English Translation for PCT..1P2006 '300633 SPECIFICATION
ACCESS APPARATUS AND ACCESS PROGRAM
TECHNICAL FIELD
[0001 ] The present invention relates to an access apparatus and an access program to access a communication device which is attached to a moving object. The present invention, for example, relates to a reader.'writer and an access program to access an 1C (Integrated Circuit) tag which is attached to a moving object.
BACKGROUND ART
[0002] A UHF-band (Ultra High Frequency band) RFID (Radio Frequency Identification)
reader writer is unable to output radio waves at all times due to problems with radio wave
interference, and is allowed to transmit radio waves only for a certain period of time after
performing carrier sense (checking if a radio wave is being used by others before
outputting its own radio wave).
[0003] As a result of carrier sense, if no other device is sending out a radio wave, the
reader'writer can access an 1C tag without regard for a timing to output a radio wave when
the 1C tag is not in motion at a time the reader/writer accesses the 1C tag.
[0004] However, when the IC tag is in motion, it is necessary' for the reader'writer to
output a radio wave at a timing when the IC tag is accessible (when the IC tag is in an area
within reach of a radio wave from an antenna of the readerwriteri. As a method for this
purpose, there is 2 method of combining a reader'writer with a sensor, wherein the
reader writer is coerated a: a timing when the sensor detects an IC tag. For example.

related arts are described as follows;
Patent Literature 1: Japanese Unexamined Patent Publication No. 2001-154647 Patent Literature 2: Japanese Unexamined Patent Publication No. 2000-25940
DISCLOSURE Of THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
[0005] However, ill the methods described in the related aits, there is a problem that when
an IC tag moves at a fast rate, the IC tag goes beyond an area within which it is accessible
from a reader'writer while carrier sense is being performed, and the reader/writer cannot
access the JC tag.
[0006] Explanation is made with reference to a time chart described in FIG 18. After a
trigger is input, carrier sense (1) is performed for a particular period of time. Then.
transmission of a tag access radio wave (2) is performed. At this time, when a time (Tl)
during which carrier sense is performed is long compared to a motion speed of an IC tag.
the IC tag misses the area within which it is accessible from the reader/writer.
[0007] In the present invention, by inputting a trigger, two operation timings are produced
and a reader/writer is activated.
MEANS TO SOLVE THE PROBLEMS [0008] There is provided according to one aspect of the present invention an access device including: a carrier sense request unit, whereto detection information is input from a detection device which detects, by being located at a prescribed position, a passage of a moving object moving with a communication device for performing communication upon being accessed attached thereto, and outputs the detection information indicating a result of detection, to output a career sense request signal which requests start of carrier sense by

using the detection information input as a trigger: an access instructing unit, whereto detection information the same as the detection information input to the carrier sense request unit is input from the detection device, to output an access instructing signal which instructs access to the communication device based on the detection information input; and a radio wave transmitting unit, whereto the carrier sense request signal output from the carrier sense request unit is input, to start carrier sense, and whereto the access instructing signal output from the access instructing unit is input, to. start a transmission of a radio wave which accesses the communication device.
[0009] Further, when the detection information is input into the access instructing unit, the access instructing unit outputs the access instructing signal based on the detection information input at a prescribed timing.
[0010] Further, when the detection information is input into the access instructing unit, the access instructing unit calculates a timing to output the access instructing signal based on the detection information input, and outputs the access instructing signal accordina to the timing calculated,
[0011] The access device further includes a timing information memory' unit to store timing information indicting a timing of when the access instructing unit outputs the access instructing signal, and when the detection information is input into the access instructing unit, the access instructing unit outputs the access instructing signal according to the timing information stored in the timing information memory unit.
[001 2] Further, when the radio wave transmitting unit determines that it is possible to transmit a radio wave by carrier sense, the radio wave transmitting unit transmits a reservation signal for reserving use of a radio wave until the access instructing signal crput from the access instructing unit is input into the radio wave transmitting unit. TOO 1 ? ] The access device further includes a pluraliy of antennas, and the radio wave

transmitting unit transmits a radio wave which accesses the communication device via each of the plurality of antennas.
[0014] Further, the carrier sense request unit, whereto the detection information is input from each of a plurality of detection devices which detect, by each being located at a prescribed position, a passage of a moving object moving with a communication device for performing communication upon being accessed attached thereto, and output the detection information indicating a result of detection, selects detection information output from a prescribed detection device from the detection information which is input respectively, and outputs the carrier sense request signal which requests start of carrier sense by using the detection information selected as a trigger, and
the access instructing unit, whereto detection information the same as the detection information selected by the carrier sense request unit is input from the prescribed detection device, outputs the access instructing signal which instructs access to the communication device based on the detection information input.
[0015] There is provided according to another aspect of the present invention an access device including: a carrier sense request unit, whereto detection information is input from a detection device which detects, by being located at a prescribed position, a passage of a moving object moving with a communication device for performing communication upon being accessed attached thereto, and outputs the detection information indicating a result of detection, to output a carrier sense request signal which requests start of carrier sense by using the detection information input as a trigger: and a radio wave transmitting unit, whereto the earner sense request signal output from the carrier sense request unit is input, to start carrier sense, and whereto an access instructing signal is input from an external device, TO start a transmission of a radio wave which accesses the communication device, wherein the extern;?. 1 device, whereto detection information ;he same ?s the

detection information input to the carrier sense request unit is input from the detection device, outputs the access instructing signal which instructs access to the communication device based on the detection information input.
[0016] There is provided according to another aspect of the present invention an access device including: a carrier sense request unit, whereto first detection information is input from a first detection device which detects, by being located at a prescribed position, a passage of a moving object moving with a communication device for performing communication upon being accessed attached thereto, and outputs the first detection information indicating a result of detection, to output a carrier sense request signal which requests start of carrier sense by using the first detection information input as a trigger; and a radio wave transmitting unit, whereto the carrier sense request signal output from the carrier sense request unit is input, to start carrier sense, and whereto second detection information is input from a second detection device, which detects, by being located at a position different from the first detection device, the passage of the moving object, and outputs the second detection information indicating a result of detection, to start a transmission of a radio wave winch accesses the communication device by using the second detection information input as a trigger.
[0017] There is provided according to another aspect of the present invention an access program which allows a computer to execute: a process to input detection information from a detection device which detects, by being located at a prescribed position, a passage of a moving object moving with a communication device for performing communication upon being accessed attached thereto, and outputs the detection information indicating a result of detection, and to output a carrier sense request signal which requests start of carrier sense by using the detection information input as a trigger: a process to input detection information the same as the detection information from the detection device, and

to output an access instructing signal which instructs access to the communication device based on the detection information input: and a process to input the carrier sense request signal output and start carrier sense, and to input the access instructing signal output and stan a transmission of a radio wave which accesses the communication device. [0018] There is provided according to another aspect of the present invention an access program which allows a computer to execute: a process to input detection information from a detection device which detects, by being located at a prescribed position, a passage of a moving object moving with a communication device for performing communication upon being accessed attached thereto, and outputs the detection information indicating a result of detection, and to output a carrier sense request signal which requests start of carrier sense by using the detection information input as a trigger; and a process to input the carrier sense request signal output and start carrier sense, and to input an access instructing signal from an external device and start a transmission of a radio wave which accesses the communication device, wherein the externa! device, whereto detection information the same as the detection information is input from the detection device, outputs the access instructing signal which instructs access to the communication device based on the detection information input.
[0019] There is provided according to another aspect of the present invention an access program which allows a computer to execute: a process to input first detection information from a first detection device which detects, by being located at a prescribed position, a passage of a moving object moving with a communication device for performing communication upon being accessed attached thereto, and outputs the first detection information indicating a result of detection, and to output a carrier sense request signal which requests sisn of carrier sense by using the first detection information input as a trigger: and e process to innut the carrier sense request signal output and star, earner cerise.

and to input second detection information from a second detection device which detects, by being located at a position different from the first detection device, the passage of the moving object, and outputs the second detection information indicating a result of detection, and start a transmission of a radio wave which accesses the communication device by using the second detection information input as a trigger.
EFFECTS OF THE INVENTION
[0020] According to the present invention, it is possible to access an IC tag attached to a
moving object reliably also at a time when carrier sense is required.
BEST MODE FOR CARRYING OUT THE INVENTION
[0021] Embodiment 1.
By using FIG. 1 through FIG 4. a description of the first embodiment is provided. The
first embodiment relates to a readerwriter which produces two operation timings by
inputting one trigger.
[0022] FIG 1 is a diagram illustrating a structure of an IC tag system 1000 according to the
first embodiment. In the IC tag system ] 000, a sensor 25 ( an example of a detection
device) connects to a reader/writer 23 (an example of an access device) through a sensor
control unit 26. Further, a control PC (Personal Computer) 24 as a control device to
control the reader/writer 23 connects to the reader/writer 23. The readerwriter 23 is
equipped with an antenna 27.
[0023] (Object 22 with an IC tag)
To an object 22 with an ]C tag (an example of a communication device), an IC tag 21 is
attached 2= shown in FIG. 1. The object with IC tag 22 is a moving object moving with
the IC tag 2 i attached thereto The object with IC tag 22 is. for example, r. package to be

carried by a conveyor belt.
[0024] flC tag 21)
The 1C tag 21 (communication device) communicates with the reader/writer 23 upon
access by the reader/writer 23.
[0025](Sensor 25)
The sensor 25 (detection device), which is placed at a particular position, detects a passage
of the object with IC tag 22, and outputs a result of detection as "detection information."
"Detection information'' includes a "trigger'' (or may be referred to as trigger information)
as information which indicates that the object with IC tag 22 has been detected, and
'•moving information'" including the position, the speed, etc. of the object with IC tag 22.
[0026] (Sensor control unit 26)
The sensor control unit 26 sends the "detection information" detected by the sensor 25 to
the reader''writer 23.
[0027] FIG 2 shows a structure of the reader/writer 23 in FIG 1. As shown in FIG. 2. the
reader/writer 23 is equipped with a command execution timing control unit 31 (an example
of a carrier sense request unit), a secondary trigger timing control unit 32 (an example of
an access instructing unit), a radio wave transmission and reception control unit 33 (an
example of a radio wave transmitting unit), and the antenna 27.
[0028] The detection information is input into the command execution timing control unit
31 (carrier sense request unit) from the sensor 25, and the command execution timing
control unit 31 outputs a carrier sense request signal to request start of carrier sense to the
radio wave Transmission and reception control unit 33, by using the input detection
information as a trigger.
[('029] Detection information the same as one input into the command execution timing
control linn 3i is input into the secondarx trigger timing control unit 32 ( access instructing

unit) from the sensor 25. and the secondary trigger timing control unit 32 outputs to the radio wave transmission and reception control unit 33 an access instructing signal which instructs access to the \C tag 21. based on the input detection information. [0030] The caixier sense request signal output from the command execution timing control unit 31 is input into the radio wave transmission and reception control unit 33 (radio wave transmitting unit), and the radio wave transmission and reception control unit 33 starts earner sense. At the same time, the access instructing signal output from the secondary trigger timing control unit 32 is input into the radio wave transmission and reception control unit 33, and the radio wave transmission and reception control unit 33 starts transmission of a tag access radio wave which accesses the IC tag 21. [0031] FIG. 3 is a flow chart describing operations in the IC tag system 1000. With reference to the flow chart in FIG. 3, a description is provided of operations at the time the reader writer 23 accesses the IC tag 21 wrhen the object with IC tag 22 is in motion. [0032] First, the control PC 24 issues a tag access command to the reader/writer 23 (SI01). The tag access command is input into the command execution timing control unit 31. [0033] The reader'writer 23 does not immediately proceed to the operation to output a radio wave in response to the command. The command execution timing control unit 31 holds a wait state (S102).
[0034] When detecting the object with IC tag 22, the sensor 25 outputs to the sensor control unit 26 the '"detection information" including the "trigger" as the information which indicates that the object with IC tag 22 is detected, and the "moving information'" including the position, the speed, etc. of the object with IC tag 22. Thus, at a time when the sensor 25 detects the object with JC tag 22. the sensor control unit 26 outputs the "detection information" {including the moving information which includes -he position and the speed i-of the obiect with IC tag 22. and the triggeri output from the sensor 25 to the

reader'writer 23 (S103).
[0035] The ''detection information' (the '"moving information" and the "trigger") input mto the reader'writer 23 is sent to the command execution timing control unit 31 and the secondary- trigger timing control unit 32 (SI04).
[0036] In response to the trigger, the command execution timing control unit 31 makes the radio wave transmission and reception control unit 33 start carrier sense (S105). That is. the command execution timing control unit 31, by outputting the carrier sense request signal as a signal which requests carrier sense to the radio wave transmission and reception control unit 33. makes the radio wave transmission and reception control unit 33 start carrier sense. When the carrier sense request signal is input into the radio wave transmission and reception control unit 33 from the command execution timing control unit 31. the radio wave transmission and reception control unit 33 starts carrier sense. [0037] At this time, the secondary trigger timing control unit 32 calculates a time for the object with IC tag 22 to reach a position of the antenna 27 based on the moving information included in the input detection information. Then, when it is time to reach the position, the secondary trigger timing control unit 32 outputs the access instructing signal which instructs access to the IC tag 21 to the radio wave transmission and reception control unit 33, and makes the radio wave transmission and reception control unit 33 access the IC tag 21 {SI06 and SI07).
[0038] A description is provided of when the secondary trigger timing control unit 32 calculates the time to reach the position of the antenna. The reader'writer 23 stores antenna position information indicating the position of the antenna 27 relative to the position of the sensor 25. in an information memory unit 34. The secondary trigger timing control unit 32 can calculate the time for the object with IC tag 22 to reach the position of the antenna 2" based on the detection information :the tn^Eier and the mo vine

information) from the sensor 25 and the antenna position information stored in the information memory unit 34. As it is described in the second embodiment below, since the time calculated by the secondary trigger timing control unit 32 differs according to the position of the antenna 27 relative to the position of the sensor 25, consideration of the position of the antenna makes it possible for the reader'writer 23 to reliably access the IC tag 21.
[0039] When the access instructing signal is input into the radio wave transmission and reception control unit 33. the radio wave transmission and reception control unit 33 sends out the tag access radio wave, and accesses the IC tag 21. As shown above, the secondary trigger timing control unit 32 calculates the timing to output the access instructing signal based on the moving information included in the input detection information, and outputs the access instructing signal according to the calculated timing. [0040] When in a case in which the object with IC tag 22 is carried by a conveyor belt moving with constant speed for example, a value of the timing calculated by the secondary trigger timing control unit 32 is the same for any objects: if it is 10 seconds, then it is 10 seconds for any objects. As in this case, when the time calculated by the secondary trigger timing control unit 32 is determined constant for any objects for any time, it is unnecessary to input the moving information (information of the position and the speed), and only necessary to input a trigger, and it is only necessary for the "detection information" to include the trigger. In this case, a value to be the same for any object, e.g., 10 seconds, is stored as "timing information.'" Then, when the detection information (which needs not include the moving information) is input into the secondary trigger timing control unit 32. the secondary trigger timing control unit 32 has onlv to output the access instructing signal based on the stored timing information to the radio wave transsmission and reception control unit 33. In FIG. 2. the information memory unit 34 'an

example of a timing information memory unit) stores the timing informaiion.
[0041] FIG 4 is a time chart showing contents of the flow chart in FIG. 3. By using the
time chart, a description of the contents as explained with FIG. 3 is provided.
[0042] First, an tag access command 41 is issued by the control PC 24.
[0043] Next, a trigger 42 (detection information) is input from the sensor 25.
[0044] (Command execution timing control unit 311
In response to the trigger 42, the command execution timing control unit 31 makes the
radio wave transmission and reception control unit 33 start carrier sense 43. Specifically,
as shown in FIG. 4, the command execution timing control unit 31. upon input of the
trigger 42, outputs a carrier sense request signal 51 to the radio wave transmission and
reception control unit 33 by using the trigger 42 as a trigger. The radio wave transmission
and reception control unit 33 starts the earner sense 43 upon input of the carrier sense
request signal 51.
[0045] (Radio wave transmission and reception control unit 33)
When the radio wave transmission and reception control unit 33 finishes the carrier sense
43 and obtains a right to output a radio wave, the radio wave transmission and reception
control unit 33 outputs a radio wave 44 (reservation signal) and continues reserving the
right to use a radio wave so as not to have a radio wave used by others. "Reservation of
the right to use a radio wave" is performed by a charge wave or a CW (Continuous Wave),
etc. A time T2 in FIG. 4 is a time calculated by the secondary trigger timing control unit
32. or the timing information stored in the timing information memory unit. After the
time T2 elapses, the secondary trigger timing control unit 32 outputs to the radio wave
transmission and reception control unit 33 the access instructing signal 52 which instructs
access to the 1C tag 21. The access instructing signal 52 is input into the radio wave
transmission and reception control unit 33. and from a point of time the access instructing

signal 52 is input, the radio wave transmission and reception control unit 33 sends out the tag access radio wave 45. Here, the time to output the radio wave for reservation of the right to use a radio wave, as shown in FIG. 4. is variable. Thus, after finishing carrier sense, when the access instructing signal 52 is input, the radio wave transmission and reception control unit 33 switches from transmission of a. charge wave or a CW for reservation of the right to use a radio wave, which has been output, to transmission of the tag access radio wave 45.
[0046] The object with IC tag 22 just reaches the position of the antenna 27 at this timing (timing of when the access instructing signal 52 is output), which enables the reader/writer 23 to access the IC tag 21. After access to the IC tag 21 is completed, the radio wave transmission and reception control unit 33 sends a return 46 of a command back to the command execution tirrung control unit 31.
[0047] Since the reader writer 23 of the first embodiment is equipped with the secondary trigger timing control unit 32. whereto the detection information the same as one input into the command execution timing control unit 31 is input from the sensor 25. to output the access instructing signal based on the input detection information, it is possible to control a timing to send out the tag access radio wave. Therefore, it is possible to reliably access the IC tag 21 in motion also in a case when carrier sense is required. [0048] In the reader/writer 23 of the first embodiment, the secondan.' trigger timing control unit 32. upon input of the detection information, calculates the timing to output the access instructing signal based on the input detection information, and outputs the access instructing signal based on the calculated timing. Thus, it is possible to reliably access the IC tag 21.
[0049] Since the reader writer 23 of the first embodiment is equipped with the information memon unit to store the timing information it is possible to reliably fucess the !C tag with

a simple structure.
[0050] In the reader'writer 23 of the first embodiment, the radio wave transmission and reception control unit 33 transmits the reservation signal to reserve the right to use a radio wave. Therefore, even when there is a time lag before the access instructing signal is output b\ the secondary trigger timing control unit 32 after earner sense is finished, it is possible to access the IC tag 21.
[0051] Embodiment 2.
By using FIG 5 through FIG 8, a description of the second embodiment is provided. The
second embodiment has a structure wherein the reader/writer 23 described in the first
embodiment includes a plurality of antennas. The radio wave transmission and reception
control unit 33 transmits tag access radio waves which access the IC tag 21 through each of
the plurality of antennas.
[0052] FIG. 5 illustrates a structure of an IC tag system 2001 according to the second
embodiment. In the IC tag system 2001. in comparison with the IC tag system 1000 in
FIG. 1. the reader/writer 23 includes two antennas 28 and 29. This shows a case wherein
the reader/writer 23 includes the antennas 28 and 29, as one example of a plurality of
antennas.
[0053] FIG. 6 is a diagram illustrating that a timing to output an access instructing signal
53 calculated by the secondary' trigger timing control unit 32 falls within the period of time
during which the carrier sense 43 is performed. As shown in FIG. 6. in a case in which a
number of other reader/writers, etc. exist and it takes time to resen'e the right to use a radio
wave, the period of time it takes to perform the carrier sense 43 becomes longer. In this
:ase. i; mav be possible that the secondary trigger timing control unit 32 cannot transmit
the 13.2 access radio wave within a time T3. which is calculated based on the triaeer

information. As shown in FIG. 6, in a case wherein the carrier sense 43 takes the time T3 or longer when a time calculated based on the moving information by the secondary trigger timing control unit 32 is the time T3. even though the tag access radio wave 45 is output thereafter, the object with IC tag 22 goes beyond a communication area of an antenna and it is impossible to access the IC tag 21.
[0054] In this case, as shown in FIG. 5. the plurality of antennas 28 and 29 are installed A time calculated based on the moving information by the secondary trigger timing control unit 32 differs depending on a position of an antenna from a position of an object detected by the sensor 25 as described in the first embodiment, by changing a distance between the sensor 25 and the antenna, the time calculated by the secondary trigger timing control unit 32 also changes.
[0055] A time (a time calculated by the secondary trigger timing control unit 32) it takes to get to the antenna 28 at a nearer position from the sensor 25 is the time T3 shown in FIG 7 A time (a time calculated by the secondary trigger timing control unit 32) it takes to get to the antenna 29, which is located at a position farther from the sensor 25 than the antenna 28 is a time T4 shown in FIG. 7. In this case, even when the reader'writer 23 cannot access the IC tag 21 via the antenna 28. the reader/writer 23 can access the IC tag 21 via the antenna 29.
[0056] A specific description is now provided. As described in the explanation of FIG 2, in the reader'writer 23. the detection information is input into the command execution timing control unit 3 I from the sensor 25. and the command execution timing control unit 31 outputs the carrier sense request signal by using the input detection information as a trigger. Further, the detection information the same as one input into the command executor, timing control unk 3! is input into the secondary trigger timing control unit 32. ?."d the ^ec.-iniE!'"v tricser timine control unit 32 outputs the access instrnctine signal based

on the input detection information. In a case of FIG. 7. the secondary trigger timing control unit 32 calculates the time T3 based on the position of the antenna 28 relative to the position of the sensor 25. and the moving information included in the detection information. Further, the secondary trigger timing control unit 32 calculates the time T4 based on the position of the antenna 29 relative to the position of the sensor 25. and the moving information included in the detection information in the same way. The secondary trigger timing control unit 32 outputs an access instructing signal 54 to the radio wave transmission and reception control unit 33 at a time the time T3 elapses. Since the radio wave transmission and reception control unit 33 is performing carrier sense at the time the access instructing signal 54 is output, the radio wave transmission and reception control unit 33 continues performing the carrier sense 43 without responding to the access instructing signal 54. Further, the secondary trigger timing control unit 32 outputs an access instructing signal 55 to the radio wave transmission and reception control unit 33 at a time the time T4 elapses. At the time the access instructing signal 55 is output, the radio wave transmission and reception control unit 33 has finished carrier sense, and is in execution of the resen'ation of the right to use a radio wave, sending out the radio wave 44. Therefore, the radio wave transmission and reception control unit 33 starts transmission of the tag access radio wave 45 in response to the access instructing signal 55. [0057] As shown above, it is possible to access the IC tag in more reliable manner by installing a plurality of antennas when it takes time to reserve the right to use a radio wave (carrier sense) due to other reader'writers, etc. In the present embodiment, an example is shown wherein a plurality of antennas are installed in one reader/writer. However, as in the IC tag system 2002 illustrated in FIG. 8. it is also the same in a case of installing a nlurahtv of reader 'wniers 23a and 23 b for the sensor 25. Structures of the reader'writers

detection information is output from the sensor 25. in the reader'writer 23a, a secondary trigger timing control unit 32a outputs the access instructing signal 54 in FIG. 7 at a timing shown in the diagram. In the reader/writer 23b. a secondary trigger timing control unit 32b outputs the access instructing signal 55 in FIG. 7 at a timing shown in the diagram. [0058] The reader-writer 23 in the second embodiment includes a plurality of antennas, and the radio wave transmission and reception control unit 33 transmits tag access radio waves which access an IC tag via each of the plurality of antennas. Therefore, it is possible to access the IC tag by a tag access radio wave transmitted from any of the antennas.
[0059] Embodiment 3.
By using FIG. 9, a description of the third embodiment is provided. FIG, 9 is a diagram describing a structure of an IC tag system 3000 according to the third embodiment. In the IC tag system 3000 when compared with the IC tag system 1000 in FIG 1 described in the first embodiment, the reader/writer 23 is further connected to a sensor 25a via a sensor control unit 26a.
[0060] The IC tag system 3000 in the third embodiment is an embodiment based on the assumption that the objects with IC tag 22 and 22a are moving from plural directions (different directions). As shown in FIG.. 9, by installing a plurality of sensors such as the sensor 25 along with the sensor control unit 26 and the sensor 25a along with the sensor control unit 26a. it deals with a case when directions from which objects move are not constant (when the objects move from plural and different directions). In FIG. 9. the reader/writer 23 is provided a plurality of trigger inputs (detection information inputs). However, processes inside the reader'writer 23 are the same as those in the reader'writer 23 ir. FIG. 2 of the first embodiment. The reader writer 23 enables either cf the triggers (detection information i at a time o* us operation 'for example, a trigger input eariier'L and

operates by the information. This makes the reader'writer 2? to operate in the same wav as in the reader'writer 23 in FIG. 2. The operations are as follows. [0061] Detection information including triggers from each of the plurality of sensors 25 and 25a is input into the command execution timing control unit 31. and the command execution timing control unit 31 selects detection information output from a certain sensor from both the input detection information. The "certain sensor" is. for example, "the sensor which has output detection information earlier" as stated above. In FIG. 9. it is assumed that the sensor 25a outputs detection information earlier, and a trigger a is input into the reader/writer 23 earlier than a trigger from the sensor 25. fn this case, the command execution timing control unit 31 selects the detection information (including the trigger a | output by the sensor 25a. The command execution timing control unit 31 outputs a carrier sense request signal to the radio wave transmission and reception control unit 33 by using the selected detection information as a trigger. Detection information (trigger a) the same as the detection information selected by the command execution timing control unit 31 is input into the secondary trigger timing control unit 32 from the sensor 25a, and the secondary trigger timing control unit 32 outputs an access instructing signal based on the input detection information.
[0062] As shown above, it is possible for the reader/writer 23 to access the IC tag 21a attached to the object with IC tag 22a also in a case when the object with IC tag 22a moves from a different direction from the object with IC tag 22.
[0063] In FIG 9. there are two sets of sensors and sensor control units, which is no more titan an example. By increasing the sets of the sensors and the sensor control units more. it is possible to handle a situation where objects move from other directions. [006-1 ir, the third embodiment, detection information of any sensor of a plurality of sensors is input into the reader writer 2?. and the reader'writer 23 performs operations of

carrier sense and transmission of a tag access radio wave based on the detection information. Thus, it is possible to access IC tags attached to objects moving from different directions.
[0065] Embodiment 4.
By using FIG. 10. a description of the fourth embodiment is provided. The fourth embodiment is an embodiment wherein an external device 40 includes the secondary trigger timing control unit 32. which is included in the reader/writer 23 in FIG. 2. [0066] FIG. 10 shows a structure of an IC tag system 4000 according to the fourth embodiment. In the first to third embodiments, the reader'writer 23 includes the secondary trigger timing control unit 32. Ln comparison with this, in the IC tag system 4000 according to the fourth embodiment, the secondary trigger timing control unit 32 is externally provided in another external device 40. Thus, the IC tag system 4000 has a structure that the external device 40 includes the secondary trigger timing control unit 32. which is included in the reader/writer 23 compared to the IC tag system 1000 in the first embodiment. Therefore, when the reader/writer is seen with inclusion of the external device 40, the IC tag system 4000 is similar to the IC tag system 1000. [0067] As shown in FiG. 10. the secondary trigger timing control unit 32 is included in another external device 40. which is externally provided. A reader'writer 39 in this case includes two trigger input terminals of a primary trigger input terminal 14 and a secondary-trigger input terminal 15 as the reader'writer 39 in the fifth embodiment to be explained below. Operations in the IC tag system 4000 is the same as those in the IC tag svstem 1000 in the first embodiment. The operations of the reader'writer in the IC tag svstem ■±000 are as follows. [0068] Detection information is input into the command execution timing control unit 31

from the .sensor 25. and the command execution timing control unit 31 outputs a earner sense request signal by using the input detection information as a trigger. Detection information the same as one input into the command execution timing control unit 31 is input into the external device 40 from the sensor 25, and the external device 40 outputs an access instructing signal based on the input detection information. The carrier sense request signal outpui from the command execution timing control unit 3 1 is input into the radio wave transmission and reception control unit 33, and the radio wave transmission and reception control unit 33 starts earner sense. At the same time, the access instructing signal is input into the radio wave transmission and reception control unit 33 from the external device 40. and the radio wave transmission and reception control unit 33 starts transmission of an access radio wave which accesses an IC tag. [0069] Since the access instructing signal is input into the radio wave transmission and reception control unit 33 from the external device, it is possible to make a structure of the reader'writer 39 in the fourth embodiment simple.
[0070] Embodiment 5.
By using FIG. 11 through FIG. 13, a description of the fifth embodiment is provided. The fifth embodiment is an embodiment wherein the first detection information and the second detection information are input into a reader/writer, and the reader'writer generates a carrier sense request signal from the first detection information, and generates an access instructing signal from the second detection information. In the first through fourth embodiments, descriptions are made of the reader/writer which generates two operating timings based on a trigger output from one sensor, whereas in the fifth embodiment, a description is made of a reader writer which generates operating timings from each of two different r-ie^ inputs..

[0071] FIG. 11 shows a structure of an IC tag system 5000 according to the fifth embodiment. FIG. 12 is a diagram describing an internal structure of the readerwriter .39 in FIG 11.
[0072] As shown in FIG. 11. the IC tag system 5000 in the fifth embodiment shows an example wherein two sets consisting of a set of a sensor 1 (35) and a sensor control unit 36. and a set of a sensor 2 (37/ and a sensor control unit 38 are provided, in comparison with the IC tag system 1000 in the first embodiment. It is the same as the IC tag system 3000 shown in FIG. 9 according to the third embodiment in that it includes two sets of sensors and sensor control units. However, in the IC tag system 5000 in FIG. 11. the reader/writer 39 does not include the secondary trigger timing control unit 32 as shown in FIG. 12. Further, the external device as in the fourth embodiment does not exist. That is. the IC tag system 5000 according to the fifth embodiment is different fi-om the first through fourth embodiments in thai the secondary trigger timing control unit 32 does not exist. Therefore, it is only necessary for detection information to be output from the sensor to include only a trigger.
[0073] A brief explanation of operations of the reader writer 39 in the fifth embodiment is provided.
(1) A trigger (hereinafter referred to as a primary trigger, which is an example of the first detection information) from the sensor 1 (35) (an example of the first detection device) is input into the command execution timing control unit 31 of the reader/writer 39. and the command execution timing control unit 31 outputs a carrier sense request signal to the radio wave transmission and reception control unit 33 by using the input primary trigger as a trigger. The radio wave transmission and reception control unit 33 starts earner sense when the earner sense request signal is input into the radio wave transmission and reception control tmn 33

(2)'Further. a trigger (hereinafter referred to as a secondary trigger, which is an example of the second detection information) from the sensor 2 (37) (an example of the second detection device) located adjacent to the antenna 27 is input into the radio wave transmission and reception control unit 33. and the radio wave transmission and reception control unit 33 sends out a tag access radio wave by using the input secondary trigger as a trigger.
[0074] A description is provided of specific operations of the reader/writer 39 in the 1C tag system 5000.
[0075] The sensor 1 (35) is located at the same position as in FIG. 1 according to the first embodiment. The sensor 2 (37) is located at an approximately the same position (adjacent to the antenna 27) as the antenna 27. A trigger from the sensor 1 (35) is input as the primary trigger, and a trigger from the sensor 2 (37) is input as the secondary trigger into the readerwnter 39. As shown in FIG. 12. the primary trigger is input into the command execution timing control unit 31. and the secondary trigger is input into the radio wave transmission and reception control unit 33.
[0076] Two types of triggers of the primary trigger and the secondary trigger are input into the reader/writer 39. In this case, the reader'writer 39 is different from the reader'writer 23 whose structure is shown in FIG. 2 in that the reader/writer 39 does not need the secondary trigger timing control unit 32.
[0077] FIG 13 is a time chart describing operations of the reader/writer 39. In FIG 7. the radio wave transmission and reception control unit 33 switches from reservation of the right to use a radio wave by sending out the radio wave 44 to transmission of the tag access radio wave 45 at an input timing of an access instructing signal output b\ the secondary :rigger timing control unit 32. Meanwhile in FiG. i 3. it is different in that the radio wave Tarismission and reception control unit 33 switches from reservation cf the right to use a

radio wave by sending out the radio wave 44 to transmission of the tag access radio wave
45 at an input timing of the secondary trigger.
[0078] As shown in the second embodiment, when a plurality of antennas exist, the similar
operations are possible by providing sensors to each antenna, and providing a plurality of
trigger inputs to the reader/writer 39.
[0079] In the readerwriter 39 according to the fifth embodiment, since the secondary
trigger is input into the radio wave transmission and reception control unit 33 from the
second sensor, it is possible to make the structure of the reader'writer 39 simple.
[0080] Embodiment 6.
By using FIG. 14 through FIG, 17. a description of the sixth embodiment is provided. The sixth embodiment is an embodiment wherein the operations of the reader/writer described in the first embodiment, the fourth embodiment and the fifth embodiment are executed by a program and a recording medium storing a program.
[0081] In the first embodiment (FIG. 2); the fourth embodiment (FIG. 10) and the fifth embodiment (FIG. 12). a sequence of the operations of each component indicated as ".. unit" in the reader/writer are related to one another, and the sequence of the operations can be replaced by processes by a program executed by a computer. By replacing the operations of each component with processes by the program, this embodiment can be regarded as an embodiment of an "access program,'' Further, by storing the "access program'" mto a computer-readable recording medium, this embodiment can be regarded as an embodiment of a computer-readable recording medium recording a program. Further, an access program described below with reference IO FIG. 14 through FIG. 16 can be considered as an invention of an "access method" by replacing a "process to ." with a
"step !:■

[0082] FIG. 14 is a flow chart wherein a sequence of the operations of the command execution timing control unit 31. the secondary trigger timing control unit 32 and the radio wave transmission and reception control unit 33 of the reader/writer 23 according to the first embodiment indicated in FIG. 2 are replaced by a sequence of processes to be executed by a computer, to make this embodiment to be considered as an embodiment of an "access program.'"
[0083] Step S201 is a process to input detection information from a sensor which detects a passage of an object (moving body) moving with an IC tag attached thereto by being located at a prescribed position, and outputs the detection information, and to output a carrier sense request signal by using the input detection information as a trigger. This process corresponds to the operation of the command execution timing control unit 31. [0084] Step S202 is a process to input detection information the same as the detection information from the sensor, and to output an access instructing signal which instructs access to the IC tag based on the input detection information. The process corresponds to the operation of the secondary trigger timing control unit 32.
[0085] Step S203 is a process to start carrier sense by inputting the output carrier sense request signal and to start transmission of a tag access radio wave which accesses the IC tag by inputting the output access instructing signal. The process corresponds to the operation of the radio wave transmission and reception control unit 33. [0086] FIG. 15 is a flow chart wherein the operation of the command execution timing control unit 31 and the operation of the radio wave transmission and reception control unit 33 of the reader'writer 39 according to the fourth embodiment as shown in FIG. 10 are replaced by processes.
[0087] Step 5301 is s process to input detection information from a sensor which detects a passage of an obiect s moving bodyi moving wiih an !C tag attached tneretc by being

located at a prescribed position, and outputs the detection information, and to output a carrier sense request signal by using the input detection information as a trisser. [0088] Step S302 is a process to start carrier sense by inputting the output carrier sense request signal, and to start transmission of a tag access radio wave which accesses the 1C tag by inputting an access instructing signal from an external device, whereto detection information the same as the detection information is input from the sensor, for outputtmg the access instructing signal which instructs access to the JC tag based on the input detection information.
[0089] FIG. 16 is a flow chart wherein the operation of the command execution timing control unit 31 and the operation of the radio wave transmission and reception control unit 33 of the readerwriter 39 according to the fifth embodiment shown in FIG. 12 are replaced by processes.
[0090] Step S401 is a process to input a primary trigger from the first sensor (the first detection device) which detects a passage of an object (moving body) moving with an 1C tag attached thereto by being located at a prescribed position, and outputs the primary trigger (the first detection information), and to output a carrier sense request signal by using the input primary- trigger as a trigger.
[0091] Step S402 is a process to start carrier sense by inputting the output carrier sense request signal, and to start transmission of a tag access radio wave to access the IC tag by using a secondary trigger input as a trigger, by inputting the secondary trigger from the second sensor (the second detection device) which detects the passage of the object by beins located at a different position from the first sensor, and outputs the secondary trigger (the second detection information).
[00921 The embodiment of the program and the embodiment of the computer-readable recording medium recording the program can be all configured by a program operable on a

computer.
[0093] FIG. 17 is a hardware configuration diagram of a computer system 800 which
executes the program (a sequence of the processes) shown in the flow charts of FIG. 14
throughFIG 16. In FIG 17, the computer system 800 includes a Central Processing Unit
(CPU) 810 to execute a program. The CPU 810 connects with a ROM 811, a RAM 812.
a communication unit 813. and a nonvolatile memory 820 (for example, a flash memory)
via a bus 825.
[0094] The nonvolatile memory 820 stores an operating system (OS) 821, a group of
programs 823, and a group of files 824.
[0095] The group ofprograms 823 are executed by the CPU 810 and the OS 821.
[0096] The group of programs 823 include an "access program." etc. to execute functions
described as''.. unit" in the reader/writer of the first through fifth embodiments.
[0097] Further, as the group of files 824. the "timing information" or the '^antenna position
information" as described in the first embodiment are stored in a file format.
[0098] It is acceptable to have the functions described as ".. unit" in the reader/writer of
the first through fifth embodiments realized by a firmware stored in the ROM 811.
Alternatively, it is also acceptable to have the functions executed only by software or
hardware, or by software in combination with hardware, or farther in combination with
firmware.
[0099] Each process in the embodiment of the program and the embodiment of the
computer-readable recording medium recording a program can be executed by programs.
which are stored as the group of programs 823 as shown above. Then, each program of
the group of programs 823 is read by the CPU 810, and the CPU 8 10 performs each
process.
["0; 00"1 Further, software or orosranis can be executed b\" firmware sirred ci the ROM 8!)

Alternatively: it is acceptable to execute programs by a combination of software, firmware
and hardware.
[0101] The access program shown in FIG. 14 makes a computer execute the process to
input the detection information from the sensor 25, and to output the access instructing
signal based on the input detection information. Therefore, it is possible to control a
transmission timing of the tag access radio wave, and to reliably access the 1C tag 21 in
motion.
[0102] The access program shown in FIG. 15 makes a computer execute the process to
input the access instructing signal from the external device and to transmit the tag access
radio wave. Therefore, it is possible to reliably access the IC tag 21 in motion.
[0103] The access program shown in FIG. 16 makes a computer execute the process to
input the second detection information from the second sensor, and to transmit the tag
access radio wave by using the input second detection information as a trigger. Therefore.
it is possible to reliably access the IC tag 21 in motion.
[0104] In the above-mentioned embodiments, the description is provided of the
reader/writer which performs transmission and reception with an IC tag. which operates at
two timings of the first operation and the second operation in response to input of external
triggers.
[0105] In the above-mentioned embodiments, the description is provided of the
reader/writer which calculates the second operating timing based on information input into
itself.
[0106] In the above-mentioned embodiments, the description is provided of the
readerwmer which performs the process to obtain the right to use a radio wave at the first
ooeratins Limine.

provided a plurality of trigger inputs for performing the first operation.
[0108] In the a hove-mentioned embodiments, it is explained the reader'writer which is
provided a trigger input for performing the second operation, and which performs the
second operation by external and different trigger timing.
[0100] In the above-mentioned embodiments, it is explained the readerwriter which is
provided a plurality of trigger inputs for performing the second operation.
[0110] In the above-mentioned embodiments, the description is provided of the
readerwriter which has the process to calculate the second operating timing outside itself.
BRIEF DESCRIPTION OF THE DRAWINGS
[0111]
[FIG. 1] A structure of the IC tag system 1000 according to the first embodiment.
[FIG 2] A structure of the reader writer 23 according to the first embodiment.
[FIG. 3] A flow chart showing the operations in the IC tag system 1000 according to the
first embodiment.
[FIG 4] A time chart showing the operations in the IC tag system 1000 according to the
first embodiment.
[FIG. 5] A structure of the IC tag system 2001 according to the second embodiment.
[FIG. 6] A time chart showing the operations in the IC tag system 2001 according to the
second embodiment.
[FIG. 7] A time chart showing the operations in the IC tag system 2001 according to the
second embodiment.
[FIG. 8] A structure of the IC tag system 2002 according to the second embodiment.
1FIG ,J' A 3truc:ure of the iC :~2 svstem 3000 according to the third embodiment.

[FIG. 11] A structure of the IC tag system 5000 according to the fifth embodiment.
[FIG. 12] A structure of the reader writer 39 according to the fifth embodiment.
[FIG. 13] A time chart showing the operations in the IC tag system 5000 according to the
fifth embodiment.
[FIG. 14] A flow chart of the access program according to the sixth embodiment.
[FIG 15] A flow chart of the access program according to the sixth embodiment.
[FIG 16] A flow chart of the access program according to the sixth embodiment.
TIG. 17] A hardware structure of the computer system 800 according to the sixth
;mbodiment.
FIG. 18] A time chart showing a conventional art.
EXPLANATION OF REFERENCES
^0112] 1 Carrier sense. 2 Transmission of tag access radio wave. 1 i Command interface :erminal. 12 Trigger input terminal. 13 Antenna terminal. 14 Primary trigger input terminal. 15 Secondary trigger input terminal 21 IC tag, 22 Object with IC tag, 23 Reader'writer. 24 Control PC. 25 Sensor. 26 Sensor control unit. 27, 28. 29 Antenna. 31 Command execution timing control unit. 32 Secondary trigger timing control unit, 33 Radio wave transmission and reception control unit, 34 Information memory unit, 35 Sensor 1, 36 Sensor control unit, 37 Sensor 2. 38 Sensor control unit. 39 Reader/writer. 40 External device. 41 Command. 42 Trigger. 43 Carrier sense. 44 Radio wave. 45 Tag access radio wave, 46 Return. 47 Secondary trigger. 51 Carrier sense request signal. 52, 53. 54. 55 Access instructing signal, 800 Computer system. 81 D CPU. S) 1 ROM. 812 RAM, 813 Communication unit. 820 Nonvolatile memory. 821 OS. 823 Group of programs. 824 Group cf fiies. 1000. 2001. 2002. 3000. 4000. 5000 IC tag system.

CLAIMS
1. An access device comprising:
a carrier sense request unit, whereto detection information is input from a detection device which detects, by being located at a prescribed position, a passage of a moving object moving with a communication device for performing communication upon being accessed attached thereto, and outputs the detection information indicating a result of detection, to output a earner sense request signal which requests start of carrier sense by using the detection information input as a trigger;
an access instructing unit, whereto detection information the same as the detection information input to the carrier sense request unit is input from the detection device, to output an access instructing signal which instructs access to the communication device based on the detection information input; and
a radio wave transmitting unit, whereto the carrier sense request signal output from the carrier sense request unit is input, to start carrier sense, and whereto the access instructing signal output from the access instructing unit is input, to start a transmission of a radio wave which accesses the communication device.
2. The access device as defined in claim 1. wherein
when the detection information is input into the access instructing unit, the access instructing unit outputs the access instructing signal based on the detection information input at a prescribed timing.
3. The access device as defined in claim 2. wherein
when the detection information is input into the access instructing unit the access

instructing unit calculates a timing to output the access instructing signa] based on the detection information input, and outputs the access instructing signal according to the timing calculated.
4. The access device as defined in claim 2. further comprising
a timing information memory unit to store timing information indicting a timing of when the access instructing unit outputs the access instructing signal,
wherein when the detection information is input into the access instructing unit, the access instructing unit outputs the access instructing signal according to the timing information stored in the timing information memory unit.
5. The access device as defined in claim 1. wherein
when the radio wave transmitting unit determines that it is possible to transmit a radio wave bv carrier sense, the radio wave transmitting unit transmits a reservation signal for reserving use of a radio wave until the access instructing signal output from the access instructing unit is input into the radio wave transmitting unit.
6. The access device as defined in claim 1, further comprising
a plurality of antennas.
wherein the radio wave transmitting unit transmits a radio wave which accesses the communication device via each of the plurality of antennas.
7. The access device as defined in claim 1. wherein
the carrier sense request unit, whereto the detection information is input from each of a plura;ity of devices which detect by each being located a prescribed pesition.

a passage of a moving object moving with a communication device for performing communication upon being accessed attached thereto, and output the detection information indicating a result of detection, selects detection information output from a prescribed detection device from the detection information which is input respectively, and outputs the carrier sense request signal which requests start of carrier sense by using the detection information selected as a trigger, and wherein
the access instructing unit, whereto detection information the same as the detection information selected by the carrier sense request unit is input from the prescribed detection device, outputs the access instructing signal which instructs access to the communication device based on the detection information input.
8. An access device comprising:
a carrier sense request unit, whereto detection information is input from a detection device which detects, by being located at a prescribed position, a passage of a moving object moving with a communication device for performing communication upon being accessed attached thereto, and outputs the detection information indicating a result of detection, to output a carrier sense request signal which requests start of carrier sense by using the detection information input as a trigger; and
a radio wave transmitting unit.
whereto the carrier sense request signal output from the carrier sense request unit is input, to start carier sense, and
whereto an access instructing signal is input from an external device, to start a transmission of a radio wave which accesses the communication device, wherein the external device, whereio detection information the same as the detection information input to the carrier sense request unit is input from the detection device, outputs the access

instructing signal which instructs access to the communication device based on the detection information input.
9. An access device comprising:
a carrier sense request unit, whereto first detection information is input from a first detection device which detects, by being located at a prescribed position, a passage of a moving object moving with a communication device for performing communication upon being accessed attached thereto, and outputs the first detection information indicating a result of detection, to output a carrier sense request signal which requests start of carrier sense by using the first detection information input as a trigger; and
a radio wave transmitting unit,
whereto the carrier sense request signal output from the carrier sense request unit is input, to start carrier sense,
and whereto second detection information is input from a second detection device, which detects, bv being located at a position different from the first detection device, the passage of the moving object, and outputs the second detection information indicating a result of detection, to start a transmission of a radio wave which accesses the communication device by using the second detection information input as a trigger.
10. An access program which allows a computer to execute:
a process to input detection information from a detection device which detects, by being located at a prescribed position, a passage of a moving object moving with a communication device for performing communication upon being accessed attached
therein. and cutouts the detection information indicating a result of deiecnon. and to output a carrier sense request signal which recmests starti of carrier sense by usirg the detection

information inpul as a trigger;
a process to input detection information the same as the detection information from the detection device, and to output an access instructing signal which instructs access to the communication device based on the detection information input; and
a process to inpur the carrier sense request signal output and start carrier sense, and to input the access instructing signa! output and start a transmission of a radio wave which accesses the communication device.
11. An access program which allows a computer to execute;
a process to input detection information from a detection device which detects, by being located at a prescribed position, a passage of a moving object moving with a communication device for performing communication upon being accessed attached thereto, and outputs the detection information indicating a result of detection, and to output a carrier sense request signal which requests start of carrier sense by using the detection information input as a trigger; and
a process to input the carrier sense request signal output and start carrier sense, and to input an access instructing signal from an external device and start a transmission of a radio wave which accesses the communication device, wherein the external device, whereto detection information the same as the detection information is input from the detection device, outputs the access instructing signal which instructs access to the communication device based on the detection information input.
12. An access program which allows a computer to execute:
a process to input first detection information from a first detection device which selects by beings a prescribed positiion a prescribed position, a parage of a novtnig obiect moving

with a communication device for performing communication upon being accessed attached thereto, and outputs the first detection information indicating a result of detection, and to output a carrier sense request signal which requests start of carrier sense by using the first detection information input as a trigger: and
a process to input the carrier sense request signal output and start carrier sense, and to input second detection information from a second detection device which detects, by being located at a position different from the first detection device, the passage of the moving object, and outputs the second detection information indicating a result of detection, and start a transmission of a radio wave which accesses the communication device by using the second detection information input as a trigger.