A semiconductor ceramic includes a BamTiO3-based composition, as a main component, having a perovskite structure represented by general formula AmBO3, wherein part of Ba constituting the A site is replaced with Na, Bi, Ca, and a rare-earth element having an ionic radius smaller than that of the Na; the content of the rare-earth element when the total number of moles of the elements constituting the A site is 1 mole is 0.0005 to 0.015 on a molar basis; and the content of the Ca when the total number of moles of the elements constituting the A site is 1 mole is 0.05 to 0.20 (preferably 0.125 or more and 0.175 or less) on a molar basis. A PTC thermistor includes a component body 1 formed of the semiconductor ceramic. Accordingly, high reliability is achieved even if an alkali metal element is present.

A barium titanate (BaTiO3)-based semiconductor ceramic generates heat as a result of application of a voltage and has PTC characteristics in which the resistance value rapidly increases when the temperature exceeds the Curie temperature Tc at which a phase transition from a tetragonal crystal to a cubic crystal takes place.
In such a semiconductor ceramic having PTC characteristics, the resistance value increases when the temperature exceeds the Curie temperature Tc due to the generation of heat caused by the application of a voltage. As a result, a current does not easily flow and the temperature is decreased. When the temperature is decreased and thus the resistance value is decreased, a current easily flows again and the temperature is increased. By repeating the above-described process in such a semiconductor ceramic, the temperature or current is caused to converge to a certain temperature or current. Therefore, such a semiconductor ceramic is widely used as a thermistor for heaters or motor starting devices.
Since a PTC thermistor used for a heater or the like is used at high temperature, the Curie temperature Tc is required to be high. Therefore, the Curie temperature Tc has been conventionally increased by replacing part of Ba in BaTiO3 with Pb.
However, Pb is an environmentally unfriendly substance and thus, in consideration of environment, the development of a lead-free semiconductor ceramic that substantially does not contain Pb has been demanded.
For example, Patent Document 1 discloses a method for producing a BaTiO3-based semiconductor ceramic, the method including adding at least one of Nb, Ta, and a rare-earth element to a structure of Ba1-2x(BiNa)xTiO3 (where 0<x≦0.15) obtained by replacing a part of Ba of BaTiO3 with Bi—Na, sintering the structure in a nitrogen atmosphere, and performing a heat treatment in an oxidizing atmosphere.
The lead-free BaTiO3-based semiconductor ceramic of Patent Document 1 has a high Curie temperature Tc of 140 to 255° C. and a temperature coefficient of resistance of 16 to 20%/° C.
Patent Document 2 discloses a semiconductor ceramic composition whose composition formula is represented by [(A10.5A20.5)x(Ba1-yQy)1-x]TiO3 (where A1 is at least one of Na, K, and Li, A2 is Bi, and Q is at least one of La, Dy, Eu, and Gd), wherein the x and y satisfy 0<x≦0.2 and 0.002≦y≦0.01.
The lead-free semiconductor ceramic composition in Patent Document 2 has a Curie temperature Tc of 130° C. or more.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 56-169301
Patent Document 2: Japanese Unexamined Patent Application Publication No. 2005-255493
Problems to be Solved by the Invention
A PTC thermistor used in a heater may be exposed to a high-humidity atmosphere for a long time, and therefore such a PTC thermistor is required to have high reliability to the extent that the degradation of its performance is prevented even in such a high-humidity atmosphere.
However, since the semiconductor ceramics disclosed in Patent Documents 1 and 2 contain an alkali metal element such as Na, Na ions may be eluted when the semiconductor ceramics are exposed to the high-humidity atmosphere for a long time.
When the semiconductor ceramics are exposed to a high-humidity atmosphere for a long time, the eluted Na ions react with water vapor contained in the atmosphere and sodium hydroxide is produced. The sodium hydroxide erodes the outer electrodes of the PTC thermistor, and may vary the resistance value (increase the resistance value). In addition, the eluted Na ions are segregated in the grain boundaries and thus the grain boundary resistance is increased. This may also vary the resistance value.
As described above, there is a problem in that the resistance value is degraded over time when the semiconductor ceramics disclosed in Patent Documents 1 and 2 are exposed to a high-humidity atmosphere for a long time, and thus reliability is impaired.
In view of the foregoing, an object of the present invention is to provide a semiconductor ceramic having high reliability even if an alkali metal element is contained therein and a PTC thermistor that uses the semiconductor ceramic.
Means for Solving the Problems
Through the intensive study of a {Ba,(Na,Bi),Ca,Ln)}mTiO3-based material (Ln being a rare-earth element) having a perovskite structure (general formula AmBO3), the inventors of the present invention have found that by dissolving a predetermined amount of rare-earth element having an ionic radius smaller than that of Na in the A site and setting the content of Ca in the A site to be 0.05 to 0.20 on a molar basis, there can be provided a semiconductor ceramic that has high reliability and in which the degradation of resistance can be suppressed even when the semiconductor ceramic is exposed to a high-humidity atmosphere for a long time.
The present invention is based on the finding described above. The semiconductor ceramic according to the present invention is a lead-free semiconductor ceramic that substantially does not contain Pb, the semiconductor ceramic including a BamTiO3-based composition, as a main component, having a perovskite structure represented by general formula AmBO3, wherein part of Ba constituting the A site is replaced with Na, Bi, Ca, and a rare-earth element having an ionic radius smaller than that of the Na; the content of the rare-earth element when the total number of moles of the elements constituting the A site is 1 mole is 0.0005 to 0.015 on a molar basis; and the content of the Ca when the total number of moles of the elements constituting the A site is 1 mole is 0.05 to 0.20 on a molar basis.
In the semiconductor ceramic of the present invention, the content of the Ca is preferably 0.125 to 0.175 on a molar basis.
The rare-earth element is at least one member selected from the group consisting of Dy, Y, Ho, and Er in the semiconductor ceramic of the present invention.
A positive temperature coefficient thermistor according to the present invention includes a component body and a pair of outer electrodes formed on surfaces of the component body, wherein the component body is formed of the semiconductor ceramic described above.
Advantages
The semiconductor ceramic of the present invention includes a BamTiO3-based composition, as a main component, having a perovskite structure represented by general formula AmBO3, wherein part of Ba constituting the A site is replaced with Na, Bi, Ca, and a rare-earth element having an ionic radius smaller than that of the Na; the content of the rare-earth element when the total number of moles of the elements constituting the A site is 1 mole is 0.0005 to 0.015 on a molar basis; and the content of the Ca when the total number of moles of the elements constituting the A site is 1 mole is 0.05 to 0.20 (preferably 0.125 to 0.175) on a molar basis. Therefore, there can be provided a semiconductor ceramic in which the degradation of resistance over time can be suppressed even when the semiconductor ceramic is exposed to high-humidity for a long time.
The PTC thermistor of the present invention includes a component body and a pair of outer electrodes formed on surfaces of the component body, wherein the component body is formed of the semiconductor ceramic described above. Therefore, there can be provided a PTC thermistor having high reliability.
Specifically, there can be provided a lead-free PTC thermistor that has high reliability and in which the percentage change in resistivity can be suppressed to 30% or less even when the PTC thermistor is kept in a high-humidity atmosphere of 85% RH for 1000 hours.
An embodiment of the present invention will now be described.
The Main component of a semiconductor ceramic according to an embodiment of the present invention has a perovskite structure represented by general formula (A).(Ba1-w-x-y-zNawBixCayLnz}mTiO3  (A)
Ln is a rare-earth element serving as a semiconductorizing agent. In this embodiment, a rare-earth element having an ionic radius smaller than that of Na is used.
By adding a rare-earth element Ln having an ionic radius smaller than that of Na in such a manner, the Na is more stably dissolved in the A site (Ba site) and thus a variation in resistance over time can be suppressed even if the semiconductor ceramic is exposed in a high-humidity atmosphere for a long time.
In the case where Ba ions in the A site are replaced with another element, an element having an ionic radius closer to that of Ba ions is easily replaced with Ba ions and dissolved in the A site, and an element having an ionic radius different from that of Ba ions is not easily replaced with Ba ions.
Thus, when a rare-earth element Ln added as a semiconductorizing agent and has an ionic radius smaller than that of Na ions is on the point of being dissolved in the A site, and Na ions having an ionic radius closer to that of Ba ions are easily dissolved in the A site more selectively than the rare-earth element Ln. The Na ions are stably dissolved in the A site, whereby precipitation of the Na ions in grain boundaries can be suppressed. Thus, a variation in resistance over time can be suppressed even if the semiconductor ceramic is exposed in a high-humidity atmosphere for a long time, and reliability can be improved.
In addition, since Ca ions have an ionic radius smaller than that of Ba ions, the size of a crystal lattice is decreased by replacing part of Ba with Ca and thus the Na is more easily dissolved in the A site. Consequently, a variation in resistance over time can be suppressed even if the semiconductor ceramic is exposed in a high-humidity atmosphere for a long time, and reliability can be improved.
A rare-earth element Ln having an ionic radius larger than that of Na ions, such as La, is not preferred because the effect, produced by Ca, of decreasing a lattice constant is eliminated.
Specific examples of the rare-earth element Ln having an ionic radius smaller than that of Na ions include Dy, Y, Ho, and Er.
Table 1 shows ionic radii of various elements.
TABLE 1ElementIonic radius (Å)ElementIonic radius (Å)Ba2+1.49La3+1.17Na+1.16Dy3+1.05Bi3+1.17Y3+1.04Ca3+1.14Ho3+1.04——Er3+1.03Cited from R. D. Shanon, "Acta. Crystallography" A, vol. 32 p. 751 (1976)
The size of ionic radii of the present invention is compared using ionic radii of six-coordination.
As is clear from Table 1, Ba and Na have a relatively large difference in ionic radius, and Na and Ca have substantially the same ionic radius. Dy, Y, Ho, and Er each have an ionic radius smaller than that of Na. La has an ionic radius larger than that of Na.
By using Dy, Y, Ho, or Er as a rare-earth element Ln and replacing part of Ba with Ca, precipitation of Na in the grain boundaries is suppressed and Na is stably dissolved in the A site. Consequently, the reliability in a high-humidity atmosphere can be ensured.
In addition, the resistance value of a semiconductor ceramic can be decreased since part of Ba is replaced with Ca as described below.
In this embodiment, the molar amount y of Ca and the molar amount z of rare-earth element Ln in the general formula (A) satisfy mathematical formulas (1) and (2), respectively.0.05≦y≦0.20  (1)0.0005≦z≦0.015  (2)The reasons why y and z are set so as to satisfy the mathematical formulas (1) and (2) will now be described.(1) Molar Amount y of Ca
As described above, since Ca has an ionic radius smaller than that of Ba, the Ca produces an effect of decreasing the size of the crystal lattice in cooperation with the effect of the rare-earth element Ln having an ionic radius smaller than that of Na. As a result, Na ions are easily dissolved in the A site and the precipitation of Na in the grain boundaries is suppressed, which contributes to the improvement in reliability.
In addition, the ratio of the c axis to the a axis among the crystallographic axes is increased by replacing part of Ba with Ca, and thus the tetragonal crystallinity of the crystal is improved. As a result, spontaneous polarization is increased and the grain boundary barrier can be eliminated. This can decrease the resistance value of the semiconductor ceramic and thus a PTC thermistor suitably used for a heater or the like can be obtained.
However, if the molar amount y of Ca in the A site is less than 0.05, the content of Ca is excessively low and the size of the crystal lattice cannot be sufficiently decreased. Consequently, Na ions and Bi ions having an ionic radius smaller than that of Ba ions are precipitated in the grain boundaries. Therefore, when the semiconductor ceramic is exposed in a high-humidity atmosphere for a long time, the precipitated Na ions having a small ionic radius may be eluted in the form of Na ions through the reaction with water vapor contained in the atmosphere. Such Na ions may erode the outer electrodes of a PTC thermistor or increase the grain boundary resistance to increase the resistance value. Thus, the degradation of resistance over time may be caused.
On the other hand, if the molar amount y of Ca is more than 0.20, the solid solubility limit of Ca is exceeded and a large number of heterophases are precipitated in the grain boundaries or at the crystal triple points. Since the heterophases are unstable, they are eluted or react with carbon dioxide or the like in the air when the semiconductor ceramic is exposed in a high-humidity atmosphere for a long time. As a result, the resistance value is increased, which may cause a variation in resistance.
Accordingly, the composition is determined so that the molar ratio y of Ca in the A site is 0.05 to 0.20. To further improve reliability, the molar ratio y is preferably 0.125 to 0.175.
(2) Molar Amount z of Rare-Earth Element Ln
Since the rare-earth element Ln serves as a semiconductorizing agent and a rare-earth element Ln having an ionic radius smaller than that of Na is used as described above, reliability can be ensured even in a high-humidity atmosphere.
However, the content of the rare-earth element Ln is excessively low if the molar amount z of rare-earth element Ln is less than 0.0005. Therefore, the amount of Na precipitated in the grain boundaries without being dissolved in the A site is increased.
On the other hand, the reliability in a high-humidity atmosphere may be decreased if the molar amount z of rare-earth element Ln is more than 0.015.
Accordingly, the composition is determined so that the molar amount z of rare-earth element Ln satisfies 0.0005≦z≦0.015.
The molar ratio m between the A site containing Ba and the B site containing Ti is not particularly limited. When the molar ratio m is 0.992 to 1.004, satisfactory PTC characteristics can be achieved.
Regarding the molar amount w of Na and the molar amount x of Bi in the A site, the total molar amount (w+x) is preferably 0.02 to 0.20. If the total molar amount (w+x) is less than 0.02, the Curie temperature Tc cannot be sufficiently increased because the Curie temperature Tc is increased by replacing part of Ba with Na and Bi. If the total molar amount (w+x) is more than 0.20, the composition is easily shifted from a theoretical composition of a sintered body because Na and Bi are easily volatilized. Any amount of each of Na and Bi can be employed as long as the combined amount is 0.02 to 0.2.
In the present invention, 0.0001 to 0.0020 parts by mole of Mn is preferably added relative to 1 part by mole of main component represented by the general formula (A) to improve PTC characteristics.
In this case, the semiconductor ceramic is represented by general formula (B).(Ba1-w-x-y-zNawBixCayLnz}mTiO3+nMn  (B)
where n satisfies 0.0001≦n≦0.0020.
Mn functions as an acceptor. Therefore, an acceptor level is formed in the grain boundaries and thus the number of PTC digits can be increased by adding Mn within the range described above. As a result, the PTC characteristics can be further improved.
The form of Mn added is not particularly limited, and any manganese compound such as a sol or powder of manganese oxide or an aqueous manganese nitrate solution can be used.
A PTC thermistor that uses the above-described semiconductor ceramic will now be specifically described.
FIG. 1 is a perspective view schematically showing an embodiment of the PTC thermistor.
The PTC thermistor includes a component body 1 formed of the above-described semiconductor ceramic and a pair of outer electrodes 2a and 2b formed on both ends (surfaces) of the component body 1. The outer electrodes 2a and 2b have a single-layer structure or a multi-layer structure composed of a conductive material such as Cu, Ni, Al, Cr, a Ni—Cr alloy, or a Ni—Cu alloy.
In this embodiment, the external appearance has a columnar shape, but may have a disc-like shape or a rectangular parallelepiped shape.
A method for producing the PTC thermistor will now be described.
First, a Ba compound, a Ca compound, a Na compound, a Bi compound, and a Ln compound containing a predetermined rare-earth element Ln are prepared as raw materials. The raw materials are weighed and mixed to obtain a mixed powder so that the semiconductor ceramic has a predetermined composition ratio.
Subsequently, an organic solvent and a polymer-based dispersant are added to the mixed powder and thoroughly mixed and ground by a wet method in a ball mill using grinding media such as PSZ (partially stabilized zirconia) balls. The solvent is then removed by drying, and sizing is performed using a mesh having a predetermined opening. The mixture is subjected to a heat treatment at 800 to 1000° C. for 2 hours to obtain a calcined powder. A vinyl acetate-based organic binder and pure water, and optionally a Mn compound, are added to the calcined powder and thoroughly mixed and ground again using grinding media to obtain a slurry. The resultant slurry is dried to obtain a raw material powder. The raw material powder is then sized using a mesh having a predetermined opening and compression-molded using a press, such as a uniaxial press, to obtain a compact.
The compact is subjected to a debinding treatment at 500 to 600° C. in an air atmosphere, a nitrogen atmosphere, or a mixed stream of air and nitrogen. Subsequently, the compact is fired in a nitrogen atmosphere whose oxygen concentration is 100 to 10000 ppm by volume at a temperature that achieves semiconductorization, e.g., at a maximum firing temperature of 1250 to 1450° C. for a predetermined time to obtain a component body 1, which is a sintered body.
Outer electrodes 2a and 2b are formed on both ends of the component body 1 by plating, sputtering, electrode baking, or the like to produce a PTC thermistor.
The present invention is not limited to the above-described embodiment. For example, the semiconductor ceramic needs only to be mainly composed of BamTiO3 and part of Ba needs only to be replaced with predetermined amounts of Na, Bi, Ca, and a rare-earth element serving as a semiconductorizing agent. Even if incidental impurities are present, the characteristics are not affected. For example, about 0.2 to 0.3% by weight of the PSZ balls in total used as grinding media when mixing and grinding are performed by a wet method may remain present, but this does not affect the characteristics. Similarly, trace amounts, such as about 10 ppm by weight, of Fe, Si, and Cu may be present in the raw materials, but this does not affect the characteristics.
The semiconductor ceramic of the present invention is a lead-free semiconductor ceramic. As described in Means for Solving the Problems, it is only required that the semiconductor ceramic substantially does not contain Pb, and Pb incidentally present in a concentration of about 10 ppm or less by weight is not necessarily excluded as long as it does not affect the characteristics.
Examples of the present invention will now be specifically described.
BaCO3, CaCO3, Na2CO3, Bi2O3, TiO2, La2O3, Dy2O3, Y2O3, Ho2O3, and Er2O3, which were raw materials of a main component, were prepared and then weighed and mixed to obtain a mixed powder so that the sintered body had the composition shown in Table 2.
Subsequently, ethanol (organic solvent) and a polymer-based dispersant were added to the mixed powder and mixed and ground in a ball mill using PSZ balls for 24 hours. The ethanol was removed by drying, and sizing was performed using a mesh having an opening of 300 μm. The mixture was subjected to a heat treatment at 800 to 1000° C. for 2 hours to obtain a calcined powder.
A vinyl acetate-based organic binder and an aqueous manganese nitrate solution were added to the calcined powder and mixed and ground by a wet method in a ball mill using PSZ balls for 16 hours to obtain a slurry. The amount of the aqueous manganese nitrate solution added was adjusted to be 0.00025 parts by mole on a Mn basis relative to 1 part by mole of main component.
The slurry was dried and sized using a mesh having an opening of 300 μm to obtain a raw material powder.
The raw material powder was compression-molded using a uniaxial press at a pressure of 9.8×107 Pa (1000 kgf/cm2) to obtain a disc-shaped compact having a diameter of 14 mm and a thickness of 2.5 mm.
The disc-shaped compact was subjected to a debinding treatment in the air at 600° C. for 2 hours. The compact was fired in a nitrogen atmosphere whose oxygen concentration was 100 ppm by volume at a maximum firing temperature of 1250 to 1400° C. for 2 hours to obtain semiconductor ceramics with a sample number of 1 to 5.
Subsequently, the fired samples were lapped and then subjected to dry plating to form outer electrodes having a three-layer structure of NiCr/NiCu/Ag. Consequently, sample Nos. 1 to 5 were prepared.
Regarding the sample Nos. 1 to 5, the electrical resistivity ρ0 at 25° C. (room temperature), the number of digits of PTC ΔR, and the Curie temperature Tc were determined.
The electrical resistivity ρ0 was measured by a direct current four-terminal method through the application of a voltage of 1 V at 25° C.
The number of digits of PTC ΔR indicates the performance of a PTC thermistor, and is defined by the logarithm of the ratio between the maximum value ρmax and the minimum value ρmin of electrical resistivity as represented by mathematical formula (3).ΔR=log(ρmax/ρmin)  (3)
Therefore, the characteristics (hereinafter referred to as "ρ-T characteristics") between temperature T and electrical resistivity ρ were measured, and the number of digits of PTC was determined using the maximum value and the minimum value.
The Curie temperature Tc was defined as a temperature at which the electrical resistivity ρ0 at room temperature was doubled, and determined from the ρ-T characteristics.
Furthermore, a humidity test was performed to evaluate reliability. Five specimens for each of the samples were left in a constant temperature and humidity chamber at 85° C. and 85% RH for 1000 hours. The electrical resistivity ρ1 after the humidity test was measured at 25° C., and the difference Δρ(=ρ1−ρ0) between the electrical resistivity ρ1 after the test and the electrical resistivity ρ0 before the test was determined. The percentage change in resistivity Δρ/ρ0 was calculated for the five specimens, and the reliability was evaluated using the average value of the percentage changes in resistivity Δρ/ρ0.
Table 2 shows the compositions and measurement results of the sample Nos. 1 to 5.
Samples having a percentage change in resistivity Δρ/ρ0 of 30% or less were judged as good.
TABLE 2Composition formula:(Ba0.749Na0.05Bi0.05Ca0.15Ln0.001)TiO3 + 0.00025MnCuriePercentageElectricalNumbertemperaturechange inSampleresistivity ρ0of digits ofTcresistivityNo.Ln(Ω · cm)PTC ΔR(° C.)Δρ/ρ0 (%)1*La94.51646202Dy154.3157213Y105.1159154Ho214.7151235Er314.215214*Outside the scope of the present invention
The sample No. 1 had an extremely high percentage change in resistivity Δρ/ρ0 of 620%. This reason is believed to be as follows. Since La (ionic radius: 1.17 Å) having an ionic radius larger than that of Na (ionic radius: 1.16 Å) was used as the rare-earth element Ln serving as a semiconductorizing agent, Na was not stably coordinated in the A site and was precipitated in the grain boundaries. As a result, the variation in resistance was increased after the humidity test.
In contrast, each of the rare-earth elements Ln used in the sample Nos. 2 to 5 (Dy: 1.05 Å, Y: 1.04 Å, Ho: 1.04 Å, Er: 1.03 Å) had an ionic radius smaller than that of Na, and the molar amount z of rare-earth element Ln and the molar amount y (=0.15) of Ca in the A site were within the scope of the present invention. Therefore, the percentage change in resistivity Δρ/ρ0 was a satisfactory value of 30% or less, specifically 14 to 23%. In addition, the electrical resistivity ρ0 was 40 Ω·cm or less, specifically 10 to 31 Ω·cm.
In Example 2, various samples containing Dy (molar ratio: 0.002) as the rare-earth element Ln and obtained by changing the molar amount y of Ca were prepared, and the characteristics were evaluated.
BaCO3, CaCO3, Na2CO3, Bi2O3, TiO2, and Dy2O3, which were raw materials of a main component, were prepared and then weighed and mixed to obtain a mixed powder so that the sintered body had the composition shown in Table 3.
After that, sample Nos. 11 to 19 were prepared by the same method and process as those in Example 1 but the firing process was performed in a nitrogen atmosphere whose oxygen concentration was 5000 ppm by volume.
Regarding the sample Nos. 11 to 19, the electrical resistivity ρ0 at 25° C. (room temperature), the number of digits of PTC ΔR, the Curie temperature Tc, and the percentage change in resistivity Δρ/ρ0 were determined by the same method and process as those in [Example 1].
Table 3 shows the compositions and measurement results of the sample Nos. 11 to 19.
As in Example 1, samples having a percentage change in resistivity Δρ/ρ0 of 30% or less were judged as good.
TABLE 3Composition formula:(Ba0.898−yNa0.05Bi0.05CayDy0.002)TiO3 + 0.00025MnCuriePercentageElectricalNumbertemperaturechange inSampleresistivity ρ0of digits ofTcresistivityNo.y(Ω · cm)PTC ΔR(° C.)Δρ/ρ0 (%)11*01573.918116512*0.02583.717667130.05263.917329140.10214.116521150.125174.016114160.15144.415411170.175194.715012180.20385.11461919*0.251334.913939*Outside the scope of the present invention
Sample No. 11 had a high electrical resistivity ρ0 of 157 Ω·cm and a high percentage change in resistivity Δρ/ρ0 of 165%. This may be because Ca was not contained and thus the size of a crystal lattice was large, and Na ions and Bi ions having an ionic radius smaller than that of Ba ions were easily precipitated in the grain boundaries.
Sample No. 12 had a high percentage change in resistivity Δρ/ρ0 of 67%. This is because, since the molar amount y of Ca was an excessively low value of 0.02, the same phenomenon as that of the sample No. 11 occurred.
Sample No. 19 had a high percentage change in resistivity Δρ/ρ0 of 39%. This is because, since the molar amount y of Ca was an excessively high value of 0.25, Ca whose solid solubility limit was exceeded was precipitated in the grain boundaries or at the crystal triple points.
In contrast, in the sample Nos. 13 to 18, have a molar amount y of Ca of 0.05 to 0.20 and Dy having an ionic radius smaller than that of Na was present within the composition range of the present invention. Therefore, the percentage change in resistivity Δρ/ρ0 could be suppressed to 30% or less and thus the reliability in a high-humidity atmosphere could be ensured. The electrical resistivity ρ0 was also a satisfactory value of 40 Ω·cm or less. In particular, sample Nos. 15 to 17 in which the molar amount y of Ca was 0.125 to 0.175 had a low percentage change in resistivity Δρ/ρ0 of 15% or less and an electrical resistivity ρ0 of 20 Ω·cm or less. Consequently, it was found that a PTC thermistor having more satisfactory PTC characteristics and higher reliability could be obtained.
In Example 3, various samples containing Y (molar amount: 0.002) as the rare-earth element Ln and obtained by changing the molar amount y of Ca were prepared, and the characteristics were evaluated.
BaCO3 CaCO3 Na2CO3, Bi2O3, TiO2 and Y2O3, which were raw materials of a main component, were prepared and then weighed and mixed to obtain a mixed powder so that the sintered body had the composition shown in Table 4.
After that, sample Nos. 21 to 29 were prepared by the same method and process as those in Example 1 except that the firing process was performed in a nitrogen atmosphere whose oxygen concentration was 5000 ppm by volume, as in Example 2.
Regarding the sample Nos. 21 to 29, the electrical resistivity ρ0 at 25° C. (room temperature), the number of digits of PTC ΔR, the Curie temperature Tc, and the percentage change in resistivity Δρ/ρ0 were determined by the same method and process as those in Example 1.
Table 4 shows the compositions and measurement results of the sample Nos. 21 to 29.
As in Example 1, samples having a percentage change in resistivity Δρ/ρ0 of 30% or less were judged as good.
TABLE 4Composition formula:(Ba0.898−yNa0.05Bi0.05CayY0.002)TiO3 + 0.00025MnCuriePercentageElectricalNumbertemperaturechange inSampleresistivity ρ0of digits ofTcresistivityNo.y(Ω · cm)PTC ΔR(° C.)Δρ/ρ0 (%)21*0693.71809922*0.025543.717756230.05384.317424240.10244.316717250.125134.516211260.15124.81588270.175135.215310280.20395.31431729*0.251144.813751*Outside the scope of the present invention
Sample No. 21 had a high percentage change in resistivity Δρ/ρ0 of 99%. This may be because, Na ions and Bi ions having an ionic radius smaller than that of Ba ions were easily precipitated in the grain boundaries since Ca was not present and thus the size of a crystal lattice was large, as in the sample No. 11 of Example 2.
Sample No. 22 had a high percentage change in resistivity Δρ/ρ0 of 56%. This is because, since the molar amount y of Ca was an excessively low value of 0.025, the same phenomenon as that of the sample No. 21 occurred.
Sample No. 29 had a high percentage change in resistivity Δρ/ρ0 of 51%. This is because, since the molar amount y of Ca was an excessively high value of 0.25, the Ca whose solid solubility limit was exceeded and it was precipitated in the grain boundaries or at the crystal triple points.
In contrast, the molar amount y of Ca was 0.05 to 0.20 and Y having an ionic radius smaller than that of Na was present within the composition range of the present invention in the sample Nos. 23 to 28. Therefore, the percentage change in resistivity Δρ/ρ0 could be suppressed to 30% or less and thus the reliability in a high-humidity atmosphere could be ensured. The electrical resistivity ρ0 was also a satisfactory value of 40 Ω·cm or less. In particular, the sample Nos. 25 to 27 in which the molar amount y of Ca was 0.125 to 0.175 had a low percentage change in resistivity Δρ/ρ0 of 15% or less and an electrical resistivity ρ0 of 20 Ω·cm or less. Consequently, it was found that a PTC thermistor having more satisfactory PTC characteristics and higher reliability could be obtained.
In Example 4, various samples containing La as the rare-earth element Ln and obtained by changing the molar amount z of La were prepared, and the characteristics were evaluated.
BaCO3, CaCO3, Na2CO3, Bi2O3, TiO2, and La2O3, which were raw materials of a main component, were prepared and then weighed and mixed to obtain a mixed powder so that the sintered body had the composition shown in Table 5.
After that, sample Nos. 31 to 36 were prepared by the same method and process as those in Example 1. The firing process was performed in a nitrogen atmosphere whose oxygen concentration was 100 ppm by volume as in Example 1.
Regarding the sample Nos. 31 to 36, the electrical resistivity ρ0 at 25° C. (room temperature), the number of digits of PTC ΔR, the Curie temperature Tc, and the percentage change in resistivity Δρ/ρ0 were determined by the same method and process as those in Example 1.
Table 5 shows the compositions and measurement results of the sample Nos. 31 to 36. The composition and measurement results of the sample No. 1 are also shown for comparison.
As in Example 1, samples having a percentage change in resistivity Δρ/ρ0 of 30% or less were judged as good.
TABLE 5Composition formula:(Ba0.75−zNa0.05Bi0.05Ca0.15Laz)TiO3 + 0.00025MnCuriePercentageElectricalNumbertemperaturechange inSampleresistivity ρ0of digits ofTcresistivityNo.z(Ω · cm)PTC ΔR(° C.)Δρ/ρ0 (%) 1*0.00194.516462031*0.00012443.417253432*0.0005743.716937233*0.005273.915131434*0.01643.413537835*0.015863.111723136*0.021563.4111427*Outside the scope of the present invention
It was found from the sample Nos. 31 to 36 and the sample No. 1 that the percentage changes in resistivity Δρ/ρ0 were more than 200% even if the molar amount of La was changed, which meant that the resistance value was significantly increased after the humidity test. This may be because, since La (ionic radius: 1.17 Å) had an ionic radius larger than that of Na (ionic radius: 1.16 Å), Na was not stably coordinated in the A site and was precipitated in the grain boundaries. It is believed that as a result, a variation in resistance was increased after the humidity test.
In Example 5, various samples containing Dy as the rare-earth element Ln and obtained by changing the molar amount z of Dy were prepared, and the characteristics were evaluated.
BaCO3, CaCO3, Na2CO3, Bi2O3, TiO2, and Dy2O3, which were raw materials of a main component, were prepared and then weighed and mixed in consideration of volatilization of Na2CO3 and Bi2O3 to obtain a mixed powder so that the sintered body had the composition shown in Table 6.
After that, sample Nos. 41 to 46 were prepared by the same method and process as those in Example 1. The firing process was performed in a nitrogen atmosphere whose oxygen concentration was 100 ppm by volume as in [Example 1].
Regarding the sample Nos. 41 to 46, the electrical resistivity ρ0 at 25° C. (room temperature), the number of digits of PTC ΔR, the Curie temperature Tc, and the percentage change in resistivity Δρ/ρ0 were determined by the same method and process as those in Example 1.
Table 6 shows the compositions and measurement results of the sample Nos. 41 to 46. The composition and measurement results of the sample No. 2 are also shown for comparison.
As in Example 1, samples having a percentage change in resistivity Δρ/ρ0 of 30% or less were judged as good.
TABLE 6Composition formula:(Ba0.75−zNa0.05Bi0.05Ca0.15Dyz)TiO3 + 0.00025MnCuriePercentageElectricalNumbertemperaturechange inSampleresistivity ρ0of digits ofTcresistivityNo.z(Ω · cm)PTC ΔR(° C.)Δρ/ρ0 (%) 20.001154.31572141*0.00012943.9161278420.0005394.116029430.005224.415417440.01283.415516450.015372.91531446*0.02742.715534*Outside the scope of the present invention
Sample No. 41 had a high percentage change in resistivity Δρ/ρ0 of 278% because the molar amount z of Dy was an excessively low value of 0.0001.
Sample No. 46 had a high percentage change in resistivity Δρ/ρ0 of 34% because the molar amount z of Dy was an excessively high value of 0.02.
In contrast, sample Nos. 42 to 45 contained Dy having an ionic radius smaller than that of Na at a molar ratio that was within the scope of the present invention, as in the sample No. 2. Therefore, the percentage change in resistivity Δρ/ρ0 obtained after the humidity test could be suppressed to 30% or less. In addition, the electrical resistivity ρ0 was also confirmed to be decreased to 40 Ω·cm or less.
In Example 6, various samples containing Y as the rare-earth element Ln and obtained by changing the molar amount z of Y were prepared, and the characteristics were evaluated.
BaCO3, CaCO3, Na2CO3, Bi2O3, TiO2, and Y2O3, which were raw materials of a main component, were prepared and then weighed and mixed to obtain a mixed powder so that the sintered body had the composition shown in Table 7.
After that, sample Nos. 51 to 57 were prepared by the same method and process as those in Example 1. The firing process was performed in a nitrogen atmosphere whose oxygen concentration was 100 ppm by volume as in Example 1.
Regarding the sample Nos. 51 to 57, the electrical resistivity ρ0 at 25° C. (room temperature), the number of digits of PTC ΔR, the Curie temperature Tc, and the percentage change in resistivity Δρ/ρ0 were determined by the same method and process as those in Example 1.
Table 7 shows the compositions and measurement results of the sample Nos. 51 to 57. The composition and measurement results of the sample No. 3 are also shown for comparison.
As in Example 1, samples having a percentage change in resistivity Δρ/ρ0 of 30% or less were judged as good.
TABLE 7Composition formula:(Ba0.75−zNa0.05Bi0.05Ca0.15Yz)TiO3 + 0.00025MnCuriePercentageElectricalNumbertemperaturechange inSampleresistivity ρ0of digits ofTcresistivityNo.z(Ω · cm)PTC ΔR(° C.)Δρ/ρ0 (%) 30.001105.11591551*0.00011944.1164307520.0005364.916217530.00284.815811540.005184.51577550.01243.71595560.015313.2157957*0.0276315842*Outside the scope of the present invention
Sample No. 51 had a high percentage change in resistivity Δρ/ρ0 of 307% because the molar amount z of Y was an excessively low value of 0.0001.
Sample No. 57 had a high percentage change in resistivity Δρ/ρ0 of 42% because the molar amount z of Y was an excessively high value of 0.02.
In contrast, sample Nos. 52 to 56 contained Y having an ionic radius smaller than that of Na at a molar ratio that was within the scope of the present invention, as in the sample No. 3. Therefore, the percentage change in resistivity Δρ/ρ0 obtained after the humidity test could be suppressed to 30% or less. In addition, the electrical resistivity ρ0 was also confirmed to be decreased to 40 Ω·cm or less.
In Example 7, various samples containing Ho as the rare-earth element Ln and obtained by changing the molar amount z of Ho were prepared, and the characteristics were evaluated.
BaCO3, CaCO3, Na2CO3, Bi2O3, TiO2, and Ho2O3, which were raw materials of a main component, were prepared and then weighed and mixed to obtain a mixed powder so that the sintered body had the composition shown in Table 8.
After that, sample Nos. 61 to 66 were prepared by the same method and process as those in Example 1. The firing process was performed in a nitrogen atmosphere whose oxygen concentration was 100 ppm by volume as in Example 1.
Regarding the sample Nos. 61 to 66, the electrical resistivity ρ0 at 25° C. (room temperature), the number of digits of PTC ΔR, the Curie temperature Tc, and the percentage change in resistivity Δρ/ρ0 were determined by the same method and process as those in Example 1.
Table 8 shows the compositions and measurement results of the sample Nos. 61 to 66. The composition and measurement results of the sample No. 4 are also shown for comparison.
As in Example 1, samples having a percentage change in resistivity Δρ/ρ0 of 30% or less were judged as good.
TABLE 8Composition formula:(Ba0.75−zNa0.05Bi0.05Ca0.15Hoz)TiO3 + 0.00025MnCuriePercentageElectricalNumbertemperaturechange inSampleresistivity ρ0of digits ofTcresistivityNo.z(Ω · cm)PTC ΔR(° C.)Δρ/ρ0 (%) 40.001214.71512361*0.00012763.7157134620.0005784.815427630.005384.514917640.01673.915213650.015723.71471266*0.021243.414939*Outside the scope of the present invention
Sample No. 61 had a high percentage change in resistivity Δρ/ρ0 of 134% because the molar amount z of Ho was an excessively low value of 0.0001.
Sample No. 66 had a high percentage change in resistivity Δρ/ρ0 of 39% because the molar amount z of Ho was an excessively high value of 0.02.
In contrast, sample Nos. 62 to 65 contained Ho having an ionic radius smaller than that of Na at a molar ratio that was within the scope of the present invention, as in the sample No. 4. Therefore, the percentage change in resistivity Δρ/ρ0 obtained after the humidity test could be suppressed to 30% or less. In addition, the electrical resistivity ρ0 was also confirmed to be decreased to 80 Ω·cm or less.
In Example 8, various samples containing Er as the rare-earth element Ln and obtained by changing the molar amount z of Er were prepared, and the characteristics were evaluated.
BaCO3, CaCO3, Na2CO3, Bi2O3, TiO2, and Er2O3, which were raw materials of a main component, were prepared and then weighed and mixed to obtain a mixed powder so that the sintered body had the composition shown in Table 9.
After that, sample Nos. 71 to 76 were prepared by the same method and process as those in Example 1. The firing process was performed in a nitrogen atmosphere whose oxygen concentration was 100 ppm by volume as in Example 1.
Regarding the sample Nos. 71 to 76, the electrical resistivity ρ0 at 25° C. (room temperature), the number of digits of PTC ΔR, the Curie temperature Tc, and the percentage change in resistivity Δρ/ρ0 were determined by the same method and process as those in Example 1.
Table 9 shows the compositions and measurement results of the sample Nos. 71 to 76. The composition and measurement results of the sample No. 5 are also shown for comparison.
As in Example 1, samples having a percentage change in resistivity Δρ/ρ0 of 30% or less were judged as good.
TABLE 9Composition formula:(Ba0.75−zNa0.05Bi0.05Ca0.15Erz)TiO3 + 0.00025MnCuriePercentageElectricalNumbertemperaturechange inSampleresistivity ρ0of digits ofTcresistivityNo.z(Ω · cm)PTC ΔR(° C.)Δρ/ρ0 (%) 50.001314.21521471*0.00013113.115497720.0005743.714922730.005394.114910740.01763.81476750.015773.7143576*0.021573.214232*Outside the scope of the present invention
Sample No. 71 had a high percentage change in resistivity Δρ/ρ0 of 97% because the molar amount z of Er was an excessively low value of 0.0001.
Sample No. 76 had a high percentage change in resistivity Δρ/ρ0 of 32% because the molar amount z of Er was an excessively high value of 0.02.
In contrast, the sample Nos. 72 to 75 contained Er having an ionic radius smaller than that of Na at a molar ratio that was within the scope of the present invention, as in the sample No. 5. Therefore, the percentage change in resistivity Δρ/ρ0 obtained after the humidity test could be suppressed to 30% or less. In addition, the electrical resistivity ρ0 was also confirmed to be decreased to 80 Ω·cm or less.
FIG. 2 is a diagram showing the relationship between the percentage change in resistivity Δρ/ρ0 and the molar amount z of rare-earth elements Ln used in Examples 4 to 8. FIG. 3 is a diagram showing the relationship between the Curie temperature Tc and the molar amount z of rare-earth elements Ln used in Examples 4 to 8. In the drawings, a solid-white square indicates La, a solid-white triangle indicates Dy, a solid-black diamond indicates Y, a solid-black circle indicates Ho, and a cross indicates Er.
As is clear from FIG. 2, the percentage change in resistivity Δρ/ρ0 obtained after the humidity test was an extremely high value of 230 to 620% in the case where La was present and thus desired reliability could not be achieved.
In contrast, it was found that when Dy, Y, Ho, or Er having an ionic radius smaller than that of Na was added at a molar amount z of 0.0005 to 0.015, the percentage change in resistivity Δρ/ρ0 obtained after the humidity test could be suppressed to 5 to 29% and high reliability could be achieved.
FIG. 3 shows that in the case where La was present, the Curie temperature was significantly decreased along with an increase in the molar amount z. In contrast, it was found that when Dy, Y, Ho, or Er, each of which was within the scope of the present invention, was used, a desired high Curie temperature could be maintained at a molar ratio z of 0.0005 to 0.015.
When a rare-earth element is added to a BaTiO3-based material, the Curie temperature Tc is normally decreased, as in the case where La is present. However, it was found that when Dy, Y, Ho, or Er, each of which was a rare-earth element within the scope of the present invention, was added in a predetermined amount, the Curie temperature Tc was not decreased.
This may be related to the fact that Na and Bi are contained in the main component of the present invention.
As is clear from Examples described above, a PTC thermistor having high reliability and a substantially constant high Curie temperature in a stable manner can be obtained in the present invention even if the composition is shifted to some degree.
In Example 9, various samples containing Y as the rare-earth element Ln and obtained by changing the molar amounts m, w, and x and the oxygen concentration in the nitrogen atmosphere during firing process were prepared, and the characteristics were evaluated.
BaCO3, CaCO3, Na2CO3, Bi2O3, TiO2, and Y2O3, which were raw materials of a main component, were prepared and then weighed and mixed to obtain a mixed powder so that the sintered body had the composition shown in Table 10.
After that, sample Nos. 81 to 89 were prepared by the same method and process as those in Example 1 except that the firing process was performed in a nitrogen atmosphere whose oxygen concentration was 5000 ppm by volume.
Regarding the sample Nos. 81 to 89, the electrical resistivity ρ0 at 25° C. (room temperature), the number of digits of PTC ΔR, the Curie temperature Tc, and the percentage change in resistivity Δρ/ρ0 were determined by the same method and process as those in Example 1.
Table 10 shows the compositions and measurement results of the sample Nos. 81 to 89. The composition and measurement results of the sample No. 26 are also shown for comparison.
As in Example 1, samples having a percentage change in resistivity Δρ/ρ0 of 30% or less were judged as good.
TABLE 10Composition formula:(Ba0.848-w-xNawBixCa0.15Y0.002)mTiO3 + 0.00025 MnElectricalNumberCuriePercentageSam-resistivityof digitstemper-change inpleρ0of PTCatureresistivityNo.mwx(Ω · cm)ΔRTc (° C.)Δρ/ρ0 (%)261.0000.050.05124.81588811.0000.100.10195.618215821.0000.0750.075175.316910831.0000.040.04154.515011841.0000.030.03144.314612851.0000.020.0294.014315861.0000.010.0173.913914871.0000.0510.049185.215313880.9920.050.05194.71569891.0040.050.05104.11615
It was found from the sample Nos. 81 to 86 and the sample No. 26 that in the case where the molar amount m was 1.000, the molar amount y of Ca was 0.15, and the total molar amount (w+x) of Na and Bi was 0.02 to 0.20, the percentage change in resistivity Δρ/ρ0 was a satisfactory value of 15% or less and the electrical resistivity ρ0 was a satisfactory value of 20 Ω·cm or less.
It was confirmed from the sample No. 87 that solving of the problems of the present invention was not affected by a slight shift of the ratios of Na and Bi from a stoichiometric ratio (w=x=0.05).
It was also found from the sample Nos. 88 and 89 that satisfactory results were obtained even if the molar ratio m was varied in the range of 0.992 to 1.004. Therefore, it was confirmed that by adding a predetermined rare-earth element of the present invention within a predetermined range and setting the content of Ca in the A site to be 0.05 to 0.20, the molar amount m was not limited to a stoichiometric ratio.
1component body2a,2bouter electrode

Semiconductor ceramic and positive temperature coefficient thermistor


A system and method for providing a voice communication service between a first user and a second user after the first user and the second user are communicating via a non-voice communication service is described. The non-voice communication service may be processed through a server in communication with the first and second users. The non-voice communication service is monitored for a voice service request, and upon receipt of the voice service request, establishment of a voice communication service is initiated between the first and second users through the server. The first and second users may be anonymous to each other over the non-voice communication service and the voice communication service.

For person-to-person communications, a myriad of technologies are available to provide live, voice communications and real-time non-voice communications between at least two people. Voice communications may be conducted through parties having appropriate telephones (or similar devices) connected on a public switched telephone network (PSTN), a private switched telephone network (PBX), a cellular telephone network or through a combination of the networks. Non-voice communications can be conducted by persons accessing appropriate terminals (or similar devices) using data networks and data channels, such as email, short message service (SMS) and others. It is also common to have devices which incorporate both voice and non-voice capabilities (e.g. cell phones with SMS messaging capabilities).
As with most person-to-person communications there is a "calling" party and a "called" party. For a typical telephone call, the called party can obtain information about the calling party, through frequency shift key (FSK) signals embedded in between rings which precede establishment of a call, unless the signals are otherwise blocked. When sending email, the sender needs to know the address of the recipient of the email. Generally, the recipient will be provided the sender's address.
While existing person-to-person communication technologies individually have advantages, there is a need for additional technologies which can bridge between two or more different protocols. There is a need for a system and method establishing person-to-person communications which incorporates various advantages of existing systems through different channels.

System and method for establishing a call


A strategy game or game of patience having a playing surface (1) of higher complexity and with increased playing incentive. According to the invention to attain that object it is proposed that the playing surface (1) has a plurality of mutually overlapping circular surfaces (2, 3, 4, 5, 6) each of the same respective radius R, and with playing elements (7, 8, 21, 22) which are respectively arranged on at least one of the circular surfaces (2, 3, 4, 5, 6), wherein all playing elements (7, 8, 21, 22) which are disposed on any circular surface (2, 3, 4, 5, 6) belonging completely to the playing surface are rotatable jointly about the respective circle center point.

The present invention concerns a game of strategy with a playing surface.
Games of patience or strategy games of the most widely varying kind are known from the state of the art. What are referred to as sliding puzzles in which square or rectangular playing elements or tiles can be displaced relative to each other on a square or rectangular playing surface are wide-spread. In that case the sliding puzzles have so many playing elements that they completely cover the playing surface except for one field of the same size as a single playing element. The playing elements themselves are of such a configuration that they are displaceable relative to each other in two mutually perpendicular directions, wherein one playing element can be respectively displaced into the region of the playing surface which is just free and is not covered by any other playing element. Printed on the playing elements are motifs and patterns which can be broken down and assembled again or ordered, only by sliding the playing elements.
The sliding puzzles known from the state of the art suffer from the disadvantage that the possible combinations are limited by the restricted mobility of the individual playing elements on the playing surface and a single prefabricated game does not allow any possible variations.
In addition, known from the state of the art is a cube which comprises various colored cube portions which are rotatable relative to each other in segment-wise fashion about three independent spatial axes and which by virtue of rotation form colored patterns which are variable in many different ways, the aim of the game with that cube being to put a turned cube back into the initial position again, in which each side of the cube is of a uniform color in respect of the individual cube segments. However reliable solution algorithms have already long been developed for that purpose, which after a certain time take the attraction away from the game.

Spielzeugdesign und Herstellung Wilfried Braun


Various embodiments are directed to a portable voice and data radio base station to couple to a mobile computing device. When coupled, the portable voice and data radio base station and the mobile computing device may cooperatively form a wireless access point to enable communications among a network and other local wireless communication devices. Other embodiments are described and claimed.

A mobile computing device such as a combination handheld computer and mobile telephone or smart phone generally may provide voice and data communications functionality, as well as computing and processing capabilities. As wireless data rates increase, having a mobile computing device may lessen or eliminate the need to have a separate home digital subscriber line (DSL) or cable modem network connection especially in cases where a subscriber has purchased an unlimited data plan as part of a wireless service subscription.
In addition, having both a home telephone number and a mobile telephone number often may result in missed voice calls such as when an incoming voice call is directed to the mobile number of a subscriber who is at home and not carrying the mobile computing device.
Accordingly, there exists the need for devices and techniques for improving wireless voice and data communications.

Portable voice and data radio base station


A memory having a single-ended sensing scheme includes a bit line, a memory cell coupled to the bit line, and a precharge circuit. The precharge circuit is configured to precharge the bit line to a precharge voltage between a power supply voltage and a ground.

A conventional single-ended sensing circuit in a memory senses a full-swing (VDD-to-VSS/Ground) signal that varies in access time due to cell current variations. Access time performance is limited by a weak bit within a cell array. Reading data "0" (logical 0) discharges a bit line with a full swing from VDD to ground and pulls down a global bit line for the read output. The bit line pre-charges back to VDD after the read operation is completed, which costs dynamic power consumption.

Taiwan Semiconductor Manufacturing Company, Ltd.


A system for tracking movable objects in a scene comprising a first overview unit arranged to capture a first overview of a first portion of a scene, and a second overview unit arranged to capture a second overview of a second portion of a scene, wherein the first portion and the second portion may be partly overlapping. The system further comprises a PTZ-camera to image selected objects in the first or second portion of the scene. The first and the second overview unit are configured to detect and locate moving objects in the scene, and to transmit positional data of said moving objects to a control unit that determines if two or more movable objects may be imaged using a single view of the PTZ-camera, and to send instructions to the PTZ-camera to image said two or more movable objects concurrently.

Monitoring cameras are commonly used to monitor building, roads, shops and various other places. In particular, cameras are often used to monitor scenes to allow automatic detection or tracking of events in the form of presence of motion or presence of an object of a specific type. Such monitoring cameras can be used both indoors and outdoors.
Closing in on the context of the present teachings there are camera arrangements consisting of one or more fixedly arranged cameras having a wide field of view and a pan-tilt-zoom camera (PTZ camera) enabling a narrow field of view (with elevated zoom). When using such camera arrangement an operator may use the fixedly arranged cameras as an input for an overview image, and subsequently utilize the PTZ camera to obtain a detailed view of a particular object located in the overview image (i.e., located in the imaged scene). A user may click on a position in an overview image whereby the PTZ camera is moved to the particular position. By defining a position and a size (e.g. by click and drag) the desired pan position, tilt position and zoom setting may be specified already in the overview image. Such a system is disclosed in US Patent Publication No. 2013/0162838.
The operation of a system having the above described functionality would require a translation from coordinates of an overview image (which may comprise views of several cameras) to pan, tilt, and zoom parameters for the PTZ camera. The calibration may be performed automatically or manually, and the result may be a system where information from an overview image, typically acquired by a statically arranged camera, may be used to control a movable camera, typically a PTZ camera. An early disclosure of such a system is found in U.S. Pat. No. 5,434,617.
In an installation where the PTZ camera is automatically guided to an object detected by the overview cameras there may be an issue as soon as a second object enters the overview scene in that some selection would have to be made; e.g. maintain the view of the first object as a default, shift to the second object as a default, or start switching between the two objects as a default.
The present teachings relate to improvements in this technical field, in particular when tracking two or more objects.

System and method for tracking moving objects in a scene


There are provided a motor and a hard disk drive including the same. The motor includes: a sleeve supporting a shaft with a lubricating fluid; and a rotor fixed to the shaft, rotating together therewith, and having a surface facing the sleeve, wherein one surface of the surface of the rotor facing the sleeve and a surface of the sleeve facing the rotor is provided with a thrust dynamic pressure groove, and the other surface of the surface of the rotor facing the sleeve and the surface of the sleeve facing the rotor is provided with an extension groove extended to the outside of the thrust dynamic pressure groove so as to partially face the thrust dynamic pressure groove.

1. Field of the Invention
The present invention relates to a motor and a hard disk drive including the same, and more particularly, to a motor capable of preventing low pressure from being generated in a thrust dynamic pressure part, and a hard disk drive including the same.
2. Description of the Related Art
A hard disk drive (HDD), an information storage device, reads data stored on a disk or writes data to a disk using a read/write head.
The hard disk drive requires a disk driving device capable of driving the disk. In the disk driving device, a small-sized spindle motor may be used.
The small spindle motor commonly uses a hydrodynamic bearing assembly. A lubricating fluid is interposed between a shaft and a sleeve of the hydrodynamic bearing assembly, such that the shaft is supported by fluid pressure generated in the lubricating fluid.
A thrust bearing may be formed between a rotor and the sleeve of the hydrodynamic bearing assembly to smoothly support rotation of the rotor.
Here, the lubricating fluid may flow smoothly by the thrust bearing inwardly in a radial direction.
Here, in the case in which a width of a clearance between the rotor and the sleeve is changed, low pressure may be generated in a location in which the clearance is a relatively narrow while the lubricating fluid passes through the clearance, such that air bubbles may be generated in the lubricating fluid as the low pressure is generated.
Since this is closely associated with the performance of the motor, research into a technology for suppressing the generation of low pressure has been urgently demanded.
In the related art described in the following Patent Document, since a clearance is narrow in a location in which a thrust dynamic pressure groove is formed, low pressure may still be generated.

Motor and hard disk drive including the same


The present invention provides an excellent electric power steering apparatus in which torque ripple caused by a quantization error of a current control system generated in case of slow steering state and steering holding state, namely, vibration and noise on a steering wheel can be suppressed. A current controller in which a steady state gain of feedback control is a finite value is used so as to be capable of suppressing the vibration and noise. Further, according to the present invention, a smoothing filter is included in a current control system so that the quantization error is smoothed so that the torque ripple is suppressed.

1. Field of the Invention
The present invention relates to an electric power steering apparatus, and particularly to the electric power steering apparatus with less vibration of a steering wheel and less noises, and with satisfactory steering feeling. Further, the present invention relates to the electric power steering apparatus having satisfactory steering feeling in which vibration and noise (hereinafter, called also as "steering holding noise") on a steering wheel in case of steering holding state can be reduced and a steering performance in a normal steering state (at the time of normal steering) can be secured.
2. Prior Art
Electric power steering apparatuses, which apply an assist torque to a steering apparatus of a vehicle by means of a rotation torque of a motor, apply the assist torque to a steering shaft or a rack shaft in such a manner a transmission mechanism such as gears or a belt applies a driving power of the motor via reduction gears. A simple constitution of such an electric power steering apparatus is explained with reference to FIG. 1.
A shaft 102 of a steering handle 101 is connected with a tie rod 106 of a steering wheel via reduction gears 103, universal joints 104a and 104b, and a pinion rack mechanism 105. The shaft 102 is provided with a torque sensor 107 that detects a steering torque of the steering handle 101, and a motor 108 that assists a steering torque of the steering handle 101 is connected to the shaft 102 via the reduction gears 103.
A control unit of the electric power steering apparatus having such a constitution is explained with reference to FIG. 2. A torque value T detected by the torque sensor 107 and a vehicle speed V detected by a vehicles speed sensor (not shown) are inputted to an assist map 190, and a steering assist command value is calculated. Further, a compensation value to be calculated by a compensation value calculating section 194 such as compensation values of convergence calculated by a convergence calculating section 191, inertia calculated by an inertia calculating section 192, self-aligning torque (SAT) and the like are added to the steering assist command value by adding sections 195, 196 and 197 so that a torque command value Tref is determined. A current command value calculating section 200 determines a current command value Iref based on the torque command value Tref. In a brushless motor, an angle of a rotor as well as the torque command value is inputted to the current command value calculating section 200, so that the current command value Iref is determined. A process portion up to the step of determining the current command value Iref based on the torque value T, the vehicle speed V and the compensation (portion surrounded by a broken line B) is called as a current command value determining section B for convenience.
On the other hand, a motor current Im to be supplied to the motor 108 is detected by a current detector 202, and it is inputted together with the current command value Iref to a subtracting section 204. The subtracting section 204 calculates an error ΔI=Iref−Im between them.
The error ΔI is inputted to a proportional-plus-integral (PI) control section as a current controller A surrounded by a broken line A. In this example, the error ΔI is inputted to a proportional section 208 as a proportional gain Kp and an integral section 206 as an integral gain Ki. An output from the proportional section 208 and an output from the integral section 206 are added by an adding section 210, and a voltage command value Vref is outputted.
A PWM (Pulse Width Modulation) control section 212 inputs the voltage command-value Vref therein, and outputs a PWM signal to an inverter circuit 214, so that the PWM signal based on the voltage command value Vref is instructed to the inverter circuit 214. The inverter circuit 214 supplies a motor current Im to the motor 108 based on the PWM signal.
The above explanation refers to the example where the proportional-plus-integral control is used in the current controller A in the control of the electric power steering apparatus. A steady state gain Gi relating to the proportional-plus-integral is expressed by the following equation 1.
                                        Gi                          =                                            lim                              s                ->                o                                                                                (                              Kp                +                                  Ki                  /                  s                                            )                                =                      ∞            .                                              [                  Equation                                                              1                ]
That is to say, even when the error ΔI has a small value, the steady state gain Gi is infinite. For this reason, the voltage command value Vref is outputted as a large value even in case of steering holding state of a steering wheel or slow steering, and the following problems arise.
That is to say, recent electric power steering apparatuses provide high output, namely, large electric current, but A/D converters or the like which are used in control devices composed mainly of CPU have, for example, still 10 bits, and thus their resolution becomes relatively rough at the time of large current. A calculating error such as quantization error caused by the roughness of the resolution is amplified by a feedback gain, which is obtained when the steady state gain becomes infinite at the time when the error ΔI at the steering holding state or slow steering state is small, and it becomes vibration or noise of the steering wheel, thereby bringing discomfort to drivers.
In the control of the electric power steering apparatus, the integral control (I control), the proportional-plus-integral control (PI control) and proportional-plus-integral-plus-derivative control (PID control) as the current control section including an integral are generally used. In the control including the integral, however, since its gain becomes infinite in a steady state, in the case where the electric power steering apparatus is in the steady state, namely, the steering holding state or in the slow steering state, the driver feels vibration or noise via the steering wheel and the driver has discomfort about the steering of the steering wheel.
In Japanese Patent application Laid-open No. 2000-108916 A, in order to solve the above problems, in the feedback control, an adjustment gain is provided before the error ΔI=Iref−Im between the current command value Iref and the actual motor current Im is inputted to the control system including the integral element. When the error ΔI is small, the adjustment gain is reduced, and when the error ΔI is large, the adjustment gain is increased.
In the conventional apparatus, however, the design (threshold value) for determining the adjustment gain which changes according to the error of the electric current feedback is difficult, and the steady state gain of the integral element is infinite. For this reason, even if the adjustment gain is reduced, the total gain becomes large, and thus the problem such that the vibration and the noise generated in case of the steering holding state and slow steering state of the steering wheel is not solved.
Further, discrete time, fixed-point arithmetic and the like which are mounting problems in the case where the CPU is utilized as a control device are not taken into consideration.


An apparatus includes a switch module, a sense circuit coupled to the switch module and configured to indicate an operating conduction mode of the switch module, and a drive circuit operatively coupled to the switch module to enable and disable forward conducting mode of the switch module. Once the switch module is in forward conducting mode, the drive circuit is configured to maintain enablement of the forward conducting mode even if the sense circuit indicates reverse conduction mode.

Technical Field
Exemplary embodiments of the invention relate generally to a system and method for improving the reliability and efficiency of an electronic device such as an inverter. Moreover, such exemplary embodiments may relate to an improved drive circuit for voltage controlled power switches.
Discussion of Art
Power electronic devices may be used in a wide variety of systems and devices for delivering power to a load. For example, traction vehicles such as locomotives employ electric traction motors for driving wheels of the vehicles. In some of these vehicles, the motors are alternating current (AC) motors whose speed and power are controlled by varying the frequency and the voltage of AC electric power supplied to the field windings of the motors. Commonly, the electric power is supplied at some point in the vehicle system as DC power and is thereafter converted to AC power of controlled frequency and voltage amplitude by a power electronic device such as an inverter. Power electronic devices may also be used in a variety of other applications, such as industrial power electronics, and stationary power conversion, among others. The power electronic device may include a set of semiconductor-based voltage controlled power switches (VCPS) such as reverse blocking insulated gate bipolar transistors (IGBTs), reverse conducting insulated gate bipolar transistors (RC-IGBTs), bi-mode insulated gate transistors (BIGTs), and the like. RC-IGBTs and BIGTs are reverse conductive power switches (RCPSs) which form a subgroup within the VCPS.

Reverse conduction mode self turn-off gate driver


The present invention relates to a control device and a control method of a high voltage inverter capable of automatically and accurately setting up neutral point information at a master controller and a plurality of cell controllers of the high voltage inverter, wherein a master controller determines information of neutral point set up to itself and performs a communication with the cell controllers each disposed at each of a plurality of U phase unit cells, a plurality of V phase unit cells and a plurality of W phase unit cells to determine the neutral point information preset on the cell controllers and to detect a cell controller set up with neutral point information different from that of the master controller, and to correct the neutral point information of the detected relevant cell controller using the neutral point information set up in the master controller, thereby operating the high voltage inverter.

The present invention relates to a control device and a control method of a high voltage inverter, and more particularly to a control device and a control method of a high voltage inverter capable of automatically and accurately setting up neutral point information at a master controller and a plurality of cell controllers of the high voltage inverter.
A high voltage inverter generating a high voltage by connecting in series a plurality of unit cells for each phase is basically formed by basically connecting the plurality of unit cells in series. Each one distal end of the plurality of unit cells is connected to form a neutral point, while the other each distal end is connected to a three-phase motor.
A master controller for controlling the operation of the high voltage inverter and each cell controller disposed at each of the plurality of unit cells are set up with the neutral point information. The master controller is configured to control the plurality of unit cells based on the set-up neutral point information. Each cell controller disposed in each of the plurality of unit cells is configured to control a switching operation of each switching element based on the set-up neutral point information to generate a high voltage.
Unless the neutral point information is accurately set up on which position the neutral points are formed in the master controller and the plurality of cell controllers in the high voltage inverter position, the high voltage inverter cannot be normally operated to generate errors such as trip and the like.
Therefore, it is imperative that the neutral point information be accurately set up in the master controller and the plurality of cell controllers.
In setting up the neutral point information, an operator who has installed a high voltage inverter must check a position where the neutral point is formed and set up the neutral point information in the master controller and the plurality of cell controllers.
However, the setting up of neutral point information by an operator suffers from a disadvantage in that it takes lots of time. Another disadvantage is that accurate neutral point information must be set up again by re-checking a connection position of the neutral point if the operator erroneously sets up the neutral point information, which occurs often.

Device and method for controlling high voltage inverter by using neutral point


A system may include a ramp generation circuit for generating a ramp waveform and comprising a first passive circuit element having an impedance pertinent to generation of the ramp waveform and a control circuit comprising a second passive circuit element which is impedance-correlated to the first passive circuit element. The control circuit may be configured to use the second passive circuit element to generate a control signal for controlling the ramp generation circuit, such that a correlation between the first passive circuit element and the second passive circuit element substantially cancels physical variations of the first passive circuit element and the second passive circuit element and use a control signal clock for generating the control signal that is related to a ramp generation clock for generating the ramp waveform such that a magnitude of the ramp waveform remains substantially independent of frequency of operation.

Numerous devices, including without limitation personal audio devices, wireless telephones, such as mobile/cellular telephones, cordless telephones, mp3 players, and other consumer audio devices, often use one or more ramp generation circuits. In operation, such ramp generation circuits produce a periodic signal that, during each periodic cycle, ramps from a minimum magnitude (e.g., zero) to a maximum magnitude. In some instances, a ramp signal generated by a ramp-generation circuit may be used by a pulse-width modulator to generate a pulse-width modulated signal, as is known in the art.
FIG. 1 depicts an example ramp-generation circuit 100, as is known in the art. As shown in FIG. 1, ramp-generation circuit 100 may include a reference-current generation subcircuit 102 for generating a reference current Iref=Vref/Rtrim, where Vref is a reference voltage and Rtrim is a resistance of a resistor 104 of reference-current generation subcircuit 102. Ramp-generation circuit 100 may also include a current-mirror stage 106 that sources an amplifier input current proportional to reference current Iref to a positive input terminal of output amplifier stage 108 and sinks an amplifier input current of identical magnitude from a negative input terminal of output amplifier stage 108. Such amplifier input currents may flow through feedback capacitors 110 of equal capacitance, integrating charge during each cycle of ramp-generation circuit 100 to generate, at each output terminal of output amplifier stage 108, a sawtooth ramp signal, which is reset to its minimum voltage (e.g., zero) during each cycle boundary of ramp-generation circuit 100 as a result of periodic activation of switches 112 by clock signal CLK.
Ramp-generation circuit 100 of FIG. 1 may have numerous disadvantages. For instance, the resistance Rtrim of resistor 104 may require trimming to account for process variations of ramp-generation circuit 100, which adds cost and design complexity to ramp-generation circuit 100. Ramp-generation circuit 100 may also be unable to track changes in frequency, temperature, and/or supply voltage.

Parameter-independent ramp signal generation


A method for production of an integrated circuit arrangement which contains a capacitor. A dielectric layer is structured with the aid of a two-stage etching process, and with the aid of a hard mask. In the case of an electrically insulating hard mask, the hard mask is removed again. In the case of an electrically conductive hard mask, parts of the hard mask may remain in the circuit arrangement.

One method of producing an integrated circuit arrangement includes the application of a dielectric layer to an electrode layer which contains at least one electrode. Followed by application of a resist layer, structuring of the dielectric layer, and removing residues of the resist layer.
At a temperature of 20° C., the dielectric layer has an electrical resistivity of, for example, more than 1010 Ωcm or even 1016 Ωcm. By way of example, silicon dioxide is used as the material for the dielectric layer. However, materials with a dielectric constant of more than 3.9 are also used, for example silicon nitride, aluminum oxide or tantalum pentoxide.
In contrast, the electrode layer contains a highly conductive material which has an electrical resistivity of less than 10−4 Ωcm, for example. However, the electrical resistivity is usually one or more orders of magnitude less than this value. Examples for materials in the electrode layer are aluminum, aluminum alloys, copper, copper alloys, silver, titanium or other metals or compounds such as tantalum nitride TaN or titanium nitride TiN.
By way of example, the resist layer could be removed once the dielectric layer has been completely structured with the aid of the resist layer. However, this has the disadvantage that, during the removal of the resist, parts of the electrode layer are exposed and are thus attacked by the chemical processes which are used to remove the resist. The removal of the photoresist is carried out, for example, by carbonization at a temperature of about 200° C. and subsequent removal of the ash using a solvent. Alternatively, it is possible to remove the photoresist just by means of a wet-chemical process.
By way of example, the material of the electrode layer may be oxidized. The oxidation products which are produced in this way must be removed again by means of a specific cleaning step. This cleaning step must be specifically developed and optimized, in particular when specific oxides must be removed, for example copper oxides. If the reaction products which are produced during removal of the resist on the electrode layer are not removed completely, then this leads to high contact resistances, resulting in a deterioration in the reliability of the electrically conductive connections.
Furthermore, the chemical compounds which are produced during removal of the resist in the area of the exposed regions of the electrode layer also penetrate under the dielectric layer. Underetching thus occurs during removal of the reaction products, making the electrical characteristics of the integrated circuit arrangement considerably worse. For this reason as well, considerable funds must be invested in the development of the cleaning step.

Method for the producing an integrated circuit bar arrangement, in particular comprising a capacitor assembly, in addition to an integrated circuit arrangement


A storage apparatus includes a memory that stores a job management information that registers a write job corresponding to a write command upon receiving the write command from other apparatus, a cache memory that stores data designated as target data by the write command, a storage drive that records the data stored in the cache memory to a storage medium based on the write job registered in the job management information, and a controller that controls a timing to output to the other apparatus a completion report of the write command based on a load condition of the storage device related to an accumulation count of write job acquired from the job management information.

A Redundant Arrays of Inexpensive Disks (RAID) apparatus is well known in the art as a storage apparatus equipped with a plurality of storage drives. A hard disk drive (HDD) is one example of a storage drive.
The HDD executes seeking of a target track using a magnetic head while a magnetic disk medium that is a storage medium is rotating at a certain rotating speed, and moves the magnetic head closer to the magnetic disk to magnetically record and play data.
Therefore, the processing speed is very slow compared to the processing speed of the CPU of the host computer since the writing and reading processing in the HDD is executed with mechanical operations. As a result, the HDD includes various functions to compensate for the discrepancy (performance limit) in processing speeds. A function called "write-back" is known as one of these functions.
A command issued by a host computer is received by a RAID apparatus controller that controls a plurality of HDDs and is stored in a queue in a job management table in a memory. The HDD is sequentially instructed to execute jobs waiting for processing registered in the job management table.
A controller of the RAID apparatus temporarily stores write data accompanying a write command in a cache memory when the command is a write command, and returns a completion report for the write command to the host computer at the time that the storing is completed (normal completion).
The write data temporarily stored in the cache memory is written in an HDD at a time when processing is available. Thus, the write-back function makes use of the feature that the storage operation of a cache memory is faster than that of an HDD. Also the performance limitations of the HDD may be alleviated.
However, write commands are issued by the host computer to the storage apparatus frequently and thus high load conditions on the storage apparatus may continue. In this case, write jobs waiting for processing to the HDDs accumulate in the job management table and there is a possibility that ultimately the storage apparatus may not be able to accept new commands and thus enter a queue full state.
Japanese Patent Laid-open No. 9-258907 and Japanese Patent Laid-open No. 2000-56932 are examples of related art.

Storage apparatus, load condition reduction method of the storage apparatus and system


Spacecraft thruster systems are disclosed. In some instances, a spacecraft thruster system may include stacked ion thrusters and/or ion thruster layers. The ion thrusters and/or ion thruster layers may be sequentially activated and jettisoned from the thruster system after use.

With the increased utility and complexity of the standardized Cubesat evolving from an early educational demonstration tool to platforms able to perform increasingly complex mission scenarios, a plethora of propulsion concepts and solutions have been developed and tested in space. Recent developments include cold gas thrusters, chemical thruster systems, and a variety of different electric propulsion solutions including electromagnetic concepts and electrostatic systems such as ion engines and Hall thrusters.


An integrated hydrocarbon trap and air filter in the soundtube of a vehicle for use in conjunction with the engine's air intake system is disclosed. The trap and air filter comprises a housing body having first and second ends. The housing includes hydrocarbon-adsorbing media and air filter media. The hydrocarbon-adsorbing and air filter trap are incorporated into a soundtube. A first soundtube portion connects the housing to the engine's air intake system while a second soundtube is open to ambient and connects the housing to a vehicle body structure such as a fender. Selection of the body diameter, thickness, and length, the dimensions and type of both air filter media and hydrocarbon-adsorbing media and position of the air filter media, NVH media, and space relative to the trap media and location of the integrated hydrocarbon trap and air filter along the soundtube provide superior tunability and adaptability.

Automobile designers are today challenged by a broad range of requirements externally imposed by customer demands at one extreme and by government regulation at the other. One such customer demand is for the reduction of overall vehicle noise, vibration and harshness (NVH). Some vehicle owners prefer a quiet vehicle riding experience both within the vehicle cabin and under the engine hood. Other vehicle owners, particularly those who prefer sports cars and audible engine noise, do not want to entirely eliminate the resonance of a well-tuned engine and find that such engine noise actually enhances the driving experience. In response to the interests of the sports car enthusiast, the assignee of the instant patent application makes available induction soundtubes between the engine's air intake and the vehicle cabin to thereby provide the vehicle occupant and particularly the driver with some measure of vehicle feedback, particularly upon acceleration.
The engine-to-cabin induction soundtube is one example of how vehicle designers are enhancing the driving experience. Another example is the provision of an induction clean air tube between the engine's air induction system and the front fender of the vehicle where the tube acts as a fresh air inlet. However, adjusting vehicle engine noise to the satisfaction of the customer is not merely a matter of transmitting sound from the engine to another point on the vehicle. Instead, the soundtube arrangement must be acoustically tuned for specific engine frequencies. This is a task that introduces other challenges to vehicle designers given that the accelerating engine generates sound ranges through a number of harmonic orders with only a couple of orders representing desirable sounds.
Correct acoustical tuning of the engine air induction clean air tube is only one challenge faced by the vehicle manufacturer. Another challenge is to meet government air evaporative emission quality standards related to the release of hydrocarbons to the atmosphere. The engine is one source of vehicle evaporative emissions. These vehicle evaporative emission regulations require the control of polluting substances (primarily hydrocarbons) from the vehicle. As an example, fuel that is sprayed into the intake manifold by the fuel injector typically remains on the walls in the intake manifold and the intake valves after engine shut down, thereby allowing fuel vapor to flow out of the air induction system. The evaporative emissions in the form of escaping unburned fuel may exceed government mandated requirements for such emissions.
Government regulations have been expanded in recent years to regulate the hydrocarbon emissions from the vehicle even when the vehicle is unused and the engine is off. During such engine off soaks, the evaporative hydrocarbons may be emitted by the engine through the air induction system. These emissions are leaked from the vehicle from many sources including the air intake system. This is an expansion from prior rules in which only emissions from the fuel tank were captured typically using carbon-filled canisters. Government requirements now regulate the total amount of hydrocarbons any vehicle is permitted to emit to the atmosphere at all times. These captured substances need to be retained within the air induction system until the powertrain is again used when the retention system will purge and burn the hydrocarbons during engine combustion.
When the air induction system is a significant contributor to overall vehicle hydrocarbon levels, a hydrocarbon trap must be utilized to capture hydrocarbons during engine off and to release and burn hydrocarbons during normal engine operation. In addition, the engine air induction clean air tube pulls atmospheric air from the environment into the engine, thus potentially introducing particulates directly into the air induction system.
A vehicle application was encountered that required an opening into the vehicle fender cavity. This opening "transmitted" the tuned sound to the vehicle occupant but allows air flow into the engine air induction system. The additional air flow path required filtration of the air to the engine as well as a hydrocarbon control device.

NVH soundtube having integrated hydrocarbon adsorption and air filtration device to control evaporative emissions


Remote control device for controlling apparatuses to be carried on the body, in particular hearing aids, and being provided with a circuit responsive to control signals. In order to give the remote control device a particularly simple and reliable design, it is provided that the remote control device comprises a permanent magnet (3) which is separate from the device (2, 8) to be controlled, and that the apparatus (2, 8) comprises at least one sensor (3; 10A, 10B) sensitive to a magnetic field and acting on a control circuit (20) via a signal converter circuit (6, 7, 12, 14; 13, 15) if so required.

1. Field of the Invention
The invention relates to a remote control device for controlling apparatuses carried on the body, in particular hearing aids comprising a device responding to a magnetic field, for example, of a magnet separated from the device to be controlled. The responsive device controls a device assuming various defined switching conditions.
2. The Prior Art
A remote control device was proposed, for example, by AT 379 929. In this known solution a single-channel acoustic remote control is provided with an activatable transmitter which transmits signals modulated on a carrier frequency which lie within the response range of a microphone of an allocated hearing aid. A frequency-selective circuit is disposed behind the microphone for separating the control signals from the voice signals. A control circuit is disposed in the signal path for processing the voice signals. A decoder acting on said control signal is disposed in the signal path for processing the control signals.
This remote control device overcomes the difficulties in the operation of the apparatuses, in particular hearing aids, caused by their miniaturization. Thus, particularly persons of advanced age, who usually have a reduced fine motor skills, have difficulties in manually setting the very small adjustment members of hearing aids, for example the volume control. In the known solution, however, a separate power supply is required. Furthermore, the remote control has to be arranged relatively large so as to enable the simple operation by the user.
Furthermore, from the DE-OS 31 09 049 a remote control device of the type mentioned above is known. In this known solution a device responsive to a magnetic field simultaneously forms a device having various, defined switching conditions. This is the case in a reed switch in which the movable contact can be magnetized and thus not only forms the switching device, but also simultaneously a device responsive to a magnetic field. But also magnetic field semiconductor switches were proposed which also form devices responsive to the magnetic field and, at the same time, elements representing the switching device.
Both cases, however, lead to the fact that the switching condition of the switching device only depends on the existence or non-existence of a sufficiently strong magnetic field and that the switching condition of the respectively selected element only remains in the working position as long as a magnet is in the vicinity of the device responsive to the magnetic field. If said magnet is removed, the switching device returns to its rest position.
This, however, is disadvantageous for many applications, because in order to maintain a certain switching condition it is necessary to maintain a respectively strong magnetic field.

Remote control device for controlling apparatuses carried on the body, in particular hearing aids


Systems and methods are provided for improved radiant heat control within a dryer of a printing system with reflective elements. One embodiment is a dryer of a printing system. The drying includes a radiant energy source configured to apply heat to a print medium. The dryer also includes a reflective element installed between the radiant energy source and the print medium. The reflective element is configured to have varying levels of reflectance. The dryer also includes a controller configured to determine an amount of heat to supply to a region of the print medium, and to adjust an amount of reflectance of the reflective element based on the determined amount of heat.

Entities with substantial printing demands typically use a production printer. A production printer is a high-speed printer used for volume printing (e.g., one hundred pages per minute or more). Production printers include continuous-forms printers that print on a web of print media stored on a large roll.
A production printer typically includes a localized print controller that controls the overall operation of the printing system, and a print engine (sometimes referred to as an "imaging engine" or a "marking engine"). The print engine includes one or more printhead assemblies, with each assembly including a printhead controller and a printhead (or array of printheads). An individual printhead includes multiple tiny nozzles that are configured to discharge ink as controlled by the printhead controller. A printhead array is formed from multiple printheads that are spaced in series across the width of the web of print media.
While the printer prints, the web is quickly passed underneath the nozzles, which discharge ink onto the web at intervals to form pixels. A radiant dryer, installed downstream from the printer, may assist in drying the wet ink on the web after the web leaves the printer. A typical radiant dryer includes an array of radiant heat lamps. Drying the web can prove challenging due to variation of a number of factors, including the web's physical characteristics, speed of the web, print quality demands, etc. Moreover, insufficient drying may result in smearing while excessive drying may result in scorching, curling, and other defects. Therefore, precise control over the amount and location of heat applied to a web is desirable.

Radiant heat control with adjustable reflective element


A method for optimizing the manufacturing of interconnects in microelectronic packages in the presence of sources of process variability. The method can estimate the contribution of multiple parameter to the quality of the interconnects, enabling the optimization of the manufacturing process.

Modem microelectronic packages such as flip-chip ball grid array (FCBGA) packages may include several hundred closely spaced interconnects, formed as solder joints distributed over the entire area of the integrated circuit (IC). Each interconnect includes a solder bump which connects a pad located on the IC with a corresponding pad on a substrate. Known substrates include for example printed circuit boards (PCBs) formed from organic laminates, and ceramic substrates.
Interconnects must be formed by a process that is both defect-free and reliable over the long term. A first type of defect that may be present immediately after manufacturing is an open circuit, for example due to the fact that a solder bump is too small to contact both the pad on the IC side and the pad on the substrate side. Another type of defect is a lateral short ("bridge") between adjacent interconnects. Moreover, interconnects must be reliable over the lifetime of a product, which may be of the order of 10 years. This requires the interconnects to have a shape and structure that can withstand long-term thermal cycling without mechanical failure.
Forming defect-free and reliable interconnects between an IC and a substrate is difficult, in part because of the high variability in many critical parameters, such as the planarity of the substrate, the volume of solder bumps, IC alignment, etc. Accordingly, there is a need for a method to optimize the manufacturing of interconnects in the presence of many sources of variability.

Method to optimize the manufacturing of interconnects in microelectronic packages

International Business Machines Corporation