A device for percutaneous venous valve repair generally including a catheter and a retractable and extendable member for deploying an object that affixes a portion of a venous valve leaflet to an adjacent vein wall. A related method for percutaneous venous valve repair is revealed to include percutaneously inserting a device as described herein into a peripheral vasculature of a living subject so as to affix at least a portion of a leaflet of a venous valve to an adjacent vein wall.

This section introduces information that may be related to or provide context for some aspects of the subject matter described herein and/or claimed below. This information is background facilitating a better understanding of that which is disclosed herein. Such background may include a discussion of "related" art. That such art is related in no way implies that it is also "prior" art. The related art may or may not be prior art. The discussion is to be read in this light, and not as admissions of prior art.
Approximately 1% of the total human population and 3% to 5% of the population over the age of 65 will suffer from a venous leg ulcer (VLU). VLUs are often recurrent, can persist for years, and can result in infection, cellulitis, osteomyelitis, and/or amputation. In the United States, the financial burden of VLUs is estimated to be $2 billion annually and is expected to grow as the total population ages.
One of the major causes of ulcer formation is venous reflux/insufficiency. In spite of the development of some procedures able to treat superficial venous dysfunction in the lower limbs, advanced chronic venous insufficiency remains a burden. Many patients have to wear compression stockings, but poor patient compliance to this treatment suggests it is not a total solution with respect to the patient's expectations.
Blood return from the legs of a person occurs mainly through the deep veins. Within such veins are multiple venous valves, which are bicuspid (two) flap-like structures made of elastic tissue. The flap-like structures are often referred to as leaflets. The function of the valves is to keep blood moving in one direction.
A healthy leg has veins with smooth, elastic walls that are designed to adapt to the changes in pressure within a vein, which keeps blood moving in one direction: toward the heart. As the heart provides positive blood pressure to the arteries—the venous valves open to allow (return flow) one-way flow in the direction of the heart. When the positive pressure of the heartbeat subsides, the valves close to stop any back-flow.
However, if the walls of a vein have been damaged (e.g., by trauma, thrombosis, and so forth), then the valves may fail to close properly. When valves fail to close properly, blood can flow backward within the vein. This may result in blood pooling, putting pressure on lower leg veins, which may cause even more valves to fail over time. Thus, when the body is upright under these circumstances, the blood being transported back to the heart may stagnate in the legs. The pressure in the superficial veins directly under the skin may increase and cause the veins to become swollen. Tired, aching legs are the most common early symptoms of this condition—particularly after prolonged standing. Later, fluid may collect in the feet and ankles causing them to swell. The skin above the ankles may become thin and discolored or even breakdown to form a venous stasis ulcer. Venous disorders caused by improper closure of valves may range from varicose veins to deep vein thrombosis and post thrombotic syndrome.
Thus, a need exists for devices and methods to repair venous valves of a living subject.

Device for percutaneous venous valve repair and related method


A display device disclosed herein comprises: a display part including a first thin plate having flexibility and a second thin plate having flexibility, the second thin plate being provided on the first thin plate; a fixing portion which fixes the first thin plate and the second thin plate together on a first direction within each main surface of the first and second thin plates; and a close contact member which is provided in a second direction perpendicular to the first direction within the main surface, and which brings the first thin plate and the second thin plate into close contact.

1. Field of the Invention
The present invention relates to a display device, and more particularly to a display device having flexibility.
2. Related Background Art
Active matrix type display devices in which active elements such as TFTs are arranged at pixels can realize flat type display devices with high image quality. As display parts of the active matrix type display devices, liquid crystal being a light shutter, organic EL which emits light, and electrophoretic devices (enclosed in microcapsules or not), can be used. These active matrix type display devices, having a thin profile and lightweight, are therefore most suitable for display devices of portable information equipment such as a notebook personal computer or PDA which can be carried.
It is conceivable that portable information equipment will be used more widely in the future with radio network improvements, and therefore display devices of the portable information equipment are required to be further reduced in thickness and weight. In response to this requirement, an active matrix type display device using a plastic substrate is proposed. Its examples include a transfer method of taking active elements, which have been formed on a heat-resistant substrate such as a glass substrate in advance, out of the glass substrate and transferring them onto a plastic substrate, a method of forming active elements directly on a plastic substrate by an ultra-low temperature process, and a method of forming organic transistors on a plastic substrate. By these methods, it is possible not only to reduce display devices in thickness and weight but also to make them flexible so that the devices can be bent.
As flexible display devices, there are known examples in which the display devices can be accommodated rolled or folded. For example, see Japanese Patent Laid-open No. Hei 11-272205 (P.2–8, FIG. 1), and Japanese Patent Laid-open No. Hei 10-257143 (P.3–5, FIG. 1).
However, the above-described display devices have a problem that they have complicated structures, and therefore a bendable display device with a simple configuration has been desired.

This patent is subject to a terminal disclaimer.

Display device having flexibility with a contact member allowing the first and second plates to be slid in the second direction


A coupling, for example, for an orthotic brace has a cam member with a first planar bearing face journalled for rotation on a planar bearing surface of a first coupling portion, and a second planar bearing face inclined to the first face and journalled to rotate relative to a planar bearing surface of a second coupling portion. A clamping device urges the faces and surfaces together to exert a frictional reaction retaining the cam member in a selected rotational position and retains the coupling portions rigidly opposed towards the cam member.

The present invention relates to a coupling and more particularly although not exclusively to a coupling for use in an orthotic brace, for example, a hip, is shoulder, wrist or ankle brace.
Known couplings of which the applicants are aware have not been as strong and rigid or as durable as may be considered desirable. For example, known ball and socket couplings that rely on set screws engaging the surface of the ball to locate the portions of the coupling are prone to slippage under bending stress, while the set screws deform and pit the surface of the ball and ultimately render it unserviceable.
In one aspect, the invention provides a coupling comprising first and second portions each comprising a planar bearing surface, a cam member having a first planar bearing face bearing rotationally on the planar bearing surface of the first portion and journalled thereto through a first journal bearing resisting lateral slippage, a second planar bearing face disposed in a plane inclined to the plane of the first bearing face and bearing rotationally toward the planar bearing surfaces of the second portion and journalled thereto through a second journal bearing resisting lateral slippage, and a clamping device urging said bearing surface toward said bearing faces of the cam member and generating a frictional reaction retaining each bearing surface in a selected rotational position with respect to the cam member.
Since the compressive forces are transmitted through opposing planar faces, great compressive stress can be applied and hence high frictional forces generated without permanently deforming the coupling elements. This provides a coupling of greatly improved strength characteristics. Further, the wedge-like cam member together with the slippage resistant journal bearings provide in effect a monolithic body in the clamped condition of the coupling, so as to provide a coupling with excellent rigidity and resistance to bending.

Coupling and orthotic brace incorporating the coupling

Becker Orthopedic Appliance Company, Inc.


A method of magnetic resonance spectroscopic imaging of an object (O) including at least one chemical species to be imaged, comprising sampling of the k-space such that a plurality of Nω first sampling trajectories through at least one k-space segment of the k-space is formed along a phase-encoding direction, each of said first sampling trajectories beginning in a central k-space region and continuing to a k-space border of the at least one k-space segment and having a duration equal to or below a spectral dwell time corresponding to the reciprocal spectral bandwidth, collecting at least one first set of gradient-echo signals obtained along the first sampling trajectories, collecting at least one second set of gradient-echo signals obtained along a plurality of Nω second sampling trajectories, the Nω second sampling trajectories and the Nω first sampling trajectories being mutually mirrored relative to a predetermined k-space line in the central k-space region.

In the present specification, reference is made to the following publications cited for illustrating prior art techniques, in particular conventional MRS imaging, and conventional implementations of certain procedural measures or partial aspects of excitation and encoding sequences.    [1] R. V. Mulkern, L. P. Panych. Echo planar spectroscopic imaging. Concepts Magn. Reson. 13: 213-237 (2001).    [2] T. R. Brown, B. M. Kincaid, K. Ugurbil. NMR chemical shift imaging in three dimensions. Proc. Natl. Acad. Sci. USA 79: 3523-3526 (1982).    [3] A. A. Maudsley, S. K. Hilal, W: H. Perman, H. E. Simon. Spatially resolved high resolution spectroscopy by "four-dimensional" NMR. J. Magn. Reson. 51: 147-152 (1983).    [4] P. Mansfield. Spatial mapping of the chemical shift in NMR. J. Phys. D: Appl. Phys. 16: L235-L238 (1983).    [5] P. Mansfield. Spatial mapping of the chemical shift in NMR. Magn. Reson. Med. 1: 370-386 (1984).    [6] D. N. Guilfoyle, A. Blamire, B. Chapman, R. J. Ordidge, P. Mansfield. PEEP—a rapid chemical-shift imaging method. Magn. Reson. Med. 10: 282-287 (1989).    [7] S. Matsui, K. Sekihara, T. Onodera, H. Shiono. NMR chemical shift imaging method. U.S. Pat. No. 4,689,568 (1985).    [8] S. Matsui, K. Sekihara, H. Kohno. High-speed spatially resolved high-resolution NMR spectroscopy. J. Am. Chem. Soc. 107: 2817-2818 (1985).    [9] S. Matsui, K. Sekihara, H. Kohno. Spatially resolved NMR spectroscopy using phase-modulated spin-echo trains. J. Magn. Reson. 67: 476-490 (1986).    [10] M. Doyle, P. Mansfield. Chemical-shift imaging: A hybrid approach. Magn. Reson. Med. 5: 255-261 (1987).    [11] R. Bowtell, M. G. Cawley, P. Mansfield, A. D. H. Clague. Proton chemical-shift mapping using PREP. J. Magn. Reson. 82: 634-639 (1989).    [12] K. Oshio, W. Kyriakos, R. V. Mulkern. Line scan echo planar spectroscopic imaging. Magn. Reson. Med. 44: 521-524 (2000).    [13] E. Adalsteinsson, P. Irarrazabal, D. M. Spielman, A. Macovski. Three-dimensional spectroscopic imaging with time-varying gradients. Magn. Reson. Med. 33: 461-466 (1995).    [14] P. Webb, D. Spielman, A. Macovski. A fast spectroscopic imaging method using a blipped phase encode gradient. Magn. Reson. Med. 12: 306-315 (1989).    [15] A. Ebel, N. Schuff. Accelerated 3D echo-planar spectroscopic imaging at 4 Tesla using modified blipped phase-encoding. Magn. Reson. Med. 58: 1061-1066 (2007).    [16] P. A. Bottomley. Selective volume method for performing localized NMR spectroscopy. U.S. Pat. No. 4,480,228 (1984).    [17] J. Frahm, K. D. Merboldt, W. Hanicke. Localized proton spectroscopy using stimulated echoes. J. Magn. Reson. 72: 502-508 (1987).    [18] S. Posse, D. Le Bihan. Method and system for multidimensional localization and for rapid magnetic resonance spectroscopic imaging. U.S. Pat. No. 5,709,208 (1998).    [19] S. Posse, C. DeCarli, D. Le Bihan. Three-dimensional echo-planar MR spectroscopic imaging at short echo times in the human brain. Radiology 192: 733-738 (1994).    [20] S. Posse, G. Tedeschi, R. Risinger, R. Ogg, D. Le Bihan. High speed 1H spectroscopic imaging in human brain by echo planar spatial-spectral encoding. Magn. Reson. Med. 33: 34-40 (1995).    [21] S. Matsui, K. Sekihara, H. Kohno. High-speed spatially resolved NMR spectroscopy using phase-modulated spin-echo trains. Expansion of the spectral bandwidth by combined used of delayed spin-echo trains. J. Magn. Reson. 64: 167-171 (1985).    [22] R. Otazo, B. Mueller, K. Ugurbil, L. Wald, S. Posse. Signal-to-noise ratio and spectral linewidth improvements between 1.5 and 7 Tesla in proton echo-planar spectroscopic imaging. Magn. Reson. Med. 56: 1200-1210 (1996).    [23] D. N. Guilfoyle, P. Mansfield. Chemical-shift imaging. Magn. Reson. Med. 2: 479-489 (1985).    [24] US 2009/0091322 A1.    [25] S. Posse, R. Otazo, S. Y. Tsai, A. E. Yoshimoto, F. H. Lin. Single-shot magnetic resonance spectroscopic imaging with partial parallel imaging. Magn. Reson. Med. 61: 541-547 (2009).    [26] K. P. Pruessmann, M. Weiger, M. B. Scheidegger, P. Boesiger. SENSE: Sensitivity encoding for fast MRI. Magn. Reson. Med. 42: 952-962 (1999).    [27] M. A. Griswold, P. M. Jakob, R. M. Heidemann, M. Nittka, V. Jellus, J. Wang, B. Kiefer, A. Haase. Generalized auto-calibrating partially parallel acquisitions (GRAPPA). Magn. Reson. Med. 47: 1202-1210 (2002).    [28] M. A. Brown. Time-domain combination of MR spectroscopy data acquired using phased-array coils. Magn. Reson. Med. 52: 1207-1213 (2004).    [29] S. Hetzer, T. Mildner, H. E. Möller. A modified EPI sequence for high-resolution imaging at ultra-short echo times. Proc. ISMRM 17: 2663 (2009).    [30] PCT/EP 2009/002345 (not published on the priority date of the present specification).    [31] A. Haase, J. Frahm, W. Haenicke, D. Matthei. 1H NMR chemical shift selective (CHESS) imaging. Phys. Med. Biol. 30: 341-344 (1985).    [32] J. P. Felmlee, R. L. Ehman. Spatial presaturation: A method for suppressing flow artifacts and improving depiction of vascular anatomy in MR imaging. Radiology 164: 559-564 (1987).    [33] R. R. Ernst, G. Bodenhausen, A. Wokaun. Principles of Nuclear Magnetic Resonance in One and Two Dimensions. Clarendon Press, Oxford (1987).    [34] F. Schmitt, P. A. Wielopolski. Echo-planar image reconstruction. In: F. Schmitt, M. K. Stehling, R. Turner, eds. Echo-Planar Imaging: Theory, Technique and Application. Springer, Berlin (1998); pp. 141-178.    [35] D. C. Noll, C. H. Meyer, J. M. Pauly, D. G. Nishimura, A. Macovski. A homogeneity correction method for magnetic resonance imaging with time-varying gradients. IEEE Trans. Med. Imaging 10: 629-637 (1991).    [36] L. C. Man, J. M. Pauly, A. Macovski. Multifrequency interpolation for fast off-resonance correction. Magn. Reson. Med. 37: 785-792 (1997).    [37] G. Bodenhausen, R. Freeman, D. L. Turner. Suppression of artifacts in two-dimensional J spectroscopy. J. Magn. Reson. 27: 511-514 (1977).    [38] J. Hennig. The application of phase rotation for localized in vivo proton spectroscopy with short echo times. J. Magn. Reson. 96: 40-59 (1992).    [39] S. W. Provencher. Estimation of metabolite concentrations from localized in vivo proton spectra. Magn. Reson. Med. 30: 672-679 (1993).    [40] M. A. Bernstein, K. F. King, X. J. Zhou. Handbook of MRI Pulse Sequences. Elsevier Academic Press, Amsterdam (2004).
Mapping of the nuclear magnetic resonance (NMR) chemical shift (i.e. spectroscopic information) is of great potential value, for example, for non-invasively studying metabolic heterogeneity of biological tissues in vivo or for investigating the three-dimensional (3D) composition of materials. In such applications, the spectroscopic information introduces a separate dimension besides the three spatial dimensions [1]. Consequently, additional scan time will be required in comparison to standard magnetic resonance imaging (MRI) methods relying on the assumption that only a single resonance from a high-concentration substance, such as the ubiquitous water in biological systems, is present. In conventional chemical shift imaging (CSI) [2, 3], pure phase encoding is used to acquire spectra from different volume elements (voxels) throughout the object. In particular, the spatial encoding step (i.e. application of a magnetic field gradient for spin-warp-type phase encoding) precedes the spectroscopic readout, during which no gradients are applied. This requires that the number of separately encoded measurements equals the number of voxels. For example, assuming a repetition time, TR, of 1 s and a single average, the time needed to encode a two-dimensional (2D), 32×32 spatial matrix for CSI would be 17:04 min!
With echo-planar spectroscopic imaging (EPSI) introduced by Mansfield [4, 5], spatial encoding is employed—at least in one dimension—during acquisition of the spectroscopic dimension, which allows for a much faster acquisition. This is possible, because the acquisition of spectroscopic information in the time domain (i.e. the collection of a free induction decay or an echo signal) is a relatively slow process with a typical sampling interval (spectral dwell time, τω) on the order of 1 ms.
For example, the major brain metabolites in an in vivo proton (1H) spectrum have resonances, which fall between the resonances of fat at 0.9 ppm (terminal methyl groups) and water at 4.7 ppm. This corresponds to a minimal spectral bandwidth, Δν, of 244 Hz (τω=4.1 ms) at a magnetic field strength, B0, of 1.5 T or 468 Hz (τω=2.1 ms) at approximately 3 T. As another example, the chemical-shift range of metabolites routinely observed in in vivo phosphorus (31P) spectra is defined by the signals of phosphomonoesters at 6.6 ppm and of the β-phosphate group of adenosine triphosphate (ATP) at −16.3 ppm, which corresponds to Δν=589 Hz and 1138 Hz (τω=1.7 and 0.9 ms) at 1.5 and approximately 3 T, respectively. Due to sensitivity constraints, a nominal voxel size on the order of 1 cm or more (instead of 1 mm or less as achieved in high-resolution MRI) is sufficient in typical spectroscopic-imaging applications. For integrating spatial encoding during the intervals defined by τω, gradient slew-rate performance is of paramount importance in addition to excellent gradient-amplitude stability and waveform reproducibility.
Further background techniques, which could be relevant for magnetic resonance spectroscopic (MRS) imaging, are discussed in the following. For simplicity, the discussion is initially restricted to the mapping of one spectral and two spatial dimensions. In particular, a slice-selective excitation scheme to select a plane of thickness Δz at position z0 from the object under investigation is considered. As signal acquisition occurs in the time domain, data is collected in k-space (i.e. a reciprocal spatial-spectral space) with axes kx, ky, and kω (note that kω=t, where t is time). A subsequent Fourier transform permits reconstruction of an image with spatial dimensions x and y and chemical shift dimension ω. The same principles as described below may then be used to expand the EPSI variants in order to achieve encoding of three spatial plus one spectral dimension.
With hybrid EPSI techniques, only one-dimensional (1D) spatial information is encoded along with the spectral dimension in a single pass ("shot") of the sequence. In particular, spatial-spectral encoding can be achieved by periodically inverting a trapezoidal read-out gradient of amplitude Gx to traverse k-space along a zig-zag trajectory while collecting a series of Ny gradient echoes [6]. Each gradient lobe encodes the same spatial information (i.e. evolution along the kx-axis) whereas the signal evolution from gradient echo to gradient echo encodes the spectroscopic information (i.e. evolution along the t-axis). Ideally, the interval between adjacent gradient echoes, Δtx/2 (i.e. one half of the modulation period), corresponds to the inverse of the spectral bandwidth in the reconstructed spectra (i.e. Δν=1/τω=2/Δtx).
For the remaining spatial dimension, a standard phase-encoding scheme preceding the echo-planar readout may be used [6-9], which has also been referred to as phase-encoded echo planar (PEEP). Alternatively, the direction of the read-out gradient may be rotated by an angle increment Δφ in the xy-plane in successive shots to obtain a projection-reconstruction echo-planar (PREP) hybrid technique [5, 10, 11]. As yet another alternative, the line-scan imaging approach may be combined with EPSI (also referred to as line scan echo planar spectroscopic imaging, LSEPSI) to avoid saturation problems when selecting a short TR [1, 12]. Besides periodically alternating trapezoidal gradients, other wave-forms including sinusoidal [9] and triangular modulations [13] have also been proposed for EPSI. An approach to halve the number of phase-encoding steps and thereby the overall scan time in PEEP variants involves adding small gradient blips (along the y-direction) in between even and odd read-out gradient lobes. The alternating blipped gradient may be applied during each reversal of the read-out gradient [14] or between pairs of even/odd read-out gradient lobes [15].
Apart from applying a simple excitation pulse of flip angle α or a spin-echo or stimulated-echo pulse sequence to excite spins in a slice (with subsequent 2D-spatial and spectral encoding) or in a 3D object (with subsequent 3D-spatial plus spectral encoding), it may be advantageous—especially in 1H spectroscopic imaging in vivo—to pre-localize a volume of interest (VOI) by combining a standard single-voxel technique, such as point-resolved spectroscopy (PRESS) [16] or stimulated-echo acquisition mode (STEAM) [17], and a spatial suppression sequence to selectively saturate the spin system outside the VOI (outer-volume suppression, OVS). In particular, such pre-localization and OVS schemes have been integrated along with water suppression (WS) in a modular fashion into an EPSI readout in the so-called proton echo-planar spectroscopic-imaging (PEPSI) technique [18].
Due to the periodic inversion of the read-out gradient scheme in all of the above EPSI variants, magnetic field inhomogeneities, imperfections in the gradient pulses, or eddy currents induced by gradient switching lead to periodic mismatches between odd- and even-numbered echoes and produce aliasing artifacts. An approach to eliminate aliasing is obtained by rearranging the echoes acquired with positive and negative gradient polarities to obtain two sets of echoes for separate reconstruction [5, 7, 9]. After correction for the sign inversion, both data sets are added to maintain the signal-to-noise ratio (SNR). A disadvantage of this strategy is a doubling of the dwell time (i.e. τω=Δtx) and, hence, a reduction of the spectral bandwidth by a factor of ½ (i.e. Δν=1/Δtx). This might lead to undersampling of high-frequency components and thus aliasing of resonances outside of the bandwidth into the observed spectral window, especially at high magnetic fields.
A method for retaining the spectral bandwidth is spatial-spectral oversampling, which also reduces chemical-shift artifacts but leads to a greater demand on the gradient performance [19, 20]. Other approaches to expand the spectral bandwidth include shifting of the gradient modulation sequence with respect to the excitation pulse by a variable delay, tD, in subsequent shots [21] or increasing the amplitudes of the negative gradient lobes to concomitantly reduce their duration [7, 9]. A disadvantage of shifting the gradient modulation sequence is an increased scan time by a factor corresponding to the number of different delays. Shorter modulation periods achieved by asymmetric gradient modulation come at the expense of an SNR loss because only echoes refocused during the positive lobes can be used for image reconstruction. The bandwidth may also be preserved by appropriately splicing together the signals for subsequent experiments with cyclically inverted starting phases of the gradient waveforms, which requires two permutations (i.e. a two-shot experiment) in the case of 1D spatial encoding [5].
In principle, continuous data sampling during the entire gradient waveform is advantageous to minimize the acquisition bandwidth and thus improve the SNR [22]. This implies that even with trapezoidal gradients nonlinear sampling is used during some fraction (i.e. the ramp times) of the total acquisition window. This requires appropriate interpolation (regridding) of the data to correct for ramp-sampling distortions of the k-space trajectory. In addition, chemical-shift artifacts become a function of k-space encoding during ramp sampling, which may cause edges of chemically shifted species, such as peripheral lipid signals, to be more displaced than metabolite resonances.
Single-shot encoding of two spatial dimensions along with the spectral dimension is theoretically possible if two gradients, Gx and Gy, are periodically inverted. With echo-planar shift mapping (EPSM), both gradients are modulated in a trapezoidal fashion but with different amplitudes and modulation periods (e.g. Gy<Gx and 2Δty>2Δtx) [5, 23]. It is noted the technique of splicing together signals from subsequent experiments with cyclically inverted starting phases of the gradient waveforms to correct for aliasing under preservation of the spectral bandwidth as described above requires four permutations (i.e. a four-shot experiment) in the case of 2D spatial encoding [5]. A major problem with using a relatively long flat-top time of a trapezoidal gradient (i.e. a constant gradient) for phase encoding is that the samples are not uniformly spaced on a rectilinear k-space grid, which requires regridding of the data prior to the Fourier transform.
More recently, a single-shot variant of the PEPSI technique has been proposed that utilizes parallel-imaging techniques for obtaining 2D spatial encoding during a single spectral dwell time [24, 25].

Method and device for magnetic resonance spectroscopic imaging

Max-Planck-Gesellschaft zur Foerderung der Wissenschaften e.V.


A method of recording and classifying data collected from an above ground marker for pipeline pig monitoring. Described herein is a method of extracting minimum data attributes from a real-time data sample and packaging same to achieve a significant volume reduction such that the information can be conveyed across communications channels with limited bandwidth. The reduced volume of information can then be utilized at a remote location to reconstruct a close approximation of the original signal with precise timing, and sufficient clarity to allow remote operators to identify pertinent information from the original data sample.

Knowledge of the path and progress of instrumented pipeline-inspection tools ("pigs") flowing with product through pipelines is highly desired, especially if the pig becomes stuck in the pipeline. It is common for a pig to carry a portable transmitter or magnets which allow its passage to be detected by instruments placed in the Right of Way on the ground surface above the pipeline. These tools are referred to herein as Above Ground Markers (AGMs). Pigs with portable transmitters may emit a continuous signal, or may emit a pulsed signal. One skilled in the art would appreciate that other variations may also occur in the transmitter signal which can be accounted for in the detection of the pigs to distinguish the transmission from noise, and improve identification.
The type of transmitter carried by a pig is determined by the purpose of the pig. When timing accuracy is important a continuous transmitter is desired, as it allows for a clearer null signal as the transmitter passes under an AGM. Similarly magnetic signals can be utilized for precise timing as they generate a clear zero crossing as the pig passes under the AGM. Precise timing is necessary to correlate the data collected by the pig's instruments with known time stamps and geographic locations. Therefore, drifts and other "dead reckoning" errors from the pig's onboard inertial navigation instruments can be adjusted to precisely determine the location of 'defect' conditions recorded by the pig.
Pulsed signals may be more desirable for instances where precise timing is not required, such as cleaning pigs. Cleaning pigs do not normally collect and record data in the pipeline, so the reason for tracking them is to ensure they are properly progressing through the system, and identify their specific location if they get stuck. Since it may take time to locate a stuck pig, the pulsed signals are desirable as they give longer running times than continuous transmitters given a specific amount of battery life. E.g., A pulsed signal pig with a 50:50 duty cycle is expected to operate for approximately twice as long as a continuous signal pig with the same battery life.
AGMs detect and report electronic signals from the pig as it passes through the pipeline. As the pig is passing through a pipe, the pipe's construction may shield its transmission signal. The pipe may also be buried under more than twenty feet (20′) of ground. This attenuation of the transmission signal means the AGM must be very sensitive. This sensitivity results in many false signals being detected which may be mistaken for the signal of the passing pig.
Typically, human operators must be on numerous sites along the pipeline to monitor these instruments and report the pig's progress (or lack thereof). This process of monitoring the pig so that its location can be approximated in the case it becomes stuck involves significant expense.
Some instrument packages exist that contain additional electronics which allow automatic unattended recording of the detected signals and thus the efficient transmission of these results to remote observers is desirable. However, due to the remote locations of most pipelines, transmission must be accomplished by satellite links which can be an expensive transmission medium.
The most cost-effective satellite links allow only a very limited amount of data per transmission, usually single packets of less than sixty (60) bytes, and rarely more than a few hundred bytes. For this reason, it has been a common practice to transmit a standard identification message when the pig passage event has occurred. No actual data of the event is transmitted by these systems. Rather, they rely purely on the time stamp applied to a message when the satellite ground server receives and forwards the standard message. This data packet is transmitted three times in approximately seven and a half minute increments to account for gaps in satellite coverage which may prevent a single data transmission from being received. The data is relayed by a satellite to a ground station where the message is forwarded by other communications means to a final destination. A common means of forwarding the data is via the Internet in the form of e-mail or Short Message Service (SMS) Text Messages.
Depending on which of the three transmitted data packets was received and forwarded, the server time stamp may differ from the actual pig passage time by as much as fifteen (15) minutes. When a pig is being utilized to determine flow rates, this delay can result in a significant error in calculations. Environmental conditions are often detected by the AGMs, and can trigger the AGM in the same manner as a passing pig. Transmitting a signal each time a triggering event occurs without any further information can result in false transmissions causing remote monitors to believe a pig has passed when such an event has, in fact, not occurred.
The current method of remote monitoring is to estimate when a pig passage is anticipated, and watch for a signal to arrive approximately at the anticipated time. If a signal is received, then the remote monitor assumes it was the signal of the pig passage. If more than one is received, then the one closest to the estimated arrival time is assumed to be the correct signal and the others are rejected as false signals. These assumptions result in a lot of unreliable "guess" work which is costly to the industry.

Method of data volume reduction for transmission on a limited communications channel


The cam follower roller device including a body, a shaft mounted on the body, a roller mounted on the shaft in a rotationally movable manner, and at least one friction element mounted on the shaft axially between the roller and the body. The friction element is separate from the body and from the roller.

One advantageous application of the invention is the use of the cam follower roller device in a fuel injection pump intended for an internal combustion engine, in particular of a motor vehicle such as an automobile or lorry.
A device such as this comprises a tappet or body and a roller mounted to rotate on the body and intended to cooperate with a cam synchronized with the camshaft of the internal combustion engine so that the rotation of the camshaft leads to a periodic displacement of a piston of the injection pump that bears against the body, to allow fuel to be delivered.
Another advantageous application of the invention is the use of the device in a rocker system intended for controlling valves of an internal combustion piston engine.
In this application, the roller of the device is intended to cooperate, by rolling on it, with a cam of the camshaft of the internal combustion engine so that the rotation of the camshaft causes a periodic pivoting of a body of the device or of a rocker body, to open and close valves of the engine.
For these devices, the roller is generally mounted freely on a support shaft fixed to the body. During operation, and taking account of the forces applied to the device, in particular axial forces, contacts are produced between the roller and the body. Such axial contacts generate friction. Now, the body of these devices is generally obtained by forging, which generates a relatively high frictional torque, or even premature wear.


Distortion compensation of an optical micro-electro-mechanical system (MEMS) device disposed on a substrate surface is effected by measuring degradation of an optical parameter of the device and applying a force to the substrate to reverse the degradation. The compensating force may be provided via a layer of piezo-electric material bonded to the opposite surface of the substrate and to which a control voltage is applied. The device distortion may arise from thermal mismatch effects in a package housing containing the device. Typically, the MEMS device comprises an optical crosspoint switch array.

This invention relates to arrangements and methods for preventing distortion of integrated opto-electronic devices.
Complex opto-electric devices for example micro-electro mechanical systems (MEMS) devices are being introduced into communications networks to provide a number of functions including switching and light source applications. These devices are typically formed on a substrate formed from a ceramic material or from a single crystal semiconductor material. As the devices become more complex, larger area substrates are required.
A characteristic feature of these devices is the critical alignment that must be maintained between the optical components of the device in order to minimise loss of optical signals between those components.
A typical device of this type is the MEMs crosspoint switch. This device comprises an array of individually actuable mirrors formed in a silicon substrate and provides a non-blocking crossbar architecture in which switching is effected between a plurality of optical inputs and outputs. Devices of this type have the potential to become key components in the rapid expansion of the Optical Internet. However, the introduction of these devices is currently constrained by their extreme sensitivity to distortion arising from mechanical stress caused e.g. by thermal mismatch in the package assembly within which the device is housed. This extreme sensitivity to distortion is a particular problem for the larger packaged devices now being developed.
Optical crosspoint switches that are currently being proposed have a typical substrate size of about 60 mm square. These devices operate by switching of optical beams having a typical beam waist of about 240 microns and, to prevent degradation of performance, it is necessary to maintain accurate alignment of the beam. It has been found for example that, over a distance of 60 mm, it is necessary to ensure that the beam does not deflect from its true path by an angle greater than 0.5 milliradian. Beam deflections of this order can easily be caused by thermal mismatch and/or mechanical stress of the package in which the MEMs device is mounted. It will further be appreciated that as devices increase in size and complexity, there will be a corresponding increase in the problem of distortion.
A potential solution to the problem of distortion is to mount the MEMs device on a stable surface within an enclosed housing provided with a thermostatically controlled temperature. However, such an assembly is relatively costly. Further, such a structure occupies a significant physical volume, which can be a disadvantage where space is at a premium. In addition, this solution does not address the problem of long term ageing effects, which may need to be considered when a high reliability working life of many years is envisaged.
An object of the invention is to minimise or to overcome the above disadvantage.
A further object of the invention is to provide an improved device construction.
According to a first aspect of the invention, there is provided an optical device disposed on a first major surface of a substrate, the device having sensing means associated with the device for detecting distortion of the substrate, and feedback control means responsive to the sensing means for applying a force to the substrate so as to compensate for the effect of such distortion.
According to another aspect of the invention there is provided an optical device disposed on a first major surface of a substrate, the device having input and output optical signal paths, sensing means associated with a said output optical signal path and arranged to detect a reduction of a signal on that path corresponding to a distortion of the substrate, means for applying a force to the substrate, and feedback control means responsive to the sensing means for controlling said force applying means so as to negate said distortion of the substrate.
According to another aspect of the invention there is provided an optical micro-electro-mechanical system (MEMS) device disposed on a first major surface of a substrate, the device having a first set of input optical waveguides, a second set of output optical waveguides, an array of switch elements disposed on said first major surface and each arranged to couple selectively optical signals between a respective input optical waveguide and output optical waveguide, signal sensing means associated with one or more of said output optical waveguides and arranged to detect a distortion of the substrate as a reduction in amplitude of a signal carried on said one or more output optical waveguides, means for applying a force to the substrate, and feedback control means responsive to the sensing means for controlling said force applying means so as to negate said distortion of the substrate.
According to another aspect of the invention there is provided an optical device disposed on a first major surface of a laminar substrate, the device having sensing means associated with the device for detecting distortion of the substrate, and means for applying a controlled force to the substrate so as to compensate for the effect of such distortion.
According to another aspect of the invention, there is provided a method of distortion compensation of an optical device disposed on a laminar semiconductor substrate, the method comprising, detecting distortion of the substrate by measurement of an optical parameter of said optical device, and, in response to said distortion detection, applying a force to the substrate so as to negate such distortion.
Advantageously, the actuator comprises a layer of piezo-electric material applied to the substrate lower surface and to which a controlled voltage is applied to impart a force to that surface so as to negate a distortion hereof. Preferably, the piezo-electric material is pre-compressed. Typically, the distortion sensitive device comprises a MEMS device such as a crosspoint switch or a laser package.
The PZT material may be provided in sheet form and bonded to the substrate by a heat curing adhesive.
In a preferred embodiment, an oscillatory signal is superimposed on an electrical control signal applied to the layer of a piezo-electric material. Phase detection of a corresponding oscillatory signal in the measured optical parameter provides a feedback for increasing or decreasing the magnitude of the control signal.
It will be understood that the above description of a preferred embodiment is given by way of example only and that various modifications may be made by those skilled in the art without departing from the spirit and scope of the invention.

Dimensionally stable device construction


A TFT array substrate includes a plurality of pixels arranged in a matrix, in which the pixel includes a thin film transistor, a pixel electrode conductively connected to a drain electrode, and a common electrode that is formed opposite the pixel electrode with an insulation film interposed therebetween. In the TFT array substrate, when one of the pixels is focused, the pixel electrode is divided into a plurality of divided pixel electrodes and includes a plurality of branch conductive parts that conductively connect each of the drain electrode and the plurality of divided pixel electrodes, and in plane view, the common electrode is not formed in at least a part of a formation region of the plurality of branch conductive parts.

1. Field of the Invention
The present invention relates to a thin film transistor array substrate, a manufacturing method thereof, and a liquid crystal display device using the same.
2. Description of Related Art
A liquid crystal display device is one of thin panels, and widely used for monitors of personal computers and portable information terminal devices and TVs taking advantages including low power consumption and small and lightweight. The mainstream of current liquid crystal display devices is an active-matrix type including a plurality of display signal wires and a plurality of scanning signal wires arranged in a lattice pattern, and a thin film transistor (hereinafter referred to as TFT) formed as a switching element in a pixel region surrounded by the display signal wires and the scanning signal wires.
There is an increasing demand to a high-definition image display device by the development of multimedia industry.
The TN (Twisted Nematic) mode which is a conventional liquid crystal mode is a method to change a display state of on and off by applying a vertical electric field vertical to the substrate, raising and dropping liquid crystal molecules against a substrate surface according to an applied state of voltage. The TN mode does not have a good viewing angle characteristic due to its principle.
IPS (In-Plane Switching and IPS is a registered trademark of Hitachi Displays Ltd.) mode is a method to change the display state of on and off by applying a horizontal electric field substantially parallel to the substrate and moving liquid crystal molecules in plane which is substantially parallel to the substrate. The IPS mode has a wider viewing angle characteristic as compared to the TN mode, and is used for TV use etc.
In recent years, the FFS (Fringe Field Switching) mode, the improved IPS mode, has been developed. The FFS mode is a method to move the liquid crystal molecules by applying an oblique electric field not only the horizontal electric field, which is substantially parallel to the substrate, and has an excellent viewing angle characteristic in a similar manner as IPS.
In the IPS mode, both of a pixel electrode and a common electrode for driving liquid crystals are made to be a comb shape, and are arranged to interdigitate without the combs not touching each other. The IPS mode is a configuration in which the pixel electrode and the common electrode do not overlap in plane view. Usually, the gap between the pixel electrode and the common electrode in the IPS mode is larger than a cell gap and an electrode width.
In the IPS mode, the liquid crystal molecules that are positioned between the pixel electrode and the common electrode are driven in plane view, however the liquid crystal molecules that are positioned immediately above the pixel electrode and the common electrode are hardly driven. Therefore, the section immediately above the pixel electrode and the common electrode cannot contribute to display, and the transmittance is low, and thus it is difficult to obtain bright display properties.
On the other hand, in the FFS mode, the pixel electrode and the common electrode are disposed opposite with an insulation film interposed therebetween, and between the pixel electrode and the common electrode, a lower electrode does not include an opening, and an upper electrode is formed in a shape including an opening that generates a fringe electric field between the upper electrode and the lower electrode. The FFS mode is a configuration in which the pixel electrode and the common electrode overlap with an insulation film interposed therebetween in plane view.
For example, in the liquid crystal display device shown in FIG. 1 and FIG. 2 of International Patent Publication No. WO2001/018597, the upper electrode includes a plurality of slit-shaped openings in a plate-shaped electrode. In the liquid crystal display device shown in FIG. 3 of Japanese Unexamined Patent Application Publication No. 2001-056476 and FIG. 3 of Japanese Unexamined Patent Application Publication No. 2003-084303, the upper electrode has a comb structure.
The gap between the pixel electrode and the common electrode in the FFS mode is smaller than the cell gap and the electrode width.
In the FFS mode, the liquid crystal molecules positioned immediately above the electrode can be driven by using the oblique electric field. Therefore, when the pixel electrode and the common electrode are formed of a transparent conductive film such as an indium tin oxide (ITO), an electrode part can also contribute to display. Accordingly, in the FFS mode, higher transmittance can be achieved than the IPS mode.
In the liquid crystal display device of the FFS mode, unlike the TN mode and the IPS mode, two layers of transparent conductive films need be laminated as the pixel electrode and the common electrode with an insulation film interposed therebetween over the same substrate. These two layers of transparent conductive films only have a thin insulation film interposed therebetween, and a short-circuit between the electrodes is generated and a pixel defect may be generated.
In order to reduce the pixel defect due to the short-circuit between the electrodes, the insulation film disposed between the electrodes can be a multilayer structure, however it is not preferable as the number of manufacturing processes increases.

Thin film transistor array substrate, manufacturing method thereof, and liquid crystal display device


A vibratory gyro piezoelectric vibrator includes a vibrating body having a laminate of piezoelectric layers stacked on each other in a lamination direction, and having a length extending in the lamination direction. The vibratory gyro piezoelectric vibrator uses longitudinal piezoelectric effects of the piezoelectric layers and operates such that a first bending vibration is excited in which the vibrating body bends in a width direction of the vibrating body substantially perpendicular to the lamination direction of the piezoelectric layers, and a Coriolis force is caused in response to the first bending vibration such that a second bending vibration is excited in which the vibrating body bends in a thickness direction of the vibrating body substantially perpendicular to both of the lamination direction and the vibration direction of the first bending vibration.

1. Field of the Invention
The present invention relates to a vibratory gyro piezoelectric vibrator and, in particular, to a structure of a piezoelectric vibrator including a vibrating body, which has a length extending in a lamination direction of a plurality of laminated piezoelectric layers and takes advantage of a longitudinal piezoelectric effect of the piezoelectric layers.
2. Description of the Related Art
Conventionally, a piezoelectric tuning bar and a piezoelectric tuning fork are known as a piezoelectric vibrator for a vibratory gyro. For example, Japanese Unexamined Patent Application Publication No. 8-320233 discloses a piezoelectric tuning bar having piezoelectric elements disposed on three sides of a right-triangular-pillar-shaped vibrating body made of metal. The piezoelectric tuning bar bends and vibrates the vibrator in a direction that is perpendicular to the surface having the piezoelectric elements in response to the application of an alternating voltage to the piezoelectric elements.
Furthermore, for example, Japanese Unexamined Patent Application Publication No. 9-269227 discloses a piezoelectric tuning bar having a pillar-shaped vibrating body, which has a length extending in a direction that extends in the direction that is perpendicular to the thickness direction of two pasted piezoelectric substrates. The piezoelectric substrates are polarized in the opposite direction of the thickness direction. Here, main surfaces of the vibrating body are opposed in the thickness direction of the vibrating body and have external electrodes provided thereon. In response to application of alternating voltage to these external electrodes, the vibrating body is bent and vibrated in the thickness direction of the piezoelectric substrate. Since a piezoelectric tuning fork has a similar construction as that of a piezoelectric tuning bar and the construction is publicly known, the descriptions will be omitted herein.
Both of these piezoelectric vibrators take advantage of a characteristic that, in response to application of alternating voltage to electrodes on both sides of the piezoelectric body in the polarization direction, a piezoelectric body stretches in the direction perpendicular to a direction of the voltage application. In other words, a plate-shaped piezoelectric body stretches in the plane direction in response to application of voltage to electrodes on both of the front and back surfaces of the piezoelectric body, which is polarized in the thickness direction. This characteristic is called a lateral piezoelectric effect (d31 effect).
In reality, a piezoelectric body stretches also in the thickness direction in response to application of voltage, and the characteristic is called a longitudinal piezoelectric effect (d33 effect). However, conventionally, a general piezoelectric vibrator does not actively use a longitudinal piezoelectric effect. This is because the stretch due to a longitudinal piezoelectric effect is smaller than the stretch due to a lateral piezoelectric effect.
In recent years, more and more electronic components are lead-free, and materials containing a lead component tend to be not used as a result. Furthermore, since many conventional piezoelectric materials contain a lead component, new piezoelectric vibrators which contain piezoelectric materials without a lead component are being demanded. However, a piezoelectric material without a lead component produces a small amount of stretch from a lateral piezoelectric effect, which is a problem. Therefore, using a piezoelectric material without a lead component is difficult for a piezoelectric vibrator having a conventional structure.
In order to produce a piezoelectric vibrator containing a piezoelectric material without a lead component, a longitudinal piezoelectric effect may be actively used instead of a lateral piezoelectric effect. In other words, a vibrating body may include a laminate of multiple piezoelectric layers stacked in a lamination direction and has a length extending in the direction of the laminate. A sum of longitudinal piezoelectric effects of the piezoelectric layers of the vibrating body may result in a certain amount of stretch of the entire integrated vibrating body.
As an example of a piezoelectric vibrator having the laminate structure, Japanese Unexamined Patent Application Publication No. 2003-69372 discloses a structure that is not for a vibratory gyro. The piezoelectric vibrator includes an integral vibrating body having a laminate of multiple piezoelectric layers polarized in the thickness direction, which is coincident with the lamination direction. In the laminate, the piezoelectric layers alternately have opposite polarization directions from each other. A piezoelectric layer between a first internal electrode and a third internal electrode and a piezoelectric layer between a second internal electrode and the third internal electrode are alternately opposed to each other. These internal electrodes are provided in substantially an entire area in the thickness direction or width direction of the vibrating body, which is perpendicular to the lamination direction in both cases.
Furthermore, the longitudinal direction is coincident with the lamination direction on a main surface on one side of the vibrator in the thickness direction. First and second external electrodes are arranged in parallel through a channel portion in the width direction perpendicular to both of the lamination direction and the thickness direction. The first and second internal electrodes are spaced from each other in parallel and are connected to and are conducted to the first and second external electrodes, respectively. The third internal electrode is not connected to any of the external electrodes and is electrically floating.
When an alternating voltage from the first and second external electrode is input to a piezoelectric vibrator disclosed in Japanese Unexamined Patent Application Publication No. 2003-69372, that is, a piezoelectric vibrator having the laminate structure, piezoelectric layers of the vibrator have opposite polarization directions from each other and stretch because of the longitudinal piezoelectric effect. Here, a piezoelectric layer between a first internal electrode and a third internal electrode and a piezoelectric layer between a second internal electrode and the third internal electrode stretch in the opposite directions from each other. As a result, the vibrating body bends and vibrates in the width direction of the vibrating body, which is perpendicular to the lamination direction of the piezoelectric layer as a whole.
The conventional piezoelectric vibrator requires a resonator mainly using an electric characteristic. Furthermore, the piezoelectric vibrator has a laminate structure because using bending vibration based on stretching due to a longitudinal piezoelectric effect is more advantageous in reduction of the size of the entire structure than using direct stretching due to a lateral piezoelectric effect. However, while a first bending vibration is being excited in which a vibrating body bends in the direction that is perpendicular to the lamination direction of piezoelectric layers in the piezoelectric vibrator and when an angular velocity about the lamination direction as the axis of rotation is applied to the piezoelectric vibrator, second bending vibration may be excited by the action of a Coriolis force. Here, in the second bending vibration, the vibrating body bends in the direction that is perpendicular to both of the lamination direction and the vibration direction of the first bending vibration.
However, since the piezoelectric vibrator does not have a detecting unit for detecting an output from the second bending vibration, the piezoelectric vibrator cannot detect an output caused by the second bending vibration. Thus, the piezoelectric vibrator cannot be used as a vibratory gyro.


A sidewall for a cargo container is provided having at least one pair of composite panels and means for joining the panels. Each composite panel includes a uniform facing member; a non-uniform facing member having major, minor and inclined portions; and a core member sandwiched between and bonded to the uniform facing member and the major portion of the non-uniform facing member. The uniform member is planar and has outer and inner surfaces. The non-uniform member has a planar major portion and a parallel minor portion which has outer and inner surfaces. The inner surface of the minor portion of the non-uniform member abuts the inner surface of the uniform member. The non-uniform member also has an inclined portion which connects the major and minor portions and which is angled with respect to the major and minor portions. Adjacent composite panels are joined within the offset formed by the abutting outer surface of the non-uniform member of one composite panel and the outer surface of the minor portion of the non-uniform member of the other composite panel.

Multi-panel constructions of the sidewalls of a trailer housing are known. A typical trailer 10 employing such construction is shown in FIG. 1. Such a trailer generally comprises a floor 14, a roof 16, a front wall 18, a pair of sidewalls 22, a rear cargo door (not shown), landing gear 24, and a wheel support assembly 26.
Each sidewall 22 and front wall 18 comprises a plurality of composite panels 12. Preferably, each composite panel is rectangular, having a height greater than its width. Although the composite panels are shown in FIG. 1 as being relatively equal in size, the width and thickness of each panel may vary.
FIG. 2 shows a prior art construction of a composite panel 12 and a method of joining or splicing adjacent panels to form the sidewalls 22 and the front wall 18. Composite panel 12 comprises a laminated sandwich including a plastic core 28 and aluminum face sheets 30 adhesively attached to each surface thereof.
As shown in FIG. 2, adjacent composite panels 12 are joined by means of an external aluminum splice plate 32 riveted thereto by vertical rows of rivets 34. The inside and outside wall surface of each panel are generally planar (i.e., lying in a plane), although the rivet heads 34 are shown as protruding.
In the construction of trailers and other cargo carriers, it is important to make available as much space as possible within the interior of the housing for the purpose of carrying cargo. In that regard, it is desired that the walls of the housing, in particular the sidewalls, be devoid of any obstructions.
It is desired to eliminate the spacer 32 at the edges of panels 12 and have the edges offset to enclose the plastic core 28. This would have the advantage of recessing the rivet heads below the inside surfaces of the panels to prevent the rivet heads from being peeled off by fork lifts or cargo. It also is desired to have the edges of the inside sheets curved inward so as not to be caught and torn by the fork lifts or cargo.
It is further desired to have a scuff plate interconnected to the inside of each sidewall 22 in a simple yet structurally sound manner to provide a relatively smooth surface facing the interior of the cargo container that will not entangle any cargo or equipment used to load or unload cargo. Such a scuff plate is disclosed in U.S. Pat. No. 5,509,714, which is herein incorporated by reference.

Composite sidewall panels for cargo containers


A method and system for relieving forging induced residual stresses in a rotor forging balances a pre-spin machine with the forging mounted thereon at a first rotational speed and then pre-spins the forging with it mounted on the machine at a substantially greater second rotational speed. A one per rev sensor is used for determining a weight placement angle and a vibration sensor is used for determining an amount of weight to add to a spinning assembly including the forging during the balancing. High-density non-metallic balance weights adhesively attached on an inside surface of the forging or spinning assembly may be used. The rotational inertia of the spinning assembly may be checked during a spin up period by determining a rate of rotational acceleration vs. torque applied to the spinning assembly and used to stop the pre-spinning if it is to great.

1. Technical Field
This invention relates to methods and machines for manufacturing rotors from forging and, more particularly, to pre-spinning rotor forgings to relieve forging induced residual stresses.
2. Background Information
During normal operations gas turbine engines may operate with high rotational speeds and relatively high temperatures. Residual stresses from a metal alloy forging process used in fabricating turbine disks in the engine may relieve during engine operation, such that the turbine disks may undesirably expand. Such disk expansion may adversely affect clearances between the rotor and surrounding casing during engine operation.
In order to reduce occurrences and degree of disk expansion, at least some known engine disks are spun during the manufacturing process in a near-finished condition to relieve the residual stresses in the disk or other rotor forging. This process is known as pre-spinning of the disks generally has the same effect on relieving the residual stress as actual engine operation. Final machining, such as, of mating or other features and/or rabbets, for example, is performed after the pre-spinning process. Conventional pre-spinning processes is a time consuming and costly process. Moreover, because the high rotational speeds are needed to relieve the residual stresses the rotor forging and its mounting fixture must be balanced which increases the complexity of the pre-spin process.
Pre-spin machines provide the capability to spin rotating parts at speeds exceeding aircraft engine core speeds which are about 13,000 RPM. In order for the machine to handle to amount of force generated by the rotating parts unbalance, the rotating part, fixture, alignment, and spindle must be balanced to values typically less than 500 gram-inches using separate balance machines. Pre-spin machines are designed to be operated in a speed range of about 5,000 RPM to 18,000 RPM and balance machines between about 100 RPM and 1200 RPM. Pre-spin machines are intended to hold the part solidly and are typically of the soft-bearing type which means the vibration response changes with increasing speed. Balance machines roll the parts on "knife-edge" bearings and try to maximize unbalance sensitivity within the pedestals holding the bearings. Pre-spin machines are not designed to balance a part, typically they just spin parts to high speeds and are designed to spin parts fast enough for the part to actually fail.
Even if the rotating part and fixture can be balanced separately in a stand-alone balance machine, they must still be aligned properly in the pre-spin machine. If not, reaching proper high speeds may not be attainable. This problem then creates significant cost prior to even pre-spinning the rotating part. Costs may include machining of rotating part to tight tolerances, balancing fixture, properly aligning fixture, and properly aligning pre-spin spindle. If unbalance is still too high, process may have to be repeated many times to be able to achieve pre-spin speeds.
Another problem relates to the wear of the pre-spin machine over time for rotating parts still having high vibration levels. This may cause premature failure of specific components or excessive preventative maintenance costs to prevent these failures. Failure within the pre-spin machine can cause significant damage to the rotating part, fixture, spindle, and machine. Yet another problem with having high unbalance and vibration in the pre-spin machine is the potential for the rotating part to shift within the fixture causing higher vibration during deceleration than during the acceleration to top pre-spin speed. This concern can also cause premature machine failure and rotating part damage.
Thus, it is highly desirable to provide apparatuses and methods that are less expensive and less time consuming machine then conventional machines and methods for balancing and pre-spinning a rotor forging to relieve forging induced stresses at rotational speeds about or above maximum operational speeds of a rotor part manufactured from the rotor forging.

Method and apparatus for pre-spinning rotor forgings


A semiconductor device of complementary structure with increased carrier mobilities of both polarities by applying orientation-dependent mechanical stresses to their respective semiconductor channel regions, comprises a semiconductor region subjected to compressive stress in a first direction along a surface and tensile stress in a second direction different from the first direction, a field effect transistor of a first conductivity type formed in the semiconductor region and including source and drain regions separately arranged along the first direction and a field effect transistor of a second conductivity type formed in the semiconductor region and including source and drain regions separately arranged along the second direction.

1. Field of the Invention
The present invention relates to a semiconductor device composed of complementary field effect transistors (MOSFETs) with increased carrier mobilities of both polarities by applying orientation-dependent mechanical stresses to their respective semiconductor channel regions and a method of manufacturing thereof.
2. Description of the Related Art
Recently, in order to increase the operation speed of MOSFETs, a method of enhancing mobilities of carriers (i.e., electrons or holes) by applying mechanical stresses to the channel-forming semiconductor portions and thereby modulating the electronic states of the conduction band and the valence band of the semiconductor has been proposed (H. Irie et al. IEDM Tech. Dig. pp. 225-228, 2004).
In order to produce such mechanical stresses in the channel regions, one can deposit an additional stress-yielding insulator film, having high internal stress, over the MOSFETs after their formation. With this method, however, most of the stress from the stress-yielding insulator would come to be applied to the gate electrodes, not to the channel regions. Thus, this method greatly suffers from its inefficiency in stress generation within the channel.
Such dissipation of stresses can be avoided by replacing a portion of each of the source and drain regions with a foreign stress-generating semiconductor substance with high internal stress other than the channel forming semiconductor (Si) (T. Ghani et al., IEDM Tech. Dig. pp. 978-980, 2003).
Compressive stress in the channel direction increases the hole mobility, whereas, tensile stress applied in the channel direction increases the electron mobility (H. Irie et al., IEDM Tech. Dig. pp. 225-228, 2004).
Thus, in order to realize a high-speed p-type MOSFET (p-MOSFET), indispensable to manufacturing of advanced complementary MOSFETs (C-MOSFETs) circuits, a portion of each of its source and drain regions must be replaced by an expansive semiconductor substance with a larger-than-silicon lattice constant (for example, a eutectic of silicon and germanium (SiGe)). Likewise, a contractile semiconductor material with a smaller-than-silicon lattice constant (for example, a eutectic of silicon and carbon (SiC)) needs to be epitaxially formed in portions of the source and drain regions to increase the speed of the n-type MOSFET (n-MOSFET).
For C-MOSFETs manufacturing, therefore, two extrinsic semiconductor materials with incompatible lattice constants have to be placed in close proximity to each other. Of course, during the epitaxial growth of one of the semiconductor materials, the adjacent region to form the other semiconductor material must be coated with an insulating layer to prevent unwanted growth of the first material. Accordingly, the completion of the C-MOSFETs naturally requires repeated steps of insulating layer deposition and extremely precise lithography as well as etching and patterning of fine structures of the insulating layer.
Besides, it is, in itself, difficult to epitaxially grow an uniform heterogeneous semiconductor material on the Si substrate in a well-controlled manner. Moreover, this unstable process step must be repeated twice for the two incompatible semiconductor materials, which results in complication of the manufacturing steps and increased manufacturing cost. In addition, an expansive semiconductor material placed in close proximity to a contractile semiconductor material results in substantial cancellation of the individual strains exerted by the semiconductor materials and, therefore, the stresses induced in the respective channels will be greatly reduced.
Furthermore, epitaxial growth of an extrinsic semiconductor material having a different lattice constant from the substrate naturally induces a large number of crystal defects at the hetero-junction between the semiconductors of the incompatible lattice constants. The dense array of the crystal defects in the vicinity of the source/drain junctions inevitably causes severe junction leakage from the source/drain regions to the substrate semiconductor below.

Semiconductor device and method of manufacture thereof


Disclosed is a method of testing electrical characteristics of a semiconductor device having a ball-shaped external electrode. The method comprises preparing a plurality of cantilever-type contactors each supported by a support plate at a given position, and formed in such a manner that a tip thereof has a flat surface with an arc-shaped edge in an outer peripheral region thereof, and a cross-sectional diameter in a vicinity of the tip is greater than a radius of the ball-shaped external electrode, and pairing the cantilever-type contactors to provide paired two contactors. The method includes the steps of: pressing either one of the support plate and the semiconductor device toward the other in such a manner that the arc-shaped edges of the paired two contactors are brought into contact with respective ones of two surface regions of the ball-shaped external electrode divided by an axis of the ball-shaped external electrode passing through a middle point between the two positions where the paired two contactors are supported, so as to form Kelvin contacts; and further overly driving either one of the support plate and the semiconductor device relative to the other in such a manner that the arc-shaped edges of the paired two contactors are slidingly moved along respective ones of the two surface regions of the ball-shaped external electrode to perform a wiping operation.

1. Field of the Invention
The present invention relates to electrical characteristic testing of a semiconductor device, such as a BGA (Ball Grid Array), a CSP (Chip Size Package), a WLCSP (Wafer Level Chip Size Package) or a flip chip, which has a ball-shaped external terminal.
2. Description of the Prior Art
Heretofore, a Kelvin contact measurement has been known as a technique for testing electrical characteristics with a high degree of accuracy. The Kelvin contact measurement is performed under a condition that two contactors connected to respective ones of a sense terminal and a force terminal of a measuring apparatus are in contact with one external electrode of a semiconductor device (i.e., Kelvin contacts). The Kelvin contact measurement is capable of cancelling influences of a contact resistance and a residual resistance of a measurement cable to provide extremely high measurement accuracy.
In an operation of testing a semiconductor device based on the Kelvin contact measurement, a cantilever-type contactor is commonly used. FIG. 1 shows the structure of a conventional cantilever-type contactor. As shown in FIG. 1, the cantilever-type contactor 11 has a beam portion 11a and a probe portion 11b. The contactor 11 is supported by a support plate of a probe card or the like, through one end of the beam portion 11a. The support plate is adapted to be moved in an upward/downward direction in such a manner as to allow the probe portion 11b to be brought into contact with an external electrode of the semiconductor device in conjunction with the movement so as to measure electrical characteristics of the semiconductor device. A testing method based on the Kelvin contact measurement using such a cantilever-type contactor is disclosed, for example, in JP 2003-270267A.
The cantilever-type contactor has a feature of being able to facilitate a wiping operation. Specifically, an oxide film or a contaminant is likely to be formed or attach on a surface of the external electrode (made of metal) and intervene between the contactor and the external electrode, to cause difficulty in accurately performing the measurement if nothing is done. Thus, it is critical to perform the wiping operation, i.e., an operation of removing the intervening substance, such as an oxide film, from the surface of the external electrode, so as to expose the original metal surface of the external electrode, in advance of the measurement.
Recent years, along with complexification in configuration of a semiconductor device for meeting needs for higher-speed operation and larger capacity, a semiconductor device (e.g., BGA or CSP) having a ball-shaped external electrode (hereinafter referred to as "bump ball"), instead of conventional types, such as a lead terminal and an electrode pad, has been increasingly used. If such a semiconductor device having a bump ball is subjected to the testing method using the above conventional cantilever-type contactor, the following problems will occur.
FIG. 2 is a schematic diagram showing a contact state between the conventional cantilever-type contactor and one bump ball. As shown in FIG. 2, the conventional cantilever-type contactor 11 has a tip end P which is fairly thinner and weaker than the bump ball 13. Specifically, the bump ball 13 has a diameter of about 100 μm, whereas the tip end P of the cantilever-type contactor 11 typically has a thickness of about 10 to 50 μm. Thus, during a process of bringing the cantilever-type contactor 11 into contact with the bump ball 13, the tip end P is likely to be deformed. In some cases, the tip end P slips off a surface of the bump ball 13 to preclude a stable contact with the bump ball 13. In some cases, the tip end P deeply sticks into the bump ball 13 to seriously damage the bump ball 13. Considering these problems, it is difficult to use the conventional cantilever-type contactor for testing of a semiconductor device having a bump ball.
For this reason, a POGO pin-type contactor has been used mainly in the electrical characteristic testing of a semiconductor device having a bump ball. FIG. 3 shows a testing method using a typical POGO pin-type contactor. The POGO pin-type contactor illustrated in FIG. 3 comprises a plunger 26 and a body member 27. A coil spring 28 is arranged inside the body member 27 in such a manner as to allow the plunger 26 to be brought into contact with one bump ball 23, with a spring load depending on elongation or contraction of the coil spring 28, and electrically connected to the bump ball 23.
However, it is hard to perform the wiping operation using the POGO pin-type contactor illustrated in FIG. 3, and thereby it is difficult to achieve a high-accuracy measurement. Moreover, dusts are likely to be trapped in notches or depressions in a measurement portion (indicated by an elliptic area in FIG. 3) of the plunger 26, and the trapped dusts are hardly removed from the depressions. The difficulty in removing the dusts is likely to cause the occurrence of defects, such as contact failure, and preclude long-term use of the contactor. In addition, in connection with recent progress in integration of a semiconductor device, a bump ball has been increasingly reduced in size. Thus, in an operation of testing electrical characteristics of a semiconductor device having such a small-sized bump ball based on the Kelvin contact measurement, it is extremely difficult to allow two POGO pin-type contactors to be brought into contact with one bump ball. This makes it difficult for the POGO pin-type contactor to achieve a high-accuracy measurement in a simple manner.

Testing method for semiconductor device having ball-shaped external electrode


A radiation curable composition including at least one radiation hardenable component, a photo-initiator, and a filler material having a population of particulates in an amount greater than or equal to 50% by weight of the printable composition. The population of particulates exhibits a median diameter (D50) of greater than or equal to 0.3 micrometer on a volume-average basis as determined using the Particle Size Test Method, and the radiation curable composition exhibits a viscosity of less than or equal to 150 Pa s when measured using the Viscosity Test Method. A method, apparatus, and systems for producing composite articles by selectively exposing a portion of the radiation curable composition to a source of actinic radiation to at least partially cure the exposed portion of the radiation curable composition, thereby forming a hardened layer, preferably by an additive manufacturing process such as stereophotolithography, are also described. The composite articles may include composite dental restorations.

Various dental restorations, for example, crowns, bridges, inlays, onlays, veneers, and pontics, are used in the practice of dentistry. Preformed dental restorations, for example dental crowns, may be manufactured in a factory, shipped in kits to dentists, and shaped or otherwise adapted chairside to create custom dental restorations. Metals such as stainless steel and aluminum have been the favored materials for such restorations, because they are strong, yet malleable. Thin wall stainless steel crowns, having a wall thickness of 150-200 microns, can be mass produced at low cost, require minimal removal of tooth structure, and can be trimmed and bent by the dentist at chair side to create a tight fitting and durable restoration. Unfortunately, tooth-like aesthetics are not usually possible with stainless steel, and attempts to substitute (co)polymers, like polycarbonate, for metals have yielded crowns with durability substantially less than steel crowns.
Ceramics, such as zirconia, may alternatively be used for fabrication of more aesthetic dental restorations, and may be pigmented or colored to match tooth color. These materials typically exhibit good durability, high strength and, in the case of zirconia, can be engineered to undergo transformation toughening to reduce the risk of brittle fracture. Because ceramic materials generally have low ductility and high hardness, the shape of the restoration is desirably custom created to precisely match the dentition of the individual patient.
Polymer-ceramic composites are alternative materials for restoring teeth. These materials may be pre-shaped in a dental laboratory or delivered to the dentist in a form that allows shaping and curing of the restoration in the mouth of the patient. The cured form of these materials offers lower strength than native tooth enamel, but the incorporation of high amounts of ceramic filler can result in restorations that exhibit wear resistance comparable to natural tooth structure.

Radiation curable compositions and composite articles made using an additive manufacturing process


A system including a steerable mirror, a waveguide, first optics, intermediate optics, and final optics. The system includes a first light path for a foveal image element, the first light path including the first optics, the steerable mirror to steer a position of the foveal image element to a particular orientation, intermediate optics, and the final optics to direct the foveal image element to an in-coupling region of the waveguide. The system further includes a second light path for a field image element, the second light path including final optics.

Near-eye displays have the competing requirements of displaying images at a high resolution, over a large field of view (FOV). For many applications in virtual and augmented reality, the field of view should be greater than 90 degrees, and ideally the binocular field of view would extend past 180 degrees. At the same time, the resolution of the display should match that of the human visual system so that little or no pixelation is perceived in the virtual images. Combining these two requirements in a single system presents a number of challenges.
Additionally, optical systems that can project wide FOV images to the user with sufficiently high resolution over the entire field of view are also difficult to design. Systems architectures that are able to present the user with high resolution images over a wide field of view, while simultaneously reducing the rendering, data rate, and panel requirements will enable new applications for augmented and virtual reality systems.
Furthermore, for many applications in augmented reality, the form factor of devices may be desired to resemble regular eye-glasses. This presents additional optical design challenges.

Steerable hybrid display using a waveguide


An ink composition includes a graft copolymer including a repeating unit having a partial structure represented by Formula (1) described below and a repeating unit having a hydrophilic group in which a graft chain includes the repeating unit and water.

1. Field of the Invention
The present invention relates to an ink composition that can be applied to the usage in ink jet recording, an image-forming method and a printed material for which the ink composition is used, and a new graft copolymer.
2. Description of the Related Art
As an image-recording method in which an image is formed on a recording medium such as paper on the basis of an image data signal, there are an electrophotographic method, a sublimation-type or melting-type thermal transfer method, an ink jet method, and the like.
In the electrophotographic method, there are problems in that a process for forming an electrostatic latent image on a photoreceptor drum through charging and exposure is required, the system becomes complicated, and consequently, the manufacturing cost becomes expensive. In addition, in the thermal transfer method, while the apparatus is not expensive, an ink ribbon is used, and thus there are problems of the expensive operation cost, the generation of waste materials, and the like.
On the other hand, in the ink jet method, since ink is discharged only to required image sections using an inexpensive apparatus, and an image is directly formed on a recording medium, ink can be efficiently used, there is an advantage of an inexpensive operation cost, furthermore, only a small amount of noise is generated, and the method is an excellent image-recording method.
Among ink compositions used to record images using the ink jet method, an active energy ray-curable aqueous ink composition has a number of excellent characteristics such that the ink composition can be preferably used for the printing of images, a pretreatment for imparting printing aptitude to recording media, a post treatment to protect and decorate printed images, and the like, the stability is excellent since the ink composition includes water as a major component, the ink composition can be applied to high-density ink jet recording by a decrease in the viscosity, and the like.
In recent years, ink images formed on a resin recording medium using an ink composition have been often provided for the usages of large-area advertisements, outdoor advertisements, and the like. Particularly, in the case of outdoor advertisements, strong water resistance is required. In addition, in a case in which a large-area printed material or a number of printed materials are continuously formed, a step for removing dirt in a printing apparatus using an organic solvent becomes necessary; however, in a case in which the organic solvent used for cleaning is scattered, and is attached to a formed ink image, when the image has poor solvent resistance, sections to which the solvent is attached are dissolved and removed, and image defects such as voids may be generated, and therefore there is a demand for an ink composition capable of forming an image having excellent water resistance and solvent resistance.
Examples of a basic constituent material of the active energy ray-curable aqueous ink composition include water, polymerizing substances, polymerization initiators initiating polymerization by generating a radical or the like by an active energy ray, and color materials (pigments and dyes). Among them, polymerizing substances and polymerization initiators can be prepared in an emulsion state, or can be present in a solution state by being imparted with water solubility by an appropriate substituent.
Examples of the active energy ray-curable aqueous ink composition in which the polymerizing substance and the polymerization initiator are water-soluble include the ink composition described in, for example, JP2005-307199A, and according to the ink composition, an ink composition for ink jet recording with which a film having excellent adhesiveness and the like can be obtained by light irradiation can be obtained.
In addition, JP2007-119449A and JP2000-160086A describe ink compositions including an active energy ray polymerizing substance having a specific maleimide structure.

Ink composition, image forming method, printed material, and graft copolymer


A conventional four wheeled lawn motor carriage having a vertically mounted electric motor with flexible cutting, lines attached to the bottom end of the motor axial drive shaft. A Hand lever is attached to the electric motor enabling the electric motor to rotate from a vertical position to a transverse horizontal position wherein the flexible cutting lines rotate in a vertical plane parallel to and outside of the carriage.

1. Field of the Invention
Lawn mowers employing rapidly rotating flexible lines for the cutting operation are rapidly replacing lawn mowers utilizing rotating metal blades. The instant invention relates to a design wherein the rotating flexible lines can be re-orientated to rotate in a vertical plane thus providing for edge cutting or edging as contrasted to rotating in the horizontal field for lawn cutting. In the present invention the rotating flexible lines are powered by an electric motor energized by a self contained storage battery that allows for a much larger cutting range as contrasted to other conventional lawn mowers that employ an extension cord to energize the cutting device.
2. Description of the Prior Art
U.S. Pat. No. 4,587,800 , 1986, Jimenez, discloses a sled type lawn mower carriage having a motor enclosed in a housing supported by a support member in a first vertical position in which the attached rotating flexible lines sweep in a horizontal plane and in a second position in which the flexible lines sweep in a substantially vertical plane. It is necessary to remove the motor supporting member and move the motor assembly inorder to change cutting planes. U.S. Pat. No. 5,092,112, 1992, Buckendorf, discloses a wheeled attachment for a grass trimmer which includes a mounting bar having a wheel at each end. The grass trimmer can be rotated to provide either cutting the grass in a horizontal plane or a vertical plane. U.S. Pat. No.4,936,886, 1990, Quillen, discloses a wheel mounted trimmer having a wheel support with a pair of wheels mounted on opposite sides thereof and handle bars extending rearwardly from the support. A gasoline motor attached to the rear end of a drive shaft housing can be rotated to adjust the trimmer head for cutting in a horizontal plane or a position for cutting in a vertical plane.


A split mechanical face seal assembly wherein stator and rotor face rings and their respective surrounding collar and gland are all split substantially diametrically and are partially factory preassembled to facilitate shipping, handling and subsequent assembly onto a machine at the job site. The split rotor face ring and the split supportive collar have the cooperating parts thereof subassembled into two subassemblies which define opposed halves for permitting them to be assembled on diametrically opposite sides of a shaft, with each subassembly having the rotor face ring segment carried on the support collar segment, and an elastomeric seal ring which cooperates between the segments being preassembled therebetween. The stator face ring and its supporting gland ring also have the respective split segments thereof, and the other cooperating components such as seal rings and the like, preassembled at the factory to define a pair of subassemblies.

This invention relates to a mechanical seal assembly for pumps and the like and more particularly to an improved split mechanical face seal assembly.
Mechanical face seal assemblies are used on a wide variety of machines including pumps and the like having rotating shafts that pass through housings, with the mechanical seal assembly typically being disposed in surrounding relationship to the shaft and cooperating with a stuffing box of the housing to create a sealed relationship between the shaft and housing. Since installation or replacement of mechanical seal assemblies employing one-piece ring members is an extremely time consuming and complex operation, numerous split seal assemblies have been developed to facilitate installation and repair.
The split face seal assemblies are typically split generally diametrically along the axis of the assembly so that the face rings as well as the support rings therefore are all diametrically split so that the various seal assembly components can be mounted on or removed relative to the shaft without requiring excessive disassembly of the overall machine. While split mechanical seal assemblies hence are recognized to possess highly desirable advantages, nevertheless the construction of split seal assemblies continues to present a significant problem with respect to manufacture, assembly and performance thereof.
As to known split mechanical face seal assemblies, most such assemblies have both the stator and rotor face rings split diametrically, and also employ a support collar and a gland member which respectively cooperate with the rotor and stator face rings and which are also diametrically split. All other associated members such as elastomeric seal rings and the like are also split to permit their positioning around the shaft. This construction and the multiple parts thereof hence creates a significant assembly problem since the numerous parts must be field assembled onto the machine (for example a pump), and the parts must cooperate with the precision and fit necessary so as to provide the desired sealing performance. In particular, the split rotor and stator face rings and the respective supporting collar and gland results in a total of eight separate pieces, not counting separate split seals and the like, such that manipulating and assembling this large number of parts at an on-site location and at the same time obtaining or maintaining proper fit and engagement between the parts is thus a relatively complex and time consuming operation. Further, many of the split seals currently commercially available have been unable to provide a consistent performance level since presence of unacceptable leakage levels in such seals has been a fairly common problem.
In addition, because of the difficulties in obtaining proper flatness and opposed flat engagement between the opposed contacting seal faces defined on the diametrically-split rotor and stator face rings, some known constructions have supported these rings and specifically the rotor on resilient support rings in an attempt to compensate for irregularities and distortion. Further, in some of the known constructions the pressure of the working fluid (i.e., the pump fluid) which exists in the stuffing box in surrounding relationship to the seal assembly acts against and urges the rotor face ring more tightly against its supporting collar, and this tends to further increase distortion and the resulting overall performance problems associated with the seal assembly.
Accordingly, it is an object of this invention to provide an improved split mechanical face seal assembly which improves on and overcomes many of the disadvantages which are present in many of the current commercially available split mechanical seals.
More specifically, the present invention relates to an improved split mechanical face seal assembly wherein the stator and rotor face rings and their respective surrounding collar and gland are all split substantially diametrically and are partially factory preassembled to define a reduced number of preassembled subassemblies so as to facilitate shipping, handling and subsequent assembly onto a machine at the job site.
In a preferred embodiment of the invention, the split rotor face ring and the split supportive collar have the cooperating parts thereof subassembled into two subassemblies which define opposed halves for permitting them to be assembled on diametrically opposite sides of a shaft, with each subassembly having the rotor face ring segment carried on the support collar segment, and an elastomeric seal ring which cooperates between the segments being preassembled therebetween. The stator face ring and its supporting gland ring also have the respective split segments thereof, and the other cooperating components such as seal rings and the like, preassembled at the factory to define a pair of subassemblies.
In the improved split mechanical seal assembly of this invention, particularly a preferred embodiment thereof, the split rotor has a rear surface thereof directly and substantially rigidly seated against an opposed surface defined on the split collar, and the rotor and stator face rings have diametrical relationships such that, when externally acted on by the pressurized pump or working fluid, the pressurized fluid exerts an unbalanced force against the rotor which acts in a direction away from the seating surface to thus minimize and in fact possibly reduce the spring-induced seating contact pressure between the rotor face ring and the collar.
Other objects and purposes of the present invention will be apparent to persons familiar with seal assemblies of this general type upon reading the following specification and inspecting the accompanying drawings.