Abstract:
In a wireless LAN system, a terminal that includes a device for wireless LAN connection is capable of simple connection setting for wireless LAN. In said terminal, a simple connection setting recorder records each methods of simple connection setting that easily sets the simple connection setting for the wireless LAN, and an access point identifier identifies connected access point by detecting an information that is output by the access point. And a connection setting selector selects a simple connection setting corresponding to the access point, which the access point identifier identified from the simple connection settings recorded in the simple connection setting recorder. Finally, a connection setting processor processes connection setting, which corresponds to each method of the simple connection settings that the connection setting selector selected.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This Application is a CONTINUATION application claiming the benefit of priority of the co-pending International Patent Application No. PCT/JP2008/052350 with an international filing date of 13 Feb. 2008 that designated the United States, which claims the benefit of priority of Japanese Patent Application No. 2007-036265, filed 16 Feb. 2007, the entire disclosures of all Applications are expressly incorporated by reference in their entirety herein. 
     BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     This invention relates to a wireless LAN system which provides simple connection setting for a wireless LAN. 
     (2) Description of the Related Art 
     An access point which is a relay for a wireless LAN is used as a device which connects plural terminals in remote area to Internet. In addition, in late years the access point begins to be used by not only the personal computer but also a family video games or household electrical appliance.  FIG. 8  shows personal computers  1 , 2  and a family game console  3  as terminals. When users use wireless LAN, users need to set connection setting of the wireless LAN for a access point  4  and each terminals  1 ,  2 ,  3 . For example, the connection setting of the wireless LAN includes security level between the access point  4  and terminals  1 ,  2 ,  3  or settings such as ESS-ID beforehand. Therefore some knowledge of the wireless LAN is required in order to set the security level and setting of ESS-ID. 
     Therefore, following method is disclosed as a method to simplify connection setting of a wireless LAN. Namely, patent document 1 discloses a method to automatically set connection setting of the wireless LAN by easy operation of a button on the access point and the terminals, or an icon. 
       FIG. 9  shows user side procedures to set regular connection setting (I). As shown in the figure, user completes setting of security level (step S 710 ), setting of common security level between terminals to be connected with each other (step S 720 ), detection of access points (step S 730 ), and inputting information elements output by the access points when it is detected (step S 740 ). In contrast, according to simple connection setting (II), as an example, the connection setting of the wireless LAN will be performed just by a button operation (step S 810 ) at the terminal side and also a button operation (step S 820 ) at the access point as the example.
     [patent document 1] Japanese Patent Laid-Open No. 2005-175,524   

     BRIEF SUMMARY OF THE INVENTION 
     The simple connection setting mentioned above is used when the access point and each terminals are connected individually. And it is necessary that the access point and each terminals must be capable of the same simple connection setting. For example, an example in  FIG. 8  is assumed that the simple connection setting that the access point  4  supports is A method, and the simple setting that terminals  1 , 2  support is also the A method, and the simple connection setting that terminal  3  support is B method. In this case, only the terminals  1 , 2  can be set by the simple connection setting with the access point  4 . And in order to set for the terminal  3 , it is necessary for the user to carry out the normal wireless LAN connection setting shown in  FIG. 9  (I). Therefore, although the terminals themselves support simple connection setting, there were cases that simple connection to the access point can not be carried out. In addition, it is necessary for the user to recognize beforehand which simple connection settings are supported by the access point if the user need to cope with the access point which supports each methods of the simple connection. Therefore the users are required with some knowledge of the wireless LAN as well as ordinal connection setting. And an advantage of the simple connection setting which makes construction of wireless LAN to be easy for the users without knowledge of the wireless LAN could not be pursued. 
     This invention relates to a wireless LAN which is capable of connection setting by simple operation for any access points and terminals corresponding to what kind of simple connection setting. 
     One aspect of the present invention provides a wireless LAN system, comprising: 
     an access point and a terminal that includes a device for wireless LAN connection is capable of simple connection setting for wireless LAN; said terminal comprises 
     a simple connection setting recorder to record each methods of simple connection setting that easily sets the simple connection setting for the wireless LAN, 
     an access point identifier to identify connected access point by detecting an information that is output by the access point, 
     a connection setting selector to select a simple connection setting corresponding to the access point, which the access point identifier identified from the simple connection settings recorded in the simple connection setting recorder, and 
     a connection setting processor to process connection setting, which corresponds to each method of the simple connection settings that the connection setting selector selected. 
     Namely, when a simple connection setting of wireless LAN system of this invention is processed, an access point identifier identifies a connected access point by detecting an information which is output by the access point. Then, a connection setting selector selects a simple connection setting corresponding to the access point which the access point identifier identified from the simple connection settings recorded in the simple connection setting recorder. 
     Therefore, since connection setting of wireless LAN can be processed automatically against any access point which adapts any kind of simple connection setting, users can accomplish connection setting easily. 
     According to another aspect of the invention, said terminal comprises said access point identifier that detects the information to identify the access point to be connected with as the first detecting operation and 
     said connection setting processor that detects the information to process the connection setting to connect with the identified access point for connection as the second detecting operation, 
     said connection setting processor uses the information that said access point identifier detects by the first detecting operation, omitting second detecting operation. 
     Namely, in order to process connection setting, the wireless LAN system of this aspect detects an access point by the first detecting operation, and determines each setting value for the selected simple connection setting using the information detected by the first detecting operation. 
     Therefore, using the information detected by the first detecting operation for the information to be detected by the second detecting operation, the second detecting operation can be omitted. Since the first and second detection operations are carried out by using a device, they take some time. Therefore omitting the second detecting operation, processing time of the simple connection setting can be shortened. 
     According to another aspect of the invention, said terminal detects one of beacon and probe response output by the access point, and detects the information stored in one of the beacon and probe response. Namely, in order to detect the information, one of a beacon and a probe response output by the access point is received, and the information stored in one of the beacon and the probe response is detected. A beacon is a signal to be broadcasted at a fixed interval in order to inform the existence of the access point, and a plurality of information are stored in the beacon. In addition, a probe response is a response which the access point replies to a probe request from the terminal. Therefore using the beacon or probe response for detecting the information, it is not necessary to equip a new signal generator for the access point. 
     Furthermore, this invention is effective for the constitution consisting of the terminal only. In addition, this invention is also effective where a program which makes the terminal operate as explained above is stored in a recording medium. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       It is to be understood that the drawings are to be used for the purposes of exemplary illustration only and not as a definition of the limits of the invention. Throughout the disclosure, the word “exemplary” is used exclusively to mean “serving as an example, instance, or illustration.” Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. 
       Referring to the drawings in which like reference character(s) present corresponding parts throughout: 
         FIG. 1  is a figure expressing constitution of hardware for the wireless LAN system of this invention. 
         FIG. 2  is a block diagram showing constitution of each hardware of the wireless LAN system. 
         FIG. 3  is a figure showing an information stored in a beacon or a probe response. 
         FIG. 4  is a flow chart which CPU of terminal  20  carries out. 
         FIG. 5  is a flow chart which CPU 23  carries out in the second embodiment. 
         FIG. 6  is a flow chart which CPU 23  carries out in the second embodiment. 
         FIG. 7  is a flow chart which a device driver carries out in the second embodiment. 
         FIG. 8  is a figure showing hardwares constituting conventional wireless LAN. 
         FIG. 9  is a flow chart showing an example of user&#39;s operation for the simple connection setting and normal connection setting. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In accordance with the following order, an embodiment of the present invention will be described.
     (1) The first embodiment   (1-1) Abstract of this invention   (1-2) The constitution of the wireless LAN system   (1-3) Simple connection setting   (2) The second embodiment   (3) Summary   

     (1) THE FIRST EMBODIMENT 
     (1-1) Abstract of this Invention 
       FIG. 1  is a figure showing constitution of hardware for the wireless LAN system  100  of this invention. As shown in  FIG. 1 , the wireless LAN system  100  constitutes wireless LAN between terminals  20 ,  30 ,  40  and the access point  50  in wireless communication area AR 1 . In addition, connection setting of the wireless LAN between the terminals  20 ,  30 ,  40  and the access point  50  can be set by a registration button  71  (explained later in detail) of the access point  50  or by operating the terminals  20 ,  30 ,  40  (a simple connection setting as follows). 
     According to the wireless LAN system  100  of this invention, users can set simple connection by easy operation between the access point  50  with any kind of simple connection setting and the terminals  20 ,  30 ,  40 . For example, where the access point  50  supports either A method of the simple connection setting or B method of the simple connection setting, the terminals  20 ,  30 ,  40  of this invention can automatically set simple connection setting with the access point  50  and carry out the connection of the wireless LAN by an easy operation of the button. 
     (1-2) The Constitution of the Wireless LAN System 
     As shown in  FIG. 1 , the wireless LAN system  100  comprises terminals  20 ,  30 ,  40 , a wireless LAN adapter  10  as a device for connecting to the terminals  20 ,  30 ,  40 , and an access point  50 . Hereby data which acquired in Internet IN through a router  80  can be output to the terminal  20  through the wireless LAN adapter  10  from the access point  50 . In addition, the connection setting of the wireless LAN between the terminal  20 ,  30 ,  40  and the access point  50  are set wirelessly. 
     The access point  50  outputs information to each terminal  20 ,  30 ,  40  by radio from server SV through Internet IN. The access point  50  possesses, as shown in  FIG. 2 , CPU 51 , ROM 52  which is mutually connected to the CPU 51  via a bus, RAM 53 , storage device  54  of non-volatilization such as a hard disk, WAN port  57  as a network interface, LAN port  59  for the connection with a wired LAN, wireless communication interface  58 , display controller  55 , and I/O controller  56 . 
     Various programs for communication with the terminal  20 ,  30 ,  40  in wireless communication area AR 1  and the data which are necessary for the connection to Internet IN are stored in ROM 52 . A push-type registration button  71  is connected to the I/O controller  56 , and allocated in the state such as its pressing part is exposed from housing surface of the access point  50 . Various indication lamps  70  that displays a connection state and a communication state of wireless LAN by flashing on and off are connected to the display controller  55 . 
     A transmitter  60  transmitting an electric wave and a receiver  61  receiving an electric wave are connected to the wireless communication interface  58 . The transmitter  60  and the receiver  61  are built-in in the access point  50  in the state such as capable of transmission of radio to out side and receiving of radio from outside respectively. In addition, the transmitter  60  broadcasts a beacon or a probe response at a scheduled interval. A beacon is a signal which the access point  50  outputs as an identity information for the terminal located around. Therefore, the beacon is used to inform being accessible by the access point  50  to the wireless LAN adapter  10  at the time of connection setting between the access point  50  and the terminal  20 ,  30 ,  40 . In addition, the beacon stores information such as ESS-ID in its frame and the terminal which received the beacon can acquire the ESS-ID of the access point and other information. Further, against a probe demand from the terminal, the access point  50  outputs the information in a probe response. 
       FIG. 3  is a figure showing, as an example, an information stored in a beacon or a probe response. As shown in the figure, the information stored in the frame of the beacon or the probe response is used to inform the terminals the various information that are necessary for communication. When the terminals  20 ,  30 ,  40  receive each information shown in the figure, the terminal  20 ,  30 ,  40  carry out identification of the access point  50  as a connecting point and various setting of wireless LAN connection. 
     The wireless LAN adapter  10  receives data and a signal transmitted from the access point  50 . And the wireless LAN adapter  10  outputs data and a signal from terminals  20 ,  30 ,  40  to the access point  50 . The wireless LAN adapter  10  is constituted so that the wireless communication interface  11 , the wireless LAN 13  and the record device  14  as a nonvolatile memory can communicate with each other through the I/O controller  12  and the bus. The record device  14  records programs to control the wireless LAN adapter  10 . In addition, an antenna  16  is connected to the wireless LAN 13  in order to receive wireless communication that is output by the access point  50  and the beacon or the probe response explained above. Under the control of the programs recorded in the record device  14 , the data, the beacon and the probe response received by the antenna  16  is output to the wireless communication interface  11  through the bus. Further, a simple connection setting button  15  to connect to the access point  50  through wireless LAN by using the simple connection setting is connected to the I/O controller  12 . And the simple connection setting button  15  is located on outside of a housing of the wireless LAN adapter  10 . 
     When the terminals  20 ,  30 ,  40  are connected with the wireless LAN adapter  10 , they receive data which are output from the access point  50 . In addition, the terminals  30 ,  40  are well-known personal computers and the terminal  20  is a family game console. In the terminals  20 ,  30 ,  40 , an connection interface  21  to transfer data with the wireless LAN adapter  10 , ROM 24  that stores various programs for CPU 23  to operate processing, RAM 25  for CPU 23  to develop the programs, a hard disk and a CD-ROM drive as nonvolatile recording medium  22  (simple connection setting recording means) that stores a program for connection setting for wireless LAN, and a device unit  26  that carries out predetermined functions are connected to the CPU 23  through a bus so that they can mutually communicate with the CPU 23 . Of course each terminals can be not only a family game console but also the other terminals such as a household electrical appliance and a PDA (Personal Digital Assistant). 
     Programs to control wireless LAN system  100  is recorded in a recording mediums  22  of the terminals  20 ,  30 ,  40 . More concretely, such programs include OS 200  that manages the whole the terminals  20 ,  30 ,  40  and offers basic functions which are commonly used by application softwares stored in the recording medium  22 , a device driver  201  to control the access point  50  and the wireless LAN adapter  10 , a plurality of simple connection setting programs  202  for simple connection setting, and a connection setting control program  203  that chooses and have run simple connection setting program  202 . In addition, a connection function to carry out the connection of the wireless LAN between the terminals  20 ,  30 ,  40  and the access point  50  is incorporated in the OS 200 . 
     The OS 200  connects the access point  50  and the terminals  20 ,  30 ,  40  by wireless LAN after having set security level and ESS-ID between the access point  50  and each terminals  20 ,  30 ,  40  in accordance with simple connection setting program  202 . In addition, the device driver  201  controls each device constituting wireless LAN adapter  10  according to an operation at terminal side. When the device driver  201  is incorporated in the terminals  20 ,  30 ,  40 , the terminals  20 ,  30 ,  40  recognize the attached wireless LAN adapter  10 , and become available to control the wireless LAN adapter  10 . 
     The simple connection setting program  202  is a program to set security level and ESS-ID for wireless LAN connection. More concretely, in order to set connection setting for wireless LAN connection, the simple connection setting program  202  automatically acquires from the access point  50  various information that the OS 200  needs in order to set connection setting of wireless LAN, and outputs them to the OS 200 . In addition, the recording mediums  22  of the terminals  20 ,  30 ,  40  of this invention store simple connection setting programs  202  corresponding to each method of the simple connection settings beforehand. And the terminals  20 ,  30 ,  40  cope with each method of the simple connection setting with them. 
     The connection setting control program carries out simple connection setting when the terminals  20 ,  30 ,  40  or a registration button  71  of access point  50  are operated by the user. In addition, according to an information output by the access point  50 , the connection setting control program  203  chooses simple connection setting program  202  that the access point  50  corresponds from ones in the recording medium  22 . More concretely, when a type of the simple connection setting of the connecting access point  50  is detected by a beacon or a probe response, a simple connection setting program  202  corresponding to the type of the detected simple connection setting is read out, and carries out simple connection setting between the terminal and the access point  50 . 
     (1-3) Simple Connection Setting 
       FIG. 4  is a flow chart which a CPU 23  of the terminal  20  carries out as the simple connection setting. The simple connection setting of the terminal  20  of this invention will be explained along with  FIG. 4  as follows. In addition, the flow chart in  FIG. 4  assumes that simple connection setting program  202   a  corresponding to the A method of the simple connection setting and simple connection setting program  202   b  corresponding to the B method of the simple connection setting are implemented to the recording medium  22  of the terminal  20  beforehand. 
     The user operates a simple connection setting button  15  of the terminal  20  or an icon for the simple connection setting on the screen which the terminal  20  displays, and further operates a registration button  71  of the access point  50 . Then the CPU 23  retrieves a connection setting control program  203  and carries out the program on a RAM 25 . Here, it is assumed that A method of the simple connection setting or B method of the simple connection setting is distinguished using an information stored in a beacon or a probe response. More concretely, if service set ID in the information stored in the beacon or the probe response is converted into a special mode, the type of the simple connection setting is the A method. In addition, if new ID (special ID) is set in the information stored in the beacon or the probe response, the type of the simple connection setting is the B method. 
     At first, the CPU 23  acquires an information output from the access point  50 , and outputs an instructions for identifying the connecting access point  50  to the wireless LAN adapter  10  (step S 100 ). More concretely, CPU 23  instructs the wireless LAN adapter  10  through the device driver  201  to detect a beacon or a probe response output by the access point  50 . The detection instructions by CPU 23  are repeated until the connecting access point  50  is identified. According to the above instructions, the wireless LAN adapter  10  receives a beacon or a probe response output by the access point  50  (the first detecting operation). Hereby CPU 23  with the connection setting control program  203  constitutes the access point identifier. 
     Then the CPU 23  carries out the simple connection setting based on the information stored in a beacon or a probe response by the wireless LAN adapter  10  through a wireless communication interface  11 , and identifies the connecting access point  50  (step S 110 ). If service set ID in the information stored in the beacon or the probe response is converted into a special mode, CPU 23  reads the simple connection setting program  202   a  corresponding to the A method of the simple connection setting from the recording medium  22  and carries it out (step S 120 ). Similarly, if special ID is stored in the information stored in the acquired beacon or probe response, CPU 23  reads the simple connection setting program  202   b  corresponding to the B method of the simple connection setting from the recording medium  22  and carries it out (step S 120 ). Hereby CPU 23  with the connection setting control program  203  constitutes the connection setting selector. 
     Hereinafter, an explanation of a flow which is carried out in accordance with A method of the simple connection setting will be mainly described. When CPU 23  carries out the simple connection setting program  202   a  in step S 120 , CPU 23  instructs it to detect an information from the access point  50  in order to set according to the A method of the simple connection setting (step S 130 ). More concretely, CPU 23  instructs the wireless LAN adapter  10  through device driver  201 . Thus the wireless LAN adapter  10  receives a beacon or a probe response output by the access point  50  by driving wireless LAN 13  (the second detecting operation). Hereby CPU 23  with the simple connection setting program  202  constitutes the connection setting processor. 
     When the CPU 23  acquires the information from the beacon or the probe response, the CPU 23  identifies the connecting access point  50  (step S 135 ). If an information is not detected, CPU 23  repeats detection instructions until the information is detected. In addition, CPU 23  may consider the state that the information is not detected to be an error state, and may terminate simple connection setting in step S 135 . When the connecting access point  50  is identified in step S 135 , connection setting between the access point  50  and the terminal  20  is decided and a decided value is output to OS 200  (step S 140 ). Furthermore, CPU 23  carries out connection of wireless LAN with a connection function implemented with OS 200  by the recording medium  22  (step S 170 ). 
     It is also true that when B method of the simple connection setting is chosen at step S 120 , the CPU 23  carries out the same flow as explained above at step S 150  to S 170 , and sets connection setting of wireless LAN in accordance with the B method of the simple connection setting. 
     (2) A FORM OF THE SECOND EMBODIMENT 
     According to the first embodiment explained above, it comprises a constitution where connection setting between the terminals  20 ,  30 ,  40  and the access point  50  with any kind of simple connection setting can be carried out by easy operation. Furthermore, according to the second embodiment, the transaction speed in the simple connection setting is increased by devising the program that CPU 23  of the terminal  20 ,  30 ,  40  carries out. 
     In detail, the CPU 23  of the terminal carries out detecting operation twice at the simple connection setting. Namely, such operations are detection (the first detecting operation) for detecting the information to identify the access point  50  and detection (the second detection movement) for detecting the information to decide various setting for the simple connection setting. The detecting operation is carried out by CPU 23  that lets through device driver  201  the wireless LAN adapter  10  detect a beacon or a probe response. The detection of the information output by the access point  50  requires some period of time, because it is physical to drive the device. Therefore, according to the second embodiment, detecting operation of the wireless LAN adapter  10  is omitted, and the processing time required for the simple connection setting is shortened. 
     An explanation for concrete constitution follows hereinafter. In addition, the construction of the access point  50  and the terminals  20 ,  30 ,  40  in the second embodiment is almost same with the one of the first embodiment. In addition, the recording medium  22  of the terminal  20  stores the same simple connection setting program  202  as with the first embodiment and that corresponds to the A method of the simple connection setting and the B method of the simple connection setting. 
     As shown in the  FIG. 5 , the user operates a simple connection setting button  15  of the terminal  20  or an icon for the simple connection setting on the screen which the terminal  20  displays, and further operates a registration button  71  of the access point  50 . More concretely, through device driver  201 , CPU 23  instructs the wireless LAN adapter  10  to detect a beacon or a probe response output from the access point  50 . Along with the instruction, the wireless LAN adapter  10  receives a beacon or a probe response output by the access point  50 . Then the access point  50  is identified using the information stored in the beacon or the probe response (step S 210 ). CPU 23  records an information of the identified access point  50  in RAM 25  (step S 215 ). Furthermore, CPU 23  reads out the simple connection setting program  202  corresponding to the simple connection setting (step S 220 ). If the access point intended in S 210  is not detected, CPU 23  loops between step S 200 -S 210  (repeats steps S 200 -S 210 ). This loop will be repeated until the access point intended in step S 210  is found. 
     Following explanation is based on A method of the simple connection setting which the CPU 23  distinguished with the acquired information. At first, CPU 23  instructs detection of the information output by the identified access point  50  in step S 230 . Then CPU 23  returns the information of the access point  50  recorded in step S 215  (step S 240 ). When the CPU 23  acquires the information from the beacon or the probe response, the CPU 23  identifies the connecting access point  50  (step S 245 ). When the connecting access point  50  is identified in step S 245 , connection setting between the access point  50  and the terminal  20  is decided and a decided value is output to OS 200  (step S 250 ). Furthermore, CPU 23  carries out connection setting with the identified access point  50  (step S 290 ). In step S 250 , CPU 23  does not instruct wireless LAN adapter  10  through device driver  201  detection of the information output by the access point  50  because CPU 23  makes decision based on the information recorded in RAM 25 . Hereby, it becomes possible to shorten time for simple connection setting without Wireless LAN adapter  10  detecting the information output by the access point  50 . 
     It is also true that when B method of the simple connection setting is chosen at step S 220 , the CPU 23  carries out the same flow as explained above at step S 260  to S 280 , and sets connection setting of wireless LAN in accordance with the B method of the simple connection setting. 
     Further, as shown in  FIG. 6  and  FIG. 7 , the CPU 23  may directly instruct a device driver  201 .  FIG. 7  shows a flow of device driver  201 . When CPU 23  records an information at step S 320  in  FIG. 6 , CPU 23  reads out the simple connection setting program  202  corresponding to the simple connection setting in step S 330 , and then instructs the device driver  201  in S 340 . If the information is recorded (steps S 400 ), the device driver  201  omits the second detecting operation by returning the result of the recorded information (step S 410 ) instead of giving an instruction to the wireless LAN adapter  10  to receive a beacon or a probe response (step S 420 ). In addition, if the access point intended for in S 310  is not detected, CPU 23  loops between step S 300 -S 310  until the access point is identified. When the CPU 23  acquires the information from the beacon or the probe response, the CPU 23  identifies the connecting access point  50  (step S 345 ). When the connecting access point  50  is identified in step S 345 , connection setting between the access point  50  and the terminal  20  is decided and a decided value is output to OS 200  (step S 350 ). Furthermore, CPU 23  carries out connection setting with the identified access point  50  (step S 380 ). 
     It is also true that when B method of the simple connection setting is chosen at step S 330 , the CPU 23  carries out the same flow as explained above at step S 360  to S 370 , and sets connection setting of wireless LAN in accordance with the B method of the simple connection setting. 
     (3) SUMMARY 
     As explained above, according to the wireless LAN system  100 , a program which corresponds each methods of simple connection setting is stored in the terminals  20 ,  30 ,  40  and the simple connection setting which the access point  50  adopts is detected by detecting an information output by the access point  50 . And the connection setting of the wireless LAN with the detected simple connection setting is carried out. Therefore, even if the access point  50  corresponds to what kind of simple connection setting, user may carry out connection setting between the access point  50  and the terminals  20 ,  30 ,  40  by an easy operation. 
     This invention is not limited to the embodiment explained above. 
     
         
         It is not to need to say if it is these skilled in the art. 
         Changing combination of any parts or elements which are replaceable with each other as described in the above embodiment appropriately, or 
         applying appropriately a change of combination of any parts or elements which are replaceable with each other and even though they are not disclosed in the above embodiment but are well known prior art, or 
         replacing any parts or elements which are available based on prior art by a person with ordinary skills with ones described in the above embodiment or applying a change of combination thereof are also described as an embodiment of this invention.