Electrical connectors – Electromagnetic or electrostatic shield – Shielding individually surrounding or interposed between...
Reexamination Certificate
2000-08-17
2001-08-21
Patel, Tulsidas (Department: 2839)
Electrical connectors
Electromagnetic or electrostatic shield
Shielding individually surrounding or interposed between...
Reexamination Certificate
active
06276966
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a jack mounted to various kinds of devices such as an audio device, a video device, etc. In particular, the present invention relates to a jack with a shield plate that improves resistance to electrical noise and interference.
Referring to
FIG. 9
, a conventional jack
100
with a shield plate
3
and a jack body
2
is shown. Jack body
2
is mounted on a circuit board
4
and has several terminals connected to a circuit pattern on circuit board
4
. The terminals are arranged within an insulating housing constructed of synthetic resin formed in a rectangular parallelepiped shape. In
FIG. 9
, reference numerals
5
a
,
6
a
and
7
a
respectively designate leg portions of a sleeve terminal, a chip terminal and a ring terminal. These leg portions extend through a rear face side of circuit board
4
. Leg portion
5
a
is solder-connected to a ground pattern of circuit board
4
, which is connected to a circuit board ground. Leg portion
6
a
and leg portion
7
a
are respectively solder-connected to unillustrated signal patterns of circuit board
4
, which provides an electrical connection to a predetermined circuit.
Jack body
2
is mounted to a metallic chassis
9
of a device with a cylindrical sleeve
8
. Sleeve
8
is located on an insertion side of jack body
2
.
Shield plate
3
has a covering portion
10
having a shape for covering front and side faces of jack body
2
. Shield plate
3
also has a pressing piece
11
arranged continuously with, and below, covering portion
10
. Shield plate
3
is formed from a single conductive metallic plate.
Pressing piece
11
is arm shaped, which permits the capability of a leafspring type response. Pressing piece
11
is integral with, and slanting forward from, a front face of covering portion
10
. When sleeve portion
8
of jack body
2
is inserted into metallic chassis
9
, pressing piece
11
is pressed against the front face of jack body
2
and resiliently contacts metallic chassis
9
. A sleeve contact piece
12
projects vertically downward and is integral with pressing piece
11
.
Shield plate
3
is mounted to jack body
2
with sleeve portion
8
inserted into a through hole
10
a
on the front face of covering portion
10
. Sleeve contact piece
12
extends along leg portion
5
a
of the sleeve terminal and is solder-connected to a ground pattern on a portion of circuit board
4
. Leg portion
5
a
of the sleeve terminal is also solder-connected to the ground pattern so that sleeve contact piece
12
and leg portion
5
a
are connected to ground.
Accordingly, metallic chassis
9
, shield plate
3
and the sleeve terminal are electrically connected to the ground pattern and have a ground electric potential. Furthermore, the front face and both the side faces of jack body
2
are covered by shield plate
3
. The terminals within jack body
2
are shielded from external interference from electrical noise, while reducing noise radiation from the device.
With this conventional structure, the jack is shielded from interfering noise on the front face and the left-hand and right-hand side faces of the jack body
2
, but is not shielded on a surface facing circuit board
4
. Accordingly, a high frequency signal is transmitted through the insulating housing of the jack and circuit board
4
. Jack body
2
is thus exposed to high frequency noise entering through the terminals on jack body
2
, which causes a mutual interference with other circuit parts mounted on circuit board
4
.
Conventional means for limiting the effects of interfering noise involve temporarily mounting jack body
2
on circuit board
4
and injecting high frequency noise through the terminals connected to jack body
2
from a noise generating source. The noise received by other noise-susceptible devices on circuit board
4
is then measured. Based on the measurements, techniques for reducing the effect of noise on the circuit configuration are taken, such as a recombination of circuits, etc. These steps taken to reduce the impact of noise contribute to increasing the complexity and length of time involved in completing production of a device.
OBJECTS AND SUMMARY OF THE INVENTION
In view of the above drawbacks in the prior art, it is an object of the present invention to provide a jack with a shield plate that overcomes the drawbacks of conventional arrangements. It is a further object of the present invention to provide an easily manufactured jack with a shield plate capable of providing excellent shield characteristics. It is yet another object of the present invention to provide a jack with a shield plate that can be produced without the need to measure and compensate for noise effects.
Briefly stated, the present invention provides a shield plate that inhibits high frequency noise generated by a circuit board from interfering with the operation of a jack connector. The jack and shield are mounted on a circuit board and the shield is connected to the shield plate and a common terminal of the jack. The shield plate is elastic and contains magnetic powder with a high flux density to interrupt high frequency noise coming from a direction of a circuit board.
When mounted to a device chassis, the shield is connected to the chassis through resilient arms. The chassis, shield, shield plate and common terminal of the jack are all connected together and to a common ground. This configuration reduces incident noise received by the jack, without the need to modify the jack or circuit to optimize noise resistance.
To achieve the above stated objects of the present invention, a jack with a jack body and shield plate is provided, in which a sleeve terminal in the jack body is connected to a ground pattern of a printed wiring board and at least one signal terminal in the jack body is connected to a signal pattern of the printed wiring board. The sleeve terminal and the signal terminal are insulated from each other, with a noise absorbing elastic shield plate connected to the sleeve terminal. The shield plate is attached to an outer side of the jack body and covers at least left-hand and right-hand side faces of this jack body. The noise absorbing shield plate is attached to a lower surface of the jack body, interposed between the jack body and the printed wiring board.
The noise absorbing shield plate has a terminal insertion hole for receiving the sleeve terminal in a press fit contact, and a notch for receiving the signal terminal without contact. The signal terminal is thus insulated from the noise absorbing shield plate.
The shield plate prevents passage of noises on at least the left-hand and right-hand side faces of the jack body. The elastic shield plate is inserted between the jack body and the printed wiring board and is electrically connected to the ground pattern through the sleeve terminal, which contacts the elastic shield plate in a press fit connection. Accordingly, noise from the printed wiring board are interrupted and prevented from adversely affecting the operation of the jack. The signal terminal of the jack body has no contact with the elastic shield plate, and is insulated when inserted into the elastic shield plate notch. The signal terminal is connected to the signal pattern of the printed wiring board without being short-circuited to the elastic shield plate.
The shield plate has a sleeve contact piece elastically contacting the sleeve terminal for the ground connection. This sleeve contact piece is inserted into the terminal insertion hole of the noise absorbing elastic shield plate in a press fit contact, together with the sleeve terminal. The sleeve terminal and the sleeve contact piece contact each other in the terminal insertion hole of the elastic shield plate and are thus electrically connected to each other. Accordingly, elastic shield plate, the shield plate and the sleeve terminal can be connected to a common ground and held at the same electric potential. The generation of noises can be more reliably prevented while maintaining or reducing the number of solder connectio
Sasa Motokazu
Suzuki Hiroshi
Yamoto Tadashi
Morrison Law Firm
Patel Tulsidas
SMK Corporation
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