Electricity: measuring and testing – Impedance – admittance or other quantities representative of... – Lumped type parameters
Reexamination Certificate
2002-03-13
2004-01-20
Le, N. (Department: 2858)
Electricity: measuring and testing
Impedance, admittance or other quantities representative of...
Lumped type parameters
C324S537000, C340S602000, C200S061040
Reexamination Certificate
active
06680618
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a leak sensing switch for detecting a leakage current and an insulating substrate having a leak sensing switch.
Power window apparatuses are used to automatically open and close the window glass panels of side doors or the like of vehicles. The window glass panels are elevated or lowered when a driver operates an up switch or a down switch of the power window apparatus. However, if the power window apparatus is immersed in water, a drive circuit for the drive motors of the power window apparatus tends to malfunction, failing to energize the drive motors. To solve the above problem, th drive circuit of the power window apparatus is provided with a leak sensing switch for detecting a leakage current. When the leak sensing switch detects a leakage current at the time the power window apparatus is immersed in water, the drive circuit becomes operational based on the detection of the leakage current.
FIG. 5
is a schematic plan view of a first conventional leak sensing switch
50
. A pair of pattern wirings
52
a
,
52
b
extend parallel to each other on a circuit board
51
, and first and second branch wirings
53
a
,
53
b
extending perpendicularly to the pattern wirings are disposed between the pattern wirings. Electrodes
54
a
,
54
b
produced by soldering are disposed respectivelyon the first and second branch wirings
53
a
,
53
b
. The electrodes
54
a
,
54
b
have a given length
11
, and are spaced from each other by a predetermined gap g
1
. When the leak sensing switch
50
is immersed in water, a leakage current flows between the electrodes
54
a
,
54
b
, thus detecting the immersion in water.
FIG. 6
is schematic plan view of a second conventional leak sensing switch
55
. A pair of pattern wirings
57
a
,
57
b
extend in series and is spaced from each other in a predetermined space on a circuit board
56
, a C-shaped first electrode support
58
a
connected to the pattern wiring
57
a
and a circular second electrode support
58
b
connected to the pattern wiring
57
b
disposed between the pattern wirings
57
a
,
57
b
. The first electrode support
58
a
is spaced from the second electrode support
58
b
by a predetermined gap g
2
and is disposed to surround the second electrode support
58
b
. Electrodes
59
a
,
59
b
produced by soldering are disposed respectively on the first and second electrode supports
58
a
,
58
b.
FIG. 7
is a schematic perspective view of a third conventional leak sensing switch
60
. A base
62
of synthetic resin having insulating properties is disposed on a circuit board
61
, and a pair of parallel electrode pins
63
a
,
63
b
are disposed on the base
62
. The electrode pins
63
a
,
63
b
are electrically connected to a wiring pattern, not shown. The electrode pins
63
a
,
63
b
have a given length
13
, and are spaced from each other bya predetermined gap g
3
.
When the difference between the temperature within the power window apparatus and the temperature outside the power window apparatus increases, moisture tends to be condensed in the power window apparatus, disadvantageously.
With the leak sensing switches
50
,
55
shown in
FIGS. 5 and 6
, when water droplets are produced between the electrodes
54
a
,
54
b
and between the electrodes
59
a
,
59
b
due to dew condensation, a leakage current may flow between the electrodes
54
a
,
54
b
and between the electrodes
59
a
,
59
b
and may be detected even though the power window apparatus is not immersed in water.
With the leak sensing switch
60
shown in
FIG. 7
, however, since the electrode pins
63
a
,
63
b
are not disposed on a plane, the possibility of a leakage current flowing between the electrodes
63
a
,
63
b
due to dew condensation is low. However, the cost of manufacture of the leak sensing switch is increased because its production needs a manual process for the worker to insert the electrode pins
63
a
,
63
b
into the base
52
.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a leak sensing switch which prevents a leakage current from flowing between electrodes due to dew condensation and manufacturing cost from increasing.
According to a first aspect of the present invention, there is provided a leak sensing switch formed on an insulating substrate. The leak sensing switch is formed on an insulating substrate and has a through hole defined in the insulating substrate and having a pair of inner side surfaces opposing each other across a predetermined space. A pair of conducting films are disposed respectively on the inner side surfaces. A pair of lands electrically connected to the conducting films, respectively are disposed on peripheral edges of the opening of the through hole in the insulating substrate. A pair of wiring patterns electrically connected to the pair of lands, respectively, are disposed on the insulating substrate.
According to a second aspect of the present invention, there is provided an insulating substrate having a leak sensing switch disposed thereon. The leak sensing switch is formed on an insulating substrate and has a through hole defined in the insulating substrate and having a pair of inner side surfaces opposing each other across a predetermined space. A pair of conducting films are formed respectively on the inner side surfaces. A pair of lands electrically connected to a pair of conducting films, respectively are disposed on peripheral edges of the opening of the through hole in the insulating substrate. A pair of wiring patters electrically connected to the pair of lands, respectively, are disposed on the insulating substrate.
REFERENCES:
patent: 11-141231 (1999-05-01), None
patent: 11-194107 (1999-07-01), None
Mori Mitsuo
Otani Kazuya
Takasu Yuji
Kabushiki Kaisha Tokai Rika Denki Seisakusho
Le N.
Nguyen Vincent Q.
Synnestvedt & Lechner LLP
LandOfFree
Leak sensing switch does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Leak sensing switch, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Leak sensing switch will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3238393