An apparatus and method for controlling and optimizing a non-planar target shape of a sputtering magnetron system are employed to minimize the redeposition of the sputtered material and optimize target erosion. The methodology is based on the integration of sputtered material from each point of the target according to its solid angle view of the rest of the target. The prospective target""s geometry is optimized by analytically comparing and evaluating the methodology""s results of one target geometry against that of another geometry, or by simply altering the first geometry and recalculating and comparing the results of the first geometry against the altered geometry. The target geometries may be of many different shapes including trapezoidal, cylindrical, parabolic, and elliptical, depending upon the optimum process parameters desired. A sputtering system is developed using this methodology, having a main magnet stack, a rotating magnet, a target having selected target shapes optimized for controlling erosion, downstream magnets, a substrate, and an electric field induced plasma stream.

1. Field of the Invention
The present invention relates to thin film deposition, and is particularly related to physical vapor deposition (PVD) of solid materials in connection with the fabrication of semiconductor integrated circuits. More particularly, this invention is related to a method for controlling the target erosion and process characteristics in a physical vapor deposition sputtering source. This invention relates to any sputtering source utilizing sputtering targets. However, specific teachings and examples will be given which relate to magnetron sputtering, and especially to hollow cathode magnetron (HCM) sputtering sources.
2. Description of Related Art
In a sputtering device, a target is subjected to bombardment by high energy ions to dislodge and eject material from the target onto a workpiece, such as a semiconductor wafer. A concise description of the related art of sputtering devices can be found in U.S. Pat. No. 4,198,283, issued to Class, et al., on Apr. 15, 1980, entitled, xe2x80x9cMagnetron Sputtering Target and Cathode Assembly.xe2x80x9d Typically, sputtering equipment includes a vacuum chamber, a target containing the material to be sputtered, a process gas source that provides a process gas to the vacuum chamber, and equipment to generate an electric field. The target forms part of a cathode assembly in the evacuated chamber containing the process gas, which is typically an inert gas, such as argon. The electric field is applied between the cathode assembly and an anode in the chamber, and the gas is ionized by collision with electrons ejected from the surface of the cathode, i.e., the electric field generates a plasma between the target and the susceptor, and accelerates the ionized gas atoms towards the target. The positive gas ions are attracted to the cathode surface, where they impact the target and dislodge particles from the target material. Once free from the target, these dislodged particles deposit themselves upon the substrate as a thin film.
One method of enhancing conventional sputtering processes is to arrange magnets behind or near the target to influence the path taken by electrons within the sputtering chamber, thereby increasing the frequency of collisions with sputtering gas atoms or molecules. In this type of magnetron sputtering device, the magnetic field is arranged orthogonal to the generated electric field. By increasing the plasma density proximate the target, the number of impacts on the target increases which directly correlates to an increased rate in film deposition on the substrate.
Sputtering apparatus are particularly sensitive to target shape for a number of reasons. The electric field distribution in the vicinity of the plasma discharge is influenced by the target shape because the target shape imposes a boundary condition upon the electric field in accordance with well-known laws of electrostatic theory. Moreover, the shape changes during the useful life of the target as target material is eroded away. Consequently, optimizing the target shape will enhance uniform deposition on the substrate throughout the useful life of the target.
The magnets are typically nickel, iron, or other ferromagnetic material, often assembled from separate segments to form an annular or rectangular body where the segments are separated by small gaps.
It is generally understood that atoms ejected from the surface of a sputter target leave at a variety of angles and that, at the vacuum levels employed in sputtering systems, the mean-free-path of the ejected metal atoms is small in comparison to the dimensions of the vacuum chamber, so that randomizing can occur. This randomization is due to collisions and gas scattering of sputtered species. In order to preserve the flux, the target-to-wafer distance is kept at a minimum to limit randomization.
In conventional magnetron sputtering, low pressures are implemented such that ejected atoms are not randomized. In ionized pvd, randomization or thermalization is needed to ionize the metal species that are sputtered off the target. By operating at high density plasma, a high ionization is achieved which ultimately may yield an isotropic distribution.
It has been a goal of manufacturers of sputtering systems to provide means for imparting greater directionality to the ejected target atoms which reach the semiconductor wafer.
Other prior art methods to improve directionality have included the following: a) increasing the distance between the sputter source and the substrate, wherein only those atoms that start out traveling at an angle close to an angle normal to the substrate will reach the substrate; b) installing a collimating filter between the source and the substrate, where the filter is essentially a network of elongated cell-like structures, each cell having an axis to the substrate surface such that atoms traveling at an acute angle are intercepted by the cell walls; c) plating using an ion beam; and d) applying an rf bias to the wafer substrate causing a negative charge to build up in a known manner, which in turn, causes gas and metal ions in the chamber to arrive to the substrate at angles close to the wafer normal.
Limitations, however, exist with the above-described methods. Increasing the distance between the sputter source and the substrate generates material loses and lower deposition rate, and is considered very inefficient. Similarly, when a collimating filter is installed, much of the target material is wasted, i.e., it does not get deposited on the substrate, and instead is accumulated on the filter cell walls. Ion plating causes space charge effects that prevent the use of a beam with sufficient flux to provide an acceptable deposition rate. Lastly, applying an rf bias on the wafer may cause undue electrical stress to the wafer elements.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a method for making a physical vapor deposition source for depositing metalization layers onto a substrate with an improved degree of directionality.
It is another object of the present invention to provide a method for making a directional source for depositing metal layers which have an acceptably high deposition rate.
A further object of the present invention is to provide for uniform erosion/removal of material from a physical vapor deposition sputtering target.
Another object of the present invention is to prevent redeposition of target material back onto the target.
Yet another object of the present invention is to provide a method for shaping a non-planar target as means of controlling target erosion.
Still another object of the present invention is to provide a method for shaping of a non-planar target as means of improving target life and utilization.
A further object of the present invention is to provide a method for shaping of a non-planar target as a means of controlling particulate generation for ultra-clean magnetron sputtering applications.
Yet another object of the present invention is to provide a method for shaping of a non-planar target as a means of controlling process characteristics such as Rs uniformity, step coverage, and the like.
Still other advantages of the invention will in part be obvious and will in part be apparent from the specification.
The above and other advantages, which will be apparent to one of skill in the art, are achieved in the present invention which is directed to, in a first aspect, a method of modeling non-planar sputtering target shapes including the steps of: a) selecting a first non-planar sputtering target geometry; b) dividing the non-planar sputtering target into a finite number of target segments, each segment defining a surface area of the target; c) calculating for each of the target segments a contribution of sputtered material from each of the other of the target segments; and, d) calculating the net erosion for each of the target segments.
This method may further include the steps of: e) selecting a second non-planar sputtering target geometry; f) performing the steps (b) through (d) on the second non-planar sputtering target geometry; and, g) comparing the net erosion calculations for the first and second non-planar target geometries.
Additionally this method may include: h) calculating process parameters for each of the target geometries; and, i) comparing the process parameter calculations for the first and second non-planar target geometries.
Furthermore, one may select a non-planar target geometry wherein the geometry is parabolic, cylindrical, elliptical, trapezoidal, hemispherical, or cone shaped. Other target shapes may include: cylindrical-elliptical, cylindrical-parabolic, cylindrical-trapezoidal, or cylindrical-domed.
A second non-planar target geometry may be selected, wherein the geometry is different from the first non-planar target geometry and is parabolic, cylindrical, elliptical, trapezoidal, hemispherical, or cone shaped. Each non-planar target may have a corrugated top surface.
In a second aspect, the invention relates to a method for optimizing a non-planar sputtering target shape comprising the steps of: a) selecting an initial non-planar sputtering target geometry; b) dividing the non-planar sputtering target into a finite number of target segments; c) calculating for each of the target segments a contribution of sputtered material from each of the other of the target segments; d) calculating the net erosion for each of the target segments; e) calculating the redeposition of sputtered material from each of the target segments; f) calculating the net deposition from each of the target segments on a wafer; g) minimally altering the target geometry and performing steps (b) through (f); and, h) repeating the step (g) until the wafer has a calculated uniform thin-film deposition of target material and optimized minimum amounts of the redeposition and the target erosion.
This method may further including the steps of: i) calculating process parameters for the selected target geometry; and, j) comparing the process parameter calculations during the step (g) such that the process parameters are optimized.
In a third aspect, the invention relates to an apparatus for sputtering particles from a magnetron type target onto a substrate, the apparatus comprising: a) a vacuum chamber for enclosing the target and the substrate; b) a process gas source; c) the magnetron type target having a geometry optimized by the method delineated above such that the target geometry is calculated to control erosion and redeposition of target material; d) a voltage source for producing an incident electric field to accelerate ionized gas atoms towards the target; and, e) a magnetic field source comprising: i) a rotating magnet; ii) downstream electromagnets; and, iii) a main magnet stack.
This apparatus may further comprise a target having a geometry comprising parabolic, cylindrical, elliptical, trapezoidal, hemispherical, or cone shaped targets. In this apparatus, the main magnet stack and the rotating magnets are comprised of electromagnets or permanent magnets.
In a fourth aspect, the present invention relates to an apparatus for sputtering particles from a magnetron type target onto a substrate, the apparatus comprising: a) a vacuum chamber for enclosing the target and the substrate; b) a process gas source; c) a trapezoidal sputtering target; d) a voltage source for producing an incident electric field to accelerate ionized gas atoms towards the target; and, e) a magnetic field source comprising: i) a rotating magnet; ii) downstream electromagnets; and, iii) a main magnet stack; and, f) an electric field induced plasma stream.
In a fifth aspect, the present invention relates to an apparatus for sputtering particles from a magnetron type target onto a substrate, the apparatus comprising: a) a vacuum chamber for enclosing the target and the substrate; b) a process gas source; c) the magnetron type target having a geometry optimized by the method delineated above such that the target geometry is calculated to control erosion and redeposition of target material; d) a voltage source for producing an incident electric field on the target; and, e) a magnetic field source comprising: i) a rotating magnet; ii) downstream electromagnets; and, iii) a main magnet stack.
In a sixth aspect, the present invention relates to a program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform the method steps for modeling non-planar sputtering target shapes, the method steps comprising: a) selecting a first non-planar sputtering target geometry; b) dividing the non-planar sputtering target into a finite number of target segments, each segment defining a surface area of the target; c) calculating for each of the target segments a contribution of sputtered material from each of the other of the target segments; and, d) calculating the net erosion for each of the target segments.
In a seventh aspect, the present invention relates to an apparatus for sputtering particles from a magnetron type target onto a substrate, the apparatus comprising: a) a vacuum chamber for enclosing the target and the substrate; b) a process gas source; c) the magnetron type target having a geometry comprising parabolic, cylindrical, elliptical, trapezoidal, hemispherical, or cone shaped targets; d) a voltage source for producing an incident electric field on the target; and, e) a magnetic field source comprising: i) a rotating magnet; ii) downstream electromagnets; and, iii) a main magnet stack.
In a eighth aspect, the present invention relates to a magnetron type target for physical vapor deposition having a parabolic, cylindrical, elliptical, trapezoidal, hemispherical, or cone shaped geometry.
In a ninth aspect, the present invention relates to a magnetron type target for physical vapor deposition having varying thickness and a parabolic, cylindrical, elliptical, trapezoidal, hemispherical, or cone shaped geometry.

Control of erosion profile and process characteristics in magnetron sputtering by geometrical shaping of the sputtering target


Known antenna array manifold information is exploited to provide for fast and accurate channel estimation and demodulation on both the forward and reverse links, thereby increasing capacity in PCS and cellular CDMA networks that use adaptive antenna arrays. On the reverse link, an xe2x80x9cextendedxe2x80x9d array manifold is used to assist the demodulator in maintaining a dynamic estimate of the spatial signature to use for beamforming and coherent demodulation. On the forward link, channel estimation is performed in the handset to provide a robust solution for beamforming.

1. Field of the Invention
The present invention relates to wireless communication systems, and in particular, to using adaptive antenna arrays in PCS and cellular CDMA networks for capacity enhancement.
2. Description of Related Art
A standard technique used by commercial wireless phone systems for increasing capacity is to divide the service region into spatial cells. Instead of using just one base station to serve all users in the region, a collection of base stations is used to independently service separate spatial cells. In such a cellular system, multiple users can reuse the same frequency channel without interfering with each other, provided the users access the system from different spatial cells. The cellular concept, therefore, is a simple type of spatial division multiple access (SDMA). Note that throughout this description, various acronyms will be used, which are listed and defined in the Table below.
In the case of digital communication, additional techniques can be used to increase capacity. One well-known method is to use spatial signal processing in code division multiple access (CDMA) systems. CDMA is normally a spread-spectrum technique that does not limit individual signals to narrow frequency channels but spreads the signals throughout the frequency spectrum of the entire band. Signals sharing the band are distinguished by assigning different orthogonal digital code sequences or spreading signals to each signal. Practical techniques for capacity enhancement in CDMA systems using an antenna array are described in commonly-owned U.S. patent application Ser.No. 08/929,638 entitled xe2x80x9cPRACTICAL SPACE-TIME RADIO METHOD FOR CDMA COMMUNICATION CAPACITY ENHANCEMENTxe2x80x9d and U.S. Prov. patent application Ser. No. 60/071,473, entitled xe2x80x9cFADING MITIGATION USING WIDE APERTURE ANTENNA ARRAY IN SPREAD SPECTRUM COMMUNICATION SYSTEMSxe2x80x9d and 60/077,979, entitled xe2x80x9cCAPACITY ENHANCEMENT FOR W-CDMA SYSTEMSxe2x80x9d, all of which are incorporated by reference in their entirety.
Spatial signal processing can be used in both the forward link (base station to mobile station) and reverse link (mobile station to base station) of a CDMA communication system to provide significant signal-to-noise ratio and capacity improvements. In the reverse link, spatial signal processing includes estimating a spatial signature (defined herein as the vector of antenna output signals, including multipath components, at a given time due to a transmitted signal at a certain location, such as described in xe2x80x9cExperimental Studies of Spatial Signature Variation at 900 MHz for Smart Antenna Systemsxe2x80x9d by S. S. Jeng, G. Xu, H. P. Lin, and W. J. Vogel, IEEE Trans. on Antennas and Propagation, vol. 46, no. 7, July 1998, pp. 953-962, which is incorporated by reference in its entirety) of an IS-95 based CDMA signal to determine multipath angle of arrival (AOA) values and coefficients. An IS-95 system is described in TIA/EIA/IS-95-A, xe2x80x9cMobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular Systemsxe2x80x9d, May 1995, which is incorporated by reference in its entirety. The reverse link coefficients are then used to combine a plurality of antenna output signals (after down-conversion to base band), i.e. beamforming. Thus, the ability to accurately estimate the spatial signature is an important objective in CDMA systems. However, with a frequency division duplexing (FDD) system, the forward link and the reverse link occupy different carrier frequencies or bands, but overlap in time. This difference between the forward and reverse link frequencies reduces the correlation between fading of the two links so that the two links have significantly different spatial signatures. Therefore, forward link beamforming using the reverse link spatial signature estimate is not possible. However, average AOA is generally preserved in FDD systems between the forward and reverse links for mobile stations far away from the base station.
Factors which limit the ability to provide for accurate spatial signature estimation include the fading rate (Doppler spread), angle spread, and delay spread profiles of the incoming signals. In particular, fast fading, which is created by the combination of multipath components of a signal being reflected from various elements (xe2x80x9cscatterersxe2x80x9d) in the neighborhood (xe2x80x9cscattering zonexe2x80x9d) of a moving transmitter with random phases, is a major concern in accurate spatial signature estimation. The wireless communication channel is assumed to have multiple scattering zones characterizing the signal propagation between the base station (BS) and the mobile station (MS). xe2x80x9cMobile Cellular Telecommunicationsxe2x80x9d by W. C. Lee, McGraw-Hill, New York, 1995, which is incorporated by reference in its entirety, describes scattering zones around the mobile station. The main scattering zone is in the neighborhood of the MS. Large objects, such as buildings and waterways, create other scattering zones. Metal objects in the vicinity of the BS can cause the signal to be reflected and can influence the transmission path. However, in most cases, the BS antenna array is located above the nearby scatterers, which are assumed to be less significant. As the fading rate or Doppler spread increases, the time available to collect coherent data (integration time) decreases. This problem becomes more severe as cellular systems move from the 800 MHz range to the 1900 MHz range or higher, which can increase the fading or Doppler spread by a factor of two or more. For example, a vehicle moving at 60 mph can induce a Doppler spread in excess of 180 Hz in a 1900 MHz system. In general, spatial signature estimation must take place in a duration that is an order of magnitude shorter than the period of the fading rate. For example, if the fading rate is 100 Hz, then spatial signature estimation must take place within 1 msec.
Various methods for spatial signature estimation or beamformer generation have been proposed. These methods can be characterized by the level of knowledge of the structure of the signal impinging on the antenna array and whether or not a training sequence is present. Characteristics of the temporal, spatial, spectral, or modulation structure of the impinging signal may be known and can be exploited in the spatial signature estimation, such as described in xe2x80x9cAlgebraic Methods for Deterministic Blind Beamformingxe2x80x9d by A. J. Van der Veen, Proceedings of IEEE, vol. 86, no. 10, October, 1998, pp. 1987-2008, which is incorporated by reference in its entirety. Many adaptive algorithms based on minimum mean-squared error (MMSE) or constant modulus (CM) and exploiting temporal or modulation signal structure to perform estimation of the spatial signature are well known, such as described in xe2x80x9cAlgebraic Methods for Deterministic Blind Beamformingxe2x80x9d by A. J. Van der Veen, referenced above, and in xe2x80x9cSpace-Time Processing for Wireless Communicationsxe2x80x9d by A. J. Paulraj and C. B. Papadias, IEEE Signal Processing Magazine, vol. 14, no. 6, November 1997, pp. 49-83 and xe2x80x9cAdaptive Filter Theoryxe2x80x9d by S. Haykin, Prentice-Hall, Englewood Cliffs, N.J., 1986, both of which are incorporated by reference in their entirety.
A disadvantage of these adaptive algorithms is that they generally do not exploit knowledge of the array spatial information or array manifold and generally require substantial time to converge.
The array manifold is a collection of array response vectors (where each array response vector is the set of antenna output signals at a given point in time due to a far-field signal with no multipath) created by stepping the angle of a narrow-band point source (in two or three-dimensional space, under far-field and no multipath conditions). The array manifold is a trace in M-dimensional space, where M is the number of antenna elements in the array. Array manifolds are well known and are described in references such as in xe2x80x9cAlgebraic Methods for Deterministic Blind Beamformingxe2x80x9d by A. J. Van der Veen, referenced above.
A signal arriving at the antenna array in a non-multipath situation produces a received vector that is on the array manifold. However, when multipath exists, the received vector is a linear combination of all arriving multipath wave fronts, which is no longer on the array manifold. The Euclidean distance between the array manifold and the received vector is a function of multipath level, multipath angle spread, and interference power and increases with an increase in each of these variables. Interference includes the sum of thermal noise and other incoming transmissions.
Another disadvantage of some MMSE adaptive algorithms based on nullifying specific interferers is that performance is reduced when the number of interference sources is large (typical for CDMA). Furthermore, using a dedicated pilot signal (e.g., for training) on the reverse link requires the pilot signal to be low power in order to minimize capacity loss in the reverse link. However, a lower power pilot in coherent demodulation requires a longer integration time to assure sufficient reference signal quality.
Also, an unknown or varying signal time of arrival (TOA) requires continuous xe2x80x9ctime searchingxe2x80x9d and determination of beamformer coefficients at each time hypothesis. In CDMA type systems, the signal timing must be recovered before any demodulation can take place. Hence, a search process is conducted by a series of hypotheses through which the system is varying the time of the reference correlating sequence and then cross-correlating with the incoming signal (e.g., IS-95). The time required by each hypothesis must be short to allow a quick search (assuming that recovery of signal timing cannot be done before determination of beamformer coefficients since there might not be sufficient signal-to-noise ratio at that point). Thus, any adaptive algorithm to determine the beamformer coefficients must provide fast convergence in order to achieve a reasonable overall search time.
Furthermore, MMSE algorithms operating in xe2x80x9cdecision-directedxe2x80x9d mode, as discussed in xe2x80x9cAdaptive Filter Theoryxe2x80x9d by S. Haykin, referenced above, tend to fail at low signal-to-interference ratio (SIR) conditions at the system input. In the presence of fast fading, instances of low SIR are common, which can cause extreme interference or even a xe2x80x9cdroppedxe2x80x9d call.
Therefore, a system and method are desired that provide channel estimation in both forward and reverse links and in fast fading and low SIR environments.
In accordance with the invention, known antenna array manifold information is exploited to provide for fast and accurate channel estimation and demodulation in both the forward and reverse links, thereby increasing capacity in PCS and cellular CDMA networks that use adaptive antenna arrays. On the reverse link, an xe2x80x9cextendedxe2x80x9d array manifold is used to assist the demodulator in maintaining a dynamic estimate of the spatial signature to use for beamforming and coherent demodulation. On the forward link, channel estimation is performed in the handset to provide a robust solution for beamforming.
A de-spread received signal vector yi (i=1 to N) from M antenna element output terminals corresponding to 1 of N possible received symbols is spatially correlated with the array manifold matrix C to produce a correlation vector p. The array manifold matrix C is an Mxc3x97K matrix, where M is the number of antenna elements, and K is the number of angles used to create the array manifold (e.g., K=256), i.e., each row of matrix C represents one antenna element of the array manifold, and each column of matrix C represents one angle in the array manifold. This matrix generally spans the whole M-dimensional space produced by the M-element antenna array.
The resulting correlation vector p represents a correlation between the de-spread, received vector corresponding to one of the N possible symbols with each of the K angles of the array. The spatial correlation is performed for each of the N possible received symbols to produce a Kxc3x97N matrix P, where the ith column of the p matrix contains values with magnitudes corresponding to the level of correlation between yi and the array manifold for all K angles. Finding the maximum element of the ith column of P is equivalent to selecting the column of the array manifold that is closest in Euclidean distance to the vector yi.
The P matrix is then used to produce a magnitude and angle of arrival (AOA) estimate each symbol time, which are accumulated to generate an AOA histogram. After low-pass filtering (or xe2x80x9csmoothingxe2x80x9d), this histogram will exhibit xe2x80x9cpeaksxe2x80x9d in the direction of the main scatterers and a distribution that follows the angular spread of the transmission source. The multipath scattering area size (or angle spread) can be estimated from the variance of the distribution around a peak. Thus, the histogram can be used to determine the AOA and angular distribution of the most probable signal paths.
Next, if the incoming signal angular distribution is known, a subspace V spanned by the columns of the array manifold matrix C associated with the given angular distribution (mean and variance of the signal AOA) can be defined. These columns (vectors) span a subspace that can be approximated by finding a set of L orthogonal vectors that contains most of the signal energy. Finding this reduced rank subspace {circumflex over (V)} can be done by singular value decomposition (or a similar procedure) of the original subspace and selecting the singular vectors corresponding to the larger singular values.
Since the de-spread, received antenna vector yi contains contributions from all directions, it contains energy in the full space spanned by the columns of the antenna array manifold C. Most interference can be filtered out of the received vector by projecting this vector yi into the confined subspace {circumflex over (V)}. Thus, the sampled received antenna vector (after de-spreading) is projected into this approximated subspace, {circumflex over (V)}, by a simple dot product of the received vector with each of the columns of matrix {circumflex over (V)}. The projection coefficient vectors corresponding to preliminary data symbol decisions are averaged over a predetermined number of symbols. The number of vectors to average is determined by the Doppler spread and is selected to correspond to a time period during which the spatial signature is relatively stable. Generally, this period is an order of magnitude shorter than the period of the Doppler spread. The averaged projection coefficient vector, Zavg, is then multiplied by the approximated subspace vectors from matrix {circumflex over (V)} to form the beamformer coefficient vector w. If more than one distinguishable AOA exists, several beamformers are used to track the multiple scattering zones.
The processed vector w contains less interference and noise than the original vector y because the subspace projection rejects all the components that are orthogonal to the selected subspace. Projecting the received vectors into a subspace of dimension L reduces the noise power by a factor of M/L, where M is the number of antenna elements. If the subspace is selected correctly, then the signal power is only slightly reduced. Thus, signal-to-noise ratio (SNR) for the beamformer coefficient vector is improved by approximately M/L. This reduces the amount of data that needs to be integrated for the purpose of estimating the beamformer coefficients. As a result, performance is improved (e.g., lower symbol error rate for a given SNR) in fast fading environments when compared with direct averaging of de-spread received vectors and compared to conventional two antenna systems with diversity combining.
The extended manifold concept also can be used to provide an initial beamformer coefficient vector for other methods such as MMSE adaptive algorithms. Since the initial coefficient vector is closer to the desired solution and has better SNR, an adaptive algorithm will converge more quickly.
Even partial knowledge of the array manifold can significantly reduce required integration times, provide improved stability, and simplify the computational process. The array manifold allows accurate AOA and multipath angle spread estimation using xe2x80x9csmoothedxe2x80x9d data, as described in U.S. Pat. App. xe2x80x9cPRACTICAL SPACE-TIME RADIO METHOD FOR CDMA COMMUNICATION CAPACITY ENHANCEMENTxe2x80x9d and U.S. Prov. Pat. Apps. xe2x80x9cFADING MITIGATION USING WIDE APERTURE ANTENNA ARRAY IN SPREAD SPECTRUM COMMUNICATION SYSTEMSxe2x80x9d and xe2x80x9cCAPACITY ENHANCEMENT FOR W-CDMA SYSTEMSxe2x80x9d, referenced above. The AOA and angle spread information can provide xe2x80x9cboundsxe2x80x9d for spatial signature estimation, thereby eliminating large beamformer errors even when the SIR becomes low.
Overall, the present invention offers 1) increased implementation efficiency since the system can be implemented cost-effectively within an ASIC not only for base stations, but also for handsets, 2) high speed operation suitable for both stationary and mobile applications, and 3) stable performance, i.e., not susceptible to convergence and stability issues associated with many adaptive spatial filtering algorithms.
The present invention will be more fully understood upon consideration of the detailed description below, taken together with the accompanying drawings.

Manifold assisted channel estimation and demodulation for CDMA systems in fast fading environments


Swimming goggles have a lens frame, lens received in the lens frame, and a strap adjusting means for adjusting a head strap. The lens frame includes a soft first frame enveloping a hard second frame. The second frame forms enhanced structure on a center of an upper portion thereof. The strap adjusting means includes buckles respectively assembled on both sides of the lens frame, and a head strap is wrapped through the buckles. The buckles have bases integrally formed with the second frame. When the swimming goggles are in use, a center of the upper portion of the second frame will not be bent or distorted, while both sides thereof are gradually distorted to fit to swimmer's foreheads, effectively guarding from water seepage.

1. Field of the Invention
The present invention relates to swimming goggles, and particularly to swimming goggles which has a mask-like protective pad and a soft first frame enveloping a hard second frame and which is formed enhanced structure on a center of an upper portion thereof and a strap adjusting means at both sides that be able to prevents the seepage of water when the swimming goggles are in use and enhance strength in assembly.
2. Related Art
Some swimming goggles with mask-like protective pads are shown in TW utility patent application Nos. 89213591, 89205145, 89215423, 89214699 and U.S. Pat. No. 6,276,794. Such swimming goggles have protective pads fitting with swimmer's foreheads and below eyeholes, that is, the swimmer's eyes are covered by the protective pads, thus the swimmer will not have a feeling of pressure on their eyes and prevent water seepage in use.
However, no matter the protective pad is assembled or integrated with lens frames, the protective pad disclosed in prior art are kept within a fixed range of span width. The width of swimmer's faces may be various sizes. For instance, when swimmer of narrow faces wear swimming goggles, the protective pad is bent inappropriately which results in the swimming goggles unable to fit closely to the swimmer's forehead or the vicinity of eyeholes. In other words, the swimming goggles cannot match different sizes of swimmer's faces and are unable to prevent water seepage in use.
Moreover, the swimming goggles with mask-like protective pads generally have strap adjusting means assembled on the lens frames which are made of soft material for adjusting length of head straps. The strap adjusting means includes a base and a cover which are made of hard material. A head straps of the strap adjusting means are wrapped along support shafts of the strap adjusting means on the bases and the covers, as disclosed in TW utility patent application Nos. 91220914, 92216640, 93202601, 93208473. Though, the hard bases and hard covers are assembled on the soft lens frames, which are weak as for integral structure.


A system and method are provided for spectral shaping of light from a broadband source using a linear spatial light modulator (SLM). The system includes an illumination source generating light including a plurality of wavelengths, a lens to collimate the light and an aperture to define its angular spread, a diffraction grating to disperse the beam by wavelength, and a focusing element to focus the dispersed beams from the diffraction grating onto a plurality of pixels of the SLM. The SLM is configured to individually modulate the dispersed beams by diffracting light output therefrom into higher orders, where a diffraction angle of output light is greater than an input cone angle of incoming light from the illumination source.

Microelectromechanical systems (MEMS) based spatial light modulators (SLMs) have been used to shape the spectrum of light sources in a number of applications including telecommunications systems to equalize the spectrum of an erbium-doped fiber amplifier, simulating the solar spectrum for testing photovoltaics and sensors, and in medical apparatus, such as Optical Coherence Tomography (OCT) systems to provide a spectrum appropriate for eye diagnostics. Typically, these applications require expensive coherent light sources, such as a laser, to work efficiently with the SLM due to a small active area of conventional MEMS based SLMs.
Accordingly, there is a need for spectral shaping systems and methods using a MEMS-based SLM and a low cost general purpose broadband light source.

MEMS based spectral shaper using a broadband source


A method of performing information storage comprises the steps of providing a medium comprising a plurality of concentric rings for storage of information. The medium is written to by a process comprising simultaneously writing and erasing elements in at least two adjacent rings, respectively a first ring and a second ring. Subsequent to simultaneously writing and erasing elements in at least the first and second rings, simultaneously writing and erasing elements in a third concentric ring, wherein the third ring is adjacent the second ring.

Designers, manufacturers, and users of electronic computers and computing systems require reliable and efficient equipment for storage and retrieval of information in digital form. Conventional storage systems, such as magnetic disk drives, are typically utilized for this purpose and are well known in the art. However, the amount of information that is digitally stored continually increases, and designers and manufacturers of magnetic recording media work to increase the storage capacity of magnetic disks.
Referring to prior art FIG. 1, shown therein is a plan view of a portion of a high areal recording density bit patterned data/information storage and retrieval system 10 designed for random access operation, comprising a bit patterned medium 12, a write pole 14 of a write head (illustratively trapezoidal wedge-shaped), and a reader sensor 16. The respective opposing directions of relative movement of the medium and write pole are indicated by the arrows in the figure. The bit patterned medium 12 comprises a plurality of spaced apart magnetic elements 18 or bits of given type, e.g., longitudinal, perpendicular, multi-layer, etc., illustratively circularly-shaped "dots" arranged in a regular array on a non-magnetic substrate, i.e., in concentric rings 36 n, n+1. n+2. n+3. . . . comprised of substantially equally spaced apart dots extending in a down-ring direction, and radially extending rows 44a, b, c. . . . comprised of substantially equally spaced apart dots extending in a cross-ring direction.
Still referring to FIG. 1, it is seen that the narrower end 20 of the trapezoidal, wedge-shaped write pole 14 forms a leading edge of the write pole 14 when the latter is moved relative to medium 12, and the wider end 22 of the trapezoidal, wedge-shaped write pole 14 forms a trailing edge of the write pole 14. If the write pole of the write head is configured in conformity with the above-described requirement for the width of the write pole to be scaled down in relation to the track and bit density of the media, and therefore the maximum width of the write pole is the same as, or smaller than, the dot pitch, i.e., the spacing between dots in adjacent rings or tracks. As may be apparent, according to this scheme the concentric rings 36 n, n+1. n+2. n+3 . . . may be accessed and written to in any desired order or pattern, i.e., randomly. For example, if 4 bits were written to 6 rings in random fashion, a writing sequence could be represented as: 1111 3333 2222 4444 6666 5555. FIG. 1 illustrates writing in a random fashion, as shown by pass 1 24, pass 2 26, and pass 3 28.
In conventional magnetic disk data/information storage, the data/information is stored in a continuous magnetic thin film overlying a substantially rigid, non-magnetic disk. Each bit of data/information is stored by magnetizing a small area of the thin magnetic film using a magnetic transducer (write head) that provides a sufficiently strong magnetic field to effect a selected alignment of the small area (magnetic grain) of the film. The magnetic moment, area, and location of the small area comprise a bit of binary information which must be precisely defined in order to allow a magnetic read head to retrieve the stored data/information.
Such conventional magnetic disk storage media incur drawbacks and disadvantages which adversely affect realization of high areal density data/information storage, as follows:
(1) the boundaries between adjacent pairs of bits tend to be ragged in continuous magnetic films, resulting in noise generation during reading; and
(2) the requirement for increased areal recording density has necessitated a corresponding decrease in recording bit size or area. Consequently, grain sizes of continuous film media have become extremely minute, e.g., on the order of nanometers (nm). In order to obtain a sufficient output signal to noise ratio from such minute bits, the saturation magnetization (Ms) should be sufficiently large and media grain size as small as possible. However, if the grain size is extremely small the loss of the magnetization of such minute bits results in a loss of stored information due to magnetization thermal fluctuation reversal, also known as the "superparamagnetic effect".
The superparamagnetic effect is a major limiting factor in increasing the areal density of continuous film magnetic recording media. Superparamagnetism results from thermal excitations which perturb the magnetization of grains in a ferromagnetic material, resulting in unstable magnetization. So-called "patterned" or "bit patterned" magnetic media ("BPM") have been proposed as a means for overcoming the magnetization reversal via the superparamagnetic effect, e.g., as disclosed in U.S. Pat. No. 5,956,216. The term "patterned" media generally refers to magnetic data/information storage and retrieval media wherein a plurality of discrete, independent regions of magnetic material form discrete, independent magnetic elements which function as recording bits are formed on a non-magnetic substrate. Since the regions of ferromagnetic material comprising the magnetic bits or elements are independent of each other, mutual interference between neighboring bits can be minimized. As a consequence, patterned magnetic media are advantageous vis-à-vis continuous magnetic media in terms of thermal stability and jitter noise from neighboring magnetic bits.
Generally, each magnetic bit or element has the same size and shape, e.g., circularly shaped "dots", and is composed of the same magnetic material as the other bits or elements. The bits or elements are arranged in a regular pattern over the substrate surface, with each bit or element having a small size and desired magnetic anisotropy, so that, in the absence of an externally applied magnetic field, the magnetic moments of each discrete magnetic bit or element will be aligned along the same magnetic easy axis. Stated differently, the magnetic moment of each discrete magnetic bit or element has only two states; the same in magnitude but aligned in opposite directions. Each discrete magnetic bit or element forms a single magnetic domain and the size, area, and location of each domain is determined during the fabrication process.
During writing operation of bit patterned media, the direction of the magnetic moment of the single magnetic domain element or bit is flipped along the easy axis, and during reading operation, the direction of the magnetic moment of the single magnetic domain element or bit is sensed. While the direction of the magnetic easy axis of each of the magnetic domains, elements, or bits can be parallel or perpendicular to the surface of the domain, element, or bit, corresponding to conventional continuous longitudinal and perpendicular media, respectively, patterned media comprised of domains, elements, or bits with perpendicularly oriented magnetic easy axis are advantageous in achieving higher areal recording densities for the reasons given above.
Notwithstanding the substantial increase in recording/data storage performance capability afforded by bit patterned media (BPM) vis-a-vis conventional continuous film-based media, the escalating requirement for even higher areal recording densities engenders a significant problem in writing data/information to ultra-high areal recording density media arising from limitation of the available write head field at very high track densities, e.g., >˜300 ktpi. From a solid angle viewpoint, it is evident that the available recording (write) field decreases as track density increases. The primary reason for this effect is the requirement for reduction in the pole width of the write head, necessitated by the reduction in track spacing (pitch) and bit size in ultra-high areal recording density media, leading to a corresponding reduction in the total write field applied to the media. In addition to the requirement for reduction in the write pole width as track density increases, the length of the write pole must be reduced in order to mitigate problems arising when the write head is at skew. Disadvantageously, however, the head-to-media spacing ("HMS") and media thickness cannot be scaled down to the same extent as the write pole width in order to remedy or at least mitigate the aforementioned problem.
In view of the foregoing, there exists a clear need for improved systems and methodology for facilitating accurate writing to media with very high to ultra-high areal recording densities.


An offshore structure having a foundation structure, wherein the foundation structure has at least a first and a second profile, the first profile is designed as a pile and the second profile is designed as a pile sleeve, the second profile encloses the first profile over a penetration length, wherein an interspace is formed between the first and the second profile, the interspace has a casting compound filling over the total penetration length, shear elements are provided on the first and/or the second profile, the shear elements extend into the interspace and effect an axial load dissipation into the casting compound filling, the shear elements are provided only over a first partial length of the penetration length, the first partial length is between 65 and 90% of the total penetration length and a second partial length is free of shear elements, wherein the second partial length forms the upper length of the penetration length in the installed position.

The invention relates in particular to a cast connection on an offshore structure. Such a cast connection is referred to in the technical jargon as a so-called "grouted joint". Grouted joints are construction elements which are crucial for the structural integrity of offshore constructions and which usually constitute the single connection between a foundation structure or a foundation and a supporting structure. In the case of so-called monopile foundations, for example, such connections are found between the monopile and a transition piece. Moreover, grouted joints are found, for example, in jacket foundations which comprise piles and pile sleeves as profiles. It is particularly in the founding of offshore wind turbines that casting compound connections of the type stated at the outset play a key role.
These connections customarily comprise two cylindrical steel tubes of different diameter which are connected to one another by a casting mortar. The tube having the smaller diameter is generally referred to as a pile, whereas the larger, enclosing tube is referred to as a pile sleeve or sleeve. The interspace remaining between the pile and the sleeve is filled with a casting mortar or a casting compound, which is also referred to as grout in the technical jargon. Casting compound connections or cast connections of this type serve primarily to dissipate axial loads of the structure into the seabed. The compressive strength of the casting compound after curing thereof is crucial for the load-bearing behaviour of cast connections.
A significant increase in the load-bearing strength of cast connections is achieved in the prior art by the use of shear ribs, which moreover also allow a reduction of the required casting length or penetration length. Shear ribs are ribs, projections, webs or the like which are fastened to the mutually facing sides of the profiles and which project into the interspace between the profiles such that they are enclosed by the casting compound. The use of shear ribs means that axial loads are dissipated into the casting mortar via the contact surfaces. The size of the shear-transferring contact surfaces is thereby increased.
In the prior art, a distinction is made in principle between cast connections with and without shear ribs, with the use of shear ribs having been found to be advantageous. Investigations on the load-bearing capacity of cast connections (see for example the dissertation "Betontechnologische Einflüsse auf das Tragverhalten von Grouted Joints" ["Concrete technology influences on the load-bearing behaviour of grouted joints"] ISBN 978-3-936634-05-1) result in the finding that, for the load-bearing capacity of cast connections, the compressive strength and stiffness of the casting mortar, the geometry of the steel tubes and of the cast interspace, the surface accuracy of the steel tubes, in particular the height and the spacing of the shear ribs, and the casting length of the profiles or steel tubes play a role.
In practice, it has been shown that failure of cast connections occurs in spite of optimizing the casting length, the geometry of the shear ribs and further measures.


A door seal is formed as an elongate strip of resilient material, the strip defining a body section having formations by which it may be secured around a door opening so that it is disposed inboard of a sideglass of the door when the door is closed and the sideglass raised; a lip section extending outwardly from the body section, the lip section being joined to the body section by a root portion and having a tip at the end remote from the root portion, the tip being directed back towards the body section such that when the door is closed with the sideglass raised, the tip will be deflected inwardly towards the root portion and the lip section will engage the sideglass on its outer surface.

The present invention relates to door seals and in particular to door seals for motor vehicles.
Currently door seals for motor vehicles which are intended to provide a seal between the vehicle body and the sideglass of the door, comprise a resilient extrusion which is located around the door opening inboard of the sideglass, so that it is abutted by the sideglass, when the door is closed and the sideglass is in its raised position. With such seals, water may collect on the top edge of the sideglass, so that when the door is opened it may drop down onto the occupant of the vehicle. Also, when fitting the door, because of tolerance variations the edge of the sideglass may not be parallel to the edge of the door opening and there will be a visible gap of varying width which will detract from the appearance of the vehicle.


A display comprises a base, a display module and a sensing device. The base has a sensing region and the display module has a control device. The sensing device is electrically connected with the control device and the display module is rotatably coupled to the base. The control device can determine that an angle of rotation of the display module with respect to the base according to a corresponding relation between the sensing device and the sensing region of the base.

1. Field of the Invention
The invention relates in general to a display, and more particularly to a display whose display module can rotate with respect to the base.
2. Description of the Related Art
In response to the renovation of computer products, the convenience and practicality of use, several displays are equipped with a rotatable display module.
The display has a display module and a base for supporting the display module. Generally speaking, when the display module of a display with a rotatable display module rotates 90 degrees with respect to the base to be vertically disposed on the base from an ordinary state, a state of being horizontally disposed on the base for instance, on screen display (OSD) which can be displayed on the display module also rotates 90 degrees along with the display module, providing the user with a more convenient operation of the display.
A conventional display uses a touch-press type switch to control the OSD to rotate along with the rotation of the display module. The touch-press type switch is disposed on a rotation axis of the display module which rotates with respect to the base. Besides, a conducting wire is used to connect the touch-press type switch with the control circuit board inside the display module.
When the display module rotates 90 degrees, due to the change of position, the display module will touch the touch-press type switch disposed on the rotation axis. Meanwhile, the touch-press type switch will output a signal to the control circuit board. After that, the control circuit board will control the OSD to rotate 90 degrees along with the display screen according to the signal.
It can be seen from the above disclosure that the conventional display uses a mechanic sensing device to sense the rotating state of the display module, so the following factors need to be taken into considerations. Firstly, the position of the touch-press type switch on the rotation axis must be touched by the display module after rotation. Secondly, whether the display module, during the course of rotation, will twist the conducting wire, which is used for electrically connecting touch-press type switch and control circuit board, and whether interference exists between the conducting wire and other elements should be taken into consideration when it comes to wiring structural design.
Therefore, conventional display is disadvantaged because its structure is complicated, manufacturing process is difficult and cost is high.


The present disclosure relates to an air spring apparatus for use with a cabin of a vehicle. The apparatus has an upper assembly, a lower assembly, a shock absorber, a bladder, a flexible bumper element and a control element. The shock absorber has a piston rod protruding therefrom and extending through the other one of the upper and lower assemblies. The bladder is attached to the upper and lower assemblies. The flexible bumper element is secured to the piston rod adjacent one of the upper and lower assemblies, and secured to the other one of the upper and lower assemblies. The control element is secured to the flexible bumper element at a first end, and to a valve at a second end, and controls operation of the valve. The flexible bumper element can flex in response to torsional or tilting forces experienced by the one of the upper and lower assemblies, to thus help to limit these forces from being imparted to the control element.

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Truck cabins are often suspended with air spring shock absorber units. As the load in the cabin can vary, and in order to maintain a constant height of the cabin, a mechanical pneumatic valve adds pressure to, or releases pressure from, the air suspension unit. The valve regulates pressure in the air spring unit and thus maintains the truck cabin at a generally constant level, regardless of the load within the cabin.
Typical air spring shock absorbers have included upper and lower assemblies, with a shock absorber-like component coupled between the two assemblies. Typically, a flexible bladder-like member encloses the shock absorber like element within an enclosed area. The upper assembly is typically coupled to the cabin, and the lower assembly is coupled to a frame portion of the vehicle. The air spring unit thus supports the cabin above the frame portion of the vehicle in a manner that permits the height of the cabin to be adjusted, depending on the load in the cabin. During operation of the vehicle, at least some small degree of tilting or torsional movement of the upper assembly relative to the lower assembly can be experienced.
In general, with traditional air spring shock absorber units, the valve that is used to control the height of the cabin has typically been located remotely from the air spring shock absorber unit. However, more recently, mechanisms have become available to integrate the valve into the internal construction of the air spring shock absorber. A major challenge to overcome with such an internally mounted valve is the mechanism which is needed to physically actuate the internally mounted valve. More specifically, the challenge is with integrating the component which physically actuates the valve into the interior area of the shock absorber unit. This has proved quite difficult for a number of reasons. For one, the actuating member has to be able move generally linearly with the upper assembly as the upper assembly moves towards and away from the lower assembly. This is needed so that the internal valve's opening and closing is directly linked to the cabin height. However, when attaching the actuating member directly to the upper assembly, the actuating member itself now becomes subject to the tilting and torsional movements of the upper assembly, relative to the lower assembly, as the cabin moves about while the vehicle is in motion. The tilting and torsional movements of the cabin, however, are problematic if the actuating member is directly tied to the upper assembly (which is directly supporting the cabin) as these movements can cause repeated bending and twisting of the actuating member. Accordingly, the significant challenge has been how to integrate the actuating member into the interior area of an air spring shock absorber so that it is able to sense the vertical movement of the upper assembly relative to the lower assembly, without being significantly affected by the tilting and torsional movements of the upper assembly relative to the lower assembly.

System and method for attaching a control element of an air spring with internal height regulating valve

Tenneco Automotive Operating Company Inc.


A pneumatic tire having a tread provided with at least one circumferential groove extending substantially parallel with the tire circumferential direction, and inclined grooves arranged at intervals in the circumferential direction of the tire, the inclined grooves being inclined at an angle with respect to the circumferential groove and the axial direction, and blocks formed by the circumferential groove and the inclined grooves and arranged at intervals in the circumferential direction of the tire, the blocks having acute angle corners formed by the circumferential groove and the respective inclined grooves, wherein (a) a sipe is formed near one of the acute angle corners which contacts the ground later in the block during tire rotating, the sipe having an opening at the circumferential groove or at a tread end, and (b) the sipe extends from the opening toward the inside of the block substantially parallel with the inclined groove and terminates in the block. It is thus possible to restrain uneven wear without degrading steering stability in a tire with a pattern of blocks having acute angle corners.

1. Field of the Invention
This invention relates to a pneumatic tire, and is concerned with restraint of uneven wear of a pneumatic tire, in particular restraint of uneven wear of a pneumatic tire of a block pattern provided with blocks having acute angle corners.
2. Description of the Prior Art
Because of problems in relation to steering stability, appearance, drainage and noise, lateral grooves in block-type tread patterns adopted on normal passenger tires are mostly arranged not to be parallel with the axial direction of the tire and the blocks are shaped as parallelograms. Further many ordinary or all-weather tires are provided with sipes (or fine grooves) substantially parallel with the axis of the tire to obtain steering stability on a wet road. However, such sipes made rigidity distribution of the blocks unbalanced, so that the blocks were distorted in the ground contact area and uneven wear was produced.
On the other hand, in the case where the sipes (or fine grooves) are arranged parallel with the lateral grooves, the rigidity of the blocks as a whole was lowered and steering stability was degraded. Therefore, means such as making the lateral grooves or sipes shallow was used. However, the above mentioned shallowing of the grooves or the sipes caused poor drainage and bad appearance at the terminal stage of use of the tire.
An object of the present invention is to overcome the above mentioned disadvantages of the prior art, and provide a pneumatic tire which restrains uneven wear without degrading drainage and appearance at the terminal stage of use of the tire.

Pneumatic tire including block having sipe


A method for recovering postage for metered mail pieces that have not been posted, the method includes: placing information that uniquely identifies the mail piece in a postal indicia ; storing the information that uniquely identifies each metered mail piece at a remote site; requesting a refund for a mail piece that has not been posted; determining if the information in the postal indicia  that appears on the face of the mail piece that uniquely identifies the mail piece is the same as the information that uniquely identifies the mail piece that is stored in the remote site; and refunding the postage if the information in the postal indicia  that uniquely identifies the mail piece is the same as the information that uniquely identifies the mail piece that is stored in the remote site.

Historically, postage meters have been mechanical and electromechanical devices that maintain, through mechanical or "electronic registers", an account of all postage printed and the remaining balance of prepaid postage; and print postage postmarks (indicia) that are accepted by the postal service as evidence of the prepayment of postage.
Small business, mailers and home mailers currently are able to use their desktop computer and printer to apply postage in the form of an Information-Based Indicia (IBI) directly onto envelopes or labels while applying an address. The IBI consists of a two-dimensional bar code containing hundreds of bytes of information about the mail piece and certain human-readable information. The indicium includes a digital signature to preclude the forgery of indicia by unauthorized parties. The postal security device (PSD) is a unique security device that provides a cryptographic digital signature to the indicium and performs the function of postage meter registers.
The IBI technology of the United States Postal Service offers the postal customer a way to pay for postage without stamps. Envelopes are franked using the postal customer's personal computer, a personal computer compatible add-on, and the customer's printer. The PSD provides postal value storage and the link to the USPS and the manufacturer of the personal computer compatible add-on.
As part of the process of applying postage to a mail piece the postage vault or registers of electronic meters, or the PSD of personal computer meters, is debited for the amount of postage that is due. Sometimes, the mailer decides not to mail the mail piece after postage has been applied to the mail piece, i.e., the mail piece has an incorrect destination address, incorrect recipient information, etc. The mailer also may decide not to mail the mail piece, because the mail piece is not mailable, since the mail piece jammed in the printer, the indicium and/or address was not correctly printed, the flap of the envelope fused to the throat of the envelope before a letter was inserted into the envelope, etc. In all of the above examples, the mailer's meter was debited for the postage that was affixed to the mail piece.
If the mailer wants a refund for the amount that has been debited to their meter they have to physically deliver to the USPS and/or the meter manufacturer the mail pieces having indicia that were not used. The foregoing is costly and time consuming for the mailer as well as the USPS and/or meter manufacturer.

Method for the recovery of unusable printed postage


A resource manager can vary content for various display aspect ratios used to display information in a computing environment. This allows providing content that is more suitable and/or especially designed for display on a particular aspect ratio. It will be appreciated that resource manager can facilitate execution of the same computer program code for various aspect ratio as content displayed can be effectively adjusted by the resource manager. In order to support multiple aspect ratios, the resource manager can use an Aspect Ratio Adaptable Data Set (ARADS) that effectively supports displaying graphical content for various aspect ratios. The (ARADS) can include “base data” and “aspect-ratio-specific data” that can complement and/or replace the base data. The base data can be used as an initial basis for displaying graphics on any one of a plurality of different aspect ratios while the aspect-ratio-specific data can be specifically designed for and/or accommodate a particular aspect ratio.

A pixel (an abbreviation of pictures) can be considered as one of the many tiny dots that make up the representation of a picture in a computer's memory. However, each such information element is not really a dot, nor a square, but an abstract sample. With care, pixels in an image can be reproduced at any size without the appearance of visible dots or squares; but in many contexts, they are reproduced as dots or squares and can be visibly distinct when not fine enough. The intensity of each pixel is variable; in color systems, each pixel has typically three or four dimensions of variability such and red, green and blue, or cyan, magenta, yellow and black.
Pixels are generally thought of as the smallest complete sample of an image. The definition is highly context sensitive. For example, we can speak of pixels in a visible mage (e.g., a printed page) or pixels carried by one or more electronic signal(s), or represented by one or more digital value(s), or pixels on a display device, or pixels in a digital camera (photo sensor elements). This list is not exhaustive and depending on context there are several synonyms which are accurate in particular contexts, e.g. pel, sample, bytes, bits, dots, sports, superset, triad, stripe set, window, etc. We can also speak of pixels in the abstract, in particular when using pixels as a measure of resolution, e.g. 2400 pixels per inch or 640 pixels per line. "Dots" is often used to mean pixels, especially by computer sales and marketing people, and gives rise to the abbreviation DPI or dots per inch.
The more pixels used to represent an image, the closer the result can resemble the original. The number of pixels in an image is sometimes called the resolution, though resolution can also be defined more specifically. Pixels can be expressed as a single number, as in a "three-megapixel" digital camera, which has a nominal three million pixels, or as a pair of numbers, as in a "640 by 480 display", which has 640 pixels from side to side and 480 from top to bottom (as in a VGA display), and therefore has a total number of 640×480=307,200 pixels.
In computer programming, an image composed of pixels is known as a bitmapped image or a raster image. The word raster originates from analogue television technology. Bitmapped images are used to encode digital video and to produce some types of computer-generated art. Since the resolution of most computer displays can be adjusted from the computer's operating system, a display's pixel resolution may not be an absolute measurement.
Modern LCD computer displays are designed with a native resolution which can be considered as the perfect match between pixels and triads (CRT displays are use red-green-blue phosphor triads, but they are not coincident with image pixels, and cannot therefore be said to be equivalent to pixels).
Typically, the native resolution will produce the sharpest picture capable from the display. However since the user can adjust the resolution, the monitor must be capable of displaying other resolutions. However, the size of the pixels on LCD displays are effectively fixed. As such, non-native resolutions have to be supported by approximate resampling in the LCD screen, using interpolation algorithms. This often causes the screen to look jagged or blurry. For example, a display with a native resolution of 1280×1024 will look best set at 1280×1024 resolution, and may be unable to display in 1600×1200 at all due to the lack of physical triads.
The aspect ratio of an image ("aspect ratio") can be defined as its displayed width divided by its height (usually expressed as "x:y"). For instance, the aspect ratio of a traditional television screen is 4:3, or 1.33:1. High definition television uses an aspect of 16:9, or about 1.78:1. Aspect ratios of 2.39:1 (2.35:1 prior to SMPTE revision in 1970) or 1.85:1 are frequently used in cinematography, while the aspect ratio of a sync-sound 35 mm film frame is around 1.378:1 (also known as "Academy" ratio). Silent films which used the full frame were shot in 1.33:1.
Today, several different aspect ratios are used to display content (e.g., graphics). The aspect ratios may vary from display device to display device and from manufacturer to manufacturer and change as new devices come to market. Varying aspect ratios provide unique challenges in a highly regulated gaming environment. As such, techniques that can accommodate displaying content for various aspect ratios would be highly useful.

Displaying content for various aspect ratios


A cylinder tube of a second hydraulic cylinder is provided separate from a first piston of a first hydraulic cylinder and integrally fixed to an input shaft. Friction members of a first clutch and friction members of a second clutch are prevented from moving in a first direction by a snap ring attached to a connecting drum. The friction members of the first clutch are friction engaged by the first piston and the friction members of the second clutch are friction engaged by a second piston.

1. Field of the Invention
The invention relates to a connecting and disconnecting apparatus of a clutch or a brake or the like. More particularly, the invention relates to a dual connecting and disconnecting apparatus in which a pair of connecting and disconnecting apparatuses are arranged in series in the axial direction.
2. Description of the Related Art
A vehicular automatic transmission is known which uses a plurality of planetary gearsets, clutches, and brakes. The automatic transmission disclosed in Japanese Patent Laid-Open Publication No. 2001-304355, which is one such example, is provided with a dual connecting and disconnecting apparatus having (i) a first hydraulic cylinder in which a piston is moved in a first direction which is parallel with an axis of the dual connecting and disconnecting apparatus by supplying hydraulic fluid into a pressure chamber, (ii) a second hydraulic cylinder which is integrally provided on a common support member (i.e., an input shaft 2) and which is concentric with the first hydraulic cylinder in a position adjacent in the first direction to the first hydraulic cylinder, and in which a piston is moved in the first direction by supplying hydraulic fluid into a pressure chamber, (iii) a cylindrical connecting drum provided on a side wall portion of a cylinder tube of the first hydraulic cylinder integrally mounted to the support member, the connecting drum being centered around the axis and protruding out in the first direction; (iv) a first friction engaging device (i.e., a clutch) positioned farther to the first direction side than the second hydraulic cylinder, the first friction engaging device having (a) a plurality of friction members provided on the connecting drum, this connecting drum being rotatable around the axis with respect to a first connecting member (i.e., a sun gear), the plurality of friction members being non-rotatable with respect to the connecting drum, and (b) a plurality of friction members provided on the first connecting member, the plurality of friction members being non-rotatable with respect to the first connecting member, the first friction engaging device connecting the support member with the first connecting member via the connecting drum by moving the piston of the first hydraulic cylinder in the first direction and engaging the plurality of friction members of the connecting drum with the plurality of friction members of the first connecting member; and (v) a second friction engaging device (i.e., a clutch) positioned farther to the first direction side than the second hydraulic cylinder and adjacent in the axial direction to the first friction engaging device, the second friction engaging device having (a) a plurality of friction members provided on the connecting drum, this connecting drum being rotatable around the axis with respect to a second connecting member (i.e., a sun gear), the plurality of friction members being non-rotatable with respect to the connecting drum, and (b) a plurality of friction members provided on the second connecting member, the plurality of friction members being non-rotatable with respect to the second connecting member, the second friction engaging device connecting the support member with the second connecting member via the connecting drum by moving the piston of the second hydraulic cylinder in the first direction and engaging the plurality of friction members of the connecting drum with the plurality of friction members of the second connecting member. The piston of the first hydraulic cylinder also serves as a cylinder tube of the second hydraulic cylinder. That piston is engaged with the connecting drum so as to be non-rotatable with respect thereto. The friction members of the second friction engaging device are fitted to the piston so as to be non-rotatable with respect thereto and held in position by a stopper member (i.e., a snap ring) attached to the piston.
In this kind of dual connecting and disconnecting apparatus, however, because the second hydraulic cylinder and the second friction engaging device within the cylinder type of the first cylinder are able to move in the axial diction, the sliding resistance and the like of these parts results in the hydraulic pressure in one of the pressure chambers affecting the hydraulic pressure in the other pressure chamber. As a result, it is difficult to finely control both the engaging torque of the first friction engaging device and the engaging torque of the second friction engaging device at the same time, thereby restricting the use of the two friction engaging devices.
Furthermore, because the friction members of the second friction engaging device are fitted to the piston of the first hydraulic cylinder so as to be non-rotatable with respect thereto, a cylindrical drum and spline teeth or the like must be provided on the piston in addition to the connecting drum provided on the cylinder tube, which results in a complex piston shape and high manufacturing costs. Also, because torque is transmitted via the piston of the first hydraulic cylinder when the second friction engaging device is engaged, the operating resistance of the piston of the first hydraulic cylinder changes depending on whether the second friction engaging device is engaged or disengaged, which makes transitional control of the engaging torque when engaging and disengaging the first friction engaging device difficult, for example.

Dual connecting and disconnecting apparatus


A method and apparatus are provided for aligning and laminating stiffeners to substrates in electrical circuits. Generally, this method includes placing a substrate within an alignment frame or tool; applying an adhesive on the substrate; placing a stiffener on the adhesive to form a chip package; applying sufficient pressure and heat to the package for a sufficient time to cure the adhesive. Another method of the present invention includes placing a substrate within an alignment tool or frame; applying an adhesive on the substrate within the alignment tool; placing a stiffener on the adhesive to form a package; applying sufficient heat and pressure to the package for a sufficient time to tack the stiffener to the substrate; removing the package from the alignment tool or frame; and heating the package for a sufficient time and temperature to cure the adhesive wherein the stiffener enhances rigidity of the package.

Single and multiple silicon chip packages, or semiconductor chip packages, are used to provide electrical connection between semiconductor chips and other electronic components in an electronic circuit, such as die-to-package or chip-to-board interconnects. These single and multiple chip packages serve as a substrate to securely anchor electronic components and as a pathway for electrical signals.
Newer technologies, such as area array attachment techniques, are driving engineers to design chip packages that more closely match the coefficient of thermal expansion (CTE) of silicon, or otherwise ensure, the reliability of such packages through thermal cycling. Embracing, and in some cases over-riding, these trends is a constant drive in the electronics industry to improve performance and simultaneously reduce cost.
Most conventional single and multiple chip packages are typically constructed from thick, mechanically robust dielectric materials, such as ceramics (e.g., alumina, aluminum nitride, beryllium oxide, cordierite, and mullite) and reinforced organic laminates (e.g., epoxies with woven glass, polyimides with woven glass, and cyanate ester with woven glass). In some cases, materials are combined to produce certain improved properties, for example, a package may have a ceramic base with one or several thin films of polyimides or benzocyclobutane (BCB) disposed thereupon.
The most common single or multiple chip electronic packages are made from injection molded plastics with metal lead frames. Sometimes, these packages include laminated interconnect structures made from materials such as FR-4 and BT resins. Recently, advances have been made with these laminated structures to somewhat increase density and performance, as in the case of laminated ball grid array packages. Such packages employing FR-4 and BT resins have a number of advantages, such as lower cost, wide availability, lower dielectric constant, lower resistivity conduction paths, and lighter weight. Unfortunately, these packages suffer from a multiplicity of shortcomings which detract from their usefulness. These shortcomings include low wiring densities, low via densities, high via capacitance, poor CTE match to silicon, non-flatness, large package size, poor thermal stability, poor thermal conduction, and thick packages. Some of these deficiencies have been addressed with the use of thin film polyimides and/or BCBs on ceramics. These materials have high via and wiring densities, small size, and lower dielectric constant. Despite these advantages, these materials still suffer from many shortcomings including high cost, highly resistive conduction paths, lower characteristic impedance, and processing problems leading to limited manufacturing sources and long lead times.
In an attempt to address the industry need for superior price-performance in single and multiple chip packages, packaging technologies have been developed which are based on thin dielectrics that are not reinforced with glass fibers or other mechanical aids. Examples of these thin dielectrics include thin polyimides and polytetrafluoroethylene (PTFE) based dielectrics, such as ceramic filled PTFE or cyanate ester impregnated porous PTFE. Compared with the conventional materials described hereinabove, these packaging technologies yield superior via and wiring density, extremely low dielectric constants, lower via capacitance, lower resistance, smaller package size, thinner packages, CTE matching over a wide range, lower package weight, greater thermal stability, and higher reliability than competing technologies. In some cases, thin dielectrics are used that contain reinforcing materials such as woven glass. Notwithstanding such advantages, these technologies are impaired by very thin, fragile packages. For example, while typical ceramic packaging has a modulus of elasticity values of 40-50.times.10.sup.6 psi, a typical modulus for a ceramic filled PTFE based package is only about 100,000 psi. Due to these constraints, packaging made from this material is very difficult to handle and assemble. Mechanical stiffeners are commonly added to thin packages made with these materials to give them the needed mechanical robustness.
However, a shortcoming in previous methods to attach the stiffener to the substrate may have resulted when the substrate and stiffener were not properly aligned. This may have created problems during the downstream chip assembly process such as improper edge registry. Another shortcoming in previous methods may have resulted when the stiffener was not properly adhered to the substrate. This may have also created problems during the downstream chip assembly process, which typically utilizes high temperatures, such as partial delamination of the stiffener from the substrate. The result may have been an adverse effect in thermal and electrical conductance. Also, long term reliability of the chip may have been effected due to temperature cycling.
The foregoing illustrates limitations that may exist in present electronic chip package methods. Thus, it is apparent that it would be advantageous to provide an improved method and apparatus for aligning and laminating stiffeners to substrates directed at overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.

Method for aligning and laminating substrates to stiffeners in electrical circuits


A VCSEL with a vertically integrated photodetector and at least one laterally integrated photodetector, including first and second stacks of DBRs and an undoped region or active region sandwiched therebetween is formed. The vertically and laterally integrated PIN photodetectors are integrated into the device by depositing the region of undoped material in alignment with the first stack of DBRs. The device is fabricated to electrically isolate the vertical cavity surface emitting laser and the vertically integrated photodetector from the at least one laterally integrated photodetector.

Automatic power control (APC) of light emitting devices allows for a constant and a consistent output from these devices. Generally, automatic power control of edge emitting laser devices is easily achieved because edge emitting devices emit light from two ends. Thus, enabling one of the light emitting ends to be used to measure the power output, which is subsequently use to adjust the power input to the edge emitting device, thereby adjusting the power output.
However, automatic power control of a vertical cavity surface emitting laser (VCSEL) having a wavelength of less than 875 nm is a difficult task because the gallium arsenide (GaAs) VCSEL substrate is absorptive to the band width emission, thus making measurement of the output and subsequent adjustment thereof a difficult task. Conventionally, in order to accomplish this task, several optical devices, such as photodiodes or photodetectors, mirrors, beam splitters, and the like are positioned manually in the optical path of the emission from the VCSEL. With the optical devices being positioned manually, several problems or disadvantages result, such as a high cost of manufacture, a lack of repeatability, and poor quality control.
In addition, in scanning type optical data storage, such as tape based rapid access data storage systems, VCSELs are typically used as the light source. The problem arises in the reading of recorded media on the data storage device, such as a CD or DVD. Typically, a photodetector, or detecting array, separately fabricated from that of the VCSEL is utilized to detect a return signal from the recorded media, which leads to a complex pickup head design. This presents an even greater problem when an array of VCSELs is used for parallel data reading.
During operation, when a focused light beam hits the recorded media, the beam is diffracted back toward the lens and pickup system. The diffracted beam is a SinC function, meaning the light is diffracted back as a center 0 order mode and two side lobes that are .+-.1 order mode. The 0 order mode will trace back the original path of the incident beam with identical geometric dimension. The .+-.1 order modes have a larger divergence angle, and will be collimated by the focal lens back toward the original light source, but with a larger dimension.
Accordingly, it can be readily seen that conventional VCSELs and signal detection from recorded media has several disadvantages and problems, thus not enabling their manufacture in a compact form. Therefore, an integrated article and method for making same that simplifies the fabrication process, reduces cost, and improves reliability would be highly desirable.
It is a purpose of the present invention to provide a new and improved integrated VCSEL and photodetectors for automatic power control (APC) of the VCSEL emission and return signal detection in a data storage read mode.
It is another purpose of the present invention to provide a new and improved integrated VCSEL and photodetectors which are simple and relatively inexpensive to manufacture.
It is still another purpose of the present invention to provide a new and improved integrated VCSEL and photodetectors which are integrated with a minimum of labor and cost.
It is a further purpose of the present invention to provide a new and improved integrated VCSEL and photodetector which can be utilized to control the output of the VCSEL and detection of RF signals in a read mode.

VCSEL with integrated photodetectors for automatic power control and signal detection in data storage


A power generation and transmission system, including: a wind turbine having an electrical generator (12) producing AC electrical power at a production frequency; a converter connected to the electrical generator (12) and configured to convert the AC electrical power to a transmission frequency below a grid frequency; an insulated transmission cable (18) connected to the converter and disposed at least partly submarine or subterranean; and a synchronous frequency converter (24) remote from the wind turbine and configured to receive the AC electrical power from the insulated transmission cable (18) and to convert it to the grid frequency for supply to a grid.

Power generation stations located remote from a load require transmission systems capable of efficiently transmitting the generated power from the power generation station to the load. Such systems include but are not limited to, for example, a remote wind turbine generator located in the sea, and a power grid located on land. Often a transmission cable of the transmission system must be located either submarine or subterranean in order to efficiently span a distance between the two. In addition, often the power generation station produces alternating current ("AC") electrical power, and often the load requires AC power. However, the transmission of AC power over long distances can be problematic.
In addition to resistive losses present in the transmission of both AC and direct current ("DC") electric power, the transmission of AC power generates reactive current resulting from a capacitance of the transmission cable and the cable consumes reactive losses from an inductance of the transmission cable. Increasing voltage and, in turn, decreasing current in AC power transmission can reduce resistive and reactive losses, which are proportional to a square of the current in the cable. However, capacitive charging current, which is a function of the voltage, frequency, cable geometry and insulation medium, may remain high, generally increasing with voltage.
The capacitance, C, per unit length of a transmission cable is determined by the geometry of the transmission cable and the dielectric constant(s) of the insulation surrounding the transmission cable. Charging the cable capacitance requires a capacitive charging current ("icc"). The capacitive charging current per phase may be given roughly by the equation:icc=Vline-neutral*ω*(Lcable*Ccable)where V is the line-neutral voltage, ω is the electrical frequency in radians per second (ω=2πf; 60 Hz=377 rad/s; 50 Hz=314 rad/s), L is the transmission cable length in kilometers, and C is a transmission cable capacitance in farads per km. It can be seen that for a given transmission cable, the conventional practice of increasing the voltage V in order to overcome resistive line losses and inductive losses generally has the effect of increasing the charging current icc, particularly in consideration of the increase in voltage and the fact that higher voltage generally necessitates thicker insulation, further increasing the capacitance.
It can be seen that for a given cable carrying a given electrical power, as the length L of the cable increases so does the charging current icc. Since a given transmission cable has a maximum current carrying capacity, any charging current icc carried by the transmission cable to accommodate the capacitance of the cable directly reduces the amount of current the cable can deliver to the load. As a result of the charging current icc of submarine and subterranean cables, conventional practice limits the transmission of AC electric power at frequencies of 50 Hz-60 Hz to distances of not more than approximately 50 km. At or below this length, the transmission cable is capable of delivering AC electric power with few operational constraints.
When transmission distances exceed 50 km, the AC electric power is conventionally converted into direct current ("DC") electric power. Transmission of DC electric power does not suffer from the reactive losses found in the transmission of AC electric power. However, in order to transmit DC power from a power generation station that produces AC power to a load that operates on AC power, generated AC power must be converted to DC power, and received DC power must be converted back to AC power for the load. Converting generated AC power into DC power requires an expensive AC to DC power transmission terminal to be installed at the power generation station (sending end), and an expensive DC to AC power transmission terminal to be installed at a receiving end, prior to the load. Additionally, there are few vendors of high voltage DC cable and submarine DC power transmission has unique operating and maintenance practices and specialized engineering, which can result in high cost of design, operation and maintenance. Consequently, there remains room in the art for improved power generation and transmission.

Power generation and low frequency alternating current transmission system


A distribution head of an impact mill rotates about a vertical axis and throws raw material against a cylindrically-shaped impact body. The latter has a rotational axis, which forms an angle with the vertical axis to equalize the wear over the height of the impact body.

Impact mills of this type are either employed for crushing tasks or only as impact dehullers to separate brittle shells, such as the shells of soybeans or cocoa beans and of other husk fruits, or, in general terms, to separate the seeds from the kernels. In DE-C 529 396 there is disclosed an impact mill comprising a vertical driving shaft with a throwing rotor as a distribution head attached thereto. Coaxially to the driving shaft, there is arranged a cylindrically-shaped, stationary body closed at its bottom side, comprising screen sections and in-between some beaters. The distribution head includes a disk with blades on its circumference, with the disk being attached to the driving shaft in an inclined arrangement. Raw material is supplied through a drum sieve until the body, or the drum sieve is almost filled. The filling ratio is held constant during operation. Due to the particular type of this construction and the operating mode, the raw material emitted by the lower blade is not capable of exerting any impact effect upon the beaters and the drum sieve as this blade solely digs through the raw material. Thus, an impact effect is only exerted by the upper blade. As a result, the drum wall will be subjected to an irregular wearing effect.
The U.S. Pat. No. 2 352 327 discloses mill, in which both a distribution head rotatable about a vertical rotational axis and a cylindrically-shaped impact ring arranged coaxially thereto are driven, with the distribution head and the impact ring being driven with different speeds. On its bottom side, the impact ring is supported by toothed wheels meshing with said impact ring. By designing this edge region in a wavelike way, an oscillating vertical motion of the impact ring will be accomplished for realizing a uniform wear of the annular lining exchangeably fastened to the impact ring by extending the surface of the impact ring hit by the particles, which in turn will result in a longer service life. The drawbacks of this construction are to be found, on the one hand, in its higher expenses for equipment, and, on the other hand, in the difficult guidance of the impact ring within the housing, since with this construction a tilting of the ring will be highly probable. In addition, the upper and lower dead points of the wave curves will lead to a longer biasing of the impact ring at those points, thus entailing an irregular wear of the annular coating.
It is an object of the present invention to avoid the drawbacks mentioned above and to suggest an impact mill, whose impact body is subjected to a uniform wear by constructionally simple means.