Patent Grant
8406830
1. Field of the Invention
The present invention relates to a radio frequency signal transmission system, radio frequency signal transmission connector and radio frequency signal transmission cable.
2. Description of the Related Art
In recent years, there has been typically utilized a transmission system using an electric signal or an optical transmission system using an optical fiber in order to transmit high-capacity signal at high speed. For example, a HDMI (High-Definition-Multimedia-Interface) cable using an electric signal is utilized for signal transmission in a TV receiver or video recorder. There is utilized optical communication using an optical fiber in a social infrastructure. There is disclosed in Japanese Patent Application Laid-Open No. 2008-28523 a transmission line technique utilizing a waveguide for transmitting a radio frequency electromagnetic field.
However, in a transmission path utilizing an electric signal, there was a problem that many problems occurred in the market, such as impedance mismatch relative to high speed. Further, in an optical transmission technique utilizing an optical fiber, the technique is difficult to widely spread in home appliances due to high cost of electric/optical converter. Furthermore, in order to actually use a transmission technique utilizing a radio frequency described in Japanese Patent Application Laid-Open No. 2008-28523 described above, there is a need to develop a transmission technique suitable for practical use such as connector or cable capable of transmitting a high-capacity signal at high speed between electronic devices.
In light of the foregoing, it is desirable for the present invention to provide a novel and improved radio frequency signal transmission system, radio frequency signal transmission connector and radio frequency signal transmission cable capable of realizing to transmit a high-capacity signal at high speed using a radio frequency signal.
According to an embodiment of the present invention, there is provided a radio frequency signal transmission system including a radio frequency signal transmission connector including an antenna for radiating a radio frequency signal having a predetermined frequency band, and a first dielectric body made of a material having a predetermined first permittivity and having the antenna cast therein, and a radio frequency signal transmission cable including a dielectric transmission path formed of a second dielectric body made of a material having substantially the same second permittivity as the first permittivity of the first dielectric body of the radio frequency signal transmission connector. The radio frequency signal transmission connector is connected with the radio frequency signal transmission cable thereby to form a radio frequency signal transmission path through which the radio frequency signal radiated from the antenna is transmitted to the dielectric transmission path via the first dielectric body.
With the structure, in the radio frequency signal transmission system, a space surrounding the antenna for radiating a radio frequency signal can be filled with the first dielectric body. A permittivity of the first dielectric body is set to be the same as that of the second dielectric body configuring the dielectric transmission path of the radio frequency signal transmission cable so that the radio frequency signal can be transmitted to the dielectric transmission path at the junction between the radio frequency signal transmission connector and the radio frequency signal transmission cable without being attenuated.
The first dielectric body of the radio frequency signal transmission connector may be connected with the dielectric transmission path of the radio frequency signal transmission cable via a buffer, and a permittivity of the buffer may be substantially the same as the first permittivity and the second permittivity.
The radio frequency signal transmission connector and the radio frequency signal transmission cable may further include a fit structure in which they are fit with each other during their connection, and the fit structures may be fit with each other when the radio frequency signal transmission connector and the radio frequency signal transmission cable are connected, thereby a contact face between the first dielectric body and the dielectric transmission path is positioned.
The radio frequency signal transmission connector may further include a radio wave absorbing member for absorbing a radio frequency signal radiated from the antenna on a predetermined face of the first dielectric body.
The radio frequency signal transmission connector may include multiple antennas and first dielectric bodies and the radio frequency signal transmission cable includes multiple dielectric transmission paths to form multiple radio frequency signal transmission paths.
The radio frequency signal transmission connector and the radio frequency signal transmission cable may further include an electric signal transmission path.
The radio frequency signal transmission connector and the radio frequency signal transmission cable may further include an optical signal transmission path.
The radio frequency signal may be a millimeter wave having a frequency band of 30 GHz to 300 GHz.
The first permittivity and the second permittivity may be about 2.2 to 2.6.
According to another embodiment of the present invention, there is provided a radio frequency signal transmission connector which is connected with a radio frequency signal transmission cable including a dielectric transmission path configured with a third dielectric body made of a material having a predetermined third permittivity, including an antenna for radiating a radio frequency signal having a predetermined frequency band, and a fourth dielectric body made of a material having substantially the same fourth permittivity as the third permittivity and having the antenna cast therein.
The radio frequency signal transmission connector may further include a buffer made of a material having substantially the same permittivity as the third permittivity and the fourth permittivity at a face of the fourth dielectric body contacting with the dielectric transmission path.
The radio frequency signal transmission connector may further include a fit structure which is fit with a fit structure provided in the radio frequency signal transmission cable to position the fourth dielectric body contacting with the dielectric transmission path during the connection with the radio frequency signal transmission cable.
The radio frequency signal transmission connector may further include a radio wave absorbing member for absorbing a radio frequency signal radiated from the antenna on a predetermined face of the fourth dielectric body.
The radio frequency signal transmission connector may include multiple fourth dielectric bodies having the antenna cast therein.
The radio frequency signal may be a millimeter wave having a frequency band of 30 GHz to 300 GHz.
The third permittivity and the fourth permittivity may be about 2.2 to 2.6.
According to another embodiment of the present invention, there is provided a radio frequency signal transmission cable which is connected with a radio frequency signal transmission connector including a fifth dielectric body made of a material having a predetermined fifth permittivity and having cast therein an antenna for radiating a radio frequency signal having a predetermined frequency band, including a dielectric transmission path formed of a sixth dielectric body made of a material having substantially the same sixth permittivity as the fifth permittivity.
The radio frequency signal transmission cable may further include a buffer made of a material having substantially the same permittivity as the fifth permittivity and the sixth permittivity at a face of the dielectric transmission path contacting with the fifth dielectric body.
The radio frequency signal transmission cable may further include a fit structure which is fit with a fit structure provided in the radio frequency signal transmission connector to position the dielectric transmission path contacting with the fifth dielectric body during the connection with the radio frequency signal transmission connector.
The fifth permittivity and the sixth permittivity may be about 2.2 to 2.6.
According to the present invention described above, it is possible to realize transmission of a high-capacity signal at high speed utilizing a radio frequency signal.
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the appended drawings. Note that, in this specification and the appended drawings, structural elements that have substantially the same function and structure are denoted with the same reference numerals, and repeated explanation of these structural elements is omitted.
The explanation will be made in the following order:
1. Outline of embodiment of the present invention
2. Basic structure of radio frequency signal transmission system
3. Variants
4. Conclusions
At first, the problem on the related art will be explicitly described and then the outline of a radio frequency signal transmission system according to one embodiment of the present invention will be described.
In recent years, there has been typically utilized a transmission system using an electric signal or an optical transmission system using an optical fiber in order to transmit a high-capacity signal at high speed.
Such an electric signal transmission technique can be utilized to transmit an electric signal between various electric devices. In recent years, there has been widely used a HDMI (High-Definition-Multimedia-Interface) connector/cable or the like capable of bidirectionally transmitting speech, video and control signals. However, there is a problem such as impedance mismatching relative to high speed, and there are many problem as a transmission technique for transmitting a high-capacity signal at high speed.
Optical communication using such an optical signal transmission technique enables to transmit high-capacity data at high speed. However, since a cost for the electric/optical converter 24 or the optical/electric converter 28 is high, there is a problem that the optical communication is widely used in the social infrastructure but is not widely used in home appliances.
Thus, the present inventor has eagerly made researches in order to solve the above problems and reached a signal transmission system made of a connector and a cable capable of transmitting a high-capacity signal at high speed by utilizing a radio frequency (RF) signal. Particularly, the RF signal referred to as so-called millimeter wave having a band of several tens GHz has a characteristic of being capable of easily passing through a waveguide or dielectric transmission path. Thus, a millimeter wave is particularly utilized among the radio frequency signals, thereby realizing a system for transmitting a high-capacity signal at higher speed.
The “millimeter wave” refers to an electromagnetic wave having a wave length of 10 mm to 1 mm and a frequency of 30 GHz to 300 GHz. The frequency used for communication in cell phones is on the order of 1.7 GHz to 2 GHz. The millimeter wave has several tens to several hundreds times of the frequency. Thus, a much wider band can be used than the band used in the current wireless LAN standard. For example, ultrafast wireless communication can be made beyond 1 Gbps in short distance communication.
Even when a millimeter wave is vertically incident from the first dielectric body having a certain permittivity into the second dielectric body having another permittivity, the millimeter wave reflects at the interface of the dielectric body. A reflectivity and a transmissivity of the millimeter wave at this time are calculate from the following equation (1) and equation (2).
Where, ∈1 denotes a permittivity of the first dielectric body and ∈2 denotes a permittivity of the second dielectric body. μ1 denotes a specific permeability of the first dielectric body and μ2 denotes a specific permeability of the second dielectric body. Typically, in the case of a resin material such as plastic, the specific permeability is about 1 and the calculation equations (1) and (2) for the reflectivity and the transmissivity are simplified and calculated as in the following equations (3) and (4).
For example, consider, from the above equations (3) and (4), the reflectivity and the transmissivity when a millimeter wave is vertically incident from a certain space into a dielectric body. The specific permittivity of air is about 1 so that ∈1=1 is assumed. Further, a resin material is assumed for the permittivity of the second dielectric body so that ∈2=3 is assumed. In this case, the reflectivity is about 7% and the transmissivity is about 93% from the above equation (3). In other words, this means that even when the millimeter wave radiated from the antenna 40 is vertically incident into the incident face of the dielectric transmission cable 36, about 7% thereof is reflected.
A radio frequency signal transmission connector 200 and a radio frequency signal transmission cable 300 configuring the radio frequency signal transmission system according to the embodiment of the present invention can eliminate the above problems. The radio frequency signal transmission system according to the present embodiment will be described below in detail.
As shown in
The radio frequency signal transmission cable 300 according to the present embodiment includes a dielectric transmission path 302 for transmitting a millimeter wave. Further, the dielectric body forming the dielectric transmission path 302 is made of a material having the same permittivity as the permittivity ∈ of the dielectric body 206 of the transmission connector 200.
When the transmission connector 200 and the transmission cable 300 are joined, the dielectric body 206 and the dielectric transmission path 302 both having the same permittivity ∈ are tightly attached to each other. Consequently, the millimeter wave radiated from the antenna 204 will be transmitted through the radio frequency signal transmission path formed by the dielectric body 206 and the dielectric transmission path 302. In other words, the millimeter wave radiated from the antenna 204 is incident into the dielectric transmission path 302 having the permittivity ∈ via the dielectric body 206 having the permittivity ∈. At this time, the permittivities of the dielectric body 206 and the dielectric transmission path 302 are the same so that the interface reflection at the contact face between the dielectric body 206 and the dielectric transmission path 302 can be prevented.
As described above, the dielectric body 206 having the antenna 204 cast therein is set in its permittivity to be the same as the dielectric body configuring the dielectric transmission path 302 of the transmission cable 300, thereby restricting attenuation of an input signal of the millimeter wave at the junction between the transmission connector 200 and the transmission cable 300. Further, a similar effect can be obtained also at the exit face of the transmission cable 300. A similar transmission cable 300 is connected to the exit side of the transmission cable 300. Consequently, the dielectric body 206 and the dielectric transmission path 302 both having the same permittivity ∈ are tightly attached to each other at the exit side of the transmission cable 300. In other words, the millimeter wave transmitted through the dielectric transmission path 302 of the transmission cable 300 is incident into the dielectric body 206 having the same permittivity ∈ as the dielectric transmission path 302. Thus, the attenuation of the input signal of the millimeter wave can be restricted at the junction between the exit side of the transmission cable 300 and the transmission connector 200.
In consideration of the transmission efficiency of the transmission cable 300, the dielectric body 206 and the dielectric body configuring the dielectric transmission path 302 are preferably made of a polypropylene-based material. This is because a dielectric loss is 0.01 to 0.001 in the case of a polypropylene-based material so that the transmission path having a low transmission loss can be realized. In this case, the permittivity ∈ is about 2.2 to 2.6. Of course, the material and the permittivity ∈ forming the dielectric body 206 and the dielectric body configuring the dielectric transmission path 302 are not limited thereto. For example, the dielectric bodies made of various materials or permittivities may be utilized depending on a requested specification or cost, of course.
As stated above, since the antenna 204 for radiating a millimeter wave is cast into the dielectric body 206 in the radio frequency signal transmission connector 200 according to the present embodiment, the space surrounding the antenna 204 can be filled with the dielectric body 206. Further, the permittivity of the dielectric body 206 is set to be the same as the permittivity of the dielectric body configuring the dielectric transmission path 302 of the transmission cable 300, thereby preventing the interface reflection of the millimeter wave at the junction between the transmission connector 200 and the transmission cable 300. In other words, in the radio frequency signal transmission system according to the present embodiment, the attenuation of the millimeter wave can be restricted at the junction between the transmission connector 200 and the transmission cable 300. As a result, the radio frequency signal transmission system according to the present embodiment can be utilized to realize the transmission of a high-capacity signal at high speed utilizing a radio frequency signal.
The dielectric body 206 having the antenna 204 of the transmission connector 200 cast therein is set in its permittivity to be the same as the dielectric body configuring the dielectric transmission path 302 of the transmission cable 300 so that the radio frequency signal transmission system according to the present embodiment can have the above characteristics. The radio frequency signal transmission system according to the present embodiment includes various structures in addition to the above structure to have the above characteristics, thereby transmitting a high-capacity signal at higher speed. There will be described below variants capable of further improving signal transmission efficiency in the radio frequency signal transmission system according to the present embodiment.
[3-1. Variant 1 (Example of Providing Buffer at Junction to Improve Transmission Efficiency)]
As stated above, in the radio frequency signal transmission system according to the present embodiment, the attenuation of a millimeter wave can be restricted at the junction between the transmission connector 200 and the transmission cable 300. It is desirable that the tightness of the junction between the transmission connector 200 and the transmission cable 300 is higher in order to further restrict the attenuation of a millimeter wave at the junction between the transmission connector 200 and the transmission cable 300. In a radio frequency signal transmission system according to variant 1, the tightness of the junction between the transmission connector 200 and the transmission cable 300 is further improved, thereby further improving the signal transmission efficiency.
Further, a millimeter wave radiated from the antenna 204 is incident from the dielectric body 206 of the transmission connector 200 via the buffer 400 into the dielectric transmission path 302 of the transmission cable 300. Thus, the buffer 400 is made of a material having the same permittivity as the dielectric body 206 and the dielectric body configuring the dielectric transmission path 302 in order to restrict the attenuation of the millimeter wave at the junction between the dielectric body 206 of the transmission connector 200 and the dielectric transmission path 302 of the transmission cable 300.
For example, the buffer 400 may be made of a polypropylene-based material having the permittivity ∈ of 2.2 to 2.6 similarly as the dielectric body 206 of the transmission connector 200 and the dielectric body configuring the dielectric transmission path 302 of the transmission cable 300. Of course, the material and the permittivity ∈ forming the buffer 400 are not limited thereto. In other words, an appropriate buffer 400 may be applied depending on the material nature and the permittivities of the dielectric body 206 and the dielectric body configuring the dielectric transmission path 302, which are determined depending on a requested specification or cost.
The buffer 400 may be provided in the dielectric body 206 of the transmission connector 200, in the dielectric transmission path 302 of the transmission cable 300 or in both the dielectric body 206 and the dielectric transmission path 302.
As stated above, in the radio frequency signal transmission system according to variant 1, the dielectric body 206 of the transmission connector 200 is joined with the dielectric transmission path 302 of the transmission cable 300 via the buffer 400. Thus, the tightness of the junction between the dielectric body 206 of the transmission connector 200 and the dielectric transmission path 302 of the transmission cable 300 can be improved. Further, the permittivity of the buffer 400 is set to be substantially the same as the permittivities of the dielectric body 206 of the transmission connector 200 and the dielectric body configuring the dielectric transmission path 302 of the transmission cable 300, thereby restricting the attenuation of the millimeter wave at the junction. Consequently, the radio frequency signal transmission system according to variant 1 is utilized to improve the transmission efficiency of the millimeter wave between the transmission connector 200 and the transmission cable 300 and to transmit a high-capacity signal at high speed.
[3-2. Variant 2 (Example of Providing Fit Structure at Junction to Improve Transmission Efficiency)]
In the radio frequency signal transmission system according to variant 1 described above, the transmission connector 200 and the transmission cable 300 are joined with each other via the buffer 400, thereby improving the tightness of the junction between the transmission connector 200 and the transmission cable 300. However, even if the tightness between the dielectric body 206 and the dielectric transmission path 302 can be improved, if the positional accuracy of the dielectric body 206 and the dielectric transmission path 302 during the junction is bad, the transmission efficiency can be lowered. Thus, in the radio frequency signal transmission system according to variant 2, the transmission connector 200 and the transmission cable 300 have a fit structure, thereby improving the positional accuracy of the dielectric body 206 and the dielectric transmission path during the junction and further improving the signal transmission efficiency.
The first fitting unit 210 and the second fitting unit 304 are not limited to a specific shape or size. In other words, the first fitting unit 210 and the second fitting unit 304 have only to be fit with each other when the transmission connector 200 and the transmission cable 300 are joined with each other, and need to only position the dielectric body 206 and the dielectric transmission path 302. For example, as shown in
As stated above, in the radio frequency signal transmission system according to variant 2, the first fitting unit 210 and the second fitting unit 304 are fit with each other so that the dielectric body 206 of the transmission connector 200 and the dielectric transmission path 302 of the transmission cable 300 can be tightly attached at a precise position. Thus, it is possible to restrict the attenuation of the millimeter wave at the junction between the dielectric body 206 of the transmission connector 200 and the dielectric transmission path 302 of the transmission cable 300. Consequently, the radio frequency signal transmission system according to variant 2 is utilized to improve the transmission efficiency of the millimeter wave between the transmission connector 200 and the transmission cable 300 and to transmit a high-capacity signal at high speed. It is naturally possible to provide the buffer 400 described in variant 1 in the transmission connector 200 and/or the transmission cable 300 according to variant 2. Thus, the transmission efficiency of the millimeter wave between the transmission connector 200 and the transmission cable 300 can be further improved.
[3-3. Variant 3 (Example of Radio Frequency Signal Transmission Cable 300 Including Multiple Transmission Paths)]
There has been described in the above embodiment the example in which one radio frequency signal transmission path is provided along with the transmission connector 200 and the transmission cable 300. In the radio frequency signal transmission system according to variant 3 described later, the transmission connector 200 and the transmission cable 300 have multiple radio frequency signal transmission paths, thereby increasing the capacity of data to be transmitted.
Only the transmission connector 200 is shown in
The number of dielectric bodies 206 provided in the transmission connector 200 is not limited to 2.
In other words, the radio frequency signal transmission system shown in
The radio frequency signal transmission system according to variant 3 can be used along with a traditional electric signal transmission path.
Only the transmission connector 200 is shown in
The electric signal transmission terminal 212 shown in
As stated above, the radio frequency signal transmission system according to variant 3 includes multiple radio frequency signal transmission paths described in the above embodiment, thereby increasing the capacity of data to be transmitted. Further, the radio frequency signal transmission system according to variant 3 can be used along with the transmission of a radio frequency signal through the radio frequency signal transmission path described in the above embodiment and additionally with a traditional electric signal transmission system and the like. Thus, the data transfer capacity can be increased and additionally the transmission system can be selected depending on a type or capacity of the data to be transferred. Consequently, the radio frequency signal transmission system according to variant 3 can be utilized to realize the transmission of a high-capacity signal at high speed utilizing a radio frequency signal.
[3-4. Variant 4 (Example of Providing Radio Wave Absorbing Member 214 to Restrict Reflected Wave)]
As stated above, in the radio frequency signal transmission system according to the present embodiment, a millimeter wave radiated from the antenna 204 is incident into the dielectric transmission path 302 of the transmission cable 300 via the dielectric body 206 of the transmission connector 200. However, typically, some millimeter waves radiated from the antenna 204 may not only be directly incident in the dielectric transmission path 302 of the transmission cable 300 but also in the dielectric transmission path 302 of the transmission cable 300 after being reflected on a predetermined face of the dielectric body 206 of the transmission connector 200. Such a reflected wave can be a cause for the problem such as so-called ghost phenomenon, which is not preferable for data transfer quality. A radio frequency signal transmission system according to variant 4 can eliminate the problem. Specifically, the radio frequency signal transmission system according to variant 4 includes the radio wave absorbing member 214 at a predetermined face of the dielectric body 206 of the transmission connector 200, thereby restricting a decrease in the transmission quality due to a reflected wave.
With the structure shown in
The structure of the radio frequency signal transmission system shown in
[3-5. Variant 5 (Example of Transmitting Data Recorded in IC Chip 500)]
The transmission connector 200 in the radio frequency signal transmission system described in the above embodiment is one example for explaining the above embodiment, and the structure, shape and the like of the transmission connector 200 can be variously modified depending on a capacity of data to be transmitted or a type of an electronic device to be connected. In the following, there will be described a radio frequency signal transmission system according to variant 5 capable of being applied to the transfer of the data recorded in an IC chip.
As shown in
A permittivity of the dielectric transmission path 302 of the transmission cable 300, a permittivity of the dielectric transmission path 506 of the transmission connector 200, and a permittivity of the IC package 502 are set to be substantially the same, thereby efficiently transmitting a millimeter wave radiated from the antenna 204. In other words, since the permittivity of the IC package 502 is substantially the same as the permittivity of the dielectric transmission path 506, the attenuation of a millimeter wave can be restricted at the contact face between the IC package 502 and the dielectric transmission path 506. Further, the attenuation of a millimeter wave can be restricted similarly also at the contact face between the dielectric transmission path 506 and the dielectric transmission path 302 of the transmission cable 300. Consequently, the radio frequency signal transmission system according to variant 5 shown in
In the example shown in
As described above, in the radio frequency signal transmission system according to the present embodiment, the antenna 204 provided in the transmission connector 200 is cast in the dielectric body 206. There is configured such that the permittivity of the dielectric body 206 is set to be substantially the same as the permittivity of the dielectric body configuring the dielectric transmission path 302 of the transmission cable 300. Thus, a millimeter wave radiated from the antenna 204 can be restricted from attenuating at the contact face between the transmission connector 200 and the transmission cable 300. Further, the radio frequency signal transmission system according to the present embodiment can include the buffer 400 at the contact face between the dielectric body 206 of the transmission connector 200 and the dielectric transmission path 302 of the transmission cable 300. Thus, the dielectric body 206 of the transmission connector 200 is connected with the dielectric transmission path 302 of the transmission cable 300 via the buffer 400, thereby improving the tightness between the dielectric body 206 and the dielectric transmission path 302. The permittivity of the buffer 400 is set to be substantially the same as the permittivities of the dielectric body 206 and the dielectric body configuring the dielectric transmission path 302, thereby restricting the attenuation of a millimeter wave at the contact face between the dielectric body 206 and the dielectric transmission path 302. Further, in the radio frequency signal transmission system according to the present embodiment, the transmission connector 200 and the transmission cable 300 can have a fit structure, respectively. Thus, it is possible to further improve the accuracy of the contact position between the dielectric body 206 and the dielectric transmission path 302 during the connection between the transmission connector 200 and the transmission cable 300. Moreover, in the radio frequency signal transmission system according to the present embodiment, the radio wave absorbing member 214 can be provided at a predetermined face of the dielectric body 206 of the transmission connector 200. Thus, the reflection of a millimeter wave radiated from the antenna 204 can be restricted, thereby improving the data transfer quality. As described above, the radio frequency signal transmission system according to the present embodiment can realize the high-speed and high-capacity signal transmission utilizing a radio frequency signal.
It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.
For example, there has been mainly described in the above embodiment a millimeter wave having a frequency band of 30 GHz to 300 GHz as one example of a radio frequency signal, but the present invention is not limited thereto. For example, the radio frequency signal transmission system having the above structure is utilized to transmit a radio frequency signal having another frequency band. Of course, the frequency band of the radio frequency signal, and the characteristics or specification of the antenna for radiating the radio frequency signal are appropriately selected depending on the data transfer capacity, transfer speed, quality, cost and the like required for the transmission system.
The material nature, permittivity, shape, size and the like of the dielectric body in the present embodiment are not limited to the above example. In other words, as long as the permittivity of the dielectric body 206 of the transmission connector 200 is set to be substantially the same as the permittivity of the dielectric body configuring the dielectric transmission path 302 of the transmission cable 300, thereby restricting the signal attenuation at the contact face between the dielectric body 206 and the dielectric transmission path 302, the permittivities are not limited to a specific permittivity.
The present application contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2009-002852 filed in the Japan Patent Office on 8 Jan. 2009, the entire content of which is hereby incorporated by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| P2009-002852 | Jan 2009 | JP | national |
| Number | Date | Country |
|---|---|---|
| 07-245507 | Sep 1995 | JP |
| 10-209725 | Aug 1998 | JP |
| 2000-114815 | Apr 2000 | JP |
| 2001-203510 | Jul 2001 | JP |
| 2003-032009 | Jan 2003 | JP |
| 2008-28523 | Feb 2008 | JP |
| 2008-236365 | Oct 2008 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20100173595 A1 | Jul 2010 | US |
