relationship with mechanical energy. For instance, when a mechanical energy, such as an external force, is applied to a ferromagnetic material, magnetic properties, such as magnetic permeability, of the material change.
U.S. Pat. No. 5,144,846 discloses a magnetostrictive stress and torque sensor. The patent discloses that stress and torque are sensed based on the principle of magnetostriction.
Similarly, U.S. Pat. No. 5,850,045 discloses a magnetostrictive stress sensor and U.S. Pat. No. 4,933,580 discloses a magnetostrictive torque sensor.
In accordance with one aspect, the present invention provides a sensor for sensing stress applied to an object. A first core member is aligned substantially parallel to the direction of applied stress. A second core member is aligned substantially perpendicular to the direction of applied stress. A central core portion connects the first and second core members. An excitation coil is operatively associated around the central core portion. The excitation coil produces a magnetic flux within the object and the first and second core members. A first detection coil is operatively associated around the first core member. A second detection coil is operatively associated around the second core member. The first and second detection coils detect changes in magnetic flux as affected by applied stress.
In accordance with another aspect, the present invention provides a sensor for sensing stress applied to an object. A grain-aligned portion has grains aligned in a direction parallel or perpendicular to the direction of stress. The grain-aligned portion is operatively associated with the object such that stress applied to the object is applied to the grain-aligned portion in a direction parallel or perpendicular to the direction of grain alignment. A core is located proximate to the grain-aligned portion. The core includes a center portion and first and second members. The first member extends from the center portion in a direction substantially parallel to the direction of grain alignment and terminates at a first end distal from the center portion. The second member extends from the center portion in a direction substantially perpendicular to the direction of grain alignment and terminates at a second end distal from the center portion. An excitation coil generates magnetic flux within the core and the grain-aligned portion. The coil is operatively associated around the core near the center portion of the core. A first detection coil develops a first metric in response to the generated magnetic flux. The first metric changes when the magnetic flux changes as a result of applied stress. The first detection coil is operatively associated around the first member near the first end of the first member. A second detection coil develops a second metric in response to the generated magnetic flux. The second metric changes when the magnetic flux changes as a result of applied stress. The second detection coil is operatively associated around the second member near the second end of the second member. The first and second detection coils are operatively connected such that the first and second metrics are summed together to increase the sensitivity of the sensor.
In accordance with another aspect, the present invention provides a sensor for sensing stress applied to an object. A grain-aligned portion has grains aligned in a direction parallel or perpendicular to the direction of stress. The grain-aligned portion is operatively associated with the object such that stress applied to the object is applied to the grain-aligned portion in a direction parallel or perpendicular to the direction of grain alignment. First detection means, aligned parallel to the direction of stress, detects changes in a characteristic of the portion that changes as a result of applied stress. The first detection means develops a first detection metric that changes in response to changes in the characteristic that occur in a direction parallel to the direction of applied stress. The first detection means outputs a first signal indicative of the changes in the metric. Second detection means, aligned perpendicular to the direction of stress, detects changes in the characteristic. The second detection means develops a second detection metric that changes in response to changes in the characteristic that occur in a direction perpendicular to the direction of applied stress. The second detection means outputs a second signal indicative of the changes in the metric. The first and second detection means are operatively connected such that the first and second output signals are summed together.
In accordance with another aspect, the present invention provides a sensor for sensing stress applied to an object. The sensor is operatively associated with the object such that stress applied to the object is also applied to the sensor. Detection means detects changes in a characteristic of the object that changes as a result of applied stress. The detection means develops a detection metric functionally related to the characteristic. The detection metric changes when the characteristic changes. The sensor outputs a signal indicative of more than twice the change in the developed metric.
In accordance with yet another aspect, the present invention provides a sensor for sensing stress applied to an object. A grain-aligned portion has grains aligned in a direction parallel or perpendicular to the direction of stress. The grain-aligned portion is operatively associated with the object such that stress applied to the object is applied to the grain-aligned portion in a direction parallel or perpendicular to the direction of grain alignment. Detection means detects changes in a characteristic of the portion. The characteristic changes as a result of applied stress. The detection means develops a detection metric functionally related to the characteristic. The detection metric changes in response to changes in the characteristic. The sensor outputs a signal indicative of more than two times the change in the developed metric.
In accordance with still another aspect, the present invention provides a sensor for sensing torque applied to a shaft. A magnetostrictive portion is associated with the shaft such that torque applied to the shaft stresses the magnetostrictive portion. A magnetic core is located proximate the magnetostrictive portion. The core has a central portion and a plurality of portions remote from the central portion. An electrically conductive excitation coil produces a magnetic flux in the core. The excitation coil is operatively associated around the core near the central portion of the core. A plurality of electrically conductive detection coils, across which a voltage is developed in response to the produced magnetic flux as affected by torque, are operatively associated around the remote portions of the core.
In accordance with yet still aspect, the present invention provides a sensor for sensing torque applied to a shaft. A magnetostrictive portion is associated with the shaft such that torque applied to the shaft stresses the magnetostrictive portion. A magnetic core is located proximate the magnetostrictive portion. The core has an origin and an arm extending there-from. An electrically conductive excitation coil produces a magnetic flux in the core. The excitation coil is operatively associated around the core near the origin of the core. An electrically conductive detection coil, across which a voltage is developed in response to the produced magnetic flux as affected by torque, is operatively associated around the arm of the core.


Polymeric, thin oriented films can be made by use of a combination of a hot blown process and a blown bubble process, i.e. a double bubble process. The resulting film has use in replacing PVC for in store stretch wrap applications. Very low density polyethylene, VLDPE, is an especially preferred material for this process. It may be used as a monolayer, or as one layer of a multilayer structure. In practicing the invention, the polymer is extruded and hot blown, and heated to a temperature above its orientation temperature. This heating can be accomplished by the use of a heated liquid reservoir or sock disposed at the lower end of the primary bubble, inside the bubble. The hot blown heated film is then passed through a first set of pinch rolls, re-inflated into a blown bubble, and collapsed at a second set of pinch rolls. Thin, tough and elastic packaging materials are obtained by this process.

The present invention pertains to packaging film, and more particularly to a thin polymeric film suitable for replacing polyvinyl chloride film especially in packaging applications.
Polyvinyl chloride (PVC) has long been used in many applications in the packaging art. One particularly widespread application for PVC is the use of such material as an overwrap material for trayed retail cuts of meat and other food products in a retail environment.
PVC has several desirable properties for this use. For example, it has excellent optics and good elasticity and stretch properties at use temperatures.
Unfortunately, PVC also has several disadvantages, including the production of hydrogen chloride gas during heat sealing and the generally corrosive effects of such gases in the packaging room.
It would be of great benefit to the packaging industry, and particular to applications requiring an instore film for overwrapping trayed food products, to provide a film with many of the advantages of PVC but without the disadvantages described above.
Applicant has discovered that a relatively thin polymeric film, preferably a polyolefin, and more preferably very low density polyethylene (VLDPE), produced by hot blowing and then stretch orienting the extruded film, exhibits excellent elasticity, toughness, stretch and optical properties.
The U.S. Pat. No. 3,456,044 (Pahlke) mentions thin films of thicknesses less than 1 mil such as 0.5 mils, and discloses a double bubble method for biaxially orienting thermoplastic films including the steps of producing a primary tubing which is inflated by introducing air into the interior thereof, and a cooling ring 22, as well as squeeze rolls 34 and 28, with rolls 34 having a greater speed than rolls 28. Between the two pairs of squeeze rolls is a reinflated secondary bubble. If annealing is desired, the tubing can be reinflated to form a bubble 70.
U.S. Pat. No. 3,555,604 (Pahlke) is a patent based on a divisional application which was derived from the same priority application as the '044 patent described above, and discloses the same information described above for the '044 patent.

Double bubble process for making strong, thin film


A steam turbine wheel has a male dovetail projecting about its peripheral margin and a gap in the margin. Buckets having bases with complementary female dovetails are disposed in the gap and register with the male dovetail of the wheel, enabling the buckets to slide about the wheel into positions stacking the bases of the buckets against one another. The final three buckets including a closure bucket are disposed about the wheel margin with two buckets straddling the closure bucket secured to the wheel margin by the dovetails. The closure bucket is secured to the straddling buckets by axially extending pins. The closure and straddling buckets, as well as the pins, are formed of materials having a higher creep rupture strength than the materials forming the remaining buckets, enhancing the capability of the closure bucket to withstand high temperature and stresses over time without creep.

The present invention relates to steam turbine buckets and particularly to a high strength steam turbine closure bucket for avoiding creep elongation.
Steam turbine buckets are currently designed using an identical material for all of the buckets for a particular stage of the turbine. The buckets are commonly formed of a Type 403 or 422 stainless steel, depending upon the stage temperature. Steam turbine buckets are also often designed for installation on the turbine wheel in a tangential direction. Consequently, the base or root of the steam bucket typically has a female dovetail configuration. The peripheral margin of the turbine wheel has a generally complementary male dovetail configuration and an insertion gap to facilitate installation of the buckets. For example, each bucket is assembled onto the rotor wheel by first locating the bucket base in the gap. Once the dovetails on the bucket and wheel are aligned, the bucket is displaced along the periphery of the wheel in a tangential direction. Additional buckets are similarly installed on the wheel and the roots or bases of the buckets stack against one another on the wheel margin. The installation process proceeds until the entire margin of the wheel, with the exception of the gap, is filled with buckets. The last bucket to be assembled to the wheel is called the closure bucket. The closure bucket typically does not have a dovetail. The closure bucket root or base may, however, be recessed to balance its weight with the weights of the other buckets about the wheel to balance the wheel. Because there is a gap in the dovetail margin of the wheel, the closure bucket must be secured to the adjacent buckets, i.e., the two buckets which straddle the gap and the closure bucket, in order to secure the closure bucket to the wheel. Typically, the closure bucket is attached to the adjacent buckets by pins extending in an axial direction engaging through the root or base portions of the adjacent buckets and the closure bucket.
It will be appreciated that during operation, the centrifugal load of the closure bucket is carried by the adjacent buckets through the pins. The applied loads on the closure and adjacent buckets are thus not uniform. High localized stresses are encountered at the location of the securement between the closure bucket and the two adjacent wheels, i.e., along the slots receiving the pins and the pins themselves. Consequently, creep and permanent deformation of the closure bucket and/or the adjacent buckets may occur after a period of operation at high temperatures and high centrifugal loads. For example, such high temperatures and loadings may occur in the reheat section of an intermediate stage turbine. As a result, the closure bucket may tend to elongate at its base or root in response to these high temperatures and stresses over time, with the result that the slot or hole for receiving the pins may elongate in a radial outward direction. Consequently, there is a need for an increase in the load-carrying capacity of at least the closure bucket in a steam turbine.
In accordance with a preferred embodiment of the present invention, the creep rupture strength of the closure bucket is increased in relation to the creep rupture strength of the majority of the remaining buckets disposed on the wheel. To increase the load-carrying capability of the closure bucket, the material of the closure bucket has a higher creep rupture strength than the majority of the buckets on the wheel. The closure bucket, for example, may be formed of a nickel-based alloy, while the majority of the remaining buckets are formed of a stainless steel. Further, because of the possibility of high local stresses at the juncture of the closure bucket and adjacent buckets, and in the pins, the pins and the two buckets straddling the closure bucket are likewise formed of a material having a higher creep rupture strength than the creep rupture strength of the remaining buckets about the wheel. Thus, a plurality of buckets about the wheel are formed of stainless steel and the closure bucket and preferably the two adjoining buckets and pins are formed of a higher strength material such as nickel-based alloy to avoid creep rupture.
In a preferred embodiment according to the present invention, there is provided a steam turbine wheel for use in a steam turbine, the wheel having a plurality of tangential entry buckets having tangentially extending dovetails for attachment to the wheel, the wheel having a generally complementary-shaped dovetail about a peripheral margin thereof and a gap in the margin for receiving the plurality of buckets and a closure bucket, the closure bucket being formed at least in part of a material having a creep rupture strength greater than the creep rupture strength of at least a majority of the plurality of buckets.
In a further preferred embodiment according to the present invention, there is provided a method of avoiding creep rupture strength failure of a first closure bucket in a tangential bucket entry turbine wheel having a peripheral dovetail-shaped margin and a plurality of tangential entry buckets having complementary dovetail-shaped bases secured to the wheel margin wherein the plurality of buckets and the first closure bucket are formed of the same materials, comprising the steps of removing the first closure bucket from the turbine wheel and securing a second closure bucket formed at least in part of a material having a higher strength than the material of the removed closure bucket to the turbine wheel in place of the first removed closure bucket.

Steam turbine high strength tangential entry closure bucket and retrofitting methods therefor


Various micro-transducers incorporating piezoelectric materials for converting energy in one form to useful energy in another form are disclosed. In one embodiment, a piezoelectric micro-transducer can be operated either as a micro-heat engine, converting thermal energy into electrical energy, or as a micro-heat pump, consuming electrical energy to transfer thermal energy from a low-temperature heat source to a high-temperature heat sink. In another embodiment, a piezoelectric micro-transducer is used to convert the kinetic energy of an oscillating or vibrating body on which the micro-transducer is placed into useful electrical energy. A piezoelectric micro-transducer also is used to extract work from a pressurized stream of fluid. Also disclosed are a micro-internal combustion engine and a micro-heat engine based on the Rankine cycle in which a single fluid serves as a working fluid and a fuel.

The need for miniaturized power sources for micro-electro-mechanical systems (MEMS) and micro-electronics has long been recognized. Much work has already been done on micro-scale batteries, and micro-scale heat engines. Micro-scale heat engines are a particularly attractive option, because of the very high density energy storage afforded by the hydrocarbon fuels they burn. Thus, a micro-heat engine which could convert the chemical energy stored in a hydrocarbon fuel to mechanical or electrical energy could form the basis of a very compact power supply.
Attempts to construct a micro-heat engine have been directed to redesigning the hardware for conventional large-scale heat engines to be fabricated on the micro-scale. So far, these attempts are still in the developmental stages and have not yet proven to be successful.
Although not true heat engines, thermally driven devices have been constructed on the micro-scale. In one such device, water contained in a cavity, when heated, pushes a drive shaft. Upon cooling, the water condenses and the capillary action of the liquid pulls the drive shaft back in. However, because the device uses electrical power to heat and vaporize the working fluid and because there is no provision to cyclically heat and cool the working fluid, the device functions as an actuator, not as a true heat engine. Other thermally driven actuators rely on the thermal expansion of solids, or the change in shape of so-called shape-memory alloys to exert forces over small distances. Again, these devices are not true heat engines because they do not operate cyclically, and they do not transform thermal energy into mechanical or electrical power.
Piezoelectric thin films have been used for years as power transducers in MEMS and micro-electronic devices. Piezoelectric films are an attractive option for power transduction because of the relative ease with which such devices can be produced using conventional micro-machining methods. Generally speaking, micro-machining involves processing techniques, such as micro-lithography and etching, that were developed and refined for use in the manufacture of integrated circuits. Micro-machining allows fine control of dimensions and is commonly employed for producing parts from silicon. However, micro-machining is not restricted in its application to the formation of workpieces from silicon or other materials conventionally used in the manufacture of integrated circuits, and it is known to apply micro-machining to other materials.
In most applications of piezoelectric films, such as in micro-actuators, pumps and valves, electrical power is converted to mechanical power. Micro-sensors that utilize piezoelectric films also have been used for mechanical to electrical transduction, however, such devices are not capable of producing usable electrical power to any significant degree. Thus, it would be desirable to utilize piezoelectric thin films for converting energy in one form, such as thermal energy or kinetic energy, to useful electrical energy to power MEMS and micro-electronic devices.
Along with the need for miniaturized power sources is the need for micro-devices that are designed to remove heat from MEMS and micro-electronics. In particular, integrated circuit manufacturers are already reaching limits on micro-processor speed and performance imposed by high operating temperatures. Consequently, reducing chip operating temperatures by removing waste heat through active cooling is considered to be among the most promising strategies available to the micro-processor industry for overcoming these obstacles. Thus, it would be desirable to implement a piezoelectric film in a micro-heat pump for cooling applications of MEMS and micro-electronics.
Therefore, there exists a strong need for piezoelectric micro-transducers for use with MEMS and micro-electronic devices.

Piezoelectric micro-transducers, methods of use and manufacturing methods for same

Washington State University Research Foundation


A guitar slide adapted to be worn on a musician's finger has an annular end including a hole adapted for receiving the musician's finger, and a semiannular end adapted to extend over a tip of the musician's finger. The semiannular end forms a recess adapted for the musician's finger to rest within and is configured such that the recess becomes wider as the distance from the annular end increases.

The present invention relates to handheld devices for pressing guitar strings against the frets of a guitar, and more particularly to a new type and system of finger-operated guitar slides for playing a guitar.
A guitar slide is an instrument used as part of a technique for playing the guitar. Normally the pitch of a guitar string is controlled by pressing the strings against the frets. A guitar slide may be used to alter the pitch of the strings by changing the vibrating length of the strings by a sliding motion of the guitar slide along the strings.
Various types of guitar slides have been made that can fit upon one or more fingers of the hand. For instance, U.S. Pat. No. 6,160,212 to Morse teaches a cylindrical guitar slide that fits over a musician's finger. U.S. Pat. No. 7,476,792 to Musser teaches a cylindrical guitar slide that fits over any musicians finger, that has a variable length depending on how it is twisted around the finger. US Patent Application Publication 2005/0045019 by Wright teaches a finger-ring type device that fits over a finger and attempts to allow the finger to bend normally while a tip of the device presses against the string of a musical instrument. US Patent Application Publication 2007/0175311 by Sloan teaches a glove with slide members affixed to the fingertips of the glove.
It would be advantageous to provide a guitar slide that may be used on different fingers, that may be made with various sizes in order to allow the guitar player to choose whether the slide will cover the first joint of the finger, or not, as well as allowing the guitar player to choose how many strings will be engaged by the slide or slides. This arrangement may give guitar players more sonic possibilities that a conventional guitar slide cannot provide, including the ability to play new chords, voicings, and techniques. Many problems and limitations of conventional guitar slides may be reduced or eliminated, and guitarists may be able to produce new sounds on their instruments.
Using some embodiments of the system of fingertip guitar slide disclosed herein, guitar players may put different slides onto various fingers, so that multiple slides may be used at the same time. Furthermore, while some conventional guitar slides cover various or all of the joints of the finger while playing, the design of the invention disclosed herein may in some embodiments allow the player free movement of his finger joints while playing, affording optimal muscular movement with minimal effort.
Furthermore, with some embodiments of the disclosed invention there may be no need to use alternate guitar tunings to play different intervals while playing in order to get the slide effect. Players may slide 3, 4, 5, and 6 note chord voicings (including barre chords) using the fingertip slides without detuning the guitar. Additionally, by using more than one fingertip slide the musician may allow the playing of open strings in between strings on which the fingertip slides are being applied.
The disclosed fingertips slide system includes embodiments that use small, ergonomic pieces allowing for quicker, more agile movements while achieving the sound of a guitar slide, and more, since the player may provide the slide effect on some strings while applying non-slide fret finger placement on another string or other strings between the strings that are receiving the slide effect.
Accordingly, in one aspect of the current invention, a guitar slide adapted to be worn on a musician's finger comprises an annular end including a hole adapted for receiving the musician's finger, and a semiannular end adapted to extend over a tip of the musician's finger, the semiannular end forming a recess adapted for the musician's finger to rest within and being configured such that the recess becomes wider as the distance from the annular end increases.


An adapter apparatus and methods for using in providing such adapter apparatus include providing a high density interconnect board (e.g., having a pattern of contact pads on a first side thereof corresponding to a packaged device, such as a micro lead frame package) and providing an interconnect device. Interconnect elements extend through a substrate of the interconnect device and are electrically connected to conductive pads on a second side of the high density interconnect board.

The present invention relates generally to adapters for use with packaged devices or other adapter apparatus (e.g., micro lead frame (MLF) devices, chip scale packages (CSP), ball grid array (BGA) packages, land grid array (LGA) or other surface mount devices, male pin adapters, female socket adapter apparatus, etc.).
Certain types of integrated circuit packages are becoming increasingly popular due to their occupancy area efficiency. In other words, they occupy less area on a target board on which they are mounted while providing a high density of contact terminals. For example, one such high density package type is a MLF device.
Generally, such packages contain an integrated circuit having its die bond pads electrically connected to respective conductive surface mount pads that are distributed in a particular configuration on the bottom surface of the package. A target printed circuit board typically has formed on its surface a corresponding configuration of conductive pads which align with the configuration of surface mount pads of the package for electrically mounting the package on the target board. The target board typically includes other conductive traces and elements which lead from the conductive pads used for mounting the package to other circuitry on the target board for connecting various components mounted thereon.
A MLF package is a type of chip scale package (CSP). The die area is a minimum of 80% of the total package area (i.e., the area of the substrate the die is encapsulated in). Further, generally, an MLF package has physical characteristics similar to LGAs, quad flat packages (QFPs), and leadless chip carrier (LCC) type integrated circuit (IC) packages. The MLF package is a leadless design. The interface to the target board is a set of solder pads (e.g., 8-104 pads) on a bottom surface of the package similar to a LGA package. The pads are typically arranged on the perimeter of the package similar to a QFP or LCC type package. MLF packages are generally square or rectangular shaped and have pads along two or four sides of the package on the bottom surface. The pitch between the pads is typically 0.5 mm or less.
Typically, to mount such a package (e.g., MLF package) to a target board, the package is positioned with the configuration of surface mount pads corresponding to the conductive pads on the target board. One or more solder techniques are used (e.g., placement of solder and subsequent heat treatment) to fuse the surface mount pads to the conductive pads of the target board.
Such area efficient packaging (e.g., MLF packages) provide a high density of terminals at a very low cost. Also, this packaging provides for limited lead lengths. Limited lead lengths may reduce the risk of damage to such leads of the package, may provide for higher speed product, etc.
Generally, circuit boards, and/or components mounted thereon, are tested by designers as the circuit boards are being developed. For example, for a designer to test a circuit board and/or a package mounted thereon, the designer must first electrically connect the package to the target circuit board. As described above, this generally includes mounting the package on the target board using a soldering technique to fuse the surface mount pads to the conductive pads of the target board. Therefore, the package may be prevented from being used again.
It is desirable for various reasons to use package adapters for mounting the packages and reuse such packages after testing. For example, such packages may be relatively expensive. Further, for example, once attached, the leads of the package and/or the connection between the surface mount pads of the package and the conductive pads of the target board are not accessible for testing. In addition, it is often difficult to rework the circuit board with packages soldered thereon.
Various adapters which are used for electrically connecting a package to a target printed circuit board are known. For example, U.S. Pat. No. 6,007,348 to Murphy, issued 28 Dec. 1999, entitled "Solder Sphere Terminal," and U.S. Pat. No. 6,325,280 to Murphy, issued 4 Dec. 2001, entitled "Solder Sphere Terminal," describe several adapter apparatus for use in mounting ball grid array packages. For example, as described therein, various intercoupling components are provided. In one of such components, an insulative support member includes a plurality of terminal elements positioned within holes extending through the insulative support member. The terminal elements are sized to be press-fit within the holes of the insulative support member.
To gain access to the signals on a target board through an ICs land pattern (e.g., configuration of surface mount pads), it is generally necessary to attach an adapter to the IC's land pattern. Ideally, the adapter is employed such that each signal is brought out individually to a probe point or some other interface which can be connected to with test clips, cables, connectors, etc. Connecting individual wires to an ICs solder pads (e.g., pads of a MLF device) is impossible in most cases due to density concerns and would be extremely time consuming work by a technician (e.g., such work would need to be done with specialized equipment under a microscope). Further, due the density of the pads and the size of the package (e.g., MLF packages or other chip scale packages), various available adapters (e.g., ball grid array type adapters or those similar thereto) are inadequate to achieve access to the signals.

Surface mount adapter apparatus and methods regarding same