A light conducting plate for back lighting which comprises a methacrylic copolymer resin comprising 90 to 99.5% by weight of a methyl methacrylate unit and 0.5 to 10% by weight of an alkyl acrylate unit containing 1 to 8 carbon atoms in the alkyl moiety thereof and having a reduced viscosity of 35 to 60 ml/g in chloroform, the chromaticity of said light conducting plate having x and y color coordinates both ranging from 0.01 to 0.001 as obtained according to JIS-Z-8701.

Methacrylic resins are excellent in transparency, weatherability and scratch resistance and are widely used particularly for their transparency as molding materials for optical parts which demand precise molding, such as optical disks and lenses, or for lighting.
The methacrylic resin has recently found use as light conducting plate for back lighting in liquid crystal displays, etc., and the severity of requirements for transparency, color tone and freedom from foreign matter has been increasing. A light conducting plate as herein referred to is a part constituting a side-lighted type surface lighting unit mainly used for back lighting of liquid crystal displays. The side-lighted type surface lighting unit is disclosed in JP-A-57-128383 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"). As shown in FIG. 1, the lighting unit of this type comprises a light source, such as a cold cathode gas discharge tube, a hot cathode gas discharge tube, a light bulb or an LED, placed at the side of a light-emitting surface. The light emitted from the light source enters the light conducting plate from the side, changes its direction by a light scattering means provided on the light-reflecting surface, and comes out through a diffusing film via a polarizer to a viewer side. The light scattering strength of the light conducting plate can be designed appropriately in conformity with the distance from the light source or the position of the reflecting surface so as to provide a uniform surface lighting unit. Because such a side-lighted type surface lighting unit has its light source provided at the side of the light conducting plate thereby to contribute to reduction in thickness and weight of the whole display, it has been recently used as a backlight of liquid crystal displays used in laptop or notebook word processors or personal computers. Since such portable equipment is demanded to work for a long period of time with batteries contained therein, the side-lighted type surface lighting unit used for back lighting is required to have a low power consumption.
In FIG. 1 is shown a schematic illustration of a side-lighted type surface lighting unit used as a backlight of a liquid crystal display. Liquid crystal panel 1 possesses a function of controlling a light transmission at a desired position on the screen thereby forming letter or image information. Since liquid crystal panel 1 per se does not emit light, a backlight 2 is needed for obtaining a clear image. As light source 25, a cold cathode fluorescent tube which consumes relatively low power of electricity and yet provides sufficient brightness is of frequent use.
Light conducting plate 21 is a transparent resin plate having provided light-scattering means 22 on the light-reflecting surface thereof. Light-scattering means 22 is formed by injection molding using a mold having a prescribed pattern or by applying a white ink to the light-reflecting side with gradation by, for example, printing. Light conducting plate 21 can have a flat shape as with the case of FIG. 1, a wedge shape having a thickness decreasing with the distance from the light source, and other special irregular shapes. Numeral 23 is a reflecting film which functions to reflect light having passed through light conducting plate 21 to a viewer side thereby to improve light utilization. Numeral 24 is a frosted glass-like cloudy film called a diffusing film. Since light-scattering means 22 has a dot or stripe pattern, diffusing film 24 is effective to prevent such a pattern from being seen through liquid crystal panel 1. At the same time, a surface lighting unit which scatters light uniformly can be obtained by blurring the pattern by diffusing film 24. Numeral 26 is a lamp cover, which is used for efficiently leading light emitted from light source 25 into light conducting plate 21. The arrows in FIG. 1 indicate the light proceeding direction.
Thus, a light conducting plate is set on the back side of a liquid crystal panel and used in a shielded state, little light from the outside is let in.
With the recent spread of color and/or wide liquid crystal displays, the demand for a surface lighting unit achieving uniform light emission at a high luminance and with freedom from unevenness in luminance or color has been increasing. To meet this demand a large number of techniques have ever been disclosed.
For example, light conducting plates having provided unevenness so as to increase the amount of scattered light with the distance from the light source are disclosed in (1) JP-A-U-61-157986 (the term "JP-A-U" as used herein means an "unexamined published Japanese utility model application"), (2) JP-A-U-62-87315, (3) JP-A-U-63-43186, (4) U.S. Pat. No. 4,059,916, (5) U.S. Pat. No. 4,937,709, (6) U.S. Pat. No. 5,134,549 and (7) JP-A-U-5-79537. A technique for molding such a light conducting plate is disclosed in (8) JP-A-4-52286, in which a mold having a prescribed pattern formed by photoetching is used. (9) JP-A-2-165504 and (10) U.S. Pat. No. 5,074,675 disclose a light conducting plate which increases the amount of scattered light with the distance from the light source, in which the surface at the bottom facing the light-emitting surface is provided with grooves having a specific section designed to efficiently reflect the light from the light source to the viewer side, and the interval and the depth of the grooves increase with the distance from the light source so as to increase the amount of scattered light accordingly. Further (11) JP-A-U-60-94605, (12) U.S. Pat. No. 4,998,809 and (13) U.S. Pat. No. 5,040,098 disclose a technique for achieving both reductions in thickness and weight and increase in luminance, which comprises forming light-scattering grooves on the bottom surface facing the light-emitting surface and shaping the light conducting plate itself into a wedge having its thickness decreased with the distance from the light source.
In addition, it has been proposed to disperse light-scattering particles in the inside of a transparent light conducting plate as described in (14) JP-B-39-1194 (the term "JP-B" as used herein means an "examined published Japanese patent application"), (15) JP-A-53-36199, (16) JP-A-54-105562 and (17) JP-A-U-56-58678. In this connection, (18) JP-A-2-221924 and (19) JP-A-2-221925 disclose a process for producing a light conducting plate in which light-scattering particles are non-uniformly distributed by taking advantage of a difference in rate of precipitation.
The above-cited patent and utility model publications have a mention that the materials suitable as light conducting plate include glass, methacrylic resins, styrene resins, polycarbonate resins, and the like, but give no particulars on the characteristics required of such transparent materials.
With respect to resins for optical disks, various techniques for obtaining a transparent methacrylic resin suffering from little discoloration have been proposed. For instance, (20) JP-B-7-132598 discloses a technique for obtaining a colorless and transparent methacrylic resin having a high optical purity by specifying the molecular weight, pyrolysis index and yellowness index of a methacrylic resin and the volatile content and fine foreign matter content in the resin.
In high-speed molding of thin-walled articles, silver streaking often occurs due to volatile components of a resin, such as the monomer or the water content. In order to minimize the volatile content of a resin as a countermeasure for silver streaks, it has been a practice to remove the volatile matter in high vacuum at the time of extrusion and pelletization. (21) JP-A-58-154751 describes that active reduction of the monomer content in a resin is effective to suppress occurrence of silver streaks.
To the contrary, there is a mention, e.g., in (22) JP-A-3-259439 and (23) JP-A-4-253752 that existence of some amount of volatile components in a resin is effective for suppression of silver streaking on molding.
On the other hand, it has been proposed to add a stabilizer to a methacrylic resin to prevent pyrolysis, thermal discoloration or oxidation discoloration as disclosed in JP-A-59-15444, JP-A-4-216806, and JP-B-57-9392.
Nevertheless, none of the above-described techniques is to solve the discoloration problem observed in a light conducting plate made of a methacrylic resin by injection molding, i.e., to eliminate luminance unevenness or color unevenness in a side-lighted type surface lighting unit.
Characteristics generally required of materials for light conducting plates include high transmission, colorlessness, freedom from foreign matter, high heat resistance, and, in the case of injection molding, satisfactory moldability and satisfactory mold release properties. Specifically, the materials include such transparent materials as glass, methacrylic resins, styrene resins, and polycarbonate resins. Actually methacrylic resins which have excellent optical characteristics and are lighter than glass are used frequently.
In recent years inexpensive mass production of a light conducting plate by injection molding has prevailed as a reflection of the drastic increase of demand of laptop or notebook word processors or computers. As to the form of a light conducting plate, a thin wedge type is increasing for the purpose of minimizing power consumption.
While a methacrylic resin has excellent transparency and thereby exhibits satisfactory performance as light conducting plate, the requirement for further improvement in transparency has been getting more strict according as full color liquid crystal displays are spreading. Compared with conventional lighting units, a light conducting plate has a very long length through which light should pass so that only slight coloration of the material causes color unevenness.
Referring to FIG. 1, since light ray a, which is reflected near the light source, has passed through the material over a relatively short distance, it is insusceptible to the influence of the color of the material and is emitted toward a viewer side as having a color near to the light source's. On the other hand, light ray b, which is emitted from the position far from the light source, is susceptible to the influence of the color unevenness of the material and tends to assume a different color from that of the light source while it is passing through the material over a long distance. It follows that the color of scattered light of a surface lighting unit varies within the same light emitting surface depending on the distance from the light source, which leads to color unevenness.
Taking, for instance, a 3 mm thick plate produced by general injection molding of a methacrylic resin having a sufficiently increased purity, the yellowness index (YI) in the transmission direction is about 0.7 to 1, which means satisfactory transparency giving rise to no problem in usual use. However, if a similarly injection molded article has a light pass length exceeding 220 mm, a delicate color of the material itself would be accumulated, sometimes reaching the yellowness index of about 5. If a material having such a yellowness index is used as a light conducting plate of a side-lighted type surface lighting unit, the yellowness becomes stronger with the distance from the light source, resulting in color unevenness as a whole. In particular, this would be a cause of reduction in color reproducibility in a full color liquid crystal display. It is desirable for a full color liquid crystal display to have a backlight whose color unevenness is within a range of from 0.001 to 0.005 as expressed in terms of a difference between the maximum and the minimum on both x and y chromaticity coordinates according to a CIE calorimetric system. It is more desirable, as a matter of course, that no change occurs on both x and y coordinates.
In order to eliminate such yellowing, improvement in tone by color toning has been attempted. For example, a method called bluing consisting in addition of a blue pigment has been widely employed to correct the above-described delicate yellowness. Although this method produces an effect of reducing color unevenness due to yellowing, it involves reduction in transmission. Therefore, application of the bluing technique to a light conducting plate results in reduction of light utilization (i.e., reduction of luminance). There is a method for tone improvement which comprises adding a milky white pigment, such as titanium oxide, and a fluorescent brightening agent to a methacrylic resin to be used as a cover of a fluorescent tube. However, a light conducting plate made of such a milky white material not only causes excessive light scattering in the vicinities of the light source, leading to local excessive brightness, but also fails to transmit light to the part far from the light source. As a result, light emitted from the light conducting plate becomes non-uniform. Thus, materials for light conducting plates must be transparent as stated above.
As another approach to an improved luminance, a method of incorporating a fluorescent brightening agent alone into a methacrylic resin has been suggested, as disclosed in (24) JP-A-62-32488 and (25) JP-A-64-42686, in which fluorescence excited by ultraviolet rays emitted from a light source is utilized for improvement of luminance. This method is deemed to be unsuitable for improving luminance unevenness and color tone because a blue tint becomes strong, depending on the intensity of the ultraviolet light of the fluorescent tube. Addition of a fluorescent brightening agent to a transparent resin for a fluorescent tube cover is disclosed in (26) JP-B-6-3682. This method aims at cutting the ultraviolet light of a fluorescent tube and produces no effect on the subject matter of the present invention, improvement of tone or light utilization. In other words, the method has no effect of converting incident light in the ultraviolet region to light in the visible region.
Accordingly, an object of the present invention is to eliminate discoloration of an injection molded methacrylic resin light conducting plate, that is, to increase the luminance, to eliminate luminance unevenness and to improve color tone of a side-lighted type surface lighting unit.
Methacrylic resins are used as material for light conducting plates for their superiority in transparency to other molding materials. With reference to resins for optical disks, (20) JP-B-7-132598 states that a colorless and transparent methacrylic resin having a high optical purity can be obtained by specifying the molecular weight, pyrolysis index and yellowness index of a methacrylic resin and the volatile content and fine foreign matter particle content in the molding material. However, where a light conducting plate is produced by injection molding, the methacrylic resin disclosed is still insufficient. That is, the resin tends to undergo pyrolysis, thermal discoloration or oxidation discoloration during molding by the influences of the temperature distribution in an injection cylinder, the shape of the cylinder, and entrained air oxygen from the hopper, etc., only to provide colored light conducting plates. From this standpoint, the aforesaid method concerning a molding resin for optical disks which comprises actively reducing the monomer content in a molding resin, as suggested in (21) JP-A-58-154751, is not favorable because of involvement of the influence of oxygen due to entrainment of air on feeding from a hopper, etc. The effect of the aforesaid technique of (22) JP-A-3-259439 and (24) JP-A-4-253752, which comprises incorporating volatile components into a resin to some extent, resides in inhibition of silver streaks during molding and differs from the inhibitory effect on discoloration as aimed in the present invention.
Variations of the size or kind of a molding machine, the screw design, and other molding conditions make it technologically difficult to completely control heat generation, air entrainment, etc. of a resin through some mechanical means.
The above-described addition of a stabilizer to a methacrylic resin to prevent thermal discoloration or oxidation discoloration thereby to improve the tone of a light conducting plate, as proposed in JP-A-59-15444, JP-A-4-216806, and JP-B-57-9392, is insufficient in effect and rather brings about coloration.
As has been reviewed, the conventional techniques fail to provide a colorless transparent light-conducting plate by injection molding, i.e., a surface scattering lighting unit which satisfies the requirements demanded for use as a backlight of color liquid crystal displays, namely, high luminance, freedom from color unevenness, and uniform light transmission and scattering.
In order to obtain a high luminance and colorless light conducting plate it is necessary to specify the molecular weight of a methacrylic resin to be used and to inhibit coloration due to thermal oxidation on injection molding.
In order to obtain a light conducting plate having a small thickness and a precise uneven pattern by injection molding it is necessary to improve fluidity of an acrylic resin. To this effect, it is a generally followed technique to reduce the molecular weight of a resin or to copolymerize a comonomer having an internal plasticizing action. A resin having a merely increased comonomer content, while exhibiting improved fluidity, has reduced heat resistance and is unsuitable. A resin having a merely decreased molecular weight, while exhibiting improved fluidity, has poor mechanical strength.
An acrylic resin exhibits relatively strong adhesion to metal. If the adhesion to an injection mold is too strong, the molded article suffers from defects such as cracks, breaks, or surface roughness, upon release from the mold. Injection molding into a light conducting plate is desirably carried out at as low a molding temperature as possible in order to prevent deterioration of tone due to the foreign matter or to prevent thermal discoloration. However, fluidity of a molding resin in a mold would be reduced at low molding temperatures, which necessitates increase of the injection pressure to avoid short molding. As a result, the adhesion between a molded article and a mold becomes stronger, giving rise to the aforesaid problem of cracking. Accordingly, in order to achieve low-temperature molding, improvement of fluidity of the resin is required. However, excessive molecular weight reduction for improving the fluidity leads to reduction in mechanical strength, which causes cracking on release from a mold. In other words, in order to obtain a thin light conducting plate by injection molding at a possible lowest temperature, it is preferable to specify the molecular weight of a methacrylic resin to be used and to improve release properties of the resin.
Known techniques for improving the release properties of acrylic resins include addition of at least one of a polyhydric alcohol fatty acid ester, a monohydric alkyl alcohol, a fatty acid, a fatty acid amide, and a fatty acid metal salt (JP-A-61-73754), addition of a glycerol higher fatty acid ester and a saturated aliphatic alcohol (JP-A-1-294763), addition of at least one of glycerol stearate, glycerol behenate, and a fatty acid alkyl ester (JP-A-2-115255), and addition of a glycerol higher fatty acid ester whose alkyl moiety has a specific carbon atom number distribution (JP-A-4-53860 and JP-A-4-253752). The resin compositions disclosed still have insufficient fluidity or release properties or exhibit low heat resistance for use as resins for light conducting plates.
Accordingly, another object of the present invention is to solve such problems as poor mechanical strength (warpage or cracks on release) and poor appearance (e.g., silver streaks) as well as unevenness in color and luminance due to discoloration.


A generator for producing an electric field for with an inspection technology system is provided. The generator provides the required variable magnitude quasi-static electric fields for the “illumination” of objects, areas and volumes to be inspected by the system, and produces human-safe electric fields that are only visible to the system. The generator includes a casing, a driven, non-conducting and triboelectrically neutral rotation shaft mounted therein, an ungrounded electrostatic dipole element which works in the quasi-static range, and a non-conducting support for mounting the dipole element to the shaft. The dipole element has a wireless motor system and a charging system which are wholly contained within the dipole element and the support that uses an electrostatic approach to charge the dipole element.

Article and personnel inspection systems and methods range from labor-intensive and intrusive manual searches to mechanized systems that use non-intrusive x-ray or electromagnetic wave imaging to expose concealed articles, damage, etc. For example, most weapons detections systems rely on the concealed weapons having x-ray absorption greater than the concealing articles or the concealed weapon and having electrical conductivity large enough to be detectable by radiated electromagnetic waves. Weapons such as ceramic knifes or plastic guns (with little or no metal content) or disassembled distributed weapons are undetectable by most non-intrusive inspection devices. These are low density systems that have been made from low density materials or made low density by distributing components through a larger volume.
In another example, the degraded electrical properties of insulation surrounding conduction wires is known to have caused fatal aircraft crashes. Most insulation integrity systems are not capable of non-intrusive quantitative detection and characterization of insulation degradation.
The co-pending United States Patent Application Number 2012-0199755 A1, the contents of which are incorporated by reference herein in its entirety, discloses an electric field quantitative measurement system which is based upon Electric Field Imaging (EFI) to overcome the disadvantages of the prior systems. An externally generated electric field is created to interrogate and inspect objects. A complication arises where large magnitude electric field strengths over large areas are needed to allow the electric field to remotely interact with and pass through the object of interest, and to do so without the electric field source being in physical contact with the object. Physical contact with the electric field source is prohibited, where electric field distortion, arcing and dangerously high current levels can occur if physical contact is made. During EFI inspections, uniform or controlled non-uniform interrogating electric fields are required to make quantitative assessments of the inspection results.
One key feature of EFI is that components that are sensitive to electric fields all have leakage currents that move electrical charges within the component to reduce the effect of the applied electric field. This is addressed in electrical systems by using dynamic fields that oscillate rapidly (described by Maxwell's equations) to counter the effects of intrinsic component current leakage while generating oscillatory (over 10 KHz) electrical currents as used in radio wave frequency (RF) reception.
Previous generation of large magnitude electric fields are based on electronic circuitry voltage doubling-tripling, step-up transformers, or by electrostatic approaches. Voltage doubling-tripling and step-up transformers are often highly lethal systems that need to have extensive safety guards in place to prohibit tampering or access to lethal components. Electrostatic approaches, such as a Van de Graaff device, are often more safe to use due to the low currents (microamps) produced. These Van de Graaff systems are limited in applicability because of the special configurations used to produce large constant voltage potentials such as those required for linear particle accelerators. Typical electrostatic applications generate fixed large magnitude electric fields that terminate on electrically conducting surfaces that form charged particle focusing elements. These electrostatic approaches are physically fixed structures operating to generate fixed electrical potential levels and do not generate the quasi-static electric fields required for EFI.
A generator which is used with the electric field quantitative measurement system of United States Patent Application Number 2012-0199755 A1 is provided herein which provides improvements to existing structures and which overcomes the disadvantages presented by previous technologies. Other features and advantages will become apparent upon a reading of the attached specification, in combination with a study of the drawings.

THE UNITED STATES OF AMERICA AS REPRESENTED BY THE ADMINISTRATOR OF THE NATIONAL AERONAUTICS AND SPACE ADMINISTRATION.


A constant voltage power supply circuit is provided with a constant voltage circuit part to convert an input voltage into a predetermined constant voltage, a first excessive current protection circuit part to control the constant voltage circuit part so as to reduce the output voltage while maintaining an output current that is output to a predetermined maximum value if the output current is greater than or equal to the predetermined maximum value when the output voltage is a rated voltage, and a second excessive current protection circuit part to control the constant voltage circuit part so as to reduce the output voltage and the output current and to output a short-circuit current if the output voltage decreases to a ground voltage when the output voltage is decreased to a predetermined value by the first excessive current protection circuit part. The second excessive current protection circuit part is disabled in response to a first test signal that is active.

1. Field of the Invention
The present invention generally relates to, and more particularly to constant voltage power supply circuits and methods of testing the same, and more particularly to a constant voltage power supply circuit having an excessive current protection circuit, and to a method of testing such a constant voltage power supply circuit by accurately measuring a set current value of the excessive current protection circuit.
2. Description of the Related Art
Conventionally, an excessive current protection circuit is provided for suppressing an output current of a constant voltage power supply circuit to a predetermined current value or less, so as to prevent damage to the load or power supply circuit, even if the output current of the constant voltage power supply circuit abnormally increases due to an excessive load, a short-circuiting of an output terminal and the like.
As general methods employed in excessive current protection circuits, there is a first method that reduces the output voltage by suppressing an increase of the output current beyond a predetermined current if the output current increases up to the predetermined current, and a second method that reduces the output current and also reduces the output current. According to the second method, the voltage-current characteristic that is obtained generally forms the shape of the numeral "7". The increase in the output power, which is the product of the output current and the output voltage, is small according to the second method, and the power consumption within the power supply circuit during operation of the excessive current protection circuit is relatively small. For this reason, although the circuit structure becomes slightly complex, inexpensive parts may be used in the power supply circuit, thereby making the second method popular.
FIG. 1 is a circuit diagram showing an example of a conventional constant voltage power supply circuit having an excessive current protection circuit employing both the first and second methods. For example, the constant voltage power supply circuit may be derived from Japanese Laid-Open Patent Applications No. 2002-169618 and No. 2003-67062.
In FIG. 1, a constant voltage power supply circuit 100 forms a series regulator having a first excessive current protection circuit 101 employing the first method and a second excessive current protection circuit 102 employing the second method.
FIG. 2 is a diagram showing an output current versus output voltage characteristic of the constant voltage power supply circuit 100 shown in FIG. 1. In FIG. 2, the ordinate indicates an output voltage Vo, and the abscissa indicates an output current io, both in arbitrary units.
Next, a description will be given of the excessive current protection operation of the first and second excessive current protection circuits 101 and 102, by referring to FIG. 2.
The element size of a PMOS transistor M2 shown in FIG. 1 is sufficiently small compared to that of a PMOS transistor M1 for output voltage control. For this reason, a drain current id2 of the PMOS transistor M2 is smaller than a drain current id1 of the PMOS transistor M1. However, the gates of the PMOS transistors M1 and M2 are connected to an output terminal of a differential amplifier circuit A1, and the sources of the PMOS transistors M1 and M2 are connected to a power supply voltage Vdd. Hence, the drain current id2 is proportional to the drain current id1. A reference voltage Vref generated from a reference voltage generating circuit 2 is input to an inverting input terminal of the differential amplifier circuit A1.
The drain current id2 becomes a drain current id3 of an NMOS transistor M3 which forms a current mirror circuit together with an NMOS transistor M4. Accordingly, a drain current id4 of the NMOS transistor M4 is proportional to the drain current id2. In addition, when the NMOS transistors M3 and M4 are formed by transistors having the same characteristics, the drain current id4 becomes equal to the drain current id2.
The drain current id1 is a sum of the output current io and a current ir that flows through a series circuit made up of resistors R1 and R2. But since the current ir is set to an extremely small current value, the drain current id1 may be considered as being equal to the output current io for current values at which the excessive current protection circuit operates. For this reason, the drain current id4 of the NMOS transistor M4 is also proportional to the drain current id1, that is, proportional to the output current io. Moreover, since the drain current id4 flows to a resistor R3, a voltage drop across the resistor R3 is proportional to the output current io.
When the output current io reaches a maximum load current imax at a point c in FIG. 2, the voltage drop across the resistor R3 becomes a threshold voltage of a PMOS transistor M5. Furthermore, when the output current io exceeds the maximum load current imax, the PMOS transistor M5 turns ON to increase the gate voltage of the PMOS transistor M1, so as to suppress the increase of the drain current id1 of the PMOS transistor M1, that is, the increase of the output current io. Consequently, the output voltage Vo decreases in a state where the output current io remains to be the maximum load current imax, as shown in FIG. 2.
In addition, the element size of a PMOS transistor M6 is sufficiently small compared to that of the PMOS transistor M1. The gate of the PMOS transistor M6 is connected to the output terminal of the differential amplifier circuit A1, and the source of the PMOS transistor M6 is connected to the power supply voltage Vdd, similarly to the PMOS transistors M1 and M2 described above. Hence, a drain current id6 of the PMOS transistor M6 is also proportional to the output current io. Since the drain current id6 flows to a resistor R4, a voltage drop across the resistor R4 is proportional to the output current io.
In addition, when the output voltage Vo decreases, an output voltage of a differential amplifier circuit A2 decreases, so as to lower the gate voltage of a PMOS transistor M7. Hence, the PMOS transistor M7 turns ON and raises the gate voltage of the PMOS transistor M1, and the drain current id1 decreases. As a result, the output voltage Vo further decreases, and both the output voltage Vo and the output current io decrease as shown in FIG. 2. A short-circuit current is indicated at a point C in FIG. 2 is the current that flows when the output voltage Vo decreases to 0 V.
A non-inverting input terminal of the differential amplifier circuit A2 is connected, via an offset voltage generating circuit 7 that generates an offset voltage Vs, to a node that connects the resistors R1 and R2. However, when a resistor for use in detecting the output voltage is additionally provided, a different voltage may be input to the non-inverting input terminal of the differential amplifier circuit A2.
When testing the constant voltage power supply circuit 100, it is necessary to measure the current values of the maximum load current imax and the short-circuit current is described above. However, it is difficult to accurately measure such current values.
For example, when measuring the current values of the maximum load current imax and the short-circuit current is of the constant voltage power supply circuit 100 shown in FIG. 1, an ammeter 13 and a dummy load 12 are connected to an output terminal OUT. In this case, it is impossible to accurately set the output voltage Vo that is required to measure the maximum load current imax and the short-circuit current is due to the contact resistance of the output terminal OUT or the contact resistance of the connection terminal of the dummy load 12 that connects to the ground voltage. In addition, because the output voltage Vo does not accurately decrease to 0 V, even though the short-circuit current is should originally have the current value at the point C shown in FIG. 2, the current value at a point D is actually measured, and an accurate measurement of the short-circuit current is difficult. In FIG. 2, Voscm indicates the voltage value of the output voltage Vo when measuring the short-circuit current is.
Moreover, if the excessive current protection circuit consists solely of the second excessive current protection circuit 102 or, a voltage value Vo1 of the output voltage Vo at which the second excessive current protection circuit 102 starts to operate is close to a rated output voltage Voro, the output current io becomes unstable. As a result, even though the maximum load current imax should originally have the current value at the point c shown in FIG. 2, the current value at a point d is actually measured, and an accurate measurement of the maximum load current imax is also difficult.

This patent is subject to a terminal disclaimer.

Constant voltage power supply circuit and method of testing the same


The present disclosure relates to an expandable antenna for a security system that is installed within a wall. The security system may include a control unit. The control unit may include a casing that houses one or more internal components of the control unit and a radio-frequency (RF) communication module that is situated within the casing. The RF communication module includes an antenna connected that is exposed to the exterior of the casing. An expandable antenna connects to the antenna connector. The expandable antenna is fit through an aperture in a wall and is then expanded to an enlarged size within the gap of the wall.

Security systems are widely used to protect property and provide personal safety. Security systems generally include a control unit that controls the overall operation of the system, one or more keypads providing user access to the system, and various detectors and sensors.
Security systems may generate an alarm in response to any number of events, such unauthorized entry, fire, medical emergency or manual alarm activation. The security system may be associated with a service that remotely monitors the status of the security system. Thus, if the security system generates an alarm, a notification signal may be transmitted via a wired and/or wireless communications link to a monitoring system. Upon receiving the notification, security service personnel for the monitoring system may attempt to contact the property owner or other party at the facility to verify the alarm. If it is appropriate to do so, a security service representative may, upon confirmation of the alarm, contact an emergency response agency such as the police department, the fire department, an emergency medical team, or other appropriate entity. Security systems are also playing a larger role in building automation, and may include a control unit that provides building automation features.
The control unit often communicates wirelessly with one or more of the devices in the system. As a result, the control unit requires antennas to allow radio frequency (RF) communications. A single control unit may require antennas for Z-Wave communications, Wi-Fi communications, Global System for Mobile Communications (GSM) communications, or others.
Designing antennas to fit within the enclosure of the control unit poses challenges. The control unit, with its various electronic components, is a "noisy" environment and antennas need to be protected from electromagnetic interference (EMI). The antennas must also be small enough to fit within the casing for the control unit. An antenna designer may have to compromise other characteristics of the antenna (such as efficiency, bandwidth, and gain) to create an antenna with the necessary dimensions. At the same time, there are benefits to keeping the antennas within the control unit; for example, the control unit casing protects the antennas from physical damage and from the elements. An external antenna can also be unsightly. In some situations, it would be desirable to have an antenna for a control unit that can be external to the control unit, but without the dangers of exposure.

Expandable in-wall antenna for a security system control unit


A wireless communication device stores a system GUI configuration file and a downloaded service provider GUI configuration file, each of which contains a text name checksum value that is calculated using the text names of the GUI parameter data stored either the system GUI configuration file or the service provider GUI configuration file. The text name checksum values are based on the text names of the GUI parameter data. After the download operation is complete, a text name checksum comparator program compares the downloaded text name checksum value to the initial text name checksum value in the system GUI configuration file. If the two text name checksum values do not match, the downloaded service provider GUI configuration file is rejected.

There are several hundred million wireless/cellular telephone customers in the world today. Within the United States, wireless/cellular service is offered by cellular service providers, by the regional Bell companies, and by the national long distance operators. The enhanced competition has driven the price of wireless service down to the point where it is affordable to a large segment of the population.
Many wireless service providers offer their customers a selection of wireless telephone handsets from different wireless telephone manufacturers. However, the wireless service providers generally also try to establish a particular look-and-feel for their wireless telephone handsets. To accomplish this, a wireless service provider may require different handset manufacturers to customize the graphical user interface (GUI) of the handsets used by the service provider's customers, so that all handsets, even ones from different manufacturers, present the customers with the same or very similar screen menus, program message strings, icons, audible sounds, and manner of operation. Thus, a cell phone used by one AT&T® customer generally has the same look-and-feel as a cell phone used by another AT&T® customer, even though one cell phone may be manufactured by NOKIA® and the other cell phone may be manufactured by SAMSUNG®. The same can be said about the cell phones used by customers of SPRINT®, PRIMECO®, and others.
However, whenever a new handset is manufactured or customized for a different wireless service provider, or a new feature is added to an existing handset, a wireless handset manufacturer must expend significant resources to modify, compile, and test the operating system software that controls the wireless telephone handset. Often, this cycle of modify-compile-test must be repeated several times before an acceptable quality and look-and-feel is achieved. The entire process is costly and time consuming and requires close cooperation between the wireless handset manufacturer and the wireless service provider that specifies the changes that it wants made to the GUI for its customer cell phones.
U.S. patent application Ser. No. 09/551,112 incorporated by reference above discloses a wireless communication device in which the functions of the basic operating system and the graphical user interface (GUI) are partitioned. The basic operating system operates the GUI by retrieving data defining the GUI from a GUI configuration file. The GUI may be readily modified by editing the definitional data in the GUI configuration file.
When the GUI parameters (i.e., menus, program strings, bitmaps, icons, animations, audio data files, etc.) are loaded into the handset, the handset must be able to determine if the data being downloaded is compatible with the current software on the handset. Each piece of GUI parameter data (e.g., menu entry, program strings, bitmaps, icons, animations, and the like) is identified by a unique human readable textual name. This textual name is unsuitable for processing by the handset software as it is inefficient. Each textual name is therefore assigned a unique positive integer value. The integer value is used by the handset software to refer to the GUI parameter data. A resource compiler assigns the integers to the textual names.
However, when a new GUI parameter data is added, the resource compiler may assign a unique integer to the new resource. This action may change the numbering of existing items. If the resulting data is downloaded to the handset, the handset has no way of knowing that the numbering has changed. This may result in an error in the operation of the handset. Maintaining a count of GUI parameter data is inaccurate, since the handset cannot distinguish the case of deleting a GUI parameter data followed by addition of a new GUI parameter data.
Therefore, there is a need for improved wireless devices that use a graphical user interface that is simple and inexpensive to modify. In particular, there is a need for apparatuses and methods for ensuring integrity of GUI parameter data used by a data-driven user interface of a wireless mobile station.

System and method for ensuring integrity of data-driven user interface of a wireless mobile station


A fence rail combination tool for supporting a fence rail during fixing comprising an elongated main body, a tip, and a head to retain at least one strap upon the elongate body said tip at a first end for piercing a fence post and an enlarged head at a second end, a lug or fin is incorporated on the body between the first end and the second end and has a slot or aperture therein receiving the strap, wherein the lug or fin acts as a stop to limit insertion of the tip into the fence post and acts to reduce, prevent or limit sagging of the tool under the weight of the supported rail.

This invention relates to A Fence Rail Combination Tool.
During my adventures constructing fencing and subsequently working alone; I have found a problem when trying to install fence rails upon and between fence posts.
Fence railings tend to be reasonably lengthy, generally having a minimum length of around ten feet and generally spanning over ten-twelve feet in length. The railings are attached to the fence posts which are commonly spaced a similar distance apart so that the rails and posts join together to construct the fence and create the boundary when the fence is complete.
The process of constructing the fence (in particular post and rail fencing) is this: the posts are firmly set in the ground and spaced approximately 12 feet apart. A minimum of two posts are needed to create one section of fence—one at each end of the rail. The workman then has to fix the rail(s) between the posts usually by hammering a nail through the rail into the post. Besides being fixed horizontally, the rails are generally also spaced vertically, several feet apart, up the post, which requires the workman to lift the rail up to the fence post (which is generally at least 4-6 ft high), and to then fix the rail to the post. The rails should be level or follow a parallel line to the ground for the fence to have maximum strength and stability and to be aesthetically pleasing to the eye.
Here's the problem: Imagine this: one man is trying to lift a 10 ft rail (which is fairly heavy), up six feet in the air, which he then has to line up perfectly between two fence posts that are spaced at least 5 ft away from either side of him, and then somehow using a hammer, he has to nail each end of the rail to the post and, if he's really good, simultaneously use a spirit level to ensure the rail is where he wants it, before he finally permanently fixes the rail to the post. It does not take a genius to work out that this is extremely difficult and more or less impossible without a second person.
The way I work around this is to try to hold the rail about mid point clutched under my arm whilst I hammer one end into the post and then, still clutching the rail, I turn around and fix the other end. With difficulty, this method does work, but the problem is that the rail will often not be level or it will be off course or not quite where it was supposed to be fastened. These small errors can have a large impact on the overall build of the fence and can make the fence way off line (despite how many times it's been marked out) especially if working to an incline or decline ground mark. It is possible to use clamps but then the rail cannot be freely adjusted and moved around to get a perfectly built fence. Also, when clients are observing one perform this balancing act, it makes one feel unprofessional, even if the final constructed fence is perfect.
There are also parts of the fence construction process (in particular with post and rail fencing), where the end of the rail is usually fastened to the centre of each post so that every post has two rails attached to it from each side of it, using the post as the central support point, obviously so that less posts are used etc. When one is working alone, each rail has to be held up to the post and marked off to be able to be cut if necessary and to ensure the rail is the correct length. This means that one has to measure the rail from the centre of the post often whilst holding the rail. Often measurements have to be taken from different sides of the post and the tape measure is often pulled and twisted around to get a rough measurement as often there are obstacles in the path of the tape such as plants, trees and bushes etc. The other problem is that it's often difficult to anchor the loose end of the tape measure and hold it in place against a post over such a long distance. There are also several different types of rail fencing with different types and sizes of timber and metal used such as rectangular timber or circular metal rails and any tool needs to be able to be used with a large range of rail types.
What is needed is an apparatus or tool that is releasably secured to the fence post and which temporarily tightly holds and/or suspends one end of the rail to the post by way of a strap or tie which may be adjustable to allow the rail to be moved and repositioned, so that the workman can fix the other end of the rail to the other post accurately and trouble free, which would therefore make the job easier, save time and labour. It means only one person is needed to construct the fence and not two. The tool could have a means of release or extracting it from the post as it would likely be temporarily nailed to the post which could be in the form of a hand grip used to pull the tool out of the post. There should also be provision for anchoring a tape measure which may be adjustable or have a range of movement to allow the tape to be held, adjusted and accurate measurements to be taken. There could also be provision to incorporate a mini spirit level and other parts incorporated such as stop lugs to stop the tool being pulled out by the weight of the suspended rail and thumb lugs etc. The tool could be made of several different pieces that could be put together as chosen by the workman for any particular fencing application, such as different types and lengths of straps and strap attachments to suit different types of rails. Sometimes longer straps are needed, stronger straps, adjustable straps, non adjustable straps and so on. The tool should make this fencing task safer to undertake, look more professional and ultimately provide a more accurately finished fence.


A net shaped latex vacuum bag as used in the fabrication of composite structural parts having complex shapes. Liquid latex is first allowed to air dry in the form of a thin flat, flexible sheet. The latex sheet is then vacuum formed over a tool having the complex shape of the part to be fabricated and assumes the shape and configuration of the tool's outer surface. The latex sheet is then rapidly cured at an elevated temperature, so as to permanently assume the part's shape for subsequent use in forming composite structural parts of the same complex shape. In one embodiment, the latex sheet may be formed on the tool by dipping the tool in liquid latex, allowing the latex coating to dry, and cutting the dry latex coating to permit separation of the tool from the latex coating which is then used in composite part fabrication.

Composite parts having complex shapes may be formed using vacuum bags comprised of pleated nylon film which may be configured to conform to the shape of the preform. The preform may be preimpregnated (prepreg) or a dry material with resin infused during consolidation. Vacuum is drawn on the vacuum bag in part to debulk the preform. These complex shapes typically include highly contoured or compound contoured surfaces or those with integral shaped details such as without limitation stringers or frames. Current approaches to fabricating composite parts with complex shapes may suffer from several limitations. For example, installing a pleated nylon vacuum bag over a preform may be extremely labor intensive, requiring highly skilled technicians to apply the intricate pleating patterns necessary to avoid bridging of a bag. Bridging may result in a localized reduced vacuum, which may result in resin pooling. In addition, the thin nylon bags may be susceptible to puncture-related leaks, which may occur during nylon bag installation. The nylon bag pleats may pinch off and render leaks more difficult to detect. When a leak is pinched off, the flow of air through the leak is restricted, making a leak harder to identify in a leak check and harder to locate once a leak is known to exist.
One attempt to avoid the leak susceptibility and labor intensive nature of pleated nylon bag installation in the fabrication of composite parts involves the dipping of a metal mandrel into latex, followed by oven curing of the latex on the mandrel. The latex bags thus formed using this approach may also suffer from several limitations. More specifically, the latex used in forming vacuum bags in this manner may shrink nonuniformly as it cures depending upon physical constraints inherent in the complex shape of the part. This limits the extent of conformance of the thus formed latex bag to the outer surface of the metal mandrel representing the composite part to be fabricated. Silicone bags have also been used, but they may be expensive to manufacture and present a clean room contamination problem. Accordingly, there is a need for a vacuum bag which overcomes the aforementioned limitations.

Vacuum heat-set of net shape latex vacuum bags


Systems and methods are disclosed for establishing and conducting communications within a network. The discloses systems and methods may include determining a scheduled time period for communications between a first communication node and a second communication node. Furthermore, the disclosed systems and methods may include determining a direction of transmission for transmitting data from the first communication node to the second transmission node and receiving data transmitted from the second transmission node and determining a direction of transmission for receiving data from the first communication node and transmitting data from the second transmission node to the first transmission node. Moreover, the disclosed systems and methods may include establishing communications between the first communication node and the second communication node.

This invention relates generally to methods and systems for establishing and conducting communications between nodes in a network. More particularly, the present invention relates to establishing communications between nodes in a network using predetermined time periods for communications between the nodes and directional pointing of the antenna of each node.
Communications between mobile network nodes have been accomplished using directional antennae, which offer the advantages of higher data rate and longer range than omnidirectional antennae. However, directional antennae alone cannot be used for communications between nodes whose locations are unknown to each other. Therefore, in prior art, directional antennae alone cannot be used to establish communication between nodes, because the location of each node is unknown to the other until both nodes join a common network. Using only directional antennae to establish communications is unreliable because a transmitting network node may not be pointing at a receiving network node when the receiving network node is pointing at the transmitting network node. Thus, an omni-directional antenna is also utilized in prior art to establish temporary, low-rate communications to determine where other nodes reside. After a first node obtains the location of at least one other node that belongs to a network the first node wishes to join, the first node can point its directional antenna towards the other node to establish high-rate, long-range communications. However, using the omni-directional antenna to establish the location of other nodes in the network requires additional spectrum space and power to compensate for the operation of the omni-directional antenna. More specifically, the omni-directional antenna requires additional power for operation as it is not focused in a particular direction. Further, the omnidirectional antenna imposes cost and weight on the node beyond the cost and weight of the directional antennae.
Thus, communicating between network nodes using an omni-directional antenna and a directional antenna is costly because two antennae are required for each network node, one antenna (omni-directional) to establish location and another antenna for directional communication. Additionally, the omni-directional antenna utilizes extra spectrum width as well as additional power to transmit data over long distances.
In view of the foregoing, there is a need for more efficient methods and systems for establishing and conducting communications within a network. Furthermore, there is a need for establishing and conducting communications within a network which utilizes a single antenna for establishing location and conducting communications, wherein the antenna utilizes a more narrow spectrum for communications, and utilizes less power in the transmission and reception of data.

Establishing and conducting communications within a network


There is provided an interior illumination lamp for a vehicle. In the interior illumination lamp for a vehicle including a lamp unit having a light source, which is a functional part, and a lens provided inside a vehicle room, which is a decorative part, the lens is engaged with the lamp unit through an inner peripheral edge of an opening in a roof trim, thereby to clamp the roof trim between them and to attach the interior illumination lamp for a vehicle in a state where the roof trim is clamped. The lamp unit is provided with a plurality of positioning projections at a position where the lamp unit is contacted with the roof trim.

As an interior illumination lamp for a vehicle to be attached to a roof trim of a ceiling in a vehicle room, the interior illumination lamp for a vehicle as disclosed in JP-A-2007-203911 has been known.
Japanese Patent Publication No. JP-A-2007-203911 is discussed below.
<The Interior Illumination Lamp for a Vehicle Disclosed in JP-A-2007-203911>
An object of the interior illumination lamp for a vehicle disclosed in JP-A-2007-203911 is to enhance its assembling workability and to facilitate maintenance works. For this purpose, specifically, in the interior illumination lamp for a vehicle which is composed of a functional part and a decorative part, a locking claw is formed on a side face of a base housing of the decorative part, and an elastically deformable operating panel having a locking part to which the locking claw can be locked is provided in a housing of the functional part. The operating panel is pressed from an inside of a bulb containing room in the decorative part to be elastically deformed, thereby enabling a locked state of the locking part with respect to the locking claw to be released.
<Merit and Demerit of the Interior Illumination Lamp for a Vehicle Disclosed in JP-A-2007-203911>
<<Merit>>
According to the interior illumination lamp for a vehicle disclosed in JP-A-2007-203911, a lamp unit can be reliably assembled to a ceiling panel having a plurality of clamping thicknesses, only by exchanging clamping holders. Therefore, constituent components of the lamp unit and a basic design of a wire harness which is connected to the lamp can be commonly used, and further, specs of the clamping holder can be exchanged according to the ceiling panel to which the lamp unit is to be attached. As the results, there is such a merit that modification of the specs of the components to comply with diversification of the specs of the lamp unit can be restrained to the least extent, and cost for the components can be reduced.
<<Demerit>>
In case where the interior illumination lamp for a vehicle is assembled by a clamp between a roof trim and a lens, utilizing the art in JP-A-2007-203911, it is necessary to mold a whole contact face of the lens to be contacted with the roof trim with high precision, for enhancing an appearance of a mated part of an outer periphery of a decorative surface of the lens to be mated with the roof trim. This incurs an increase of the cost.


A faucet with a water outlet controlled by a central pull stick capable of being installed easily comprises a valve body consisting of a main body and a head portion connected together by screw threads. The valve body further comprises a main body and a head portion connected to the main body by a screwing mechanism. A stopper on the main body and a retaining part on the head portion are coupled together upon the screwing so that the retaining part will be fixed on an attached object after the valve body penetrated through the object. Thereby, idle rotation between the head portion and the main body can be prevented. Further, the valve body can be locked onto the attached object by screws applied through the upper surface of the object, facilitating quick installation of the valve body.

A faucet of the prior art connected to a bath tub or a toilet basin has the structure shown in FIG. 6. The faucet comprises a valve body having outer screw threads and consisting of a head portion and a main body that are different parts on an integral body. The bottom end of the main body is extended with a valve tube shrinking toward the connection port of a shower head. The installation of the faucet onto a bath tub or a basin is done by the engagement with a clipping part underneath the attached surface. A water outlet is mounted on the valve body, and a water divider is seal with in the valve body for controlling the water direction.
However, because of the expanded portion of the valve tube of the faucet, the faucet should be inserted into the installation hole on the attached material from below, special installation tools and a variety, of faucets corresponding to bath tubs of different styles are necessary.
Further, the faucet of the prior art has a water outlet for a shower head; but, due to that the valve body is an integral part of the faucet, a water divider controlling the outward direction of water will be disposed within the valve body by a special tool and from above, which is a difficult and therefore time-consuming process.
Further, the installation of the faucet of the prior art to a bath tub needs a single hand extending to a tight space under the surface of installation, which is difficult to apply force and to attain required precision. If the space is too tight, a special tool is needed to assist the applying hand. Therefore, such a tedious assembling process needs to be improved.

Faucet with a water outlet controlled by a central pull stick


A system and method for Near Video On Demand (NVOD) transmission of a program from a server to a plurality of clients. The program is partitioned into segments. Each segment is transmitted repeatedly, with the transmission rate of segments subsequent to the first segment being lower than the transmission rate of the first segment. The transmission of the segments is scheduled in a manner that minimizes the aggregate transmission bandwidth, subject to constraints related to client parameters such as client storage capacity and client recording rates. Preferably, the sequences are partitioned further into subsequences, and redundant subsequences are used for error correction. Preferably, the segments, or the subsegments, include metadata such as segment or subsegment length, segment or subsegment sequence number, or the time until the next transmission of the sequence or subsequence.

The present invention relates to a method and system for transmitting a program to a plurality of viewers, permitting flexible, nearly on demand viewing by an unlimited number of concurrent viewers, and, more particularly, to a method and system for transmission that minimizes transmission bandwidth, possibly subject to certain constraints.
Video-On-Demand (VOD) is the on-line version of traditional video-rental services. As with video rental services, each viewer receives a dedicated xe2x80x9ccopyxe2x80x9d of the movie and can view it in a flexible manner, including the ability to pause and resume, rewind, and possibly even fast-forward. With VOD, the xe2x80x9crentalxe2x80x9d operation is essentially instantaneous, and viewing can begin within seconds of the decision to view.
The xe2x80x9ccopyxe2x80x9d in VOD is a dedicated video stream. This stream is generated by a video server and sent to the viewer over a communication network. An important advantage of VOD over tape rental is the great flexibility in allocation of resources: the maximum number of concurrent viewers is independent of viewing choices, and is limited only by the server""s total streaming capacity. The required bandwidth resources, both in the server and in the communication network, are proportional to the number of concurrent viewers.
There are important situations in which a large number of people wish to view the same content during the same period of time, albeit not simultaneously. One example is viewing emergency-preparedness instruction in the hours or days prior to the arrival of a major storm. Another example is a newly released xe2x80x9chotxe2x80x9d movie that is advertised heavily. Yet another example is a movie whose viewing is assigned as homework, or even a recorded lecture viewed (individually) in class by the students. These pre-recorded instructions, movies and lectures are examples of programs that are to be viewed by many viewers, concurrently but not necessarily simultaneously.
Although VOD could be used to address such situations, it is both highly desirable and intuitively possible to do better. The desire stems from the fact that even the total (over all programs) number of concurrent viewers may be temporarily much higher than usual, so it would be very costly if not impossible to design the infrastructure (server and communication network) for such peaks. The intuition that something can be done arises from the observation that the many viewers of the xe2x80x9chotxe2x80x9d program are viewing the same material concurrently but not simultaneously. The various schemes for doing better than VOD in this situation are called xe2x80x9cNear Video On Demandxe2x80x9d. The goal of NVOD is to provide an unlimited number of viewers of the same program similar service flexibility to that of VOD at a reasonable cost to the server and communication network. Ideally, this cost is independent of the number of viewers. xe2x80x9cNearxe2x80x9d is defined to mean commencement of viewing within a reasonable time interval following viewer request, for example one minute in the case of a movie, as well as the ability to pause and resume at any time. Rewind and fast-forward functions are not obligatory.
There are two categories of NVOD systems: open-loop systems and closed-loop systems. In both systems, the viewers are provided with devices, called herein xe2x80x9cclientsxe2x80x9d because of their relationship with the server, that receive program copies transmitted by the server and display those copies to their respective viewers. In open-loop systems there is no feedback from the viewing client to the server, so neither server transmissions nor routing on the network are affected by viewer actions (other than the possible effect on routing due to a viewer joining a multicast group). Open-loop schemes lend themselves most naturally to broadcast-based networks, such as cable television networks, and even to networks that have only one-way communication, which is the common case in satellite-based information-dissemination networks. Closed-loop systems permit some feedback that allows the server to adjust to client requests throughout the viewing period. Note that the terms xe2x80x9cplayxe2x80x9d and xe2x80x9cdisplayxe2x80x9d are used interchangeably herein, to refer to the displaying of the received program by a client.
Recently, several open-loop NVOD schemes have been proposed. These schemes are based on partitioning the program into several segments, on the assumption that every client has a substantial amount of available storage capacity, for example on a hard disk, which can be used to temporarily store the segments. In such schemes, the server""s transmission schedule, and the algorithm used by the client to decide whether or not to record any given transmitted segment, jointly ensure that every segment of the movie is stored in the client""s recording medium by its viewing time.
One such scheme is taught by DeBey in U.S. Pat. No. 5,421,031, which is incorporated by reference for all purposes as if fully set forth herein. DeBey""s partitioning and scheduling scheme is illustrated in FIG. 1, for the case of segments of equal length. The vertical axis of FIG. 1 is segment number. The horizontal axis of FIG. 1 is the time at which a given segment is broadcast by the server, with the unit of time, as well as the basic time interval, being the duration of one segment. For each segment, the time during which that segment is broadcast by the server is represented by a double-headed arrow. The first segment is broadcast in every time interval, the second segment is broadcast every second time interval, the third segment is broadcast every third time interval, and in general the n-th segment is broadcast every n-th time interval. Note that all segments are transmitted at the same transmission rate of one segment per time interval. In addition, the transmissions continue throughout the time period during which the viewers are permitted to view the program.
A client that tunes in to the broadcast at the beginning of any time interval receives all the segments promptly enough to display the program with no interruptions. For example, a client that tunes in at the beginning of the seventh time interval, and that actually begins to display the movie to its viewer at the beginning of the eighth time interval, receives and records the seventh copy of the first segment during the seventh time interval, the fourth copy of the second segment during the eighth time interval, the third copy of the third segment during the ninth time interval, the second copy of the fourth segment during the eighth time interval, etc. In this case, the first segment is displayed during the eighth time interval, the second segment is displayed during the ninth time interval, the third segment is displayed during the tenth time interval, the fourth segment is displayed during the eleventh time interval, etc.
DeBey""s scheme imposes certain burdens on the server and on the clients. With N segments, the mean transmission bandwidth, in units of segments transmitted per time interval, is approximately ln(N); but the actual transmission bandwidth varies widely. For example, in prime-numbered time intervals after the first time interval, only two segments are broadcast, vs. e.g. six segments during the twelfth time interval. The client must be able to record the received segments fast enough to keep up with the peak aggregate transmission rate. Furthermore, the client must have enough storage capacity to store all recorded segments that are received too soon to play.
There is thus a widely recognized need for, and it would be highly advantageous to have, a NVOD method that imposes less of a burden on the resources available to the server and to the clients.
According to the present invention there is provided, in a system wherein a server transmits a program having a certain duration, the program being received by at least one client, a method for scheduling the transmission of the program, including the steps of: (a) partitioning the program into a plurality of sequential segments; (b) selecting a transmission rate for each segment, the transmission rate that is selected for a first the segment being faster than the transmission rate that is selected for any other the segment; and (c) transmitting the segments, by the server, each segment being transmitted at the transmission rate of the each segment.
According to the present invention there is provided a system for transmitting a program to a plurality of viewers, including: (a) a software module including a plurality of instructions for scheduling a transmission of the program by: (i) partitioning the program into a plurality of sequential segments, and (ii) selecting a transmission rate for each segment, the transmission rate that is selected for a first the segment being faster than the transmission rate that is selected for any other the segment; (b) a processor for executing the instructions; (c) a server for transmitting each segment at the respective transmission rate; and (d) for each viewer, a client for receiving the transmitted segments, recording the received segments and playing the recorded segments in the sequence.
According to the present invention there is provided, in a system wherein a server repeatedly transmits a program that is partitioned into a plurality of segments and wherein a client receives and records the segments and displays the program, the transmitting, receiving and recording of the segments being effected according to a schedule, a method for displaying the program intermittently, including the steps of: (a) transmitting, along with the segments, metadata describing the schedule, by the server; (b) pausing the display of the program, by the client; (c) resuming the display of the program, by the client, subsequent to the pausing; and (d) during the pausing, continuing to record at least a portion of the segments then received, by the client.
In its most basic embodiment, the present invention is a modification of the NVOD scheme of DeBey that smoothes out the instantaneous transmission bandwidth to always be close to the mean transmission bandwidth. This is accomplished by broadcasting all the segments concurrently, starting at the first time interval, but taking n time intervals to broadcast the n-th segment. In other words, if the first segment is transmitted at a transmission rate of T bits per unit time, then the n-th segment is transmitted at a transmission rate of T/n bits per unit time. This is illustrated in FIG. 2. Note that all transmissions end at the same times as in FIG. 1, but start at different times. Specifically, all the first transmissions of all the segments start at the beginning of the first time interval; and subsequently, as soon as the transmission of any segment ends, that segment is immediately retransmitted.
The simultaneous commencement shown in FIG. 2 is illustrative, and applies primarily to the basic embodiment illustrated therein. More generally, because the segments are transmitted repetitively and concurrently throughout the period during which the program is being offered to the viewers, the starting times of the transmission of different segments may be chosen at will.
The most basic embodiment of the present invention relieves the burden on the server, but not necessarily the burden on the clients. For example, a client that tunes in must receive and record all the data being transmitted until such time as it has finished recording a given segment and can cease recording the data for that segment. Thus, this client must be capable of receiving and recording data at a rate equal to the server""s aggregate transmission rate. Furthermore, towards the middle of the program, the client""s storage medium must have sufficient capacity to store a significant portion of the program even if the client discards the data of a segment once it is displayed. These stringent requirements may be relaxed if the start of the recording by a client of later segments is delayed long enough for earlier segments to be recorded, displayed and possibly even discarded, thus freeing up client resources to accommodate the later segments. Clearly, this implies an increase in the aggregate transmission rate, because a segment must be transmitted in its entirely during the time in which it is being recorded by the client; so that shortening this time without changing segment size mandates an increase in its transmission rate. In fact, the optimum overall system design is a tradeoff between minimizing the aggregate transmission rate and meeting client constraints such as limited recording rate and limited storage capacity. The ability to optimally design the system to optimize certain aspects of performance while adhering to constraints on others is a salient feature of the current invention. Algorithms for minimizing the aggregate transmission bandwidth subject to these constraints are presented in the Appendix.
More generally, the scope of the present invention includes NVOD methods and systems in which the first segment is transmitted at a higher transmission rate than the subsequent segments. Preferably, transmission rates of successive program segments are such that the latest time, measured from the time of a client""s viewing request, at which the client may begin to record a segment such that the recording of the segment is completed before that segment must be displayed, is no earlier for a later program segment than for an earlier one. It should be noted that this transmission rate of a segment is defined in terms of the overall transmission rate of the segment as a whole. For example, a server may use time division multiplexing to transmit all the segments concurrently on a single channel, by partitioning the segments into subsegments, interleaving the subsegments and transmitting all the subsegments at the same rate. Consider, for example, in the context of the most basic embodiment of the present invention, a case in which 100-second segments are partitioned into 1-second subsegments of B bits each, that are transmitted on a 1 gigabit-per-second channel. The duration of the transmission of each subsegment is Bxc3x9710xe2x88x929 seconds, no matter which segment is the source of the subsegment; but the 100 subsegments of the first segment are transmitted over the course of 100 seconds, for an overall transmission rate of B bits per second, whereas the 100 subsegments of the second segment are transmitted over the course of 200 seconds, for an overall transmission rate of B/2 bits per second.
It also is clear that a client may ignore, and not record, transmitted copies of any particular segment, until the transmission of the last such copy that is transmitted in its entirety before the segment must be displayed. To facilitate this, each transmitted copy of the segment includes metadata that describe various aspects of the segment, including, for example, the segment number, the size of the segment, the transmission rate of the segment, and a temporal value related to the time interval between the start of the transmission of this copy of the segment and the start of the transmission of the next copy of the segment. An example of this temporal value is the length of this time interval itself. Similarly, in an embodiment of the present invention in which the segments are partitioned into subsegments, each copy of a subsegment includes metadata that describe various aspects of the subsegment, including, for example, the number of the segment to which the subsegment belongs, the sequence number of the subsegment within its segment, the size of the subsegment, and a temporal value related to the time interval between the start of the transmission of this copy of the subsegment and the start of the transmission of the next copy of the subsegment.
When a segment is not partitioned into subsegments, the preferred embodiments of the current invention nonetheless include metadata that provides sufficient identification so as to permit the recording of the segment""s data to begin without waiting for the beginning of the segment. Similarly, when a segment is partitioned into subsegments, the metadata permits the subsegments to be recorded by the client in any order and to subsequently be assembled to form the original segment. Thus, the recording of a given segment by a client may commence essentially as late as one transmission time of the entire segment prior to the earliest time at which that segment may have to be displayed. The time to transmit the entire segment is, in turn, essentially equal to the size of the segment divided by the rate at which the segment is transmitted. Similarly, as soon as a segment is displayed, that segment may be deleted from the recording medium to free up the storage space occupied by that segment.
In one preferred embodiment of the present invention, the subsegments of at least one program segment are used to compute a larger number of such subsegments, such that the original segment can be derived from any sufficiently large subset of the subsegments; and all the subsegments are transmitted such that the time between successive transmissions of the same subsegment remains unchanged. This increases the transmission rate of the segment, but permits the use of error correcting codes to receive the segment successfully even in the event of communication problems.
In one application of the present invention, in order to allow a viewer to tune in to a broadcast of an entire live program after the program has started but before the program has ended, the basic embodiment of the present invention is initiated simultaneously with the live broadcast, with the repeated transmission of each segment initiated after the live transmission of that segment.
In some embodiments of the present invention, only one copy of each segment is stored at the server. In other embodiments of the present invention, multiple copies of the program data are stored at the server, to increase the efficiency of storage access when transmitting the program.
Optionally, the segments are encrypted and/or compressed by the server prior to transmission, and are decrypted and/or decompressed by each client prior to display.
A system of the present invention includes a software module that embodies the algorithm of the present invention, a processor for executing the instructions of the software module, and a server that includes both a data storage area for storing the program segments and a mechanism for transmitting the program segments according to the transmission rates assigned by the algorithm. Preferably, the software module and the processor also are included in the server; although it also is possible, within the scope of the present invention, for the server to obtain a rate allocation table or a transmission schedule from another device that includes the software module and the processor of the present invention and that operates off-line. The system also includes, for each viewer, a client for receiving, recording and displaying the segments, and a distribution network for broadcasting the segments to the clients.
The scope of the present invention also includes a method for pausing and resuming the display of the program by a client, whether the NVOD transmission rates are selected according to the teachings of the present invention or according to prior art schemes such as DeBey""s. Essentially, the client stops displaying the program, but continues to record incoming segments as though the program were being displayed at the point, in the program, where the display was temporarily stopped. To conserve the client""s storage space, metadata are transmitted along with the segments to indicate when the segments will be transmitted again, and segments that will be transmitted and recorded again before they need to be displayed, if displaying were to be resumed immediately, are discarded.

SYSTEM FOR OPTIMIZING VIDEO ON DEMAND TRANSMISSION BY PARTITIONING VIDEO PROGRAM INTO MULTIPLE SEGMENTS, DECREASING TRANSMISSION RATE FOR SUCCESSIVE SEGMENTS AND REPEATEDLY, SIMULTANEOUSLY TRANSMISSION

Technion Research and Development Foundation Ltd.


Disclosed is an object detection method used to detect an object in an image pair corresponding to a current frame. The image pair includes an original image of the current frame and a disparity map of the same current frame. The original image of the current frame includes at least one of a grayscale image and a color image of the current frame. The object detection method comprises steps of obtaining a first detection object detected in the disparity map of the current frame; acquiring an original detection object detected in the original image of the current frame; correcting, based on the original detection object, the first detection object so as to obtain a second detection object; and outputting the second detection object.

1. Field of the Invention
The present invention relates to the field of digital image processing, and particularly relates to an object detection method and an objection detection device.
2. Description of the Related Art
An object detection method has been widely used up to now. In particular, in the field of computer vision, the detection and tracking of an object has become a hot research topic. The reason is that it may automatically sense the key information provided by a specific object for a computer, and may provide a bottom-layer service to some upper-lay applications (e.g., recognizing the activity of an object and understanding the relevant scenario). For example, a method of detecting a vehicle on a road in a driver assistance system may effectively detect or recognize the existence or non-existence, the distance, the velocity, and the orientation of the vehicle, so as to be able to assist a driver to avoid a traffic accident.
At present, there are mainly two kinds of object detection methods.
On the one hand, there is a kind of object detection method of detecting an object on the basis of a disparity map (or called a "depth map"). For example, it may detect, on the basis of the disparity map, a pedestrian, a vehicle, a fence, etc. Since the object detection method on the basis of the disparity map is not easily influenced by an environmental factor such as lighting, it is very robust to the change of environment. In addition, this kind of object detection method is also called a "disparity map based object detection method".
However, sometimes due to the performance restriction of a camera or the characteristic of a corresponding scenario, the camera may only obtain a disparity map in which the disparities are relatively sparse. Hereinafter this kind of disparity may is also called a "sparse disparity map". Here it should be noted that a sparse disparity map refers to one in which there are only a few pixel points having valid disparities (hereinafter, a pixel point having a valid disparity is also called a "disparity point") discontinuously existing on the boundary of an object. The reason of the occurrence of this kind of phenomenon may be that some stereo matching algorithms only match strong texture based pixel points or only adopt high confidence degree based pixel points. As a result, this kind of sparse disparity map may result in difficulty detecting or incompletely detecting an object such as a pedestrian or a vehicle.
On the other hand, there is a kind of object detection method of detecting an object on the basis of an original image (e.g., a grayscale or a color image). For example, it may utilize abundant grayscale or color information to detect various objects. In addition, this kind of object detection method is also called an "original image based object detection method".
However, in this kind of object detection method, the grayscale or color feature may be easily influenced by an environmental factor such as lighting. As a result, the visual feature of a same object may change in different frames (i.e., images), thereby resulting in not being able to match the objects, eventually resulting in the object missing detection.


Installation for the analysis or transformation of the surface of samples placed in a vacuum or controlled atmosphere, including a main enclosure in which is positioned a support plate for at least one device, called SXM, in which a microprobe such as a light or electricity conducting tip is positioned close to the surface of the sample to be examined, whether in the air or in a vacuum. The device is intended for the microscopy, spectroscopy or etching of the sample surface by scanning of the surface by the microprobe. The support plate is equipped with elements for disconnecting it from the main enclosure and with elements for rotating the support plate around a central axis allowing the use of a series of SXM devices fitted into the periphery of the support plate. The main enclosure is completed by a scrubbing enclosure for the surface of the samples and by an introduction and storage enclosure for the samples, which can be handled through the installation by the end of a conveyor rod that can be moved longitudinally and in axial rotation along the alignment axis of the enclosures.

1. Field of the Invention
This invention relates to an installation for the study of the surface of samples placed in a vacuum or controlled atmosphere. It applies in particular to electronic tunneling effect microscopy and/or spectroscopy, namely in ultravacuum, to optic tunneling effect microscopy and/or spectroscopy or further to the etching of nanometric structures through optic and/or electronic microlithographical processes.
2. Discussion of Background Information
It is a well known fact that certain microscopy, spectroscopy or microlithography processes can only be conducted in a particularly clean, controlled atmosphere especially in order not to pollute the surface of the samples being studied, or the samples on which tiny structures are to be realized, such as optic or electronic integrated circuits. In this respect, the vacuum is a particularly useful controlled medium and some applications even require the samples and measuring or etching means to be placed in an ultravacuum, i.e., in a high vacuum. In this sense, a series of microscopy or spectroscopy techniques have been developed employing a lateral scanning of the surface of a sample by an electricity or light conducting tip, this tip being an integral part of a microprobe collecting, by tunneling effect, electrons or photons in numbers that largely depend on an exponential function of the distance separating the tip from the surface; it is common usage to call electronic tunneling microscopy, or STM (Scanning Tunneling Microscopy), the technique using electrons, and optic tunneling microscopy, or PSTM (Photon Scanning Tunneling Microscopy) the technique using photons. As a general rule, these two techniques and equivalent techniques, i.e., those in which a microprobe should be positioned close to the surface of a sample to be studied, either in the air or in a vacuum will be collectively referred to as SXM. Moreover, these initials will be used to refer to microscopes or means of study using these techniques. Finally, it should be noted that SXMs all operate in the same way as a roughometer, and that this expression will be generally used without distinguishing the physical principle applied during measurement.
In all cases, the distances to be maintained between the surface and the microprobe or tip are extremely small, i.e., 1-2 nanometers for the STM and approximately one micrometer for the PSTM. Such small values mean that risks of error in manipulation should be reduced to a minimum and therefore require the use of highly reliable mechanical, electronic or optical components. Without such highly reliable components destructive impacts car more or less, occur between the microprobe and the surface of the sample to be studied or etched, these impacts being caused by the loss of control of the spatial position of the tip. Another cause of damage results from too quick a scanning of the surface with regard to the response time of the components or mechanical and/or electronic circuits controlling the distance between the tip and the surface. Moreover scanning speed is an obvious function of the roughness of the surface. This means that a smooth surface can be scanned quicker than a rough surface, but it is never easy to know exactly before the study. In the case of an impact caused for some reason, the microprobe or the tip must be changed frequently, or at least controlled, which is not always possible directly in an enclosure where a vacuum has been made or where a controlled atmosphere is concerned. In addition, the aging of the tips, especially metal tips in the case of STM, or optic tips in the case of PSTM, is a normal phenomenon requiring their replacement. For example, an STM tip might have to be replaced due to a rearrangement of the terminal atoms of the tip or due to capturing a foreign atom or due to a thermal expansion effect. A final case, also very important, for which it is essential to change the microprobe or tips in order to study the surface of a sample is that where the measurements taken with a first microprobe are uncertain or at least surprising enough to have to be confirmed by a second series of measurements. In particular, it is a well known fact that STM only gives an exploitable topographic image of the surface of a sample if the metal tip has a theoretical profile whose effects on the formation of the image are well established, i.e., vis-a-vis the intensity of the tunnel current being set up between the surface and the tip (the exploitation of a "rough" image thus consists in the deconvolution of the image, in the mathematical sense of the term). Because this condition is not always realized, it might be useful to establish successive cartographs of the same surface, using various tips, the ideal being that these tips are available "in situ" so as to avoid any risk of contaminating the surface under examination by placing the sample in a normal, uncontrolled atmosphere, or simply, due to the delay between successive scannings. Indeed, we know that a scrubbed surface placed in a vacuum becomes covered with a coat of oxides or oxygen within about 1 hour after its scrubbing, even if the vacuum is an ultravacuum, i.e., the surface is contained within an enclosure where the pressure is lower than 10.sup.-9 torr.
Few installations are known that are adapted to the study or etching of the surface of samples placed in vacuum by SXM type techniques offering the possibility of quickly changing the microprobe or the tip used for carrying out this study or etching without having to "interrupt" the vacuum to come back to atmospheric pressure, without dismantling the enclosure to reach the microprobe, or without interrupting the study of the sample for an excessive lapse of time. In this respect, an electric tunneling effect microscope developed by the British company W.A. Technology Limited is equipped with a device allowing the replacement of the tip used for measuring, without having to open the ultravacuum enclosure; the mechanisms used for this purpose are however complex and only allow the tip to be replaced. However, damage can also be done to the microscope itself, or part of it, which will still make it necessary for the ultravacuum enclosure to be opened.
Moreover, it is known that the introduction of a sample in an enclosure in controlled atmosphere or an enclosure in vacuum or ultravacuum is not at all easy. In particular, it is essential to preserve as far as possible the tightness and the cleanliness of the enclosures where the microprobe or the tip used for measuring or etching is located which requires a particularly careful study if samples are to be introduced into the study or etching enclosure without risk of "breaking" the vacuum or contaminating the surrounding atmosphere. This problem has not yet been solved with the existing prototypes, or it has been solved, but in a very complex way, which limits the industrial applications of the SXM installations, and, in particular, that of tunnel microscopes operating in controlled atmosphere or in the ultravacuum.

Installation for the study or the transformation of the surface of samples placed in a vacuum or in a controlled atmosphere