JP2707844B2 - Noise filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise filter.

[0002]

2. Description of the Related Art Conventionally, a noise filter has generally been constituted by an LC composite component including an inductor L and a capacitor C as shown in, for example, an equivalent circuit diagram of FIG.

[0003]

Incidentally, in the conventional noise filter, a phenomenon such as resonance occurs between the inductor L and the capacitor C, thereby distorting the effective signal component or distorted waveform component generated. Therefore, there is a problem that secondary radiation occurs.

The present invention has been made in view of the above problems, and has been made in view of the above circumstances. Accordingly, a noise filter capable of removing noise without distortion and sufficiently responding to recent demands for downsizing electronic components has been developed. It is intended to provide.

[0005]

In order to achieve the above object, the present invention provides a resistive pattern comprising a thin film resistor, which is arranged on one surface of a substantially rectangular dielectric substrate in parallel with each other, A ground pattern buried in parallel with the one surface and facing the resistance pattern, an end of the resistance pattern is drawn out to one facing end surface of the dielectric substrate. Connected to the input / output electrode provided on the opposite end face, and the end of the ground pattern is drawn out to the other opposite end face of the dielectric substrate and connected to the ground electrode provided on the opposite end face. The noise filter was constructed from the above.

[0006]

According to the above configuration, a noise filter composed of an RC composite component is formed by the distributed capacitance generated between the resistance pattern and the ground pattern and each resistance pattern.
In the RC composite component having such a configuration, the end of the ground pattern is connected to the ground electrode, and the resistance pattern is arranged between the ground electrodes.
The inductance generated in the ground pattern is suppressed, and as a result, a resonance phenomenon and a secondary radiation phenomenon do not occur in the noise filter. Further, since a noise filter is composed of a plurality of resistor patterns formed in parallel and a ground pattern disposed opposite to the resistor pattern, the noise filter can be multiplied, and the multiplied noise filter can be simply formed. It can be formed at a narrow pitch on one dielectric substrate. Furthermore, since the ground pattern is buried in a state parallel to one surface (= resistance pattern) of the dielectric substrate, the capacitance formed between the ground pattern and the resistance pattern can be arbitrarily provided without variation. Furthermore, an arbitrary capacitance value can be obtained by adjusting the separation distance between the resistance pattern and the ground pattern (the position where the ground pattern is buried). In addition, since the resistor pattern is composed of thin film resistors,
The dimensional accuracy of the resistance pattern to be formed can be increased.

[0007] Since the noise filter is composed of a plurality of resistor patterns formed in parallel and a ground pattern arranged opposite to the resistor pattern, the noise filter can be multiplied. It can be formed at a narrow pitch on a single dielectric substrate.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. FIG. 1 is a perspective view of an embodiment of the present invention, and FIGS. 2 and 3 are cross-sectional views taken along lines AA and BB of FIG.

The noise filter 10 has a rectangular dielectric substrate 1 on which resistance patterns 2... And ground patterns 3 are provided.

A plurality of resistance patterns 2 are formed on one surface 1a of the dielectric substrate 1. The resistance patterns 2 are formed in a thin film by sputtering or vapor deposition, and are arranged in parallel with each other substantially in parallel with the short side end surfaces 1b and 1c of the dielectric substrate 1. Both ends of each resistance pattern 2 reach the long side end surfaces 1d and 1e. Long side end surface 1d, 1
e, input / output electrodes 4A ..., 4B ... are formed.
Are connected to input / output electrodes 4A and 4B, respectively. The input / output electrodes 4A and 4B extend to the back side. Then, the dielectric substrate surface 1a
The whole is covered with an insulator film 5, and the surfaces of the resistance patterns 2... Are covered with the insulator film 5.

The ground pattern 3 is buried inside the dielectric substrate 1 as shown in the sectional views of FIGS.
That is, the ground pattern 3 is buried in the dielectric substrate 1 in parallel with the surface 1a and slightly below the surface 1a, and the ground pattern 3 and each of the resistance patterns 2. They are opposed to each other in a spaced state. The ground pattern 3 has a size that covers the entire formation region of the resistance patterns 2. Also,
Both ends 3a, 3b of the ground pattern 3 reach the short side end surfaces 1b, 1c of the dielectric substrate 1, and these end surfaces
b, 1c. The short side end surfaces 1b, 1c
Are formed with ground electrodes 6 and 7, respectively, and the ground pattern 3 is connected to the ground electrodes 6 and 7.

The noise filter 10 thus formed
Generates a distributed capacitance C between each of the resistance patterns 2 and the ground pattern 3, and constitutes a multiple RC composite component as shown in the equivalent circuit diagram of FIG. Therefore, EMI
When a high-frequency signal requiring a countermeasure is input to each of the resistance patterns 2, the generated distributed capacitance C reduces the impedance on the input side and removes noise in the signal. that time,
Since there is no inductance component in these circuits, neither distortion of the signal waveform such as ringing nor secondary radiation occurs.

Further, the formation pitch of the RC composite parts formed in a multiple connection can be easily changed by changing the formation intervals of the resistance patterns 2 formed in parallel. Therefore, it is relatively easy to form the noise filter 10 in multiples at a narrower pitch.

In the above-described embodiment, the resistance patterns 2 are formed in a long rectangular shape between the long side end surfaces 1d and 1e. However, the present invention is not limited to this. The spiral pattern as shown in FIG. Shape, meander shape as shown in FIG. 6, or zigzag shape as shown in FIG.

Further, in the above-described embodiment, the ground pattern 3 is formed on substantially one surface inside the dielectric substrate 1, but the invention is not limited to this, and the ground pattern 2 may be divided into two or more in the longitudinal direction.

[0016]

As described above, according to the present invention, since the inductance component is eliminated from the components of the noise filter, undesired phenomena such as resonance phenomena and secondary radiation phenomena leading to signal distortion do not occur. Noise removal without noise. In addition, since the noise filter is composed of the resistor pattern formed in parallel and the ground pattern opposed to the resistor pattern via the dielectric substrate, the noise filter can be multiplied, and the noise filter can be multiplied. It has become possible to form noise filters at a narrow pitch on a single dielectric substrate. Therefore, the size of the noise filter can be reduced. further,
Embed the ground pattern parallel to one surface of the dielectric substrate (= resistor pattern) and adjust the separation distance between the resistor pattern and the ground pattern (embedding depth position of the ground pattern) Can be obtained. Thus, the capacitance formed between the ground pattern and the resistance pattern can be arbitrarily provided without variation, and a highly accurate noise filter can be designed with a high degree of freedom. In addition, since the resistor pattern is formed of a thin-film resistor, the dimensional accuracy of the resistor pattern to be formed can be made higher, and the accuracy of the noise filter can be further improved.

Further, since the noise filter is composed of the resistor pattern formed in parallel and the ground pattern formed opposite to the resistor pattern via the dielectric substrate, it is possible to increase the number of noise filters. It has become possible to form a continuous noise filter at a narrow pitch on a single dielectric substrate. Therefore, the size of the noise filter can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of one embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is an equivalent circuit diagram of the embodiment.

FIG. 5 is a first modification of the resistance pattern.

FIG. 6 is a second modification of the resistance pattern.

FIG. 7 is a third modification of the resistance pattern.

FIG. 8 is an equivalent circuit diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dielectric substrate 2 Resistance pattern 3 Ground pattern

Claims (1)

(57) [Claims] 1. A substantially rectangular dielectric substrate comprising a thin film resistor.
Resistor pads arranged in parallel with each other on one surface of the plate (1)
A turn (2) and the inside of the dielectric substrate (1);
The resistance pattern is buried in parallel with one surface
And a ground pattern (3) opposed to the dielectric substrate.
(1) is pulled out to one of the opposed end faces,
Connected to the input / output electrodes (4A, 4B)
And an end of the ground pattern (3) is connected to the dielectric substrate.
(1) is pulled out to the other opposing end face and
A noise filter which is connected to provided ground electrodes (6, 7) .