The invention relates to a loudspeaker which includes one or more drivers, a front panel and a further panel extending rearwardly therefrom. The rearwardly extending panel is typically offset towards one side of the front panel and includes an outer edge with at least portion which is curved. The provision of the arrangement of the said panels provides significant improvement in terms of the sound quality which can be achieved from the loudspeaker.

The invention to which this application relates is a loudspeaker.
It is well known to provide a loudspeaker in which an electromagnetic driver is moved back and forth to produce sound waves. The driver is typically mounted in an enclosure, which helps prevent the sound waves produced from the back of the driver from interfering with those produced from the front thereof.
The simplest type of driver mount is a flat panel with holes cut into it for the drivers. However, frequencies with a wavelength greater than the dimensions of the panel are still affected because the antiphase sound waves from the back of the driver interfere with those from the front.
In addition, the shape of the enclosure can diffract the sound waves, particularly where the higher frequencies have wavelengths similar to or smaller than the dimensions of the enclosure or sharp edges are encountered.
Diffraction can therefore change the sound from its original quality, causing peaks and troughs in the frequency response. Such degradation in sound quality is obviously undesirable for the user, and so manufacturers often use electronic systems to compensate for the diffraction.
Nevertheless, it is difficult to fully compensate for diffraction across the full range of audible sound, as compensated sound still has to travel past both external and internal corners of the enclosure, which causes time-delayed bleed through the driver cones from internal diffraction and phase-shifts from exterior cabinet corners as external diffraction.
A further type of loudspeaker is the electrostatic loudspeaker, in which a membrane is suspended in an electrostatic field, which is varied to move the membrane thereby generating sound waves. The structural design of electrostatic loudspeakers, which are generally dipole by design, allows them to be flatter than those containing conventional drivers, but a disadvantage is that the lack of enclosure, and the large size of the electrostatic membrane necessary for the generation of bass frequencies, engenders a limited off-axis frequency response.
An aim of the present invention is to provide a loudspeaker with high sound quality that overcomes at least some of the above issues.
According to an aspect of the invention, there is provided a loudspeaker comprising:                a front panel;        one or more drivers;        a panel extending rearwardly from the front panel;        characterised in that said rearwardly-extending panel has an outside edge, of which at least a portion is curved.
Typically the rearwardly-extending panel is offset towards one side of the front panel and in one embodiment extends from an edge of the front panel.
Typically substantially the whole of the outside edge of the rearwardly extending panel is curved.
In one embodiment the outside edge defines a substantially constantly changing radius of the rearwardly extending panel.
Typically the rearwardly extending panel is shaped as a portion of an ellipse or an oval. In one embodiment the portion is defined by two chords, typically at the intersection there between.
Advantageously, the shape of the rearwardly extending panel, which can also be referred to as a side panel or wing, and its arrangement, which is perpendicular to the front baffle and preferably set at an inclined angle of 7°, makes use of boundary reflection and the consequent phase change arising from when a sound-wave encounters a hard boundary, i.e. the boundary's displacement remains zero and the reflected wave changes its polarity (undergoes an 180° phase change). Therefore, that part of the wave that is reflected is now in phase with that from the front; which noticeably results, when say a 50 Hz wave is reflected, in a more substantial bass response. This particular characteristic of the rearwardly extending panel can be referred to as a Positive Phase Transformer (P.P.T.); which is quite unlike the conventional dipole characteristic, where the positive and negative phases meet and cancel to the detriment of the overall bass response.
In one embodiment of the invention the rearwardly extending panel provides a polar response with cardioid-like characteristics in a forward axis, and a combination of sub-cardioid (as a result of P.P.T.) and dipole polar response in a rearward axis. With the deepest null occurring at the rearwardly extending panel's edge; so the combination of polar patterns provides a complex pseudo-hypercardioid response at above or around 250 Hz and a sub-cardioid/dipole response below or around 250 Hz. As such, frequencies above ˜250 Hz have a much more uniform polar response than is conventionally achieved, and there are therefore substantially fewer fluctuations in sound in locations around the speaker.
As to those frequencies which are below ˜250 Hz, and as a result of the phase change characteristics of the rearwardly extending panel or wing (P.P.T) and in accordance with the invention, there is a reduction in the typical effects of bass cancellation resulting from a conventional dipole design. In practice it is found that those frequencies below 35 Hz, and in a suitably proportioned room, increasingly follow a more dipole-like characteristic; that is, the positive and negative phases meet and cancel out one another, leading to a consequent drop in sensitivity at sub-bass frequencies.
The rearwardly extending panel mitigates diffraction step loss, substantially preventing the formation of peaks and troughs in the frequency response as the constantly changing radius of the edge of the panel means that there are no significant regions along the edge thereof wherein diffraction of a particular wavelength is concentrated. The frequency response closely mimics that of the perfect sphere, as determined by Dr Olsen in the 1930's, wherein under anechoic room conditions the bass rolls off gently at around 6 dB-per-octave, without any peaks or troughs in the frequency response.
In contrast, a conventional enclosure is provided with a rear panel at a constant distance from the front panel, which defines a dimension wherein wavelengths similar or smaller thereto may cause significant diffraction in the corresponding range compared to other frequencies, thereby leading to peaks and troughs in the overall frequency response. In such enclosures the sound appears to emanate predominantly from the front thereof.
In one embodiment the provision of the rearwardly extending panel, and its defined shape, aids the detachment of a launched sound wave such that there are no significant or large drops in sound in locations around the speaker i.e. the polar response is substantially uniform as the sound wave smoothly leaves the rearwardly extending panel. This can be referred to as Enhanced Wave-launch Technology (E.W.T.)
Typically the rearwardly extending panel extends from the front panel at approximately right angles thereto.
In one embodiment the rearwardly extending panel is provided with ribs. In one embodiment the rear face of the front panel is also provided with ribs.
Typically the ribs substantially traverse the surface of the front and/or rearwardly extending panel in a non-uniformly spaced arrangement.
Typically the ribs are positioned on the rearwardly extending panel at different angles to each other, and may be straight or curved.
The ribs aid in the reduction of induced panel resonances therein. In addition they reduce the pressure drag, in an analogous manner to vortex generators utilised in aerofoil design, which create vortices for putting energy back into the flow of the boundary layer.
In one embodiment the rearwardly extending panel is provided with one or more channels between the ribs. Typically the channels extend linearly in a divergent fashion. Typically the channels are U-shaped or V-shaped.
In one embodiment the rearwardly extending panel is provided with a pattern of shapes arranged substantially across the surface of the panel, and/or at a substantially constant distance from the curved edge. Typically the shapes are arranged in an undulating formation.
Typically the shapes are recesses or protrusions having a depth of around 0.5-2.0 mm.
In one embodiment the shapes are denticular. Typically the denticular shapes are provided with longitudinal ridges, the shapes being arranged such that the ridges form a pattern of divergent lines.
In one embodiment the shapes are embossed onto sheets of material such as leather, which sheets are adhered to the side panel.
The shapes generate vortices to help prevent premature detachment of air flow and thus the sound wave from the surface, particularly the panel edge where the most turbulence is found. These forms of air flow manipulations can be referred to as Denticular Assisted Wave-launch Technologies (D.A.W.T).
In one embodiment the panels are made of a sheet material such as plywood. Typically the panels are made of a substantially void-free sheet material such as a beech or maple. These materials provide a superior impulse response.
Typically the loudspeaker drivers are mounted in the front panel.
In one embodiment the front panel is provided with two drivers each corresponding to different frequency ranges.
In one embodiment the front panel is trapezoid. In a further embodiment the front panel is substantially triangular. Typically the front panel is asymmetric.
In one embodiment the edge of the front panel defines a substantially constantly changing radius.
In one embodiment the front panel is shaped as a portion of an ellipse or an oval. Typically the portion is defined by two chords.
In one embodiment the front panel is inclined inwardly at around 5 degrees in order to time align the drivers. The top of the loudspeaker is thus inset compared to the bottom.
In one embodiment the angle between at least one of the side edges of the front panel and the lower edge is around 83 degrees. Thus the top of the loudspeaker is narrower than the bottom, and the rearwardly extending panel is inclined by around 7 degrees.
In one embodiment crossover components are provided on isolation mounts.
According to a further aspect of the invention, there is provided a loudspeaker comprising:                a front panel;        one or more drivers mounted in the front panel;        a panel extending rearwardly from the front panel;        characterised in that the rearwardly extending panel has a curved outside edge defining a substantially constantly changing radius.
With reference to FIGS. 1a-d, there is illustrated a loudspeaker 2 comprising a front panel 4 provided with an upper aperture 6 and a lower aperture 8 for receiving loudspeaker drivers corresponding to high and low frequency ranges respectively.
The front panel may be trapezoid as illustrated in FIG. 1a, with the following dimensions: top edge 150 mm; bottom edge 610 mm; left edge 1540 mm; right edge 1555 mm.
The front panel may be inclined at an angle of 85 degrees from horizontal for the purpose of time alignment of the two drivers' acoustic centres, resulting in a height of 1535 mm.
As shown in FIGS. 1a and 1b a rearwardly extending panel 10 extends rearwardly at a right angle from the front panel and is typically offset to one side of the front panel and yet further can be located at one edge of the front panel. The rearwardly extending panel 10 has a curved outside edge 11 which defines a substantially constantly changing radius. This helps prevent the formation of peaks and troughs in the frequency response that may otherwise form if a significant portion of the edge was at a constant distance from the drivers in the front panel, as tends to be found with faces of a conventional rectangular cuboid enclosures.
The front panel may also have a curved edge for similar reasons, such as that illustrated in FIG. 6 wherein the front panel 4′ is substantially triangular and the right hand edge 46 has a substantially constantly changing radius.
The rearwardly extending panel may have the following dimensions: long straight side edge 1520 mm; short straight bottom edge 440 mm; maximum radius (i.e. distance between intersection of straight edges and curved edge) 510 mm.
The rearwardly extending panel 10 is, in the embodiment shown, provided with three spaced ribs 12 extending thereacross at different angles to each other. The ribs allow for the reduction and even distribution of induced panel resonances, thereby avoiding large resonant peaks, therein which may otherwise distort the sound.
Crossover components 14, 16 on isolation mounts are also provided in the base 15 of the loudspeaker to separate out the high and low frequencies from the source for reproduction by the respective drivers.
The crossover components may include a 1st Order Butterworth alignment, with a crossover point of 295 Hz. This is linear phase and provides a superior impulse response, when compared to 2nd, 3rd and 4th Order crossover alignments.
A single inductor may be used for the bass leg, and a single capacitor for the tweeter leg. The product may incorporate drivers in the form of a Manger 8″ full range driver and an Acoustic Elegance 15″ bass driver.
Isolation mounts have been applied to three aspects of the design:                a) Full range driver mounting. This decouples the 'full-range driver' from the negative effects of unwanted vibration from the bass driver.        b) Isolation of the 'spiked' base 15 from the front panel 4, side panel 10 and sub-base assembly; effectively isolating the loudspeaker from transmitting vibration to the floor on which the base is positioned and thereby inhibiting subsequent floor interaction.        c) Isolation of the crossover boxes 'cylinders' from the front panel 4, side panel 10 and sub-base assembly. This last method of decoupling, isolates the crossover components, capacitor and inductor (these are potentially microphonic) from outside vibrations.
When viewed from above as shown in FIG. 1d, it can be seen that the front 4 and rearwardly extending 10 panels are inclined inwardly by a small angle with respect to the vertical planes 17, 19 respectively and in one embodiment the angle is 5 degrees for the front panel 4 and 7 degrees for the rearwardly extending panel 10 from the base to the top and with respect to the vertical axis, and this feature helps time align the drivers.
As illustrated in FIG. 2a, the polar response of a conventional speaker 18 is dipole 20, in contrast to that of the speaker of the invention shown in FIG. 2b, wherein the defined shape of the rearwardly extending panel 10, and its arrangement, provides a polar response with cardioid-like characteristics 22 in a forward axis, and a sub-cardioid/dipole response 24 in a rearward axis, such that the combination of the two polar patterns provides a pseudo-hypercardioid response 26.
FIG. 3a illustrates a further embodiment of the rearwardly extending panel 10 of the invention wherein divergent linear channels 28 are formed between the ribs 12 of the rearwardly extending panel 10, which help reduce pressure drag across the back face of the side panel.
These channels could be V-shaped 28′ or U-shaped 28″, as respectively illustrated in FIGS. 3b-c. The channels can be machined into the panel with a width of around width 3.175 mm and depth of around 1.5-2.0 mm. The removed material would thereby leave ridges across the surface area of the panel. The edges of each machined channel, nearest the constantly changing radius, would form the basis of a 'clam-shell' undulating pattern.
FIG. 4a illustrates a further embodiment of the rearwardly extending panel of the invention wherein a pattern extends across a portion 21 of the panel with the pattern portion at a constant distance of 153 mm from the curved edge, as indicated by dashed line 30. In each case the pattern's shapes generate vortices to help prevent premature detachment of air flow and thus the sound wave from the surface, particularly the panel edge 11 where the most turbulence is found.
The pattern may be in the form of dimples in the form of large and small shallow holes having respective diameters of around 6.35 mm and around 3.175 mm as illustrated in FIG. 4b. The depth of these holes is around 1.5-2.0 mm, with a V or U shaped cross-section.
Alternatively, as illustrated in FIG. 4c, a slotted pattern may be routed into the surface of the side panel to a depth of around 1.5-2.0 mm, the slots having alternating lengths of around 8.0 or 15.0 mm and a width of around 3.175 mm.
A further alternative is to provide denticle-shaped veneers, having a depth of 0.5 mm-0 mm, which may be attached to the surface of the rearwardly extending panel with adhesive, as illustrated in FIG. 4d.
FIG. 5a illustrates a further embodiment of the rearwardly extending panel 10 of the invention wherein sheets of material, in this case, leather 38 are applied to the rear of the rearwardly extending panel 10, the leather sheets being embossed with a denticle pattern, which is anatomically analogous to those found naturally, such as a sharks skin.
As illustrated in FIGS. 5c-e, the denticles 42 are provided with ridges 44. The shapes are arranged such that the ridges 38 form a pattern of divergent lines 40, as illustrated in FIG. 5b, and help reduce pressure drag, akin to the channels described in FIGS. 3a-b.
Thus in use, the loudspeaker produces a sound with a more uniform polar response, as the rearwardly extending panel assists the smooth detachment of the launched sound wave; and mitigates diffraction step loss.
The effect is that the sound quality is higher than a conventional loudspeaker, resulting in a more uniform off-axis reproduction across different locations.
It will be appreciated by persons skilled in the art that the present invention may also include further additional modifications made to the device which does not affect the overall functioning of the device.
While the invention has been described with a certain degree of particularity, it is manifest that many changes may be made in the details of construction and the arrangement of components without departing from the spirit and scope of this disclosure. It is understood that the invention is not limited to the embodiments set forth herein for purposes of exemplification, but is limited only by the scope of the attached claims, including the full range of equivalency to which each element thereof is entitled.


A semiconductor device has a first guard ring surrounding a circuit region, a second ring disposed between the circuit region and the first guard ring, and first connections connecting the first guard ring and the second guard ring to each other. An area sandwiched between the first guard ring and the second guard ring is divided by the first connections into a plurality of subareas. Even if the first guard ring is partly defective, water enters from outside into only the subarea which is contiguous to the defective part of the first guard ring.

1.Field of the Invention
The present invention relates to a semiconductor device having a circuit region where semiconductor components such as transistors or the like are formed.
2.Description of the Related Art
Heretofore, semiconductor devices have had a circuit region where circuits such as memories, logic circuits, etc., are formed, and a guard ring for preventing water from entering the circuit region from the surrounding area. The guard ring extends along the periphery of the chip and is made of a metal such as copper (Cu) or the like. One known guard ring is disclosed in Japanese Patent Laid-open Publication No. 45766/97,for example, as follows: A semiconductor device has an outer guard ring disposed near the periphery of a chip and an inner guard ring disposed between the outer guard ring and a circuit region. The outer guard ring and the inner guard ring jointly make up a double guard ring assembly. The double guard ring assembly is advantageous in that even if the outer guard ring is defective, allowing water to enter a region inward of the outer guard ring from outside of the chip, the inner guard ring prevents the water from entering the circuit region.
However, the double guard ring assembly is a mere combination of two guard rings. Therefore, when water happens to enter a region inward of the outer guard ring from outside of the chip through a defect in the outer guard ring, if the inner guard ring has a defect somewhere therein, the water finds its way through the defect in the inner guard ring into the circuit region, tending to corrode circuit interconnections in the circuit region.

Semiconductor device with guard ring for preventing water from entering circuit region from outside


The shock-absorbing packing material has a pair of first grooves each formed in a portion of the interior face of the first wall in connection with the interior face of the second wall, and a pair of second grooves each formed in a portion of the interior face of the first wall in connection with the interior face of the third wall.

1. Field of the Invention
The present invention relates to a shock-absorbing packing material which is put in a gap between an electronic device such as a television receiver and a cardboard box when the electronic device is packed in the cardboard box.
2. Description of Related Art
A television receiver, which is also hereinafter referred to as "TV receiver" for short, is packed in a cardboard box at the time of factory shipment. In packing a TV receiver in a cardboard box, a shock-absorbing packing material is put in a gap between the cardboard box and the TV receiver. The shock-absorbing packing material is a foamed resin molding, and specifically a member which absorbs a physical shock to prevent the shock from reaching the TV receiver when the cardboard box with the TV receiver packed therein receives the shock owing to e.g. drop of the cardboard box or collision with other object.
FIG. 10 is a front-side sectional view showing the condition where a TV receiver is packed in a cardboard box, which is known in the art. FIG. 11 is a lateral sectional view of the cardboard box with the TV receiver packed therein as shown in FIG. 10. FIG. 12 is a perspective view of a shock-absorbing packing material conventionally used for a TV receiver. As shown in FIGS. 10 and 11, a TV receiver 3 is packed in a cardboard box 1, and each shock-absorbing packing material formed from a foamed resin molding is arranged in contact with adjacent four faces of the cardboard box 1. Now, in the description below, a corner portion formed by butting different exterior faces on each other is termed "an exterior ridgeline", a corner portion formed by butting different interior faces on each other is termed "an interior ridgeline", a point where different exterior ridgelines gather is termed "an exterior apex", and a point where different interior ridgelines gather is termed "an interior apex".
Shock-absorbing packing materials 92b arranged against a lower portion of the TV receiver 3 is disposed so as to support the lower portion of the TV receiver 3 from left and right sides thereof. Shock-absorbing packing materials 92a and 92c arranged against an upper portion of the TV receiver 3 are disposed so as to support the upper portion of the TV receiver from front and rear sides thereof.
The shock-absorbing packing material 92a shown in FIG. 12 is arranged so as to support the exterior ridgeline of the front side of the upper portion of the TV receiver. However, the shock-absorbing packing materials 92b and 92c arranged in the other places have a similar shape. As shown in FIG. 12, the shock-absorbing packing material 92a has: a first wall 921 which is an elongated member; a second wall 922 having the same length as the first wall 921 has; and a pair of third walls 923 provided integrally with the first wall 921 and the second wall 922 at right angles with respect to the lengthwise directions of the first and second walls. The first wall 921 and second wall 922 are joined with their ends abutting against each other so that they coincide in lengthwise direction with each other.
When the TV receiver 3 is packed in the cardboard box 1, the shock-absorbing packing material 92a is disposed so that the interior ridgeline formed by the interior face of the first wall 921 and the interior face of the second wall 922 abuts against a corner ridge portion of the TV receiver 3 on the front side of the upper portion thereof. In addition, the paired third walls 923 are disposed with their interior faces abutting against two opposing side faces of the TV receiver 3. Likewise, the corner ridge portion located on the rear side of the upper portion of the TV receiver 3, and left and right corner ridge portions of the lower portion of the TV receiver are held by the shock-absorbing packing materials 92b and 92c (see FIGS. 10 and 11). Because of such arrangement that the TV receiver 3 is arranged in the cardboard box 1 with shock-absorbing packing materials 92a, 92b and 92c put therebetween, physical shocks owing to drop of the cardboard box 1 and collision with other object never reach the TV receiver.
Meanwhile, a TV receiver is often out of balance in weight on the whole depending on the shapes and layout of members and constituents arranged therein, which include a CRT (Cathode Ray Tube) and a power supply device, etc. In many TV receivers, they are heavier on the front side where an image-display portion of CRT is located compared to the other sides. When a cardboard box in which a TV receiver heavier on its front side as such is packed drops from an elevation, a corner ridge portion or an apex portion of the front side of the cardboard box will come into contact with the face of the floor first.
Hence, drop tests in which actual dropping conditions of a cardboard box with a TV receiver 3 packed therein are duplicated have been carried out. FIG. 13 is an illustration for explanation of such drop tests. The indications of front and bottom faces in FIG. 13 represent the faces which the front and bottom faces of the TV receiver 3 front on.
As described above, the TV receiver 3 is out of balance in weight on the whole. Therefore, in the first test, the cardboard box is dropped so that an apex formed by its front, upper and side faces comes into contact with the face of the floor first, as shown in FIG. 13. After that, in the second test, the cardboard box is dropped so that a ridgeline formed by the front face and upper face comes into contact with the face of the floor first. In this test, the exterior face of the first wall 921 of the shock-absorbing packing material 92a abuts against the upper face of the cardboard box 1, the exterior face of the second wall 922 abuts against the front face, and the exterior faces of the paired third walls 923 abut against the two side faces.
FIG. 14 is a sectional view showing the result of the drop test. After the first test, in the shock-absorbing packing material 92a, a crack Cr arose extending from the following three ridgelines: i.e. the interior ridgeline formed by interior faces of the first wall 921 and the second wall 922; the interior ridgeline formed by interior faces of the second wall 922 and the third wall 923; and the interior ridgeline formed by interior faces of the third wall 923 and the first wall 921 located near the apex that reached the floor face first.
As shown in FIG. 14, formed was a crack Cr running from the interior ridgeline formed by the first wall 921 and the second wall 922 of the shock-absorbing packing material 92a to the exterior ridgeline formed by the first wall 921 and the second wall 922, i.e. a crack Cr running at an angle of 45 degrees with respect to the faces of the first wall 921 and the second wall 922 against which the TV receiver 3 abutted. The shock-absorbing packing material 92a with the crack Cr thus formed was used to execute the second test. Then, the cardboard box received a shock owing to the weight of the TV receiver 3 which widened the crack Cr of the shock-absorbing packing material 92a, namely a shock enough to jam the corner ridge portion of the TV receiver 3 into the crack Cr. Consequently, the crack Cr of the shock-absorbing packing material 92a reached the exterior ridgeline, and the TV receiver 3 ended up as crashing into the face of the floor and being fractured.
To avoid the transmission of a physical shock to the TV receiver 3 in the two tests, it is sufficient to make larger the thickness of the shock-absorbing packing material, thereby to enhance the shock-absorbing ability of the shock-absorbing packing material 92a. However, the increase in the thickness of the shock-absorbing packing material 92a boosts the amount of the foamed resin used to form the shock-absorbing packing material 92a and therefore raises the cost. In addition, the increase in the thickness of the shock-absorbing packing material 92a makes larger outer dimensions of the cardboard box 1. Such increase of the outer dimensions decreases the number of cardboard boxes which can be loaded in a container used for shipment of TV receivers 3, resulting in the increase in the transportation cost.
Under these circumstances, a method for reducing the fracture of the shock-absorbing packing material owing to the shock by drop has been proposed. For instance, JP-UM-A-58-65268 discloses a device in which relief portions having the shape of a groove are provided in two faces forming a ridgeline in order to disperse a stress produced in a corner portion at the time of drop, and in the other face, i.e. the remaining one of three faces forming the ridge corner of interest, a relief portion is provided diagonally with respect to the ridge corner. According to the device, the stress arising at the time of drop can be dispersed.
Also, JP-UM-A-61-77372 discloses a device in which a reentrant portion is provided in a corner portion to control the force caused by a physical shock, whereby a fracture is minimized.
Further, in the device disclosed by Japanese Utility Model Registration No. 3,072,574, a gap is formed between a corner portion of a shock-absorbing material and a corner portion of a TV receiver, thereby preventing direct transmission of the force caused by a physical shock to the TV receiver.
However, the device disclosed by JP-UM-A-58-65268 is based only on the assumption that a corner ridge portion comes into contact with a floor first, i.e. only the condition where the second test as shown in FIG. 13 is executed is assumed therein. In reality, it is conceivable that the force is applied all the three corner ridge portions as assumed in the first test. In such case, the stress can be concentrated on a corner ridge portion where no relief portion is formed.
Also, while in the device disclosed by JP-UM-A-61-77372, a reentrant portion is provided in a corner portion to control the force caused by a physical shock, the reentrant portion for controlling such force has a complicated form, and needs labor and time for manufacturing. In addition, with the device, a corner portion of a cardboard box is squashed thereby to reduce the first shock for the purpose of dispersing the force caused by a physical shock. Therefore, when drop of the cardboard box (the second test) is executed so that the corner ridge portion reaches a floor first after the first drop of the corner portion (the first test), the effect of the reentrant portion cannot be expected.
Moreover, with the device disclosed by Japanese Utility Model Registration No. 3,072,574, the transmission of the force caused by a physical shock from the shock-absorbing material to the TV receiver is delayed thereby to consume the energy when the shock-absorbing material is deformed, and thus the force caused by a physical shock is weakened. However, when the shock-absorbing material receives a physical shock such that the shock-absorbing material is fractured, the shock will be transmitted to the TV receiver.

Shock-absorbing packing material, and shock-absorbing packing material for television receiver


A check valve assembly for a shock absorber includes a tapered valve seat and a polygonal check valve which includes a plurality of flat surfaces. Each pair of flat surfaces intersects at a linear engagement surface which slidably engages a cylindrical chamber. When the polygonal check valve is in an open position, fluid flows along the flat surfaces even though the linear engagement surfaces are essentially in contact with the cylindrical chamber. Lateral movement of the check valve is effectively eliminated which minimizes noise and vibration of the cheek valve assembly.

This invention relates to a shock absorber check valve, and more particularly, to a shock absorber having a check valve damping adjustment.
Shock absorbers are used in vehicles to dampen inputs from roadways. For some vehicle applications, such as snowmobiles, it may be highly desirable to provide the operator with the ability to externally adjust damping characteristics of the shock absorber. To this end, some shock absorbers have incorporated a fluid passageway in the shock absorber piston rod to fluidly connect the rebound and compression fluid chambers. The rod includes a longitudinal bore with a plunger arranged within the bore. An adjustment knob, which is accessible to the vehicle operator from the exterior of the shock absorber, cooperates with the plunger to move the plunger between various positions to control the flow of fluid through the passageway. In this manner, the operator may adjust damping characteristics.
A fluid bypass passageway typically extends between portions to fluidly connect rebound and compression chambers. In this manner, fluid is permitted to flow through the rod to provide damping characteristics in addition to those damping characteristics typically provided by the piston. A valve assembly, which may include a one-way check valve, is arranged within the passageway for controlling the flow of fluid between the rebound and compression chambers through the passageway. Disadvantageously, the shock absorber rod may encounter erratic and noisy behavior in recoil forces verses displacement due to operation of the check valve.
Accordingly, it is desirable to provide a check valve assembly which minimizes or eliminates the erratic and noisy behavior.

Shock absorber non-vibrating check valve assembly


An improved dynamic random access memory (DRAM) having self refresh mode is provided. After initiation of a self refresh term Ts, and in a first term Tc1 and a last term Tc2, a concentrated refresh using a refresh clock signal /REFS having a short period Pc is carried out for all rows in a memory cell array. During the remaining term, a normal self refresh operation using a signal /REFS having a long period Ps is carried out. Stored data is maintained effectively because the refresh interval of each row in a memory cell array is prevented from exceeding significantly a predetermined time length Ps.

1. Field of the Invention
The present invention relates generally to dynamic random access memory devices, and more particularly, to improvement of a dynamic random access memory device having a self refresh mode.
2. Description of the Background Art
A dynamic random access memory (referred to as "DRAM" hereinafter) having a memory cell formed of one switching transistor and one data storing capacitor is widely used as a semiconductor memory suitable for increase in integration density in a semiconductor substrate. Because a DRAM holds a data signal by a capacitor, it is necessary to amplify periodically the data signals stored in the capacitor, i.e. a refresh operation must be carried out. Almost all of the recent DRAMs have a function to carry out refresh operation without needing an internal or external refresh control (generally called "a self refresh function"). An example of a DRAM including a self refresh feature is disclosed in U.S. Pat. No. 4,933,907 granted to the applicant of the present application. A document entitled "MITSUBISHI LSIs" (October 1991; pp. 1/28-10/28, 20/28) discloses a more specific self refresh operation in a DRAM.
FIG. 7 is a block diagram of a DRAM for showing the background of the present invention. Referring to FIG. 7, a DRAM 100 includes a memory cell array 1 including 4,718,592 memory cells arranged in rows and columns, a row decoder 2 for selecting a word line in memory cell array 1, a column decoder 3 for selecting a column of a memory cell to be accessed, an address buffer 4 for receiving address signals A0-A9 externally applied in a time divisional manner, a sense refresh amplifier 5 connected to a bit line in memory cell array 1, and an IO gate circuit 6 responsive to an output signal of column decoder 3 for selectively connecting a bit line in memory cell array 1 with an input buffer 7 and an output buffer 8. In FIG. 7, line 100 also indicates a semiconductor substrate.
A clock signal generator 9 responds to an externally applied row address strobe signal /RAS and a column address strobe signal /CAS to generate various clock signals for controlling a circuit in DRAM 100. Refresh control circuit 10 operates in response to a refresh control signal CBR provided from clock signal generator 9 to generate a refresh address signal RFA.
In writing operation, externally applied data signals DQ0-DQ8 are provided to IO gate circuit 6 via input buffer 7. Column decoder 3 selectively conducts one switching circuit (not shown) in IO gate circuit 6 by decoding a column address signal CA provided via address buffer 4. Therefore, the data signal is applied to a bit line (not shown) in memory cell array 1. Row decoder 2 decodes a row address signal RA provided via address buffer 4 to selectively activate one word line not shown. Thus, one data signal on a bit line is written into one memory cell (not shown) specified by row decoder 2 and column decoder 3.
In reading operation, a stored data signal is applied on a bit line (not shown) from a memory cell specified by row decoder 2. The data signal on the bit line is amplified by sense refresh amplifier 5. Because column decoder 3 selectively conducts one switching circuit (not shown) in IO gate circuit 6, the amplified data signal is provided to output buffer 8. Thus, data stored in memory cell array 1 is output via output buffer 8.
FIG. 8 is a circuit diagram showing a portion of a conventional bit line peripheral circuit. FIG. 9 is a timing chart for describing the operation shown in FIG. 8. The bit line peripheral circuit of FIG. 8 is described in Digest of Technical Papers, pp. 252-253 of International Solid-State Circuits Conference (ISSCC 85) held in 1985.
Referring to FIGS. 8 and 9, when a word line WLi is activated in reading operation, a switching transistor Qs of a memory cell MC is turned on. Therefore, the data signal stored in a capacitor Cs in memory cell MC appears on a bit line BLj. Because sense amplifier 5 formed by transistors Q1-Q4 is activated in response to activation control signals S.sub.P and S.sub.N, a slight potential difference between bit lines BLj and /BLj is amplified by sense amplifier 5. A column select signal Yj of high level from column decoder 3 is supplied to the gates of transistors Q8 and Q9, whereby transistors Q8 and Q9 are turned on. Therefore, the data signal amplified by sense amplifier 5 is supplied to a pair IO lines 6a and 6b. The data signal on IO line pairs 6a and 6b is sent to output buffer 8.
Although a general read out operation has been described in the foregoing, it is to be noted that a similar operation is carried out in a refresh operation. However, a column select signal Yj of a high level is not provided in a refresh operation, so that transistors Q8 and Q9 are not turned on. The data signal amplified by sense amplifier 5 is applied to capacitor Cs again via a conductive switching transistor Qs. That is to say, although the signal charge held in capacitor Cs gradually decreases in accordance with time, the signal charge is restored by a periodic amplification and rewrite operation by sense amplifier 5. A refresh operation of a DRAM is carried out as described above in a detailed circuit.
FIG. 10 is a circuit block diagram of a refresh control circuit 10 shown in FIG. 7. Referring to FIG. 10, clock signal generator 9 includes a CBR detection circuit 14 for detecting a CAS-before RAS (referred to as "CBR" hereinafter) refresh mode. CBR detection circuit 14 detects a low level of an externally applied column address strobe signal /CAS prior to the fall of an externally applied row address strobe signal /RAS, whereby an externally requested CBR refresh mode is detected. When a CBR refresh mode is detected, CBR detection circuit 14 generates a signal CBR.
Refresh control circuit 10 includes an oscillator 11 for generating a clock signal .phi.i, a timer circuit 12 for generating a refresh clock signal /REFS, and a refresh address counter 13 for generating an internal refresh address signal RFA.
FIG. 11 is a timing chart for describing the operation of the circuit shown in FIG. 10. Referring to FIG. 11, after the fall of signal /CAS at time t3, signal /RAS falls at time t4. CBR detection circuit 14 shown in FIG. 10 supplies signal CBR to oscillator 11 and timer circuit 12.
Oscillator 11 responds to signal CBR to generate a clock signal .phi.i. Timer circuit 12 initiates a self refresh mode operation by detecting a continuation of signal /RAS at a low level for more than a predetermined time length Tw (for example 100 .mu.s) after the provision of signal CBR. More specifically, timer circuit 12 generates a clock signal /REFS for self refresh in response to clock signal .phi.i after time t5 shown in FIG. 11. Clock signal /REFS is applied to clock signal generator 9 and refresh address counter 13.
Therefore, after time t5, refresh address counter 13 counts a self refresh clock signal /REFS to generate a refresh address signal RFA. The refresh address signal RFA is supplied to row decoder 2 via address buffer 4 shown in FIG. 7, whereby a refresh operation of memory cell array 1 is carried out. Self refresh clock signal /REFS has a predetermined period Ps. The increment interval of refresh address signal RFA is determined by the time length of Ps.
At time t8, signals /RAS and /CAS rise, whereby the self refresh operation is completed. After time t8, the DRAM returns to the normal operation mode. Referring to FIG. 11, term Ts indicates a self refresh period (not less than 100 .mu.s), and term Tn indicates a normal operation period.
For a 1 megabit DRAM having an organization of (256 rows.times.256 columns).times.16 bits, the maximum time interval required for 256 memory cells connected to one row is 4 ms, for example. It is necessary to sequentially refresh 256 rows in the memory cell array during this time interval. The refresh period Ps in a self refresh operation is generally set to 8-16 times an externally requested refresh period, for example, a CBR refresh period. The power consumption in a self-refresh operation can be reduced by reducing the number of times of charging a bit line per a unit time. Here, a refresh period is equivalent to a time length from a refresh operation of one row in a memory cell array to the next refresh operation of that row. Presuming that the self refresh period is set to 64 ms, the period Ps of clock signal /REFS shown in FIG. 11 is 250 .mu.s (=64 ms.div.256 rows).
FIG. 12 is a timing chart showing the operation of the circuit of FIG. 11 in a range of a longer time period. Referring to FIG. 12, it is presumed that memory cells of all the rows (for example 256 rows) in the memory cell array are refreshed by an externally requested refresh operation (for example, a CBR refresh) within term Tec starting from time t1 to time t2. During term Tec, 256 rows in the memory cell array are refreshed starting from a beginning row SR1 to a last row LR1.
A self refresh operation is initiated from time t5. During term .DELTA.T0, a starting row SR2 to a last row LR2 are refreshed of the 256 rows in the memory cell array. This time length .DELTA.T0 is equivalent to a self refresh period, i.e. 64 ms in the above-described example. A DRAM in this embodiment is ensured by design that stored data is effectively maintained as long as each memory cell row is refreshed at a time interval of .DELTA.T0.
However, it can be appreciated from FIG. 12 that a last row in the memory cell array is refreshed at time t2 (LR1), and then refreshed at time t6 (LR2). It is apparent that the time length .DELTA.T1 starting from time t2 to time t6 exceeds the time length of .DELTA.T0. This means that the maintenance of the data stored in the last memory cell row is not guaranteed. In other words, the data stored in the last memory cell row may be lost.
Similarly, it is presumed that an externally requested refresh operation is initiated at time t9 after the termination of a self refresh operation at time t8. Therefore, a beginning row SR4 to a last row LR4 of 256 rows in the memory cell array are refreshed during term Tec starting from time t9 until time t10. As a result, the last row in the memory cell array is refreshed at time t6 (LR2), and then the refreshed at time t10 (LR4). It is apparent that the time length of .DELTA.T2 from time t6 to time t10 is longer than the time length of .DELTA.T0. Therefore, the data stored in the last memory cell row may be lost.
In order to prevent stored data from being lost, the time length from time t2 to t4 shown in FIG. 12 was limited to be not so longer than time length .DELTA.T1 in a conventional DRAM. That is to say, operational limitation in an external circuit was required.

Dynamic random access memory device having a self refresh mode


A method is provided for forming a sand core which is suitable for use in casting processes, and in particular squeeze casting processes, to form internal features and intricate external features of a cast article. The core forming method involves the use of a single-component gelatin binder whose degradation at elevated temperatures is catalyzed by additions of a ferric compound. The gelating binder is a mixture of proteins derived from amino acids such as glycine, alanine, L-glutamic acid, L-aspartic acid, and/or small percentages of others, such that the gelatin binder is water soluble and therefore easily eliminated from the core sand at the end of the casting process. Due in particular to the presence of the ferric compound, the gelatin binder readily degrades at low temperatures, such as those associated with aluminum casting processes, such that the core degrades sufficiently to permit the sand to freely flow from the cast article without the need for core removal operations. Finally, the gelatin-based binder is nontoxic, such that its elimination from the sand to reclaim the sand for reuse does not pose an environmental hazard.

The present invention generally relates to binders used with sand casting processes and operations. More particularly, this invention relates to an improved binder for cores of the type which are placed in a mold cavity to form the interior surfaces of a casting, wherein the binder is characterized as imparting improved hot strength to the core while also being composed primarily of gelatin so as to be water soluble and nontoxic, and therefore capable of being readily and economically removed from the sand after the casting process, so as to facilitate the recycling of the sand for continued use without imposing an environmental hazard.
Metal casting is a widely practiced process for making ferrous and nonferrous articles which involves providing a mold cavity and pouring molten metal into the cavity so as to form a cast article. Where an intricate and complex casting is required, a core molding process is employed which entails placing a shaped and somewhat rigid form or core within the mold cavity to form particular features of the casting, such as interior surfaces of cavities and intricate features in the casting's exterior surface. One or more cores can be readily used in a casting process, either as assembled units or individually in separate areas of the mold cavity. Cores can be used in both sand-casting and permanent-mold casting methods and are typically formed of sand.
The shape of the core is maintained by the use of binders which adhere the sand particles together. The type of binder employed depends upon such factors as the green strength required of the core for handling, the anticipated interval between the time the core is formed and used, possible degradation by moisture or other atmospheric conditions, and the hot strength required of the core during the molding operation for maintenance of the core geometry until the casting has sufficiently solidified.
Hot strength is a particularly important property for cores used in squeeze casting processes, wherein high pressure is typically applied by a hydraulic press and maintained on the molten metal as it solidifies. Squeeze casting is a highly desirable technique for forming castings because it can be used for a variety of ferrous and nonferrous alloys to produce pore-free, fine-grain castings with excellent mechanical properties. Furthermore, squeeze casting is a relatively economical process and can be automated to operate at high rates of production. However, in combination with the elevated temperatures created by the molten metal, the high pressures associated with squeeze casting are particularly detrimental to the structural integrity of sand cores used within the mold cavity.
In the prior art, various types of binders are known, both organic and inorganic, for adhering the sand particles together. Linseed oil-based organic binders are widely used and contain a resin and thinner, such as high-grade kerosene, to provide good wetting and workability properties. Other known organic binders, including plastics of the urea- and phenol-formaldehyde groups, are also widely used. These organic binders generally entail a two-part polymer resin which is set during the core forming process so as to form an extremely durable core.
While plastic binders have generally performed well in iron casting operations, such binders are not readily volatilized or broken down at lower molding temperatures, such as those associated with aluminum casting operations. As a result, all or some of the core sand may not be readily removable from the casting after it has cooled. Obviously, a casting will be unusable if the core cannot be removed from the casting. Furthermore, where the core has not sufficiently degraded to allow the sand to flow freely from the casting, mechanical operations used to forcibly shake or extract the core from the casting may result in the destruction of the casting. In addition, because most current binders are thermoplastic materials, they also tend to flow or distort under the high heat and pressure of a squeeze casting operation, and therefore do not produce dimensionally accurate cavities when used in such operations.
An additional shortcoming of these conventional binders is that gases produced when such binders are volatilized are undesirable from the standpoint of causing porosity in the casting, as well as the potential environmental hazards which they may pose. Environmental hazards often persist after the casting operation when the core sand is disposed of or recycled for reuse within the foundry. Whether the binder residue is soluble in some medium or must be combusted, the process necessary to reclaim the sand will often have a harmful byproduct which cannot be returned to the environment because the binder residue within the byproduct may leach off into the ground water and cause contamination. Because such binders are not usually removable by use of a solvent, the need to burn the residue becomes a costly disadvantage which still poses an environmental hazard in the form of air pollution. Furthermore, disposal of the used core sands without clean-up is costly with current binders because the binder residues are toxic and render the sand/binder mixture a toxic waste, requiring disposal in an appropriate land fill.
As a result, binders which can be more readily extracted from the sand with less concern for their impact on the environment are generally preferred. Such binders include corn flour and dextrin, which both rely upon the hydrolysis of starch to form a colloidal product which can bind the sand particles together. However, both of these binders must often be used in conjunction with adjuncts, such as urea- or phenol-formaldehyde resins and acid catalysts, to achieve adequate green strength and/or improve its shelf life. As an example, U.S. Pat. No. 4,711,669 to Paul et al suggests mixing the reaction product of glyoxal, urea, formaldehyde, ethylene glycol, an acid catalyst and a solvent with a polyol to improve the crosslinking of the polymers and thereby improve the resistance of the core to deterioration by moisture. However, a particular disadvantage to increasing the crosslinkage of the polymers is that higher temperatures are necessary to break the bonds of the polymer structure, and therefore sufficiently degrade the binder so as to free the sand from the casting. In addition, such an adjunct-doped binder poses to some degree the same environmental hazards and economic disadvantages noted above with plastic binders.
Other alternatives known in the prior art include protein binders such as gelatin, casein and glues. These binders may generally be characterized as providing improved flowability of the sand, high binding power, rapid drying, fair resistance to moisture, and a low burn-out temperature, with only a small volume of gas being produced as the binder becomes volatilized. Protein binders also have a crystalline structure and therefore do not have a transition temperature for melting as do thermoplastics. As a result, protein binders do not soften when heated, but hold their crystalline structural shape until they begin to decompose by oxidation. In addition, disposal of protein binders does not pose an environmental hazard in that such binders readily decompose to a nontoxic form. However, the nature of the green strength of cores made with protein binders and their slow breakdown by oxidation generally hinder the ability of protein binders to be tailored to a particular casting process, in view of such factors as temperature, pressure and casting size.
Thus, it would be desirable to provide a core sand binder which is relatively economical to use and provides adequate structural strength to the core and, in particular, sufficient hot strength to withstand the high pressures associated with squeeze casting processes. In addition, it would be desirable that such a binder be readily and controllably degraded at elevated temperatures and easily washed from the sand, so as to permit the core sand to be recycled within a foundry operation or returned to the environment without posing an adverse environmental impact. Moreover, it would be particularly desirable if such a binder would have the above characteristics even when used with relatively low temperature casting operations, such as that associated with casting aluminum alloys.


A computer system for interpreting seismic signals to identify reflective horizons is disclosed. The seismic signals are retrieved and conventional corrections are applied. A seismic survey is displayed, and a human analyst places horizon lines or surfaces above or below suspected reflective events in the survey. The disclosed method then operates on a trace by trace basis to identify the location in time at which the attribute, which may be amplitude, envelope amplitude, phase, frequency and the like, meets a draping criterion. The interpreted horizon is set at the identified depth or time location, and the interpreted horizon points are connected into an interpreted horizon surface (in the case of a 3-D survey). Traces having only weak or no reflections may not have an interpreted surface point, or may have an interpolated point set therefor. An automated and efficient horizon interpretation method and system, even for large surveys of complex geology, is thus provided.

The use of seismic surveys, such as those obtained through vibratory surveys of subsurface geology, is fundamental in the prospecting for oil and gas reservoirs. As, known in the art, conventional seismic surveys of both the marine and land-based variety are based upon signals detected by arrays of receivers in response to many seismic "shots" imparted to the earth in the survey area. Dramatic improvements in the data acquisition and data processing technologies over recent years have made the generation of three-dimensional seismic surveys commonplace in the art, and have greatly improved the sensitivity and resolution of the surveys. These improvements have been necessitated by the inherent difficulty in finding those reservoirs of the world that have not been previously exploited.
After recording and storage of the detected seismic signals, conventional seismic signal processing techniques process and spatially arrange the data into a survey of the subsurface geology. Conventional techniques such as normal moveout, migration to correct for dip and diffraction effects, and noise filtering, are first applied to the seismic signals to remove known sources of error. Spatial arrangement of the corrected signals, using conventional techniques such as common midpoint gathers and stacks, generation of amplitude-versus-offset ("AVO") indicators, and the like, is then performed to result in a seismic survey (either two- or three-dimensional in nature) indicative of the subsurface geology in the survey region. Modern computing systems enable the handling of large volumes of signal data in the generation of these surveys, and also enable the human analyst to view three-dimensional surveys along any orientation.
After the seismic survey has been acquired, processed, and generated, the survey must be interpreted in order to fully understand the geology represented by the signal data. This interpretation, which is typically performed by a skilled analyst, generally includes the digitization of horizon surfaces within the three-dimensional survey volume. Horizon surfaces are surfaces that are selected, or numerically interpreted, to coincide with reflections in the volume represented by the seismic survey. The digitization of horizon surfaces can thus be considered to convert an arrangement of time-domain seismic signals into a graphic representation of the subsurface geology, in two or three dimensions. The depth, size, and locations of interfaces between geological formations can be deduced from such a representation, and used in guiding exploratory and production drilling, and in defining new survey techniques and arrangements. Of course, the accuracy with which the horizon surfaces are digitized or interpreted is critical in the success of such activities.
A first conventional method for interpretation of horizons from the seismic survey is commonly referred to in the art as direct manual picking. According to this approach, a planar "slice" in the three-dimensional survey volume is selected by the interpreter and is displayed, generally on an interactive computer system but also possibly by way of printed output (in more primitive systems). While the slice is typically made along one of the three orthogonal axes in the volume of line, crossline, and time, a slice may also be made along traverses not aligned with any one axis. In direct manual picking, the human analyst merely selects the location of horizon surfaces using his or her judgment, based upon the seismic signals themselves, and indicates the selection by activating a pointing device (mouse, trackball, etc.). While direct manual picking may be quite accurate when done by an experienced analyst, the sheer volume of seismic data in conventional three-dimensional surveys makes such an approach extremely slow, time-consuming, and costly.
By way of further background, an operation commonly referred to as "snapping" is conventionally applied to manually picked interpreted horizons. As is known in the art, hand-picked horizons are generally not precisely located on reflection events because of manual picking errors. The snapping operation is performed by moving the horizon along each trace from the initial manually picked position to a local maximum amplitude (or minimum amplitude, or zero crossing, as desired), thus adjusting the horizon to precisely match the reflection event being interpreted.
A conventional semi-automated approach to horizon interpretation is commonly referred to as autotracking, or volume autotracking. According to this technique, slices are again made in the seismic survey volume, and displayed by the computer system. The human interpreter selects "seed" points which he or she considers to be at a horizon surface, but need not pick an entire surface. After such selection, the computer system begins to extend horizon surfaces from the seed points, based on a selected algorithm and according to the seismic signals at neighboring locations, resulting in a connected surface extrapolation of the horizon. Volume autotracking is generally most successful when applied to surveys of relatively smooth and well-behaved geology, however, due to its requirement that the horizon surfaces remain connected; discontinuities, faults, reflection event splitting, and other ambiguities in the geology present problems to conventional volume autotracking systems.
A third conventional approach to horizon interpretation is referred to in the art as surface-slice interpretation. This approach is described in Stark, "Surface slices: Interpretation using surface segments instead of line segments", Expanded Abstracts of the 1991 Society of Exploration Geophysicists Annual Meeting, and in Stark, "Surface slice generation and interpretation: A review", The Leading Edge, Vol. 15, No. 7 (July 1996), pp. 818-819. Surface-slice interpretation is an automated approach in which the analyst selects a thin slab of the seismic volume, for example at a selected depth or time, in which the automated computer system identifies potential reflective events. For example, seismic signal amplitudes above a certain threshold may be identified as reflective events. Reflective events are then similarly identified in the next incremental slab in time or depth, and are "joined" to those reflective events in the previous slice that can be considered as part of the same horizon. A set of surfaces are thus generated through the repetition of this process; for example, an anticline would appear as a set of concentric shells. The surface-slice interpretation system is often referred to as "21/2-dimensional", due to its linking of events from two-dimensional slices. While the surface-slice interpretation approach is somewhat more efficient than the volume autotracking approach, this process can be time-consuming and difficult when the geologic structure is complex or when the seismic signal is weak. In addition, discontinuities and faults encountered in complex geology can also result in ambiguities when interpreted by the surface-slice method.
While the automated approaches of volume autotracking and surface-slice interpretation are quite efficient for certain geologies, each of these conventional techniques are quite slow in the interpretation of complex geologies, as, of course, is direct manual picking. In addition, conventional 3-D seismic surveys now generally involve huge volumes of data; for example, a typical modern survey may consist of on the order of 2000 shot lines, each shot line having 1500 traces per shot line, and each trace having 3000 time samples. As a result, these conventional manual or automated horizon interpretation techniques can be quite time-consuming, especially when applied to large surveys involving complex geologies. Since the prospecting for oil and gas reserves are now often concentrated in difficult and deep locations of the earth, considering that many of the shallow reservoirs have already been exploited and surveyed, there is an important need in the field for an efficient approach to horizon interpretation of seismic surveys.
It is therefore an object of the present invention to provide an automated system and method for performing horizon interpretation which can be efficiently applied to complex geological survey regions.
It is a further object of the present invention to provide such a system and method in which the human effort is efficiently applied to the interpretation process.
It is a further object of the present invention to provide such a system and method which performs the interpretation process in a robust manner when encountering discontinuities, faults, reflection event splitting (doublets), and other complexities in the surveyed geology.
It is a further object of the present invention to provide such a system and method which results in a full three-dimensional horizon interpretation when 3-D seismic data is available, but which is also applicable to 2-D seismic data, and to pre-stack seismic data.
It is a further object of the present invention to provide such a system and method which can readily handle large volumes of seismic data, such as those obtained from multiple 3-D surveys, either for adjacent regions or as repeat surveys.
Other objects and advantages of the present invention will be apparent to those of ordinary skill in the art having reference to the following specification together with its drawings.

Method and system for horizon interpretation of seismic surveys using surface draping


An improved system and method for recommending a service are disclosed. A data translation system may comprise a server and a computing device. In preferred embodiments, executable logic and descriptors reflective of data designated for transformation by a hard-copy generation device and in response to the logic recommends a suitable service for completing the transformation. A method for intelligently routing hard-copy generation tasks, can be summarized by the following steps: accessing imaging service data; accessing imaging data; recommending at least one capable service; and initiating a hard-copy generation request.

As computer technology has advanced, the role of computers in our daily lives has expanded, as has the need for various peripheral support devices. One typical peripheral device used with computers is a printer, which generates hard copies of electronic data. The types and capabilities of available printers are also expanding, resulting in a variety of printers with a range of printing capabilities, performance, and price.
One significant expansion in the use of computer technology is the networking of computers. The networking of computers allows the interconnected computers to communicate with one another, as well as with other devices, such as printers. As computer networks, such as the Internet, continue to develop, there is an increasing demand for additional and improved functions that expand and exploit the potential of computer networks.
Despite the printing facilities now available due to computer networking, there still is a need for efficient and convenient printing services, as well as efficient printing resource management. Although some printing solutions exist, each is lacking in one respect or another.
For example, with one such solution, entire documents to be printed must be uploaded to a remote service to determine an appropriate fee for printing the document. This uploading can be time-consuming, particularly for large documents, and wasteful where the user determines not to print the document because he or she considers the expense too great or the capabilities of the remote service lacking.
Concerning print solution management, operators of network connected computing devices are often presented multiple print destination devices for each print task associated with a particular application. Often operators are unaware of the respective print rates and other capabilities of the various available printing devices. The resulting lack of information regarding the capabilities of the available printing devices can often lead to unnecessary operator frustration caused by frequent printing bottlenecks and repeat tasking of misrouted print jobs.

System and method for intelligent routing of tasks across a distributed network

Hewlett-Packard Development Company, L.P.


An examination system that recognizes a glycosylated antigen in Dane particles of hepatitis B virus (HBV) and a neutralizing antibody that recognizes the glycosylated antigen and that exhibits an infection-inhibiting activity. It was elucidated that Dane particles are associated with specific glycan structures, and this enabled the construction of a new detection system for infectious, i.e., nucleic acid-containing, hepatitis B virus particles and the provision of a neutralizing antibody that recognizes a glycosylated antigen and that exhibits an infection-inhibiting activity.

Hepatitis B virus (HBV) is a virus that belongs to the Hepadnaviridae family, has DNA that is not fully double-stranded, and specifically infects the human liver. HBV infection can lead to the development of acute hepatitis B, chronic hepatitis, cirrhosis, and hepatocellular carcinoma, which are serious health problems. It is believed that approximately 1% (approximately 1.1 to 1.4 million people) of the population in Japan are hepatitis B virus (HBV) carriers, and approximately 5% (350 million people) of the population worldwide are infected (as reported by the WHO).
Interferon (antiviral drug) immunotherapy and nucleic acid analogues (reverse transcriptase inhibitors) are used for the treatment of hepatitis B, but issues such as side effects and the occurrence of resistant viruses have been indicated, and new drugs with new targets are expected.
Meanwhile, vaccination is effective to prevent the spread of HBV infection. Although universal vaccination against HBV is currently being implemented in various countries and regions around the world, it is considered difficult to prevent the occurrence of new HBV infections, in part because universal vaccination was not performed in Japan until recently. Currently, vaccines (recombinant S-HBs antigen (S-HBsAg)) made in yeast are used, but all are used as proteins without glycosylation.
To induce an increase in antibody titers after vaccination, a plurality of doses (three doses) is required, and antibody acquisition is observed in nearly 90% of vaccinees with the current vaccines. However, the acquired antibody titers differ greatly between individuals. These issues of antibody induction efficiency also need to be improved to curb the costs of universal vaccination. Meanwhile, cases have been recently reported in which the HBV vaccine is not able to prevent HBV infection even though the vaccine can prevent the onset of hepatitis B. In addition, escape mutants and occult infections, which are not recognized by antibodies induced by HBV vaccination, are reported, and it is important to develop next-generation HBV vaccines (e.g., vaccines that are effective even with a low number of doses and have broader antiviral effects) and anti-HBV antibodies that can also accommodate these mutant HBVs.
Infectious HBV particles (Dane particles) and non-infectious subviral particles (SVPs) are present in the blood of HBV-infected individuals. The infectious Dane particles have a structure containing DNA in a core (containing HBcAg proteins) that is further enveloped (by HBsAg proteins), whereas the non-infectious subviral particles (SVPs) contain only HBsAg and no DNA (FIG. 1).
The HBs genes are composed of PreS1, PreS2, and S, and encode three membrane proteins (L-HBsAg, M-HBsAg, and S-HBsAg) starting from distinct translation-initiating methionine codons. Differences in the composition of these different HBsAgs-form the HBV particles (Dane particles and SVPs) described above. Conventional vaccines have glycan-free S-HBsAgs (S (−Gly)) expressed in yeast as the antigens and do not contain the glycan-bearing L, M, S (+Gly) glycoproteins contained in the actual HBV-particles. It has been suggested that SVP is present in patients' sera a thousand times or more than Dane particles, and it is assumed that the HBV recognized by the current HBV vaccination is predominantly the non-infectious SVP.
Although the proportion of the infectious Dane particles is only about 1/1000 of the non-infectious SVP, HBV is a highly contagious virus. To accurately measure the HBV particles (Dane particles) or to raise the HBV detection limits, one approach is to concentrate the infectious Dane particles. Moreover, in order to generate vaccines that efficiently induce antibodies, it is critical to select targets (antigens) that can distinguish between Dane particles and the non-infectious small particles (SVPs).
In addition, although the safety of blood donations is ensured by screening with nucleic acid tests (NAT), HBV infection is established at a low copy at or below the detection limit, so infectious accidents caused by blood transfusions still take place compared with HCV and HIV. That is, techniques to concentrate Dane particles are essential to increase the accuracy of HBV detection.

Method for efficiently inducing antibody, antibody and detection system for hepatitis virus

NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL


A dual time delay interferometer (TDI) enables remote sensing of phase modulated information, such as the detection of ultrasonic vibrations from highly diffuse surfaces, preferably in the range from about 10 kHz to 100 MHZ or more. The system can also be configured in a transceive mode with a dual pass through a single TDI, which is well suited to optical communications. A non-steady-state photo-electromotive-force detector tracks the movement of interference fringes (whose position shifts as the surface vibrates), rather than their absolute position. A phased array of the sensors can be used for enhanced imaging applications requiring better signal/noise ratios, or alternatively, when lower power optical sources are employed.

1. Field of the Invention
This invention relates to optically-based ultrasonic sensors, including optical communicators and displacement/velocity remote sensing methods, which are based on time delay interferometry.
2. Description of the Related Art
Ultrasonic acoustic waves are commonly used to probe a variety of materials, especially for thickness gauging and flaw detection. The conventional approach is to generate the waves with a contact piezoelectric transducer. The launched waves propagate through the material, reflecting from interfaces between layers of different materials in thickness gauging applications, or from internal features in flaw detection applications. The scattered waves propagate back to the surface of the material, causing its surface to vibrate at the ultrasound frequency. The surface vibration is generally detected with a contact piezoelectric transducer similar to the one used to generate the ultrasonic waves.
Optical detection techniques, such as those described by C. B. Scruby and L. E. Drain in Laser Ultrasonics, Techniques and Applications, Adam Hilger, New York (1990), pages 325-350, can be used instead of piezoelectric transducers to detect a surface's displacement. Generally, a laser beam illuminates the surface so that when it vibrates, a phase shift is imparted to the reflected beam. The reflected beam is interfered with a reference beam that originates from the same laser source as the reflected beam. The amplitude and frequency of the intensity fluctuations of the interfering beams correspond to the surface's motion and can be detected with a photodetector.
A "velocity-sensing", or time-delay, interferometer produces an output that is proportional to the velocity (or differential displacement), rather than the displacement, of the moving surface. Time-delay interferometric configurations (described in the Scruby et al. reference, pp. 123-127) provide one technique for doing this. In time-delay interferometry, a probe beam is reflected from the target surface, and the reflected beam is then split into two beams. One of the two beams is time delayed with respect to the other, i.e. it traverses a longer distance. The two beams are recombined along a common axis and propagate collinearly towards a photodetector where they constructively or destructively interfere: the light intensity at the photodetector is proportional to the velocity (or differential displacement) of the target surface. If the surface being probed is diffusely reflecting or scattering, a "speckle" field distribution will be formed on the photodetector. Since the reflected beam is interfered with a time-delayed replica of itself, the wavefronts of the two interfering beams are substantially matched. Consequently, a phase shift in one arm of the interferometer is common to all speckles, and all speckles can be detected optimally. Unlike a conventional interferometer, which has a flat frequency response with respect to phase shifts, a time delay interferometer has a bandpass-type of response in which low frequency vibrations (below ultrasonic frequencies) are suppressed.
There are two problems with this time-delay, or velocity, sensing system, however. First, the speckles are generally so numerous and small that the time delayed arm of the interferometer cannot be easily aligned with the other arm. Unfortunately, introducing a time delay is most easily accomplished with a multimode fiber which further increases the number of speckles and scrambles their locations, making speckle registration very difficult. The second problem is that the time delay must be held constant and stabilized in quadrature, which is a requirement for homodyne detection. If the path length difference that causes the time delay between the beams is not maintained to within a fraction of a wavelength, the sensitivity and temporal resolution of the system will be greatly reduced. As a result, both time-delay and conventional interferometers must typically employ active stabilization techniques. In industrial environments, however, the effectiveness of these techniques is reduced by noise-induced vibrations.
A velocity, or differential, sensing interferometer system which circumvents some of these problems is described in a copending application to P. V. Mitchell, D. M. Pepper, T. R. O'Meara, M. B. Klein, S. W. McCahon and G. J. Dunning, "A System and Method for Detecting Ultrasound Using Time-Delay Interferometry" (Ser. No. 08/481,673, filed Jun. 7, 1995). This system includes a time delay interferometer (TDI), a fringe processing unit (FPU) and a processor that extracts information from the output signal of the FPU. The FPU is preferably a non-steady-state photo-electromotive-force (NSS-photo-EMF) detector made from a photoconductor. Various NSS-photo-EMF detectors are described by M. P. Petrov et al. in "Non-steady-state photo-electromotive-force induced by dynamic gratings in partially compensated photoconductors", Journal of Applied Physics, Vol. 68, No. 5 (1990), pp. 2216-2225, and by S. I. Stepanov et al. in "Measuring vibration amplitudes in the picometer range using moving light gratings in photoconductive GaAs:Cr", Optics Letters, Vol. 15, No. 21 (1990), pp. 1239-1241.
With an NSS-photo-EMF detector, a space charge grating is formed in the photoconductor in response to alternating light and dark interference fringes which move in accordance with the velocity of the surface being examined. If the interference fringes move at a rate that is faster than the response time of the space charge grating, a net current flows through the photoconductor. An NSS-photo-EMF detector is sensitive to the frequency of the overall fringe pattern motion, rather than the exact shape of the fringe pattern as is the case with conventional detectors. When it is combined with a TDI, a system is produced that is relatively insensitive to the surface roughness of the target. Nevertheless, this approach requires lasers with long coherence lengths (on the order of meters) in order to coherently detect the desired high frequency modulated information produced by the vibrating surface. This means that a rather costly laser must be used, such as a single mode diode pumped solid state laser or a stabilized diode laser.
A dual time delay interferometer scheme that relaxes this long coherence length requirement is described by D. J. Erskine and N. C. Holmes in "White-light velocimetry," Nature, pp. 317-320, Sep. 28, 1995. It uses two TDIs and enables sensing of white light encoded information even over an aberrated path. The first interferometer imprints the illumination light with a coherent echo having a delay time given by the path length difference of its two arms. Light passing through the first interferometer and reflected from the target is observed by a second interferometer having its own characteristic delay time. As long as the speed of light times the difference in the delay times (i.e. the difference between the respective path length differences of the two interferometers) is less than the coherence length of the illumination light, partial fringes will be formed. This permits light sources with relatively short coherence lengths (e.g. white light) to be used as the illumination light. On the other hand, the dual-interferometer described by Erskine and Holmes is bulky (which severely limits its use, practicality and portability), since it must perfectly image and register the light reflected from the target onto a time delayed replica of itself, so that their wavefronts are spatially matched. Furthermore, this device requires that its optical components be interferometrically stable, and it cannot be used for phased array detection of objects.
The white light approach demands precision alignment and perfect imaging of the time-delay and through-beams in order to realize fringes; the precise alignment matches the two patterns, and the imaging maintains a near-field, phase-only field distribution, thereby avoiding speckle problems. It also demands interferometric stability and quadrature maintenance of the time-delay and through-beams to generate the desired fringe pattern, and requires that the incident beam be spatially coherent as it probes the workpiece; the precision imaging in the initial time-delay interferometer follows from this requirement.
The prior white light approach requires a 2-dimensional recording medium to evaluate and process the diagnostic output (such as a film plane or a video camera, in the case of real-time implementation), as well as precision image-preserving relay optical systems. These systems must possess high-resolution, flat-field, large field-of-view, distortion-free imaging capabilities to enable ultrasonic sensing. Moreover, in general the two imaging systems must be identical in terms of magnification and registration, and they must possess a large depth-of-focus when probing three-dimensional (i.e., non-planar) structures.

Ultrasonic sensor using short coherence length optical source, and operating method


A system and method for accurately communicating color production printer color requirements include color selector software to display an interactive original document on a monitor. Tools enable navigating the displayed original document, tagging at least one critical color of the displayed document, and selection of a color tolerance in connection with each tagged critical color of the displayed document. Target builder software creates a master critical colors chart displaying only tagged critical colors for the original document, a master color aim chart, and a master color tolerance chart of critical colors and associated color tolerances identified in the displayed document. At least the critical colors chart and original document are printed. A printed master color aim chart and master color tolerance chart and customer printed charts are compared to the production end printed master critical colors chart for visually determining tolerances of customer printed charts.

Most typical printing jobs include an interaction between a customer or similar source and a print production company. In particular, a customer will create a document which may then be printed in a larger production run at a production printer. For the production printer, a significant amount of time is devoted to pre-press activities such as adjustment of color and tone to achieve a close match to a proof provided by the customer. For a large production run, the production printer will recover expenses incurred in the pre-press activities by a volume of printing. However, in a short run printing job, the production printer is less likely to realize expenses due to the reduced volume of printing.
In certain printing jobs, for example short run printing jobs, it is therefore an advantage to reduce the amount of time spent on pre-press activities. A particular complication for the production printer is that while a customer proof provides a visual reference to the customer's expectations, it provides no information regarding the customer's acceptable range of color variations for the provided proof. It is typically the case that any two printers will output a common document having differing tones, hues and quality of color, possibly rendering an unacceptable document for production printing from the customer's point of view. Although a customer may send a proof to the production printer in order to provide a visual reference identifying his expectations, it does not indicate a tolerance for mismatch or color variations that will likely occur at the production printer's unit. For a typical printing job, the time between selection and final press may also include providing a return proof to the customer for final approval.
Color tolerances are difficult to specify in the context of a document and it is further likely that the tolerances may be different for different parts of the document. For example, a document containing a graphic of a company trademark is likely to have very tight color tolerances, while the colors used in a pie chart or histogram may have a very loose color tolerance. Further, color tolerances can vary between different parts of an image. For example, skin tones may have a tighter tolerance than the colors of objects such as clothing or automobiles. Finally, color tolerances may be dependent upon a final intended use of the document. For example, advertisers may be more concerned about the color tolerances on their product than about the colors of background or models. Likewise, pictures of sports team uniforms may require a more accurate reproduction than other elements of the picture.
Accordingly, there is a need to overcome these and other color management problems and to provide an efficient and economically practical method for communicating color tolerances within a source document to an end production printer. Further, any method or system for overcoming the problem should be simple for the customer to implement, without the need for extensive training or explanation.

Critical color tolerance guide for printers


A multiple-antenna system including a base station apparatus and a plurality of antenna apparatuses connected to the base station via optical cables is provided. The system comprises a first antenna apparatus and a second antenna apparatus connected to each other via an electric cable. Each of the first and second antenna apparatuses receives a reference pulse from the base station apparatus via the optical cables, and estimates a time difference between the received pulse and the reference pulse supplied from the counterpart antenna apparatus via the electric cable. At least one of the first and second antenna apparatuses adjusts signal transmission timing based on the time differences estimated by the first and second antenna apparatuses.

1. Field of the Invention
The present invention generally relates to a wireless communication technique, and more particularly to a multiple antenna system comprising a plurality of antenna devices, each being provided in one of multiple sectors, and a base station apparatus connected to the antenna devices via optical cables.
2. Description of the Related Art
In mobile communications systems, the space in which communication services are provided is divided into multiple cells or sectors, and wireless communication is carried out between mobile terminals located in certain sectors (or cells).
FIG. 1 is a schematic diagram illustrating a part of a code division multiple access (CDMA) system, which is typically employed in the wireless communication field. Multiple antenna units (AU) 104 are connected to the base station apparatus 110 via associated signal converters 106 and optical cables 108. The base station apparatus 110 includes optical to electric converters 112, each being connected to one of the optical cables 108, and baseband processors 114 connected to the associated signal converters 112.
One of the antenna units 104 is provided in each sector to transmit and receive radio signals to and from a mobile terminal (not shown) located in the sector. When receiving signals, the antenna unit 104 converts the radio signals to digital signals. When transmitting signals, the antenna unit 104 converts digital signals to analog signals.
The signal converter 106 performs electric-to-optical conversion to convert electric signals (uplink signals) received at the antenna unit 104 and converted into the digital format, into optical signals. In addition, the signal converter 106 performs optical-to-electric conversion to convert optical signals (downlink signals) carrying information into electric signals.
The optical cable 108 transmits optical signals between the antenna unit 104 (to be more precise, the signal converter 106) and the base station apparatus 110. The optical cable 108 is capable of signal transmission with less transmission loss and less signal degradation because it allows optical signals to propagate through it.
The signal converter 112 converts the optical signals (uplink signals) to electric signals, and converts electric signals (downlink signal) carrying information into optical signals.
The baseband processor 114 carries out baseband processes, such as spread spectrum using a code for a transmission signal and despreading of a received signal. The baseband processor 114 communicates with a higher-layer apparatus or a core network (neither shown).
The above-described baseband apparatus is disclosed in, for example, JP 2002-335560A and JP 2002-118870A.
A mobile terminal moves across sectors in a service area, while continuing wireless communication, using handover. Signals input to and output from the antenna units 104 provided to the respective sectors have to be synchronized with each other. To this regard, the technique disclosed in JP 2002-335560A assumes that the quantity of delay is measured and adjusted manually, and therefore, manual work is required not only when setting or adding a new base station apparatus, but also when modifying the route of the optical fiber or repairing degradation due to elapse of time. Burden and cost of maintenance and control operations increase.
In JP 2002-118870A, the quantity of delay is measured by test radiation of radio waves in the air. However, since the communication environment changes every moment, the main path of the test wave may happen to be blocked by obstacle. Accordingly, the delay cannot always be measure at high precision. The radio wave transmitted from and received at a mobile terminal requires only such a power level so as to propagate between the mobile terminal and the antenna unit connected to the base station apparatus. In contrast, the test wave emitted from an antenna unit is strong enough to propagate to another antenna unit located in the adjacent cell. Accordingly, the test wave becomes a large interfering wave for the radio signal transmitted from the mobile terminal.
Returning to FIG. 1, one of the baseband processors 114 is provided for each antenna unit 104 by one-to-one correspondence. Accordingly, when increasing the number of sectors, additional antenna units 104 and baseband processors 114 have to be provided. This arrangement is suitable to such applications when the number of users accommodated in the system is increased by increasing the resources of the antenna units 104 and baseband processors 114. However, this arrangement is unsuitable to an application of increasing the area size of each baseband processor, that is, an application where the number of the antenna units 104 is increased to expand the communicating space, while maintaining the number of users accommodated by the system (or the overall sectors). This is because increasing the number of antenna units 104 to expand the communicating space results in excessive resources and processing capacity. Such application includes communications in mountain areas, sparsely populated regions, underground malls, and inside tunnels or buildings.
FIG. 2 illustrates the above-described application to increase the area size per baseband processor. In this example, at most a hundred people are likely to conduct wireless communication inside the five-story building. Each baseband processor 114 is capable of performing baseband processing for signal transmission of a hundred users. To allow wireless communications at all the floors, an antenna unit 104 has to be provided to each floor. In this conventional case, the base station apparatus 110 located in the basement has to be furnished with five baseband processors 114, which is excessive for a hundred users accommodated in this building.