Antenna loop configuration for more efficiently surrounding the high intensity area of the magnetic field produced by an IC card

Patent metadata

Field	Value
Publication number	US-9870493-B2
Application number	US-201515529081-A
Country	US
Kind code	B2
Filing date	Nov 18, 2015
Priority date	Nov 25, 2014
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

A communication device including a device-side antenna 30 for wireless communication with an IC card 10 including a card-side antenna 11 wound in a rectangular form. The antenna 30 is formed in one or multiple loops. During the wireless communication with the IC card 10 having an inner perimeter with a long dimension of 69 mm and a short dimension of 38 mm at a distance of 25 mm, an inner perimeter of the antenna 30 is formed at a position at which intensity H of a magnetic field produced by the card-side antenna 11 in a direction perpendicular to a surface on which the antenna 30 is disposed is in a range expressed by inequation (1):

0.037 I /4Π< H <0.063 I /4Π  (1)

where I is a current of the card-side antenna [A] and Π is pi.

First claim

The invention claimed is:

1. A communication device comprising a device-side antenna for wireless communication with an IC card including a card-side antenna wound in a rectangular form, wherein
the device-side antenna formed in one or multiple loops, and
during the wireless communication with the IC card having an inner perimeter with a long dimension of 69 mm and a short dimension of 38 mm at a distance of 25 mm, an inner perimeter of the device-side antenna is formed at a position at which intensity H of a magnetic field produced by the card-side antenna in a direction perpendicular to a surface on which the device-side antenna is disposed is in a range expressed by inequation (1):
0.037 I/ 4Π< H< 0.063 I/ 4Π  (1)

where I is a current of the card-side antenna and Π is pi.

2. The communication device according to claim 1 , wherein the inner perimeter of the device-side antenna is formed at a position at which the intensity H of the magnetic field is in a range expressed by inequation (2):
0.046 I/ 4Π< H< 0.06 I/ 4Π  (2).

3. The communication device according to claim 1 , wherein the inner perimeter of the device-side antenna is formed at positions where the intensity H of the magnetic field at one of the positions is equal to the intensity H at another one of the positions.

4. A display device comprising:
the communication device according to claim 1 ;
a lighting device for emitting light; and
a display device including a display portion for displaying an image with the light emitted by the lighting device and transmitted through the device-side antenna.

5. The display device according to claim 4 , further comprising a bezel holding an edge portion of the display device from a front side, wherein a portion of the device-side antenna is formed in an area covered with the bezel from the front side.

6. A communication system comprising:
the IC card; and
the communication device according to claim 1 .

Assignees

• Sharp Kk

Inventors

• Yashiro Yuhji
• Ogawa Hiroyuki
• Sugita Yasuhiro

Classifications

• G06Q20/105

  involving programming of a portable memory device, e.g. IC cards, "electronic purses" · CPC title

• H01Q1/44 Primary

  using equipment having another main function to serve additionally as an antenna {, e.g. means for giving an antenna an aesthetic aspect}(H01Q1/27 - H01Q1/34 take precedence) · CPC title

• H01Q7/00

  Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop · CPC title

• H01Q7/005

  with variable reactance for tuning the antenna · CPC title

• G06K7/10336

  the antenna being of the near field type, inductive coil · CPC title