Antenna unit for a car navigation device

Claim 2

An antenna unit for a car navigation device for attachment to a magnetically-attractive object, comprising: a unit casing for accommodating a circuit board and an antenna body and having a bottom cover in which a bottom recess is formed; a permanent magnet magnetically held on a back yoke and not adhesively attached to said back yoke which is fixedly set in said bottom recess, said permanent magnet for magnetically holding said bottom cover on a surface of said magnetically-attractive object so that said antenna unit is detachably mounted on said magnetically-attractive object; and an adhesive seal bonded to a surface of said permanent magnet which confronts the surface of said magnetically-attractive object, wherein said adhesive seal adjusts a gap between said surface of said magnetically-attractive object and a surface of said permanent magnet such that said permanent magnet is magnetically attracted toward said back yoke more than towards said magnetically-attractive object.

Claim 3

An antenna unit according to claim 1, wherein said adhesive seal has a thickness larger than a gap formed between said permanent magnet and said surface of said magnetically-attractive object.

Claim 4

An antenna unit according to claim 1, wherein said adhesive seal has an elastic layer which has a free-standing thickness larger than that of a gap formed between said permanent magnet and said surface of said magnetically-attractive object.

Claim 5

An antenna unit according to claim 1, wherein said adhesive seal has a sponge layer having a thickness larger than that of a gap formed between said permanent magnet and said surface of said magnetically-attractive object.

Claim 6

An antenna unit according to claim 1, wherein said adhesive seal has substantially a same shape as said permanent magnet.

Claim 7

An antenna unit according to claim 1, wherein said adhesive seal has a sponge layer having a thickness larger than that of a gap formed between said magnet and said surface of said magnetically-attractive object, and wherein said adhesive seal has substantially a same shape as said permanent magnet.

Claim 8

An antenna unit for a car navigation device for attachment to a magnetically-attractive object, comprising: a substantially hemispherically-shaped unit casing; a back yoke covered with a bottom of said unit casing, said back yoke having a bottom recess; a circuit board on which a plurality of circuit elements are mounted, said circuit board being mounted in said unit casing; a metal shield cover covering said circuit board; an antenna body mounted on said circuit board; a permanent magnet magnetically held on a back yoke and not adhesively attached to said back yoke which is fixedly set in said bottom recess, said permanent magnet for magnetically holding said back yoke on a surface of said magnetically-attractive object so that said antenna unit is detachably mounted on said magnetically-attractive object; and a magnetic force adjusting member for adjusting a gap between said surface of said magnetically-attractive object and a surface of said permanent magnet such that said permanent magnet is magnetically attracted toward said back yoke more than towards said magnetically-attractive object, wherein said magnetic force adjusting member comprises an adhesive seal bonded to a surface of said permanent magnet.

Claim 9

An antenna unit for a car navigation device for attachment to a magnetically-attractive object, comprising: a substantially hemispherically-shaped unit casing; a back yoke covered with a bottom of said unit casing, said back yoke having a bottom recess; a circuit board on which a plurality of circuit elements are mounted, said circuit board being mounted in said unit casing; a metal shield cover covering said circuit board; an antenna body mounted on said circuit board; a permanent magnet magnetically held on a back yoke and not adhesively attached to said back yoke which is fixedly set in said bottom recess, said permanent magnet for magnetically holding said back yoke on a surface of said magnetically-attractive object so that said antenna unit is detachably mounted on said magnetically-attractive object; and a magnetic force adjusting member for adjusting a gap between said surface of said magnetically-attractive object and a surface of said permanent magnet such that said permanent magnet is magnetically attracted toward said back yoke more than towards said magnetically-attractive object, wherein said magnetic force adjusting member comprises an adhesive seal bonded to a surface of said permanent magnet.

Claim 10

An antenna unit for a car navigation device as claimed in claim 7, wherein said magnetic force adjusting member includes an adhesive seal bonded to the surface of said permanent magnet, a surface of said adhesive seal confronting the surface of said magnetically-attractive object.

Claim 11

An antenna unit according to claim 7, wherein said magnetic force adjusting member comprises an adhesive seal, said adhesive seal having a thickness larger than a gap formed between said permanent magnet and said surface of said magnetically-attractive object.

Claim 12

An antenna unit according to claim 7, wherein said magnetic force adjusting member comprises an adhesive seal, said adhesive seal having an elastic layer which has a free-standing thickness larger than that of a gap formed between said permanent magnet and said surface of said magnetically-attractive object.

Claim 13

An antenna unit according to claim 7, wherein said magnetic force adjusting member comprises an adhesive seal, said adhesive seal having a sponge layer having a thickness larger than that of a gap formed between said permanent magnet and said surface of said magnetically-attractive object.

Claim 14

An antenna unit according to claim 7, wherein said magnetic force adjusting member comprises an adhesive seal, said adhesive seal having substantially a same shape as said permanent magnet.

Claim 15

An antenna unit for a navigation device for attachment to a magnetically-attractive object, comprising: a casing for accommodating an antenna body and having a bottom cover in which a bottom recess is formed; a magnet magnetically held on a back yoke and not adhesively attached to said back yoke which is fixedly set in said bottom recess, said magnet for magnetically holding said bottom cover on a surface of said magnetically-attractive object so that said antenna unit is detachably mounted on said magnetically-attractive object; and a seal bonded to a surface of said magnet which confronts the surface of said magnetically-attractive object, wherein said magnet comprises a permanent magnet and wherein said seal adjusts a gap between said surface of said magnetically-attractive object and a surface of said permanent magnet such that permanent magnet is magnetically attracted toward said back yoke more than towards said magnetically-attractive object.

Claim 16

An antenna unit for a navigation device for attachment to a magnetically-attractive object, comprising: a casing for accommodating an antenna body and having a bottom cover in which a bottom recess is formed; a magnet magnetically held on a back yoke and not adhesively attached to said back yoke which is fixedly set in said bottom recess, said magnet for magnetically holding said bottom cover on a surface of said magnetically-attractive object so that said antenna unit is detachably mounted on said magnetically-attractive object; and a seal bonded to a surface of said magnet which confronts the surface of said magnetically-attractive object, wherein said magnet comprises a permanent magnet and wherein said seal adjusts a gap between said surface of said magnetically-attractive object and a surface of said permanent magnet such that permanent magnet is magnetically attracted toward said back yoke more than towards said magnetically-attractive object.

Claim 17

An antenna unit according to claim 13, wherein said seal comprises an adhesive seal and said casing has a substantially hemispherical-shape.

Claim 18

An antenna unit according to claim 13, wherein said seal has a thickness larger than a gap formed between said magnet and said surface of said magnetically-attractive object.

Claim 19

An antenna unit according to claim 13, wherein said seal has an elastic layer which has a free-standing thickness larger than that of a gap formed between said magnet and said surface of said magnetically-attractive object.