KR20010021286A - Variable inductance element - Google Patents

Abstract

PURPOSE: To raise a Q-value while an inductance is efficiently fine-adjusted by separating a specified island region from a conductor provided on the surface of an insulating substrate by trimming so that a zigzag inductor pattern is formed. CONSTITUTION: After the upper surface of an insulating substrate 1 is polished, a wide-area conductor pattern 2 is formed on it by a thin-film forming method. Then a laser beam is emitted to form an U-shape trimming groove 10 on a variable inductance element 9, and two island-like square regions 3 are separated from the conductor pattern 2 to form a zigzag inductor pattern 4. Here, a pattern width V of a part of the insulating substrate 1 of the inductor pattern 4 which extends parallel in its widthwise direction is equal to a pattern width H of a part which extends parallel in its lengthwise direction, with a distance D between legs of the U-shape trimming group 10 being set twice the pattern width V or longer.

Description

Variable Inductance Element

The present invention relates to a variable inductance element, and more particularly to a variable inductance element used in a mobile communication device such as a mobile telephone.

In recent years, mobile communication devices such as portable telephones have become extremely miniaturized, and there is a strong demand for reducing the size of electronic components used in the devices. In addition, when the high frequency is used in a mobile communication device, the circuit of the device becomes more complicated, and furthermore, the electronic components mounted in the device are required to have uniform characteristics and high precision.

However, even if each electronic component including parameters having uniform characteristics and high precision is used to form a circuit, the parameter variation of each mounted electronic component has an overall combined effect, and in some cases, a desired function. This can be done. Thus, if necessary, some parameters of the electronic components constituting the electronic circuit can be changed. Some electronic components may not be able to perform the desired circuit function even if the parameters are finely adjusted.

8 shows an example of such a conventional fine adjustment method. According to the fine adjustment method, a trimming area 34 serving as an inductance element is formed between the signal patterns 31 and 32. Trimming area 34 is irradiated with a laser beam emitted from a laser trimming machine (not shown) when the beam moves linearly. The trimming area 34 is partially removed in accordance with the movement track of the laser beam, resulting in a linear trimming groove 35. Therefore, the area of the trimming region 34 is changed so that the inductance of the trimming region 34 is finely adjusted.

In the conventional variable inductance element, if the area of the trimming region 34 is small, the variable width of the inductance is narrowed, so that the circuit cannot be finely adjusted. Therefore, the trimming area 34 has a large area. On the other hand, when using a high precision laser trimming machine, the groove width (trim width) of the trimming groove 35 formed by one trim is generally thin. For this reason, when a wider trimming width is required, radiation by the laser must be repeated when the radiation positions move in parallel as shown in FIG. Therefore, it takes a long time to make a fine adjustment.

Accordingly, it is an object of the present invention to provide a variable inductance comprising a high Q factor in which the inductance can be effectively and precisely adjusted.

1 is a perspective view showing the appearance of a variable inductance element according to a first embodiment of the present invention;

2 is a perspective view showing a method of changing the inductance of the variable inductance element of FIG. 1;

3 is a plan view of a tortuous inductor pattern of the variable inductance element of FIG. 1;

4 is a plan view showing a conductor pattern of the variable inductor element according to the second embodiment of the present invention;

5 is a plan view showing a tortuous inductance pattern of the variable inductance element of FIG. 4;

6 is a plan view showing a modified embodiment of the tortuous inductor pattern;

7 is a plan view showing another modified embodiment of the serpentine inductor pattern;

8 shows a method of adjusting an inductance value of a conventional variable inductance device,

9 illustrates a problem of a method of adjusting an inductance value of a conventional variable inductance device.

<Explanation of symbols for the main parts of the drawings>

1 ... insulated substrate 2, 22 ... conductor pattern

3, 23 ... island shape rectangular part 4, 24 ... inductor pattern

9, 20 ... Inductance element 10, 27 ... U-shaped trimming groove

21 Circuit board D distance

V, H ... Width L ... Pulse Laser Beam

In order to achieve the above object, according to the present invention, a substantially twisted inductor pattern bordered by trimming a conductor provided on the surface of the insulated substrate such that a) the insulated substrate and b) a predetermined island portion is separated from the inductor pattern. There is provided a variable inductance element comprising a.

In addition to the above configuration, by changing the shape and size of the trimming pattern, the number and area of the island-like portions and the distance between the island-like portions change. For this reason, the width and the number of twisting of the inductor pattern change, thereby changing the inductance. Preferably, the pattern width of the substantially inductance is set to a constant value, and the distance between neighboring portions of the substantially inductor pattern is made to be twice the pattern width of the inductor pattern, thereby creating The distance between the magnetic fields can be increased, and the magnetic fields can be prevented from interfering with each other.

Hereinafter, embodiments of the variable inductance element of the present invention will be described with reference to the accompanying drawings.

(Example)

(First embodiment)

As shown in FIG. 1, after the upper surface of the insulating substrate 1 is polished to have a smooth surface, the conductor pattern 2 having a large area is formed on the upper surface of the insulating substrate 1 by a thin film forming method such as thick film printing or photolithography. Is formed. According to the thick film printing method, a mask having an opening is made in a desired pattern so as to cover the top surface of the insulating substrate 1, and an electrically conductive paste is electrically applied on the mask, whereby a conductor having a relatively large thickness The upper surface of the insulating substrate 1 exposed through the opening of the mask is formed in a desired pattern (conductor pattern 2 in the first embodiment).

Examples of photolithography are described below. A relatively thin conductive film is formed over substantially the entire upper surface of the insulating substrate 1. Then, a resistive film (for example, a photosensitive resin or the like) is formed almost all over the conductive film by spin coating or printing. Next, a mask film having a predetermined image pattern is disposed to cover the upper surface of the resistive film, and the desired portion of the resistive film is cured by radiation such as UV light. After this, the resistive film is removed, and its cured portion remains, and the exposed portion of the conductive film is removed, thereby forming a conductor in a desired pattern, and then the cured resistive film is also removed.

Next, according to another photolithographic method, a photosensitive conductive paste can be applied on the upper surface of the insulating substrate 1, and a mask film having a predetermined image pattern formed thereon covers the photosensitive conductive paste, and is then exposed and developed. . The conductive pattern 2 is provided almost all over the insulating substrate 1.

One end 2a of the conductive pattern 2 is drawn to the left rear portion of the insulating substrate 1 as shown in FIGS. 1, 2 and 3, while the other end 2b is the right front portion of the insulating substrate 1 as shown in FIGS. 1, 2 and 3 Is derived. Glass, glass ceramics, alumina, ferrite, and the like may be used as the material of the insulating substrate 1. Ag, Ag-Pd, Cu, Au, Ni, Al, or the like may be used as the material of the conductor pattern 2.

In addition, a liquid insulating material (polymide, etc.) is coated on the entire upper surface of the insulating substrate 1 by spin coating and printing, and dried, thereby forming an insulating protective film (not shown) covering the conductor pattern 2. .

Next, external input / output electrodes 6 and 7 are provided in the longitudinal direction on each end of the insulating substrate 1, respectively. The external input / output electrode 6 is electrically connected to the end 2a of the conductor pattern 2, and the external input / output electrode 7 is electrically connected to the end 2b of the conductor pattern 2. The external input / output electrodes 6 and 7 are formed by coating and firing with conductive pastes such as Ag, Ag-Pd, Cu, Ni, NiCr, and NiCu, and drying or wet plating, or by mixing the coating with the firing and plating. The variable inductance element 9 obtained as described above is mounted on a printed circuit board or the like and the conductor pattern 2 is trimmed. In particular, as shown in FIG. 2, the upper surface of the variable inductance element 9 is radiated with the pulse laser beam L while the pulse laser beam L is moved, so that the U-shaped trimming groove 10 is formed in the variable inductance element 9. As shown in FIG. 3, the two trimming grooves 10 separate the island-shaped two rectangular portions 3 from the conductor pattern 2 to form a tortuous inductor pattern 4. Terminals 2a and 2b of the serpentine inductor pattern 4 are electrically connected to the external input / output electrodes 6 and 7, respectively.

By changing the shape and size of the pattern of the trimming groove 10, the number of island-shaped portions 3 (two in this embodiment), the area, and the distance between the island-shaped portions 3 change. In this way, by changing the width and the number of twists of the inductor pattern 4, the inductance of the inductor pattern 4 can be continuously changed over a wide range, and can be effectively and precisely adjusted to the desired inductance. In this case, the Q factor required for the high frequency circuit may be provided to the inductance element 9.

By forming the U-shaped trimming grooves 10 in the conductor pattern 2 to form the serpentine inductor pattern 4, the inductance can be adjusted over a wider range as compared with the conventional linear trimming. For example, when the size of the variable inductance element is 2.0 mm x 1.25 mm, the conventional linear trimming can only adjust the range of about 0.15 nH. On the other hand, according to the U-shaped pattern trimming as in the first embodiment, the range of about 1.0nH (about 6.7 times wider than that of the conventional trimming method) is adjusted.

In addition, in the first embodiment of the present invention, the portion of the pattern width V of the inductor pattern 4 extending parallel to the width direction of the insulating substrate 1 is the portion of its pattern width H extending parallel to the longitudinal direction of the insulating substrate 1. The distance D between the leg portions of each U-shaped trimming groove 10 is determined to be at least two times longer than the pattern width V (or pattern width H). In this way, the pattern width of inductor pattern 4 is substantially constant over its entire length. The distance between neighboring portions of inductor pattern 4 is at least twice as long as the pattern width. As a result, the distance between the magnetic fields generated in the neighboring portion of the inductor pattern 4 becomes far, which prevents the magnetic fields from interfering with each other. Therefore, the Q factor of the inductor element 9 can be higher. Specifically, the Q factor can be increased by about 40% compared to that of the conventional variable inductance element.

The trimming of the conductor pattern 2 is not limited to the method using the laser beam, but can be performed by any method such as sand blasting. Moreover, trimming groove 10 need not be provided. If the conductor pattern 2 is electrically cut, it is not necessary to form the trimming groove 10 in a physical sense.

(Second embodiment)

In the second embodiment of the present invention, the conductor pattern 22 is formed directly on the printed circuit board 21. Conductor pattern 22 serving as inductance element 20 is provided between signal patterns 28 and 29. As shown in FIG. 5, by radiating the conductor pattern 22 with the pulsed laser beam as the beam moves, a portion of the conductor pattern 22 radiated by the laser beam is removed due to energy to form a U-shaped trimming groove 27 in the conductor pattern 22. As shown in FIG. Two island-shaped rectangular portions 23 are separated from the conductor pattern 22 to form a trimming groove 27 with a tortuous inductor pattern 24. Both ends of the zigzag inductor pattern 24 are electrically connected to signal patterns 28 and 29, respectively.

By varying the shape and size of the pattern of the trimming groove 27, the width and the number of twists of the tortuous inductor pattern 24 can be changed, and the inductance value of the tortuous inductor pattern 24 can vary continuously over a wide range. Thus, the inductance can be effectively and precisely adjusted to the desired value.

(Other embodiment)

The variable inductance element of the present invention is not limited to the embodiment described above. Changes and variations may be made within the spirit and scope of the invention.

The previous embodiment describes the production of each variable inductance element. In the case of mass production of variable inductance elements effectively, a mother substrate (wafer) is provided which is provided with a plurality of variable inductance elements, and in the final process, wafers are used for dicing, scribe break, laser cutting, etc. By cutting to product size. In addition, the outline of the inductor pattern may have a serpentine shape. For example, it may be a pattern of a shape including a sine curve.

In addition, in the variable inductance element, the trimming groove 10 can be formed in such a manner that one island portion 3 (see FIG. 6) is created. In addition, trimming groove 10 may be formed to produce three island shaped portions 3 (see FIG. 7).

As seen in the foregoing description, in accordance with the present invention, by varying the shape and size of the trimming pattern, the width and the number of twists of the tortuous inductor pattern are changed such that the inductance of the inductor pattern changes. Thus, the inductance can be continuously and effectively finely adjusted over a wide range. High precision variable inductance elements with desired inductance and high Q factors can be provided.

By setting the pattern width of the substantially inductance pattern to a substantially constant value, and by setting the distance between neighboring portions of the substantially inductor pattern at least twice as long as the pattern width, The distance between the magnetic fields generated is greater, which can prevent the magnetic fields from interfering with each other. Therefore, the Q factor of the inductance element can be further increased.

Claims (2)

Insulated substrate; And And the substantially inflexible inductor pattern defined by trimming a conductor provided on the surface of the insulated substrate to separate a predetermined island portion from the inductor pattern. The pattern width of the substantially inductor pattern is substantially constant, wherein the distance between neighboring portions of the substantially inductor pattern is at least twice as long as the pattern width. Variable inductance element.