Abstrict The air flow rate detecting resistance element 1A or the temperature
sensing resistance element 1B comprises a dielectric substrate 5A
or 5B, a thin film type conductor 6A or 6B as a resistance element
forming conductor, and a thin film type conductor 7A or 7B as a
shield electrode element forming conductor. The resistance element
conductor 6A or 6B and the shield electrode element conductor 7or
7B are formed by evaporation on the dielectric substrate 5A or 5B.
The shield electrode element conductor 7A or 7B is provided in the
vicinity of the resistance element conductor 6A or 6B an electrostatic
capacity is formed therebetween. The shield electrode element conductor
7A or 7B is maintained at the lowest potential such as ground or
a common potential. The guidance of high frequency radio waves to
the resistance element 1A or 1B can be effectively prevented, so
that the radio interference resistance of the hot film type air
flow meter can be improved.
Claims We claim:
1. A hot film type air flow meter having a thin film type conductor
(6A), which is formed on one surface of a dielectric substrate member
(5A; 12A; 13A; 14A), as an air flow rate detecting resistance element
(1A), characterized in that
a thin film type conductor (7A) for shielding electromagnetic waves
as a shield forming an electrode element is provided in the vicinity
of said air flow rate detecting resistance element forming thin
film type conductor (6A), and
said shield electrode element forming thin film type conductor
(7A) is connected to a low potential.
2. A hot film type air flow meter according to claim 1 characterized
in that
said shield electrode element forming thin film type conductor
(7A) is connected to ground (E).
3. A hot film type air flow meter according to claim 1 characterized
in that
said dielectric substrate member (5A) consists of a flat member
in form,
said air flow rate detecting resistance element forming thin film
type conductor (6A) is formed on one surface of said flat member
(5A), and
said shield electrode element forming thin film type conductor
(7A) is formed around said air flow rate detecting resistance element
forming thin film type conductor (6A) on the same surface of said
flat member (5A).
4. A hot film type air flow meter according to claim 3 characterized
in that
said shield electrode element forming thin film type conductor
(7A) is connected to ground (E).
5. A hot film type air flow meter according to claim 1 characterized
in that
said dielectric substrate member (5A) consists of a flat member
in form,
said air flow rate detecting resistance element forming thin film
type conductor (6A) is formed on one surface of said flat member
(5A), and
said shield electrode element forming thin film type conductor
(7A) is formed on the other surface of said flat member (5A).
6. A hot film type air flow meter according to claim 5 characterized
in that
said shield electrode element forming thin film type conductor
(7A) is connected to ground (E).
7. A hot film type air flow meter according to claim 1 characterized
in that
said dielectric substrate member (12A; 13A) consists of a member
having a cylindrical outer circumferential surface, and
both said air flow rate detecting resistance element forming thin
film type conductor (6A) and said shield electrode element forming
thin film type conductor (7A) are formed respectively on said cylindrical
outer circumferential surface of said dielectric substrate member
(12A; 13A).
8. A hot film type air flow meter according to claim 7 characterized
in that
said shield electrode element forming thin film type conductor
(7A) is connected to ground (E).
9. A hot film type air flow meter according to claim 1 characterized
in that
said dielectric substrate member (14A) consists of a member having
a cylindrical outer circumferential surface and a cylindrical inner
circumferential surface,
said air flow rate detecting resistance element forming thin film
type conductor (6A) is formed on said cylindrical outer circumferential
surface of said dielectric substrate member (14A), and
said shield electrode element forming thin film type conductor
(7A) is formed on said cylindrical inner circumferential surface
of said dielectric substrate member (14A).
10. A hot film type air flow meter according to claim 9 characterized
in that
said shield electrode element forming thin film type conductor
(7A) is connected to ground (E).
11. A hot film type air flow meter for use in an automobile having
a first thin film type conductor (6A), which is formed on one surface
of a first dielectric substrate member (5A; 12A; 13A; 14A), as an
exothermic resistance element (1A) for detecting an air flow rate,
a second thin film type conductor (6B), which is formed on one surface
of a second dielectric substrate member (5B; 12B; 13B; 14B), as
a temperature sensing resistance element (1B) for sensing an air
flow temperature, a control module (3) with an air flow state detecting
circuit mounted thereon, and a flow meter main body (4) constituting
a part of a suction passage in an engine of the automobile and being
molded with a resin material, said exothermic resistance element
(1A) and said temperature sensing resistance element (1B) being
disposed respectively in a predetermined position of said suction
passage in the engine characterized in that
a first shield electrode element forming thin film type conductor
(7A) for shielding electromagnetic waves as a shield forming an
electrode element is provided in the vicinity of said exothermic
resistance element forming thin film type conductor (6A),
said first shield electrode element forming thin film type conductor
(7A) is connected to a low potential,
a second shield electrode element forming thin film type conductor
(7B) for shielding electromagnetic waves as a shield forming an
electrode element is provided in the vicinity of said temperature
sensing resistance element forming thin film type conductor (6B),
and
said second shield electrode element forming thin film type conductor
(7B) is connected to a low potential.
12. A hot film type air flow meter for use in an automobile according
to claim 11 characterized in that
both said first shield electrode element forming thin film type
conductor (7A) and said second shield electrode element forming
thin film type conductor (7B) are connected respectively to ground
(E).
13. A hot film type air flow meter for use in an automobile according
to clam 11 characterized in that
said first dielectric substrate member (5A) consists of a first
flat member in form,
said exothermic resistance element forming thin film type conductor
(6A) is formed on one surface of said first flat member (5A),
said first shield electrode element forming thin film type conductor
(7A) is formed around said exothermic resistance element forming
thin film type conductor (6A) on the same surface of said first
flat member (5A),
said second dielectric substrate member (5B) consists of a second
flat member in form, and
said second shield electrode element forming thin film type conductor
(7B) is formed around said temperature sensing resistance element
forming thin film type conductor (6B) on the same surface of said
second flat member (5B).
14. A hot film type air flow meter for use in an automobile according
to claim 13 characterized in that
both said first shield electrode element forming thin film type
conductor (7A) and said second shield electrode element forming
thin film type conductor (7B) are connected respectively to ground
(E).
15. A hot film type air flow meter for use in an automobile according
to claim 11 characterized in that
both said first dielectric substrate member (5A) and said second
dielectric substrate member (5B) consist respectively of an alumina
plate, and
both said first shield electrode element forming thin film type
conductor (7A) and said second shield electrode element forming
thin film type conductor (7B) are formed respectively by the platinum
evaporation.
16. A hot film type air flow meter for use in an automobile according
to claim 11 characterized in that
said first dielectric substrate member (5A) consists of a first
flat member in form,
said exothermic resistance element forming thin film type conductor
(6A) is formed on one surface of said first flat member (5A),
said first shield electrode element forming thin film type conductor
(7A) is formed on the other surface of said first flat member (5A),
said second dielectric substrate member (5B) consists of a second
flat member in form,
said temperature sensing resistance element forming thin film type
conductor (6B) is formed on one surface of said second flat member
(5B), and
said second shield electrode element forming thin film type conductor
(7B) is formed on the other surface of said second flat member (5B).
17. A hot film type air flow meter for use in an automobile according
to claim 16 characterized in that
both said first shield electrode element forming thin film type
conductor (7A) and said second shield electrode element forming
thin film type conductor (7B) are connected respectively to ground
(E).
18. A hot film type air flow meter for use in an automobile according
to claim 16 characterized in that
both said first dielectric substrate member (5A) and said second
dielectric substrate member (5B consist respectively of an alumina
plate, and
both said first shield electrode element forming thin film type
conductor (7A) and said second shield electrode element forming
thin film type conductor (7B) are formed respectively by the platinum
evaporation.
Description BACKGROUND OF THE INVENTION
1. (Field of the Invention)
The present invention relates to a hot film type air flow meter
using a thin film type exothermic resistance element as an air flow
rate detecting resistance element and a thin film type air flow
temperature sensing resistance element, and more particularly to
a hot film type air flow meter having a resin material flow meter
main body suitably used as a suction air flow meter in an internal
combustion engine for an automobile.
2. (Prior Art)
In recent years, a suction air flow meter has been used extensively
for controlling a gasoline engine for an automobile. Recently, a
hot film type air flow meter has been used as this suction air flow
meter in the gasoline for the automobile. This hot film type air
flow meter has a thin film type an air flow rate detecting resistance
element as a main resistance element and also has a thin film type
temperature sensing or temperature compensating resistance element
as an auxiliary resistance element. Such a hot film type air flow
meter is disclosed in, for example, Japanese Patent Laid-Open No.
236029/1985.
It is considered that the hot film type air flow meter having a
thin film type resistance element such as an air flow rate detecting
resistance element etc. enables the reliability to be improved and
the manufacturing cost of the air flow rate detecting resistance
elements and temperature sensing resistance elements as the hot
film type resistance element to be reduced, respectively, and users
in this technical field expect much from this hot film type air
flow meter.
However, in the above-described prior art, no consideration is
given to the radio interference resistance caused by electromagnetic
waves or a considerably high frequency noise voltage of the hot
film type air flow rate detecting resistance element etc. in the
hot film type air flow meter. Consequently, in an automobile provided
with the wireless equipment and various kinds of the oscillators
as an electric equipment, the malfunction of the hot film type air
flow meter occurs due to the radio guidance.
Especially, in recent years, a flow meter main body of the hot
film type air flow meter in an engine for the automobile has been
made of a resin material or plastics. This gives rise to a big problem
concerning the radio interference resistance of the above-mentioned
prior art hot film type air flow meter.
The hot film type air flow meter for use in a suction air flow
meter in an engine for an automobile comprises a thin film type
exothermic resistance element or resistor, for use of detecting
the air flow rate of an air current or suction air, a thin film
type temperature sensing resistance element or resistor for use
of sensing the temperature of the suction air, a control module
with an air flow state detecting circuit mounted thereon, and a
flow meter main body constituting a part of a suction air passage
in an engine.
The exothermic resistance element and the temperature sensing resistance
element are assembled unitary with the control module. Since the
control module is fixed to the flow meter main body which is molded
integrally out a resin material. The exothermic resistance element
and the temperature sensing resistance element are retained in the
respective predetermined position in the suction air passage. The
exothermic resistance element and the temperature sensing resistance
element are projected greatly from the control module and retained
in this state.
In the meantime, with a viewpoint to reducing the manufacturing
cost of the hot film type air flow meter, the flow meter main body
has been molded out of a resin material or plastics. Consequently,
for example, when the wireless equipment is provided as an electric
instrument in the automobile, the exothermic resistance element
and the temperature sensing resistance element become exposed to
a considerably high frequency electric field.
As a result, the exothermic resistance element and the temperature
sensing resistance element work as antennas, so that an electromagnetic
waves or a considerably high frequency noise voltage is introduced
into the control module to cause the radio interference resistance
of the hot film type air flow meter to decrease.
The characteristics of various radio interference resistance of
the hot film type air flow meters having the exothermic resistance
element and the temperature sensing resistance element will be described
with reference to FIG. 4.
One example of the radio interference resistance of the conventional
hot film type air flow meter has the characteristics curve a shown
in FIG. 4 in which the radio interference resistance lowers greatly
in the vicinity of, especially, the value of 470 MHz of frequency.
This conventional hot film type air flow meter as it was remained
substantially unendurable to practical use.
A hot film type air flow meter provided with a shield structure
for the control module so as to improve the radio interference resistance
thereof has also been proposed. To be concrete, the number of nodes
between a shield base being disposed in the control module and the
flow meter main body in the control module to ground is increased
from one, which is the number referring to the conventional case
of the hot film type air flow meter, to two to three.
The radio interference resistance characteristics of the node-increased
hot film type air flow meter is as shown by curve b in FIG. 4. In
this hot film type air flow meter, the radio interference resistance
is improved to only a small extent. It is understood that it is
difficult to obtain a satisfactory countermeasure by taking only
such a step.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a hot film type
air flow meter wherein a sufficiently high radio interference resistance
can be obtained.
Another object of the present invention is to provide a hot film
type air flow meter wherein the malfunction of a high radio interference
resistance can be easily prevented even when a flow meter main body
of the hot film type air flow meter is made of a resin material.
According to the present invention, a hot film type air flow meter
has a thin film type conductor, which is formed on one surface of
a dielectric substrate member, as an air flow rate detecting resistance
element.
A thin film type conductor for shielding electromagnetic wave as
a shield electrode element is provided in the vicinity of the air
flow rate detecting resistance element forming thin film type conductor,
and the shield electrode element forming thin film type conductor
is connected to a low potential.
Since a shield electrode element forming thin film type conductor
is provided in the vicinity of a resistance element consisting of
a thin film type conductor, an electro-static capacity is formed
therebetween.
Since this shield electrode element forming thin film type conductor
is maintained at the lowest potential such as ground or a common
potential, this electro-static capacity functions as a bypass condenser,
and the guidance of high frequency radio waves, which has entered
the shield electrode element forming thin film type conductor, to
the resistance element can be effectively prevented, so that the
radio interference resistance of the hot film type air flow meter
can be improved.
According to the present invention, a hot film type air flow meter
can be furnished with an excellent radio interference resistance,
by a simple structure provided with the shield electrode element
thin film type forming conductor or electro-static capacity forming
film type conductor.
Therefore, the flow meter main body of the hot film type air flow
meter can be made of a resin material in a satisfactory manner.
This enables the manufacturing cost to be reduced easily.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1a is a perspective view of one embodiment of a resistance
element for a hot film type air flow meter according to the present
invention;
FIG. 1b is a front elevation view of one embodiment of a thin film
type resistance element for a hot film type air flow meter according
to the present invention;
FIG. 1c is a side elevation view of one embodiment of a thin film
type resistance element for a hot film type air flow meter according
to the present invention;
FIG. 2 is a cross-sectional view of one example of an air flow
meter being disposed within a flow meter main body to which one
embodiment of a thin film type resistance element of the present
invention is applied;
FIG. 3 is a circuit diagram of a control module;
FIG. 4 is characteristic diagrams showing the radio interference
resistance of the conventional hot film type air flow meters and
the hot film type air flow meter of the present invention;
FIG. 5a is a front elevation view of another embodiment of a thin
film type resistance element for a hot film type air flow meter
according to the present invention;
FIG. 5b is a side elevation view of another embodiment of a thin
film type resistance element for a hot film type air flow meter
according to the present invention;
FIG. 5c is a back elevation view of another embodiment of a thin
film type resistance element for a hot film type air flow meter
according to the present invention;
FIG. 6 is a cross-sectional view of further embodiment of a thin
film type resistance element for a hot film type air flow meter
according to the present invention;
FIG. 7 is a cross-sectional view of still further embodiment of
a thin film type resistance element for a hot film type air flow
meter according to the present invention; and
FIG. 8 is a cross-sectional view of another further embodiment
of a thin film type resistance element for a hot film type air flow
meter according to the present invention.
DESCRIPTION OF THE INVENTION
A hot film type air flow meter according to one embodiment of the
present invention will now be explained in detail with reference
to the illustrated embodiments.
FIG. 2 shows a hot film type air flow meter of the present invention
applied to a suction air flow meter in an internal combustion engine
for an automobile.
In FIG. 2 reference numeral 1A denotes a thin hot film type exothermic
resistance element for use of detecting the air flow rate of an
air current, 1B a thin hot film type temperature sensing resistance
element for use of sensing the temperature of the air current, 3
a control module with an air flow state detecting circuit mounted
thereon, and 4 a flow meter main body constituting a part of a suction
air passage in the internal combustion engine for the automobile.
The thin film type or air flow rate detecting exothermic resistance
element 1A as a main resistance element and the thin film type temperature
sensing resistance element 1B as an auxiliary resistance element
have the same construction, an example of which is shown in FIGS.
1a, 1b and 1c.
The thin film type exothermic air flow rate detecting resistance
element 1A or the thin film type temperature sensing resistance
element 1B comprises a dielectric substrate member 5A or 5B, a thin
film type conductor 6A or 6B as a resistance element forming conductor,
a thin film type conductor 6a as an electrode element forming conductor
for the thin film type conductor 6A or 6B, two terminals 8a, another
thin film type conductor 7A or 7B as a shield electrode element
forming conductor, and two terminals 8b.
For example, the thin film type resistance element forming conductor
6A or 6B of platinum is formed by evaporation on one surface of
the flat type dielectric substrate member 5A or 5B, which consists
of a rectangular alumina flat plate of about 10.0 mm in length,
about 5.0 mm in width and 0.2-0.5 mm in thickness, in such a manner
that the thin film type resistance element forming conductor 6A
or 6B is used as a part of a resistance element.
Another thin film type shield electrode element forming conductor
7A or 7B is formed by the evaporation of platinum on that portion
of the same surface of the dielectric substrate member 5A or 5B
which is around the thin film type resistance element forming conductor
6A or 6B and the thin film type shield electrode element forming
conductor 7A or 7B.
The resultant film type conductor 7A or 7B is used as an electrode
element. The electrode element 7A or 7B works as a shield electrode
element forming conductor for shielding the electromagnetic waves
or noise. The thin film type resistance element forming conductor
6A or 6B and the shield electrode element forming 7A or 7B are then
provided with the terminals 8a or the terminals 8b so that they
can be connected to outer parts.
FIG. 3 shows the connected condition in the electric circuit diagram
of an air flow state detecting circuit mounted on the control module
3 to the exothermic or air flow rate detecting resistance element
1A and the temperature sensing resistance element 1B which are constructed
as shown in FIG. 2.
In this arrangement, the film type resistance element forming conductor
6 (6A or 6B) in the exothermic or air flow rate detecting resistance
element 1A and the temperature sensitive resistance element 1B are
connected as shown in FIG. 2.
In this arrangement, the thin film type resistance element forming
conductors 6 (6A or 6B) in the exothermic or air flow state detecting
resistance element 1A or the temperature sensitive resistance element
1B is connected to the respective predetermined portion of the air
flow rate detecting circuit through the terminals 8a or the terminals
8b with the shield electrode element forming film type conductor
7 (7A or 7B) connected to ground E such as engine block and an automobile
body and kept at a common potential which is the lowest potential.
The exothermic or air flow rate detecting resistance element 1A
and the temperature sensing resistance element 1B are assembled
unitary with the control module 3 having a shield base member 3a.
Since the control module 3 is fixed to the flow meter main body
4 which is molded integrally out of PBT (polybutylene terephthalate)
resin material or PPS (polypropylene sulfide) resin material, the
exothermic or air flow rate detecting resistance element 1A and
the temperature sensing resistance element 1B are retained in the
respective predetermined positions in the suction air passage of
the engine.
The operation of the above-stated embodiment of the present invention
will now be explained.
As generally known, in a hot film type air flow meter, an electric
current is supplied to the thin film type conductor 6A in the exothermic
or air flow rate detecting resistance element 1A, which is controlled
so as to be maintained at a constant temperature, for example, around
200.degree. C. As a result, an air flow rate Qa can be detected
as a function of the electric current supplied to the exothermic
or air flow rate detecting resistance element 1A.
Accordingly, it is necessary that the exothermic or air flow rate
detecting resistance element 1A and also the temperature sensing
resistance element 1B be exposed sufficiently to the air current
the flow rate of which is to be detected. The exothermic or air
flow rate detecting resistance element 1A and the temperature sensing
resistance element 1B are projected greatly from the control module
3 and retained in this state as shown in FIG. 2.
According to the above-stated embodiment of the present invention
shown in FIG. 1 the shield electrode element forming thin film
type conductor 7A or 7B is provided, which is connected to the ground
E and maintained at the lowest potential and a common potential.
Consequently, the thin film type shield electrode element forming
conductor 7A or 7B is maintained at the lowest potential and the
common potential with a sufficiently low impedance in the range
of frequency in question, and a radio interference resistance of
not less than the value of 100 V/m of the electric field strength
shown by curve c in FIG. 4 can be obtained.
Therefore, a hot film type air flow meter having sufficient practicality
can be obtained in spite of the increase of the embodiment of the
resin material or plastics flow meter main body 4.
FIG. 5 shows another embodiment of the exothermic or air flow rate
resistance element 1A or the temperature sensing resistance element
1B in the present invention. The shield electrode element forming
thin film type conductor 7A or 7B is formed on the substantially
whole of that surface of a dielectric alumina substrate member 5A
or 5B which is on the opposite side of the surface which has a resistance
element forming thin film type conductor 6A or 6B.
The thin film type resistance element forming conductor 6A or 6B
of platinum is formed by evaporation on one surface of the flat
type dielectric substrate member 5A or 5B, which consists of a rectangular
alumina plate. The thin film type shield electrode element forming
conductor 7A or 7B of platinum is formed by evaporation on another
surface of the dielectric alumina substrate member 5A or 5B.
Therefore, according to this embodiment of the present invention,
a considerably large electro-static capacity as a bypass capacitor
can be obtained, and the bypassing effect can be improved. Moreover,
an excellent radio interference resistance can be obtained.
FIG. 6 shows a further embodiment of the exothermic resistance
element 1A or the temperature sensing resistance element 1B in the
present invention. In the embodiment shown in FIG. 6 an alumina
tube 12A or 12B of about 0.5 mm in diameter and about 2.0 mm in
length is used as a dielectric substrate member, and platinum (Pt)--iridium
(Ir) wires 9 are inserted into both end portions of the alumina
tube 12A or 12B and held firmly by a glass bonding agent substance
10A or 10B.
A resistance element forming thin film type conductor 6A or 6B
and a shield electrode element forming thin film type conductor
7A or 7B are then formed in the mentioned order on the outer circumferential
surface of the resultant alumina tube 12A or 12B with a dielectric
film member 11A or 11B of glass sandwiched between the thin film
type resistance element forming conductor 6A or 6B and the shield
electrode element forming conductor 7A or 7B.
The thin film type resistance element forming conductor 6A or 6B
of platinum is formed by evaporation on the outer surface of the
alumina tube 12A or 12B. The thin film type shield electrode element
forming conductor 7A or 7B of platinum is formed by evaporation
on the outer surface of the dielectric film member 11A or 11B.
A lead wire is connected to the shield electrode element forming
thin film type conductor 7A or 7B so that the shield electrode forming
thin film type conductor 7A or 7B can be connected to ground E.
Accordingly, in the embodiment shown in FIG. 6 electro-static
capacities are formed between their respective inner and outer thin
film type resistance element forming conductor 6A or 6B and shield
electrode element forming conductor 7A or 7B with the outer thin
film type shield electrode element forming conductor 7A or 7B connected
to ground E, whereby a sufficiently high radio interference resistances
can be obtained.
FIG. 7 shows a still embodiment of the exothermic resistance element
1A or the temperature sensing resistance element 1B in the present
invention using a rod type dielectric substance member.
In this embodiment, a rod type alumina dielectric substance member
13A or 13B is used, and a resistance element forming thin film type
conductor 6A or 6B and a shield electrode element forming thin film
type conductor 7A or 7B are laminated on the outer circumferential
surface of the alumina dielectric substrate member 13A, 13B with
a dielectric film member 11A or 11B of glass sandwiched between
the thin film type resistance element forming conductor 6A or 6B
and the shield electrode element forming conductor 7A or 7B.
The thin film type resistance element forming conductor 6A or 6B
of platinum is formed by evaporation on the outer surface of the
alumina dielectric substrate member 13A or 13B. The thin film type
shield electrode element forming conductor 7A or 7B of platinum
is formed by evaporation on the outer surface of the dielectric
film member 11A or 11B.
Accordingly, in the embodiment shown in FIG. 7 electro-static
capacities are formed between their respective inner and outer thin
film type resistance element forming conductor 6A or 6B and shield
electrode element forming conductor 7A or 7B with the outer thin
film type shield electrode element forming conductor 7 connected
to ground E, whereby a sufficiently high radio interference resistances
can be obtained.
FIG. 8 shows an another further embodiment of the exothermic or
air flow rate detecting resistance element 1A or the temperature
sensing resistance element 1B in the present invention using a bottomed
tube type dielectric substrate member.
In this embodiment, a bottomed tube type alumina dielectric substrate
member 14A or 14B is used, and a resistance element forming thin
film type conductor 6A or 6B is laminated on the outer circumferential
surface of the alumina dielectric tube 14A or 14B and a shield electrode
element forming thin film type conductor 7A or 7B is laminated on
the inner circumferential surface of the alumina dielectric tube
14A or 14B.
The thin film type resistance element forming conductor 6A or 6B
of platinum is formed by evaporation on the outer surface of the
alumina dielectric tube 14A or 14B. The thin film type shield electrode
element forming conductor 7A or 7B of platinum is formed by evaporation
on the inner surface of the alumina dielectric tube 14A or 14B.
Accordingly, in the embodiment shown in FIG. 8 electro-static
capacities are formed between their respective inner and outer thin
film type shield electrode element forming conductor 7A or 7B and
resistance element forming conductor 6A or 6B with the inner thin
film type shield electrode element forming conductor 7A or 7B connected
to ground E, whereby a sufficiently high radio interference resistances
can be obtained.
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