Coaxial connector and communication device having the same

Information

  • Patent Grant
  • 6585532
  • Patent Number
    6,585,532
  • Date Filed
    Monday, July 23, 2001
    23 years ago
  • Date Issued
    Tuesday, July 1, 2003
    21 years ago
Abstract
A coaxial connector includes an upper insulating case provided with columnar ribs in the four corners thereof. These ribs are provided to position a fixed terminal and a movable terminal. The tops of the ribs are arranged so that the fixed terminal is easily guided. Half-circular concavities are formed on both of the sides of the fixed terminal. The concavities are fitted onto the ribs of the upper insulating case, so that the fixed terminal can be incorporated into the upper insulating case with a high positional accuracy. Thereafter, the ribs are thermally deformed into a dome shape by a welder, so that the fixed terminal is fixed to the upper insulating case.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The present invention relates to a coaxial connector and a communication device including a coaxial connector.




2. Description of the Related Art




In conventional mobile communication devices such as portable telephones, a surface mount type coaxial connector performs a switching function for changing a signal path. In the known configuration of such coaxial connectors, resin members and signal terminals are separately manufactured, and thereafter, the signal terminals are incorporated into the resin members, respectively. For incorporation of the signal terminals into the resin members, in some cases, the configuration in which the signal terminals are sandwiched between two resin members is adopted. In the other cases, the configuration in which the signal terminals are inserted into the resin members under pressure is used.




In the case in which the signal terminals are sandwiched between the two resin members, the signal terminals are sometimes separated and released from the resin members, due to vibration and impact caused when the device elements are conveyed during assembling.




Moreover, in the case in which the signal terminals are inserted between the resin members under pressure, the signal terminals will be inserted under pressure, which causes scraping of the resin members, if the positional relationship between the signal terminals and the resin members set in an assembling apparatus is deviated. Resin dusts and burs are produced, which deteriorates the qualities of the resulting products. Accordingly, to prevent this, the number of control items in the assembly process is increased, and much time is spent to adjust the positions of manufacturing facilities.




SUMMARY OF THE INVENTION




In order to overcome the problems described above, preferred embodiments of present invention provide a coaxial connector in which signal terminals can be accurately positioned and fixed with respect to resin members, and a communication device having such a coaxial connector.




According to a preferred embodiment of the present invention, a coaxial connector includes a first resin member having a concave portion into which a center contact of a mating coaxial connector is inserted, a second resin member for defining an insulating case with the first resin member, a fixed terminal and a movable terminal mounted inside of the insulating case, and an external terminal mounted on the outside of the insulating case and electrically connected to an outer conductor of the mating coaxial connector, wherein one of the first resin member and the second resin member is provided with ribs that are arranged to position the fixed terminal and the movable terminal, respectively.




In the above-described unique configuration, the ribs arranged to position the fixed terminal and the movable terminal, respectively, are disposed on one of the first and second resin members, so that the fixed terminal and the movable terminal are accurately positioned via the ribs.




Preferably, the ribs are thermally deformed so that the fixed terminal and the movable terminal are fixed to one of the first resin member and the second resin member. More preferably, the ribs thermally deformed with a dome shape are provided on one of the first resin member and the second resin member, and rib receiving portions having a reversed dome shape are provided on the other resin member.




In the above-described configuration, the ribs being thermally deformed fix the fixed terminal and the movable terminal, which are signal terminals, to one of the first and second resin members. Accordingly, there is no possibility that the signal terminals are erroneously released from the resin members, which may be caused in conventional devices by vibration and impact while the device elements are conveyed during assembling.




The communication device according to another preferred embodiment of the present invention includes the coaxial connector having the above-described configuration. Thus, a high reliability can be obtained in the communication device.




Other features, elements, characteristics, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the present invention with reference to the attached drawings.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is an exploded perspective view of a coaxial connector according to a preferred embodiment of the present invention;





FIG. 2

is a perspective view illustrating an assembly process of the coaxial connector shown in

FIG. 1

;





FIG. 3

is a side view illustrating an assembling process of the coaxial connector shown in

FIG. 2

;





FIG. 4

is a side view illustrating an assembling process of the coaxial connector shown in

FIG. 3

;





FIG. 5

is a perspective view illustrating an assembling process of the coaxial connector shown in

FIG. 4

;





FIG. 6

is a perspective view illustrating an assembling process of the coaxial connector shown in

FIG. 5

;





FIG. 7

is a perspective view illustrating an assembling process of the coaxial connector shown in

FIG. 6

;





FIG. 8

is a perspective view illustrating an assembling process of the coaxial connector shown in

FIG. 7

;





FIG. 9

is a perspective view illustrating an assembling process of the coaxial connector shown in

FIG. 8

;





FIG. 10

is a partial cross sectional view illustrating self-alignment effects between the insulating cases;





FIG. 11

is a perspective view illustrating an assembling process of the coaxial connector shown in

FIG. 9

;





FIG. 12

is a perspective view illustrating an assembling process of the coaxial connector shown in

FIG. 11

;





FIG. 13

is a perspective view showing the appearance of the coaxial connector of

FIG. 1

;





FIG. 14

is a cross sectional view of the coaxial connector shown in

FIG. 12

;





FIG. 15

is a cross sectional view showing a mating coaxial connector fitted into the coaxial connector of

FIG. 12

; and





FIG. 16

is a block diagram showing a preferred embodiment of a communication device of the present invention.











DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS




Hereinafter, preferred embodiments of the coaxial connector and the communication device of the present invention will be described with reference to the accompanying drawings.





FIG. 1

is an exploded perspective view showing the constitution of a preferred embodiment of the coaxial connector of the present invention. The coaxial connector (coaxial receptacle)


1


preferably includes an insulating case made of synthetic resin which includes a lower insulating case


2


A and an upper insulating case


2


B, a fixed metallic terminal


21


, a movable terminal


31


, and an external terminal (outer conductor)


41


, which are preferably made of metal.




The lower insulating case


2


A preferably has a substantially rectangular shape. Guiding protuberances


3


for positioning the upper insulating case


2


B are provided preferably at the four corners on the upper surface (dividing plane) of the case


2


A. Rib receiving portions


4


for receiving the ribs


18


(see

FIG. 2

) of the upper insulating case


2


B are provided in the vicinity of the respective guiding protuberances


3


. The rib receiving portions


4


each has a concave plane shape, i.e., have a reverse dome shape (see FIG.


10


). Moreover, substantially rectangular cuts


6


and


7


are formed in the centers of the two opposed sides of the lower insulating case


2


A, respectively. In the cut


6


, the lead


24


of the fixed terminal


21


is disposed. On the other hand, the lead


34


of the movable terminal


31


is disposed in the cut


7


.




The upper insulating case


2


B preferably includes a substantially rectangular cover


11


and a columnar introduction portion


12


disposed in the center of the upper surface of the cover


11


. The columnar introduction portion


12


is opened in the upper portion thereof so as to have a cone-shape, and has an introduction hole


13


having a substantially circular cross-section. The introduction hole


13


elongates through the upper insulating case


2


B. The center contact of a mating coaxial connector protrudes into the introduction hole


13


from the cone-shaped opening side.




Moreover, the columnar ribs


18


are preferably provided in the four corners on the bottom (dividing plane) of the upper insulating case


2


B as shown in FIG.


2


. These ribs


18


are arranged to position the fixed metallic terminal


21


and the movable terminal


31


. The tops of the ribs


18


are worked so as to have a C-shaped plane, so that the terminals


21


and


31


can be easily guided. A groove


15


having a substantially V-shaped cross section is formed between the introduction hole


13


and the side of the upper insulating case


2


B from which the fixed terminal


21


is led out. The groove


15


is elongated in a direction that is substantially perpendicular to the leading-out directions of the metallic fixed terminal


21


.




The metallic fixed terminal


21


is preferably formed by punching a metallic flat sheet and bending it. The metallic fixed terminal


21


preferably includes a contact portion


22


that contacts with the movable terminal


31


, a fixed portion


23


fixedly sandwiched between the insulating cases


2


A and


2


B, and the lead


24


that is bent to have a substantially L-shaped configuration. The contact portion


22


has both side portions thereof bent at a predetermined angle, and thus, has a horizontal plane


22




a


and inclined planes


22




b


on both of the sides of the horizontal plane


22




a.






The fixed portion


23


is provided with half-circular concavities


26


on both of the sides thereof. The concavities


26


are fitted onto the ribs


18


of the upper insulating case


2


B, respectively, so that the fixed terminal


21


is incorporated in the upper insulating case


2


B at a high positional accuracy. At this time, the fixed terminal


21


is incorporated with the horizontal surface


22




a


and the fixed portion


23


of the contact portion


22


being in close contact with the bottom of the upper insulating case


2


B. A gap is generated in the area where the fixed terminal


21


intersects the groove


15


.




Then, as shown in

FIG. 3

, the head chip


81


of a welder is lowered from the upper side of each rib


18


positioning the fixed terminal


21


to be pushed against the rib


18


.

FIG. 3

is a side view of the coaxial connector taken in the direction indicated by arrow K in FIG.


2


. The top surface


81




a


of the head chip


81


preferably has a concave plane shape, i.e., has a reversed dome shape. At this time, the head chip


81


is sufficiently heated at a temperature at which the rib


18


can be thermally deformed. Accordingly, as shown in

FIG. 4

, the rib


18


is thermally deformed by the tip


81




a


of the heat chip


81


so as to have a domed shape. Thereafter, the head chip


81


is elevated. Similarly, the other rib


18


positioning the fixed terminal


21


is thermally deformed so as to have a domed shape. Thus, as shown in

FIG. 5

, the fixed terminal


21


is welding-fixed to the bottom of the upper insulating case


2


B via the thermally deformed dome-shaped ribs


18


.




The movable terminal


31


(see

FIG. 1

) is preferably formed by punching a metallic sheet having a spring property into a predetermined shape and bending it. The movable terminal


31


is constructed to have a spring-movable function, and includes a movable contact portion


32


that contacts with the fixed terminal


21


, a fixed portion


33


fixedly sandwiched between the insulating cases


2


A and


2


B, and a lead


34


bent into a substantially L-shaped configuration. The movable contact portion


32


is bent so as to rise upward in an arc shape. Spring supports


37


are provided on both of the ends of the movable contact portion


32


, and a spring contact portion


38


is provided in the center thereof.




Half-circular concavities


36


are provided on both of the sides of the fixed portion


33


. As shown in

FIG. 6

, the concavities


36


are fixed onto the ribs


18


of the upper insulating case


2


B, respectively, so that the movable terminal


31


is incorporated into the upper insulating case


2


B with a high positional accuracy. At this time, the movable terminal


31


is incorporated with the fixed portion


33


so as to be in close contact with the bottom of the insulating case


2


B.




Next, head chips


81


of a welder are pushed against the two ribs


18


positioning the movable terminal


31


using the same procedures as described in reference to

FIGS. 3 and 4

, so that the ribs


18


are thermally deformed into a dome shape. Thus, as shown in

FIG. 7

, the movable terminal


31


is welding-fixed to the bottom of the upper insulating case


2


B via the ribs


18


that are thermally deformed into a domed shape.




In order for the external terminal


41


(see

FIG. 1

) to come into contact with the outer conductor of a mating coaxial connector, the external terminal


41


is preferably formed by punching a metallic sheet, e.g., made of brass, spring-use phosphor bronze, or other suitable material, via bending, drawing, or other suitable process. A flat portion


42


in the center of the sheet body is arranged to cover the upper surface of the upper insulating case


2


B. Legs


43


are disposed preferably at the four corners of the flat portion


42


, respectively. Moreover, in the center of the flat portion


42


, a substantially cylindrical through-hole portion


45


is arranged so as to be concentric with the columnar introduction portion


12


of the upper insulating case


2


B. The substantially cylindrical through-hole portion


45


is fitted into the outer conductor of the mating coaxial connector. Ordinarily, the external terminal


41


functions as a ground. The outer surface of the external terminal


41


is plated, if necessary.




As shown in

FIG. 8

, the upper insulating case


2


B having the terminals


21


and


31


fixed thereto is incorporated into the external terminal


41


. That is, the columnar introduction portion


12


of the upper insulating case


2


B is fitted into the substantially cylindrical through-hole portion


45


of the outer terminal


41


. Thereafter, as shown in

FIG. 9

, the lower insulating case


2


A is overlaid on and incorporated into the upper insulating case


2


B.




Ordinarily, as shown in

FIG. 10

, the size a of the upper insulating case


2


B is preferably smaller than the size b of the lower insulating case


2


A. This is carried out to improve the working efficiency with which the lower insulating case


2


A is incorporated into the upper insulating case


2


B.

FIG. 10

is a partial cross sectional view of the coaxial connector taken along the direction of X—X in FIG.


9


.




However, if the sizes a and b have the relationship of a<b, the incorporated lower insulating case


2


A is shaky, that is, the phenomenon occurs, in which the position of the lower insulating case


2


A becomes unstable. Accordingly, in the first preferred embodiment of the present invention, the ribs


18


of the upper insulating case


2


B are thermally deformed to have a dome shape, and also, the rib receiving portions


4


of the lower insulating case


2


A have a reversed dome shape. That is, when the ribs


18


are combined with the rib relief portions


4


, a self-alignment effect is produced, so that the lower insulating case


2


A can be incorporated into the upper insulating case


2


B with a high accuracy, and moreover, errors in the location can be prevented (see FIG.


11


).




Next, as shown in

FIG. 12

, the legs


43


of the outer terminal


41


are bent along the side surface and the bottom of the assembly including the terminals


21


and


31


, and the insulating cases


2


A and


2


B. Accordingly, the assembly has a stiff, rigid, and stable structure.





FIG. 13

is a perspective view of the coaxial connector


1


having a switching function, assembled as described above and viewed from the upper surface of the connector


1


. In the coaxial connector


1


, the top portions of the leads


24


and


34


of the terminals


21


,


31


, and


41


, and those of the legs


43


are formed substantially on the same plane as the bottom of the lower insulating case


2


A. Thus, the coaxial connector


1


has such a structure that surface-mounting can be carried out. Moreover, in the external terminal


41


, the substantially cylindrical through-hole portion


45


is arranged so that stable and secure connection to the mating coaxial connector can be achieved.




As shown in

FIG. 14

, in the inner space of the insulating case, defined by the combination of the insulating cases


2


A and


2


B, the fixed terminal


21


and the movable terminal


31


are arranged so that the fixed terminal


21


lies on the movable terminal


31


. In the coaxial connector


1


, the sizes of the contact portion


22


of the fixed terminal


21


and the movable contact portion


32


of the movable terminal


31


are relatively small. Thus, it is a large factor in enhancement of the mechanical performance (the spring performance of the movable contact portion


32


) of the coaxial connector


1


that the contact positions of the contact portion


22


and the movable contact portion


32


are accurately determined. On the other hand, the positions of the terminals


21


and


31


can be accurately determined via the ribs


18


provided for the upper insulating case


2


B, and therefore, the contact position between the movable contact portion


32


of the movable terminal


31


and the contact portion


22


of the fixed terminal


21


can be accurately determined. Accordingly, the coaxial connector


1


having high qualities can be obtained.




Furthermore, the dome-shaped ribs


18


fix the terminals


21


and


31


to the upper insulating case


2


B. Accordingly, there is no danger that the terminals


21


and


31


are released or shifted from the upper insulating case


2


B, which was caused by vibration and impact that occurs when the device elements are conveyed, during assembling. Furthermore, since the ribs


18


, which are arranged to position the terminals


21


and


31


, are thermally deformed by the welder so that the heights are reduced. Therefore, the overall thickness of the overlapped terminals


21


and


31


can be reduced, and thus, the total thickness of the assembly, obtained when the insulating cases


2


A and


2


B are overlaid is minimized. Thus, the coaxial connector


1


having a reduced thickness can be provided.




Hereinafter, operation of the coaxial connector


1


will be described with reference to

FIGS. 14 and 15

.




As shown in

FIG. 14

, when the mating coaxial connector is not mounted, the movable contact portion


32


is in the state that the center portion thereof is bent upward, and thereby, the movable terminal


31


is in contact with the fixed terminal


21


, due to the elastic force generated by the spring property of the movable contact portion


32


. Thus, both of the terminals


21


and


31


are electrically connected to each other.




On the other hand, as shown in

FIG. 15

, when the mating coaxial connector is mounted, the center contact


65


of the mating coaxial connector is inserted through the introduction hole


13


disposed on the upper side of the coaxial connector


1


to push the center portion of the movable contact portion


32


downward. Thus, the center portion is inverted and moves into the state that the center portion is bent downward into an arc shape. Thereby, the spring contact portion


38


of the movable terminal


31


is released from the contact portion


22


of the fixed terminal


21


, so that the electrical connection between the fixed terminal


21


and the movable terminal


31


is interrupted, while the center contact


65


and the movable terminal


31


are electrically connected to each other. Simultaneously, the outer conductor (not shown) of the mating coaxial connector is fitted onto the outer terminal


41


, so that the outer conductor and the external terminal


41


are electrically connected to each other.




When the mating coaxial connector is released from the coaxial connector


1


, the center portion of the movable contact portion


32


is restored to the state that the center portion is bent upward, utilizing the spring property. Thereby, the fixed terminal


21


and the movable terminal


31


are electrically connected to each other again, while the electrical connection between the center contact


65


and the movable terminal


31


is interrupted.




A portable telephone as an example of a communication device according to a second preferred embodiment of the present invention will be described.





FIG. 16

is an electric circuit block diagram of the RF circuit portion of a portable telephone


120


. In

FIG. 16

, an antenna


122


, a diplexer


123


, a change-over switch


125


, a transmission side isolator


131


, a transmission side amplifier


132


, a transmission side inter-stage band-pass filter


133


, a transmission side mixer


134


, a reception side amplifier


135


, a reception side inter-stage band-pass filter


136


, a reception side mixer


137


, a voltage control oscillator (VCO)


138


, and a local band-pass filter


139


are shown.




Here, as the change-over switch


125


, the coaxial connector


1


of the first preferred embodiment can be used. Thereby, for example, when an apparatus manufacturer checks the electrical characteristics of the RF circuit portion during the manufacturing process of a portable telephone


120


, a measuring probe (mating coaxial connector)


126


connected to a meter, is fitted onto the coaxial connector


1


, and thereby, the signal path from the RF circuit portion to the antenna


122


can be changed to the signal path from the RF circuit portion to the meter. When the measuring probe


126


is released from the coaxial connector


1


, the signal path is returned to the signal path from the RF circuit portion to the antenna


122


. Thus, the portable telephone


120


having a high reliability can be realized by including the coaxial connector


1


in the portable telephone


120


.




The present invention including the coaxial connector and the communication device including the coaxial connector is not limited to the above-described preferred embodiments. The present invention can be modified within the scope and the sprit of the present invention. The ribs to be provided for the insulating case may be formed on the upper insulating case


2


B as described in the above-described preferred embodiments, or may be provided on the lower insulating case


2


A. Moreover, as the outer profile of the insulating case and the shape of the concave portions, optional shapes and sizes such as substantially rectangular and substantially circular shapes may be selected, as desired.




As seen in the above description, according to preferred embodiments of the present invention, since the ribs for positioning the fixed terminal and the movable terminal are disposed on one of the first resin member and the second resin member, the fixed terminal and the movable terminal can be accurately positioned by the ribs. Thus, a coaxial connector and a communication device having high qualities can be obtained.




Moreover, the ribs, which are thermally deformed, fix the fixed terminal and the movable terminal, which define signal terminals, to one of the first resin member and the second resin member. Thus, there is no danger that the signal terminals are released or shifted from the resin members, caused by vibration and impact while the device elements are conveyed during assembling. For this reason, it is unnecessary to provide additional counter-measures against vibration and impact in the production facilities. Thus, the cost of the production facilities can be reduced. Moreover, rejected products can be prevented, caused by release of the signal terminals during production. Thus, great improvement of the production efficiency and reduction in cost of the products are achieved.




Moreover, when the first resin member and the second resin member are joined together, the ribs which are thermally deformed into a dome shape, cooperate with the rib receiving portions having a reversed dome shape, so that relative shift between the first resin member and the second resin member is prevented.




While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details can be made without departing from the spirit and scope of the present invention.



Claims
  • 1. A coaxial connector comprising:a first resin member having a concave portion into which a center contact of a mating coaxial connector is inserted; a second resin member arranged to mate with and define an insulating case with the first resin member; a fixed terminal and a movable terminal mounted inside of the insulating case; and an external terminal mounted on the outside of the insulating case to be electrically connected to an outer conductor of the mating coaxial connector; wherein the first resin member is provided with ribs at corner portions thereof, the ribs being arranged to position the fixed terminal and the movable terminal, respectively, and the fixed terminal is provided with a fixed portion fixedly sandwiched between the first and second resin members, said fixed portion includes at least one concavity which is fitted onto at least one of the ribs disposed on the first resin member.
  • 2. A coaxial connector according to claim 1, wherein the ribs are thermally deformed so that the fixed terminal and the movable terminal are fixed to the first resin member.
  • 3. A coaxial connector according to claim 1, wherein the ribs are thermally deformed and have a dome shape, and are provided on the first resin member, and rib receiving portions having a reversed dome shape are provided on the second resin member.
  • 4. A coaxial connector according to claim 1, wherein the fixed terminal, the movable terminal and the outer terminal are made of metal.
  • 5. A coaxial connector according to claim 1, wherein the first resin member is smaller than the second resin member.
  • 6. A coaxial connector according to claim 1, wherein the first resin member includes guiding protuberances for positioning the first resin member on the second resin member.
  • 7. A coaxial connector according to claim 1, wherein the fixed terminal includes a contact portion that is in contact with the movable terminal, a fixed portion fixedly sandwiched between the first and second resin members, and a lead that has a substantially L-shaped configuration.
  • 8. A coaxial connector according to claim 1, wherein the movable terminal includes a movable contact portion that contacts with the fixed terminal, a fixed portion fixedly sandwiched between the first and second resin members, and a lead having a substantially L-shaped configuration.
  • 9. A coaxial connector according to claim 8, wherein the fixed portion includes concavities which are fitted onto the ribs disposed on the first resin member.
  • 10. A communication device comprising:at least one coaxial connector including: a first resin member having a concave portion into which a center contact of a mating coaxial connector is inserted; a second resin member arranged to mate with and define an insulating case with the first resin member; a fixed terminal and a movable terminal mounted inside of the insulating case; and an external terminal mounted on the outside of the insulating case to be electrically connected to an outer conductor of the mating coaxial connector; wherein the first resin member is provided with ribs at corner portions thereof, the ribs being arranged to position the fixed terminal and the movable terminal, respectively, and the fixed terminal is provided with a fixed portion fixedly sandwiched between the first and second resin members, said fixed portion includes at least one concavity which is fitted onto at least one of the ribs disposed on the first resin member.
  • 11. A communication device according to claim 10, wherein the ribs are thermally deformed so that the fixed terminal and the movable terminal are fixed to the first resin member.
  • 12. A communication device according to claim 10, wherein the ribs are thermally deformed and have a dome shape, and are provided on the first resin member, and rib receiving portions having a reversed dome shape are provided on the second resin member.
  • 13. A communication device according to claim 10, wherein the fixed terminal, the movable terminal and the outer terminal are made of metal.
  • 14. A communication device according to claim 10, wherein the first resin member is smaller than the second resin member.
  • 15. A communication device according to claim 10, wherein the first resin member includes guiding protuberances for positioning the first resin member on the second resin member.
  • 16. A communication device according to claim 10, wherein the fixed terminal includes a contact portion that is in contact with the movable terminal, a fixed portion fixedly sandwiched between the first and second resin members, and a lead that has a substantially L-shaped configuration.
  • 17. A communication device according to claim 10, wherein the movable terminal includes a movable contact portion that contacts with the fixed terminal, a fixed portion fixedly sandwiched between the first and second resin members, and a lead having a substantially L-shaped configuration.
  • 18. A communication device according to claim 17, wherein the fixed portion includes concavities which are fitted onto the ribs disposed on the first resin member.
Priority Claims (1)
Number Date Country Kind
2000-221400 Jul 2000 JP
US Referenced Citations (4)
Number Name Date Kind
3893194 Hayden et al. Jul 1975 A
4141617 Freeman Feb 1979 A
5108300 Weber Apr 1992 A
6099334 Togashi Aug 2000 A
Foreign Referenced Citations (7)
Number Date Country
0 929 128 Jul 1999 EP
0 993 080 Apr 2000 EP
62-188066 Nov 1987 JP
11-307188 Nov 1999 JP
2001-176612 Jun 2001 JP
2001-196136 Jul 2001 JP
WO 0033425 Jun 2000 WO