Patent ID: 8497765

Claim:
An apparatus for communicating with a radio frequency identification (RFID) tag, comprising; a radio communication device configured to conduct radio communication with a plurality of RFID tag circuit elements, each of the RFID tag circuit elements having an IC circuit part storing information and a tag antenna for transmission and reception of the information; a tag number estimation portion configured to estimate the number of said RFID tag circuit elements in a peripheral area of said apparatus; a storage device configured to store a list of identification information of each of a plurality of said RFID tag circuit elements as search targets; and a mode switching portion configured to switch a mode into a plural tag detection mode or a response determination mode on the basis of a estimation result by said tag number estimation portion, the plural tag detection mode being a mode in which identification information is sequentially specified in said list stored in said storage device before the RFID tag circuit element corresponding to the specified identification information is detected through said radio communication device, the response determination mode being a mode in which identification information is obtained from each of all the RFID tag circuit elements in said peripheral area through said radio communication device before presence of each of the RFID tag circuit elements respectively corresponding to the identification information in said list is determined on the basis of the obtained identification information, wherein said mode switching portion switches a mode into said plural tag detection mode in the case that the number of said identification information included in said list stored in said storage device is less than a predetermined first threshold value, said mode switching portion switches a mode into said response determination mode in the case that the number of said RFID tag circuit elements in said peripheral area estimated by said tag number estimation portion is less than a predetermined second threshold value and into said plural tag detection mode in the case that the number of said RFID tag circuit elements in said peripheral area estimated by said tag number estimation portion is not less than said second threshold value, said tag number estimation portion conducts communication for estimation with said RFID tag circuit elements in said peripheral area through said radio communication device and estimates the number of said RFID tag circuit elements in the peripheral area according to a communication result, and said mode switching portion is configured for switching a mode into a single tag detection mode in which communication for position detection for specific said RFID tag circuit element is conducted through said radio communication device and a position of the specific said RFID tag circuit element is detected on the basis of the communication result.