Electrical audio signal processing systems and devices – Electro-acoustic audio transducer – Electromagnetic
Reexamination Certificate
2002-04-05
2004-10-19
Donovan, Lincoln (Department: 2832)
Electrical audio signal processing systems and devices
Electro-acoustic audio transducer
Electromagnetic
C381S412000
Reexamination Certificate
active
06807282
ABSTRACT:
FIELD OF INDUSTRIAL USE
This invention is primarily a vibration generator; it concerns improvement of electromagnetic induction actuators with the function of generator a ring or buzz; a structure for mounting an electromagnetic induction actuator that is improved by means of a more secure electrical connection between the electromagnetic induction actuator and the conduction pattern of the circuit board; and portable information equipment, including portable telephones, that is fitted with electromagnetic induction actuators.
PRIOR ART
Generally speaking, electromagnetic induction actuators have, as shown in
FIG. 36
, a cylindrical housing
10
that encloses a magnetic circuit that consists of a pole piece
13
, a magnet
11
connected to the pole piece
13
, and a yoke
12
that holds the magnet
11
to the pole piece
13
separated by an electromagnetic gap G; the magnetic circuit is suspended within the housing
10
by spring suspension
14
a
,
14
b
; there is a diaphragm
15
with a voice coil
16
mounted inward from the diaphragm
15
, of which the voice coil
16
is inserted into the electromagnetic gap G between the pole piece
13
and the yoke
12
and the diaphragm
15
is suspended at the framework
10
a
of the housing
10
; metal terminals
58
a
,
58
b
are attached to the terminal block
10
d
that projects from the end of the housing
10
, and the voice coil
16
is electrically connected to the metal terminals
58
a
,
58
b.
This electromagnetic induction actuator is constituted such that the magnetic action of the magnet
11
and the current applied on the voice coil
16
cause vibration of the springs
14
a
,
14
b
that support the magnetic circuit when a low frequency signal is applied, and a ring or buzz from the diaphragm
15
when a high frequency signal is applied.
To electrically connect between the conduction pattern on the circuit board inside the portable telephone or other portable information equipment to the voice coil in order to vibrate during operation, the conventional electromagnetic induction actuator described above uses a flexible cord that extends from a metal terminal that is electrically connected to the voice coil. This flexible cord itself can withstand vibration, but there is a problem in that contact is easily broken because of the load placed on the contact with the metal terminal or the contact with the conductive pattern on the circuit board.
Therefore, in order to resolve such problems, proposals have been made for the electrical connection between the vibration mechanism and the conduction pattern on the circuit board, including a method of extending a leaf spring at a slant from the case of an eccentric weight vibration mechanism have an eccentric weight and pressing it against the power feed land to make an electrical connection between the vibration mechanism and the conduction pattern of the circuit board, (JPO Kokai Patent Report H11-136901 of 1999), and a method of pressing the leaf spring against the power feed land by using an elastic pressure body attached to the outside of the vibration mechanism case to make an electrical connection between the vibration mechanism and the conductive pattern of the circuit board (JPO Kokai Patent Report 2000-78790).
In the case of these leaf spring electrical contacts, however, it is necessary to mount the vibration mechanism with accurate positioning that maintains a steady gap between the vibration mechanism and the surface of the printed circuit board. When the leaf spring is pressed by an elastic pressure body attached to the outside of the vibration mechanism case, especially, excessive pressure on the leaf spring is liable to cause it to eat into the elastic pressure body, causing poor contact.
Moreover, the conventional electromagnetic induction actuator shown in
FIG. 36
is mounted in the case of the portable telephone or other equipment by placing the side where the diaphragm
15
attaches toward the outer casing of the portable information equipment and the side where the cover
18
attaches toward the surface of the circuit board, and electrically connecting the metal terminals
58
a
,
58
b
to the conduction pattern of the circuit board.
With the electromagnetic induction actuator described above, in order to increase the speed of the physically heavy magnetic circuit as it vibrates, flux leakage from the magnetic circuit modulates the vibration frequency and creates an alternating magnetic field; this creates an alternating magnetic field leak outside the portable electronic equipment from the side where the diaphragm
15
attaches, and so there is concern about the effect on magnetic memory cards outside the equipment.
One conceivable way to prevent the effects of this alternating magnetic field is to turn the side where the cover
18
is mounted, where there is little flux leakage, toward the outer casing of the equipment instead of the side where the diaphragm
15
is mounted, and placing it inside the telephone or other equipment with the diaphragm
15
side toward the surface of the circuit board.
However, if the electromagnetic induction actuator described above is simply reversed, the side where the leads
8
a
,
8
b
of the voice coil
16
are soldered to the metal terminals
58
a
,
58
b
will be positioned opposite the conduction pattern of the circuit board, and so there is a danger that the solder mound will interfere with the electrical contact between the metal terminals
58
a
,
58
b
and the conduction pattern of the circuit board.
In view of the problems described above, first of all, a sure means of conduction between the voice coil and the conduction pattern of the circuit board without using a flexible cord is desired.
Second, and even better, a means of resolving the problem of flux leakage in addition to the sure means of conduction is desired.
Accordingly, the purpose of this invention is to enable a sure electrical connection by pressing the metal terminals of the vibration mechanism against the conduction pattern of the circuit board while maintaining the relative gap between the vibration mechanism and the circuit board, and also to provide a structure for mounting the electromagnetic induction actuator that is improved so as to prevent damage to the internal mechanism due to impact, and to prevent resonance that would result from excessive vibration of the ringing mechanism being transferred to the circuit board or the outer casing.
A further purpose is to provide a structure for mounting the electromagnetic induction actuator that is improved so as to prevent acoustical leakage within the outer casing and thus improve the acoustic characteristics.
In addition, it has the purpose of providing a structure for mounting the electromagnetic induction actuator that is improved so as to enable simple mounting of the electromagnetic induction actuator while accurately maintaining the relative gap between it and the circuit board.
Moreover, this invention has the primary objective of suppressing the effects of the alternating magnetic field by mounting the electromagnetic induction actuator in the equipment with the side where the diaphragm is mounted turned toward the surface of the circuit board and the opposite side turned toward the cover panel of the equipment, and has the purpose of providing an electromagnetic induction actuator that can be mounted easily within equipment with an electrical circuit connection between the metal terminal and the power feed land of the circuit board.
This invention also has the purpose of providing an electromagnetic induction actuator that firmly attaches the metal terminals to the terminal block of the housing and makes a sure electrical contact with the conduction pattern of the circuit board, and one which is a compact unit overall, as well as the purpose of providing portable telephones and other portable information equipment that suppresses the alternating magnetic field while incorporating an electromagnetic induction actuator as a mechanism for generating vibrations, ringing or buzzing.
DESCRIPTION
Fujimori Fumio
Kaneda Shoichi
Kyono Tsuneo
Ueda Minoru
Donovan Lincoln
Namiki Seimitsu Houseki Kabushiki Kaisha
Nixon & Peabody LLP
Studebaker Donald R.
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