Magnetic sheet for radio frequency identification antenna, method of manufacturing the same, and radio frequency identification antenna using the same

Abstract

Provided are a magnetic sheet for use in a radio frequency identification (RFID) antenna, an RFID antenna including the magnetic sheet, and a method of manufacturing the magnetic sheet, in which the magnetic sheet includes an amorphous alloy selected from the group consisting of Fe—Si—B, Fe—Si—B—Cu—Nb, Fe—Zr—B and Co—Fe—Si—B. The magnetic sheet is made by laminating amorphous alloy ribbons made of an amorphous alloy between magnetic sheet layers formed of alloy powder including at least one amorphous alloy and then compression-molding the amorphous alloy ribbons, to thereby control microcrack of the amorphous alloy ribbons and enhance characteristic of an end-product. The magnetic sheet is also thin, and has an excellent magnetic permeability, and a simple manufacturing process.

1 . A magnetic sheet for a radio frequency identification (RFID) antenna comprising: 
 at least one amorphous alloy selected from the group consisting of Fe—Si—B, Fe—Si—B—Cu—Nb, Fe—Zr—B, and Co—Fe—Si—B.    
   
   
       2 . The magnetic sheet for a RFID antenna according to  claim 1 , wherein the amorphous alloy is heat-treated at the temperature of 300° C. to 600° C. for ten hours or less.  
   
   
       3 . The magnetic sheet for a RFID antenna according to  claim 1 , wherein the magnetic sheet comprises a mixture of at least two amorphous alloys selected from the group consisting of Fe—Si—B, Fe—Si—B—Cu—Nb, Fe—Zr—B, and Co—Fe—Si—B.  
   
   
       4 . The magnetic sheet for a RFID antenna according to  claim 1 , wherein a magnetic sheet layer made of a mixture of the amorphous alloy powder and a resin; and 
 an amorphous alloy ribbon which is laminated onto the magnetic sheet layer and comprising the at least one amorphous alloy.    
   
   
       5 . The magnetic sheet for a RFID antenna according to  claim 4 , wherein the amorphous alloy ribbon is made of a number of slit alloy ribbons.  
   
   
       6 . The magnetic sheet for a RFID antenna according to  claim 1 , wherein the magnetic sheet is 0.35 mm thick or less.  
   
   
       7 . A magnetic sheet for a RFID antenna comprising: 
 amorphous alloy powder including at least one kind of an amorphous alloy selected from the group consisting of Fe—Si—B, Fe—Si—B—Cu—Nb, Fe—Zr—B, and Co—Fe—Si—B; and    a resin for a binder mixed with the amorphous alloy powder in order to be molded into a sheet form.    
   
   
       8 . The magnetic sheet for a RFID antenna according to  claim 7 , wherein the amorphous alloy powder and the binder resin are mixed with a weight ratio in the range of 5:1 through 9:1.  
   
   
       9 . The magnetic sheet for a RFID antenna according to  claim 7 , wherein the binder resin is one selected from the group consisting of rubber, polyimide, polyamide, urethane, silicon, and phenol resin.  
   
   
       10 . A radio frequency identification (RFID) antenna comprising: 
 a magnetic sheet including at least one kind of an amorphous alloy selected from the group consisting of Fe—Si—B, Fe—Si—B—Cu—Nb, and Fe—Zr—B, and Co—Fe—Si—B;    an antenna coil which is patterned on the surface of an insulating layer using a conductive material; and    a bonding layer for bonding the magnetic sheet and the insulating layer.    
   
   
       11 . The RFID antenna according to  claim 11 , wherein a partially hardened prepreg resin is coated on at least one surface of the insulation layer.  
   
   
       12 . The RFID antenna according to  claim 11 , further comprising an amorphous alloy ribbon layer which is laminated on one surface of the insulating layer on which the partially hardened prepreg resin has been coated and is made of at least one kind of the amorphous alloy.  
   
   
       13 . The RFID antenna according to  claim 10 , further comprising an amorphous alloy ribbon layer which is laminated on the lower surface of the magnetic sheet and is made of at least one kind of the amorphous alloy.  
   
   
       14 . The RFID antenna according to  claim 13 , wherein the amorphous alloy ribbon layer comprises a plurality of slit alloy ribbons.  
   
   
       15 . The RFID antenna according to  claim 10 , wherein the antenna is built in a battery of a mobile phone.  
   
   
       16 . A multi-layered magnetic sheet for a radio frequency identification (RFID) antenna, the multi-layered magnetic sheet comprising: 
 first and second magnetic sheet layers made of alloy powder including at least one kind of an amorphous alloy selected from the group consisting of Fe—Si—B, Fe—Si—B—Cu—Nb, Fe—Zr—B, and Co—Fe—Si—B; and    a first amorphous alloy ribbon including at least one kind of the amorphous alloys and which is laminated between the first and second magnetic sheet layers.    
   
   
       17 . The multi-layered magnetic sheet for a radio frequency identification (RFID) antenna, further comprising: 
 a second amorphous alloy ribbon laminated on the surface of any one of the first and second magnetic sheet layers and made of one kind of the amorphous alloys; and    a third magnetic sheet layer which is laminated on the surface of the second amorphous alloy ribbon and manufactured with the alloy powder including at least one kind of the amorphous alloy.    
   
   
       18 . The multi-layered magnetic sheet for a radio frequency identification (RFID) antenna, according to  claim 16 , wherein the thickness of a multi-layered sheet is 0.2 mm or less.  
   
   
       19 . The multi-layered magnetic sheet for a radio frequency identification (RFID) antenna, according to  claim 16 , wherein the amorphous alloy has a grain size of a nanometer unit by heat treatment.  
   
   
       20 . The multi-layered magnetic sheet for a radio frequency identification (RFID) antenna, according to  claim 16 , wherein the amorphous alloy ribbon which is laminated between the first and second magnetic sheet layers has microcracks which occur by a compression-molding process.  
   
   
       21 . A magnetic sheet for a radio frequency identification (RFID), the RFID magnetic sheet comprising: 
 a plurality of magnetic sheet layers which is made of alloy powder including at least one kind of an amorphous alloy selected from the group consisting of Fe—Si—B, Fe—Si—B—Cu—Nb, and Fe—Zr—B, and Co—Fe—Si—B; and    a plurality of amorphous alloy ribbons which are made of at least one kind of the amorphous alloys and which are laminated between the plurality of magnetic sheet layers.    
   
   
       22 . A radio frequency identification (RFID) antenna comprising: 
 a multi-layered magnetic sheet including a plurality of magnetic sheet layers which is made of alloy powder including at least one kind of an amorphous alloy selected from the group consisting of Fe—Si—B, Fe—Si—B—Cu—Nb, and Fe—Zr—B, and Co—Fe—Si—B, and a plurality of amorphous alloy ribbons which are made of at least one kind of the amorphous alloys and which are laminated between the plurality of magnetic sheet layers;    an insulating layer formed on the surface of the magnetic sheet; and    an antenna coil pattern which is patterned on the surface of the insulating layer using a conductive material.    
   
   
       23 . The RFID antenna according to  claim 22 , wherein the antenna is built in a battery of a mobile phone.  
   
   
       24 . A method of manufacturing a magnetic sheet for a radio frequency identification (RFID) antenna, the magnetic sheet manufacturing method comprising the steps of: 
 mixing amorphous alloy powder including at least one kind of an amorphous alloy selected from the group consisting of Fe—Si—B, Fe—Si—B—Cu—Nb, Fe—Zr—B, and Co—Fe—Si—B and a resin for a binder; and    depositing the mixture on a base member in the form of a thin film and then drying the deposited base member, to thereby obtain a dried magnetic sheet from the base member.    
   
   
       25 . The method of manufacturing the magnetic sheet for the RFID antenna, further comprising the step of compression-molding the magnetic sheet.  
   
   
       26 . A method of manufacturing a magnetic sheet for a radio frequency identification (RFID), the magnetic sheet manufacturing method comprising the steps of: 
 preparing first and second magnetic sheet layers made of alloy powder including at least one kind of an amorphous alloy elected from the group consisting of Fe—Si—B, Fe—Si—B—Cu—Nb, Fe—Zr—B, and Co—Fe—Si—B;    preparing a first amorphous alloy ribbon made of one kind of the amorphous alloys; and    laminating the first amorphous alloy ribbon between the first and second magnetic sheet layers and then compression-molding the laminated multilayer magnetic sheet layer in order to increase a relative density of the laminated magnetic sheet layer and simultaneously form a microcrack on the first amorphous alloy ribbon.    
   
   
       27 . The method of manufacturing the magnetic sheet for the RFID, further comprising the steps of: 
 preparing a second amorphous alloy ribbon made of one kind of the amorphous alloys and a third magnetic sheet layer made of alloy powder including at least one kind of the amorphous alloys; and    before compression-molding the laminated magnetic sheet layer, laminating the second amorphous alloy ribbon on the surface of any one of the first and second magnetic sheet layers and laminating the third magnetic sheet layer on the surface of the second amorphous alloy ribbon.    
   
   
       28 . The method of manufacturing the magnetic sheet for the RFID, according to  claim 26 , wherein the step of compression-molding the laminated multilayer magnetic sheet layer can be executed by one of hot rolling, hot pressing, cold rolling, and cold pressing.  
   
   
       29 . The method of manufacturing the magnetic sheet for the RFID, according to  claim 26 , wherein the thickness of the compression-molded multi-layered magnetic sheet is 0.2 mm or less.  
   
   
       30 . The method of manufacturing the magnetic sheet for the RFID, according to  claim 26 , wherein the amorphous alloy is heat-treated at the temperature of 300° C. to 600° C. for ten hours or less.