JPH10335573A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mount a variable passive element on a resin-molded electronic device. SOLUTION: An electronic device is provided with a first resin-molded section 2 formed by sealing an electric circuit constituted of an active element and a passive element with a resin and a second resin-molded section 4 formed by sealing an optical element with a transparent resin. A variable passive element 12 is housed in a recessed section 10 integrally formed at the side edge section of the second resin-molded section 4 and electrically connected to the electric circuit. At a prescribed position of the recessed section 10, a regulating section 14 of a projection, etc., is provided at the position of an angle of rotation at which the electrical characteristic of the variable passive element 12 becomes discontinuous. When the element 12 is adjusted by using a jig, the electrical characteristic of the element 12 can be prevented from becoming discontinuous, because the element 2 comes into contact with the regulating section 14 on this side of the angle of rotation at which the electrical characteristic of the element 12 becomes discontinuous.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device which is formed into a module by resin sealing, and more particularly, to a semi-fixed resistance element or a variable capacitance capacitor whose electric characteristics change according to mechanical displacement of a movable portion. The present invention relates to an electronic device including a variable passive element.

[0002]

2. Description of the Related Art In an electronic device such as a hybrid IC, an electric circuit composed of an active element such as a transistor and a fixed passive element such as a resistor or a capacitor having fixed electric characteristics is mounted on a lead frame. A module is achieved by sealing these with resin. However, since it is necessary to fine-tune the electric circuit after resin sealing, a variable passive element for fine adjustment, such as a variable resistance element or a variable capacitor, is mounted on one end of the lead frame in an exposed state without resin sealing. Was.

[0003]

However, in the former electronic device in which the variable passive element is exposed, the portion of the lead frame that is not sealed with resin is easily bent, and the variable passive element is also damaged by the bending. There was a problem that it was easy. For example, in an optical module used for optical communication, etc., in order to reduce the size and weight, an active element and a fixed passive element for forming an electric circuit are mounted on an extremely thin and easily bendable lead frame, and these are sealed with a resin. The structure which keeps mechanical strength by the resin molding part formed by doing is employ | adopted. For this reason, the variable passive element exposed and mounted on the lead frame separated from the resin molded part is placed in a state of extremely low mechanical strength, and requires careful handling.

In some cases, a variable passive element having low mechanical strength and a storage structure for reinforcing a mounting portion thereof are provided separately from the electronic device, but this causes a substantial increase in the size of the electronic device. As a result, there is a problem that the effects of miniaturization and weight reduction by resin sealing cannot be sufficiently enjoyed.

Further, the variable resistance element has a movable part such as a slider that slides on the resistor, and the relative displacement between the slider and the resistor is determined by using a jig such as a small driver. The resistance value is changed by changing the resistance value. In the rotary type variable resistance element, the slider can rotate at an arbitrary angle. On the other hand, the resistor is inevitably completely set to set a resistance value according to the rotation angle of the slider. Landolt ring (Landolt ri)
ng). Therefore, if the slider is inadvertently rotated during fine adjustment, the resistance value becomes substantially infinite when passing through the cut portion of the resistor, and an excessive current flows into the electric circuit. This causes problems such as electrical damage. In addition, the variable capacitor also has a movable portion for changing the capacitance, and there is a position where the capacitance value is discontinuous depending on the position of the movable portion. Had similar problems.

As described above, in order to prevent electrical breakage due to discontinuous characteristics, a fixed resistor or a fixed capacitor can be added in series, but there is a problem that the number of components is increased. there were.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides an electronic device having a structure for protecting a variable passive element and restricting discontinuous electrical characteristics of the variable passive element. The purpose is to do.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a variable passive element whose electrical characteristics change according to a mechanical displacement of a movable part and a variable passive element arranged around the variable passive element. In an electronic device in which the active element and the fixed passive element are mounted on a lead frame and the respective elements are electrically wired, the active element disposed around the variable passive element except for the variable passive element is provided. The variable passive element is provided in a region surrounded by a resin molded part formed by the resin sealing by integrally sealing the element and the fixed passive element with the resin.

Further, a restricting means for restricting a mechanical displacement of a movable portion of the variable passive element within a predetermined range is integrally formed at one end of the resin molded portion.

[0010]

The mechanical strength of the electronic device itself can be improved by the resin molding formed by resin sealing. The variable passive element is surrounded by a resin molded portion formed by sealing the active element and the fixed passive element disposed around the variable passive element with resin, thereby simultaneously protecting the variable passive element. When the variable passive element is operated using the jig, the jig abuts on the restricting means provided at a predetermined position, and further displacement is regulated, so that the electrical characteristics of the variable passive element become discontinuous. Prevent the situation before it happens.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical module used for optical communication and the like will be described as an embodiment of the present invention. The structure of the optical module will be described with reference to FIG. 1. A first resin formed by resin-sealing a first mounting portion of a metal lead frame and an electric circuit (not shown) mounted on the mounting portion. A molded part 2, a second mounting part provided on another part of the lead frame, and a second resin molded part 4 formed by resin-sealing an optical element mounted on the mounting part are provided.
The first and second resin molded portions 2 and 4 are mechanically connected by a plurality of inner leads 6 formed in advance on a lead frame, and the inner leads 6 allow the optical element and the electric circuit to be connected. Are electrically connected. Further, a plurality of external lead terminals 8 extend from the rear end of the first resin molded part 2 to the outside.

In the optical module for transmission, an optical element (ie, a light emitting element) such as a semiconductor laser or a light emitting diode is resin-sealed in the second resin molded part 4. The electric circuit includes a driving circuit for driving the light emitting element.

In the optical module for reception, an optical element (ie, a light receiving element) such as a pin photodiode or a Schottky diode is resin-sealed in the second resin molded part 4, and the first resin molded part 2 The inner electric circuit is provided with a preamplifier circuit for amplifying a detection signal detected by these light receiving elements.

Further, at the tip of the second resin molded part 4,
A condenser lens 16 whose optical axis is aligned with the light emitting surface of the light emitting element or the light receiving surface of the light receiving element, which is sealed with resin, is integrally formed.

A substantially rectangular concave portion 10 exposing a predetermined region of the first mounting portion is provided at a side end portion of the first resin molded portion 2.
A small variable passive element 12 such as a semi-fixed resistance element for fine adjustment or a variable capacitor is accommodated in the recess 10 and fixed to the predetermined area, so that the electric circuit is electrically connected to the electric circuit. Connected.

At a predetermined position on the inner side wall of the concave portion 10, a restricting portion 14 facing the movable portion of the variable passive element 12 is integrally formed. This restricting section 14 is, for example, shown in FIG.
As shown in (b), one or two or more projections facing the variable passive element 12 housed in the concave portion 10 or facing the variable passive element 12 as shown in FIGS. This is realized by one or two or more steps.

When the movable portion of the variable passive element 12 is mechanically displaced (rotated) using a jig such as a small driver, the electric characteristics of the variable passive element 12 are discontinuous. It is provided at a position where the jig abuts just before the rotation angle. Therefore, when finely adjusting the electric circuit sealed with resin in the first resin molded part 2, a jig is used within a range of the rotation angle at which the electric characteristics of the variable passive element 12 continuously change. The movable part of the variable passive element 12 can be freely rotated to set desired electrical characteristics such as a resistance value and a capacitance value, while the rotation in which the electrical characteristics of the variable passive element 12 become discontinuous can be performed. The rotation of the movable portion within the range of the corner is prohibited by the restricting portion 14 so that an accident such as breakage of an electric circuit is prevented.

Next, a manufacturing process of the optical module will be described. In FIG. 3, a first mounting portion 20 of the lead frame 18 on which a predetermined wiring pattern is formed,
The electric circuit is configured by fixing an active element or a passive element having a fixed value by die bonding. here,
Region 22 of first mounting portion 20 corresponding to recess 10
The wiring pattern of the lead frame 18 is designed in advance so that the above-described electric circuit is formed by arranging these active elements and fixed passive elements in the peripheral portion except for the above. Furthermore, the second mounting portion 24 of the lead frame 18
The optical element LD is fixed by die bonding.

Next, the lead frame 18 is mounted between the lower mold 26 and the upper mold 28 having a predetermined shape with the mounting surfaces of the optical element LD and the electric circuit facing downward. Then, by introducing a thermoplastic resin transparent to the emission wavelength sensitivity or the reception wavelength sensitivity of the optical element LD, the first mounting portion 20
And a first resin molded part 2 for resin-sealing the electric circuit
Then, a second resin molded part 4 for sealing the second mounting part 24 and the optical element LD with resin is formed.

That is, as shown in the vertical sectional view of FIG. 4, the lower mold 26 and the upper mold 28 have concave portions 30 and 32 serving as cavities for forming the first resin molded portion 2, 2
The concave portions 34 and 36 serving as cavities for forming the resin molded portion 4 are formed by processing. Further, the upper mold 28
The concave portion 32 is provided with a concave portion 10 for accommodating the variable passive element 12 and a projection 38 having a predetermined shape for forming the regulating portion 14. In the recess 30 of the lower mold 26, a projection 3 of the same shape facing the projection 38 of the upper mold 28 is provided.
8 ′ is provided, and the condensing lens 16
Is provided. Then, the lead frame 18 is positioned and clamped between the lower mold 26 and the upper mold 28, and the first resin molded part 2 and the second resin molded part 4 are introduced by introducing a transparent resin. To form

Next, the resin-sealed lead frame 18
Are removed from the molds 26 and 28, unnecessary portions of the lead frame 18 are cut off, and the variable passive element 12 such as a semi-fixed resistance element or a variable capacitor is placed in the concave portion 10 formed in the first resin molded part 2. Stored first mounting part 20
The electric circuit is electrically connected to the electric circuit by being fixed to the predetermined region 22 of the above. Furthermore, the optical module shown in FIG. 1 is formed by bending the exposed inner leads 6 and external lead terminals 8.

As described above, according to this embodiment, since the restricting portion 14 for restricting the rotation angle of the movable portion of the variable passive element 12 to a predetermined range is provided, when the variable passive element 12 is adjusted, In this way, it is possible to prevent a situation in which the target characteristic is discontinuous, and thus to prevent an accident such as breakage of an electric circuit to be finely adjusted. Further, since the mechanical strength can be improved by housing the variable resistance element 12 in the concave portion 10 formed in the first resin forming portion 2, the variable resistance element 12 can be protected from bending due to external force and the like. Can be. Furthermore, by encapsulating the optical module LD with a resin transparent to the light receiving wavelength sensitivity or light emitting wavelength sensitivity, an optical spot lift is used when soldering to a substrate or the like of an electronic device using the optical module. Can be applied.

Although the description has been given of the optical module mounting either the light emitting element or the light receiving element, the present invention is not limited to this. It can also be adapted to modules.

Although the optical module has been described as a representative, the present invention is not limited to the optical module.
The present invention can be applied to various electronic devices that include a variable passive element and are modularized by a resin mold.

[0025]

As described above, according to the present invention, the active element and the fixed passive element disposed around the variable passive element are integrally sealed with resin, and the variable passive element is surrounded by the resin molding. The movable passive element can be protected by the resin molded portion.

Since the regulating means is formed at a predetermined position in the concave portion, when the variable passive element is operated using the jig, the displacement of the jig is regulated by the regulating means, and the electric power of the variable passive element is controlled. It is possible to prevent a situation in which the target characteristic becomes discontinuous.

By molding with a resin transparent to the wavelength of light used for spot reflow, effects such as the use of optical spot reflow can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an external structure of an optical module according to an embodiment of the present invention.

FIG. 2 is a plan view of a main part showing a mounting structure of a variable passive element and a shape of a restricting means.

FIG. 3 is a perspective view for explaining a manufacturing process of the optical module.

FIG. 4 is a longitudinal sectional view for further describing a manufacturing process of the optical module.

[Explanation of symbols]

2 1st resin molded part, 4 2nd resin molded part, 6 ... inner lead, 8 ... external lead terminal, 10 ... concave part, 12
... variable light receiving element, 14 ... regulator, 16 ... condenser lens, 2
0: first mounting portion, 22: area, 24: second mounting portion,
26: Upper mold, 28: Lower mold, 38, 38 ': Projection, LD: Optical element.

Claims (6)

[Claims] 1. A variable passive element whose electrical characteristics change according to a mechanical displacement of a movable part, and an active element and a fixed passive element disposed around the variable passive element are mounted on a lead frame, and each of them is mounted on a lead frame. In an electronic device in which the elements are electrically wired, except for the variable passive element, the active element and the fixed passive element disposed around the variable passive element are integrally sealed with resin, The electronic device, wherein the variable passive element is provided in a region surrounded by a resin molded part formed by the resin sealing. 2. A first mounting part of a lead frame, comprising: a variable passive element whose electrical characteristics change according to a mechanical displacement of a movable part; and an active element and a fixed passive element arranged around the variable passive element. An electronic device, wherein at least one of the light emitting element and the light receiving element is mounted on a second mounting portion of the lead frame, and the respective elements are electrically wired. An element is integrally sealed together with the second mounting portion with a resin transparent to emission wavelength sensitivity or reception wavelength sensitivity, and the active element disposed around the variable passive element except for the variable passive element. And the fixed passive element is integrally sealed together with the first mounting portion by a resin, so that the variable passive element is provided in a region surrounded by a resin molded portion formed by the resin sealing. The electronic device according to claim Rukoto. 3. A restricting means for restricting a mechanical displacement amount of a movable portion of the variable passive element within a predetermined range is formed at one end of the resin molded portion.
Or the electronic device according to any one of 2. 4. The electronic device according to claim 3, wherein the restricting means is a projection integrally formed on the resin molded portion so as to face a movable portion of the variable passive element. 5. The electronic device according to claim 3, wherein the restricting means is a step formed integrally with the resin molded portion so as to face a movable portion of the variable passive element. 6. The variable passive element according to claim 1, wherein the variable passive element is a semi-fixed resistance element or a variable capacitor.
The electronic device according to any one of claims 1 to 5.