JP2005285335A - Circuit module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve transmission performance of a differential signal using a lead pin of a circuit module and an outer circuit with a simple structure. <P>SOLUTION: In a module case 3, a plurality of lead pins 4 are projected in a configuration penetrating a case wall from inside to outside of the case. Each lead pin 4 is connected with a circuit board 2 in the module case 3, respectively. The plurality of lead pins 4 comprise a pair of adjacent differential signal transmission lead pins 4 (4B<SB>1</SB>, 4B<SB>2</SB>) for transmitting the differential signal, and a dielectric body 12B is provided between the adjacent differential signal transmission lead pins 4 (4B<SB>1</SB>, 4B<SB>2</SB>). With this derivative 12B, the differential impedance between the differential signal transmission lead pins 4 (4B<SB>1</SB>, 4B<SB>2</SB>) can be adjusted, and impedance between the differential signal transmission lead pins 4 (4B<SB>1</SB>, 4B<SB>2</SB>) and a differential signal transmission circuit formed on a circuit board 2 can be matched. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a circuit module having a configuration for electrically connecting to an external circuit using a lead pin.

  FIG. 7A shows a simplified schematic cross-sectional view of one embodiment of the circuit module, and FIG. 7B shows a schematic exploded view of the circuit module. The circuit module 1 includes a circuit board 2, a module case 3 for housing the circuit board 2, and a plurality of lead pins 4 protruding from the inside of the module case 3 toward the outside through the case wall. And is configured.

  The circuit board 2 is provided with electronic components (not shown), circuit patterns (not shown) and the like to form an electric circuit. The module case 3 includes an upper case 5 and a lower case 6, and the circuit board 2 is accommodated in an internal space of the module case 3 formed by combining the upper case 5 and the lower case 6.

  The plurality of lead pins 4 are respectively arranged in such a manner as to penetrate the case wall of the lower case 6, and the tip inside the case of each lead pin 4 is in a lead pin insertion through hole 7 formed in the circuit board 2. It is inserted and fixed to the circuit board 2 with, for example, solder. All of the plurality of lead pins 4 or a part of the lead pins 4 specified in advance are electrically connected to the electric circuit of the circuit board 2 and serve as lead pins for transmitting an electric signal.

  Such a circuit module 1 is mounted on the mother board 8 with the lower case 6 facing the mother board 8 side, for example. In a state in which the circuit module 1 is mounted on the mother board 8, for example, the protruding tip portions of the lead pins 4 are respectively inserted into through holes 10 for pin insertion formed in the mother board 8, and are, for example, soldered to the mother board 8. Connection is fixed. Thereby, the lead pin 4 for electric signal transmission is electrically connected to the electric circuit formed on the mother board 8. For this reason, the electric circuit of the circuit board 2 in the module case 3 can be electrically connected to the electric circuit of the external motherboard 8 via the lead pins 4 for electric signal transmission.

JP 10-335563 A JP 2002-57266 A

  In recent years, for example, electric signals for transmitting information tend to have higher frequencies. As electrical signals become higher in frequency, the noise problem (that is, the problem that it becomes difficult to transmit information accurately due to noise) increases, so as a countermeasure against the noise problem, information is transmitted in the form of differential signals. There is a case.

When a differential signal is energized in the electric circuit of the circuit board 2 of the circuit module 1, the circuit board 2 is provided with adjacent differential signal transmission lines forming a pair for transmitting the differential signal. It is done. Further, when conducting a differential signal between the electric circuit of the circuit board 2 and an external electric circuit of the motherboard 8, for example, at least a pair of adjacent differential signal transmissions among the plurality of lead pins 4. Lead pins 4 are included. For example, the lead pins 4A ₁ and 4A ₂ forming a pair as shown in FIG. 7 (b) are differential signal transmission lead pins for inputting a differential signal from the mother board 8 side to the electric circuit of the circuit board 2. The lead pins 4B ₁ and 4B ₂ forming another pair constitute differential signal transmission lead pins for outputting a differential signal from the electric circuit of the circuit board 2 to the mother board 8 side.

  By the way, adjacent differential signal transmission lines formed on the circuit board 2 and the mother board 8 are provided so that the differential impedance between the lines has a predetermined set value such as 100Ω. Yes. It is desirable that the adjacent differential signal transmission lead pins 4 are also provided so that the differential impedance between the adjacent differential signal transmission lead pins 4 becomes a set value (for example, 100Ω). This is because the differential impedance between the differential signal transmission lead pins 4 is different from the differential impedance between the differential signal transmission lines of the circuit board 2 and the motherboard 8 (that is, the state of impedance mismatch). When the differential signal transmission line of the circuit board 2 or the mother board 8 and the differential signal transmission lead pin 4 are connected to each other, a part of the differential signal is reflected due to impedance mismatch. This causes a problem of adversely affecting information transmission of differential signals. Therefore, in order to prevent such a problem and improve the performance of information transmission by differential signals, the differential impedance between the differential signal transmission lead pins 4 is the differential signal of the circuit board 2 or the motherboard 8. The differential impedance between the transmission lines is preferably the same.

  However, the configuration related to the lead pins 4 such as the pitch interval between the lead pins 4 is often determined by the standard, and the differential impedance between the adjacent lead pins 4 for differential signal transmission is reduced due to the low degree of design freedom. It is difficult to achieve the same differential impedance between the differential signal transmission lines of the circuit board 2 and the motherboard 8.

  Various methods have been proposed to solve such problems (see, for example, Patent Documents 1 and 2). However, in these methods, the structure is complicated and the manufacture is not easy. Actually, the differential impedance between the lead pins 4 for differential signal transmission is set to the differential signal transmission of the circuit board 2 or the motherboard 8. There is a problem that it is difficult to match the differential impedance between the two lines, which is not satisfactory.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and its object is to easily match the impedance of a differential signal transmission lead pin to a differential signal transmission line on a circuit board with a simple structure. Another object of the present invention is to provide a circuit module having a configuration that can be made.

  In order to achieve the above object, the present invention has the following configuration as means for solving the above problems. That is, according to the present invention, a plurality of lead pins are formed to protrude from the inside of the module case to the outside through the case wall, and the electric circuit formed on the circuit board housed inside the module case is a predetermined circuit. In a circuit module having a configuration in which a lead pin is electrically connected to an external circuit, the plurality of lead pins include adjacent differential signal transmission lead pins that form a pair for transmitting differential signals, Between the pair of adjacent differential signal transmission lead pins, a dielectric is provided in a portion on the protruding tip side from the circuit board except for the protruding tip portion, and between the other lead pins, a case wall is provided. It is characterized in that no dielectric is interposed in the portion protruding from the surface.

  Further, according to the present invention, a plurality of lead pins project from the inside of the module case to the outside so as to protrude through the case wall, and the electric circuit formed on the circuit board accommodated inside the module case is a predetermined circuit. In a circuit module having a configuration in which a lead pin is electrically connected to an external circuit, the plurality of lead pins include a pair of adjacent differential signal transmission lead pins for transmitting a differential signal. Each lead pin is covered with a dielectric on the projecting tip side from the circuit board except for the projecting tip, and between the at least one adjacent lead pins, the electrical Another feature is that a gap for adjusting the degree of coupling is provided.

  According to the present invention, by providing a configuration in which a dielectric is interposed between adjacent pairs of differential signal transmission lead pins, the capacitance between the differential signal transmission lead pins is such that the space between the lead pins is air. Increased compared to some cases. Thereby, the capacitive coupling between the differential signal transmission lead pins is strengthened, and the differential impedance between the differential signal transmission lead pins can be reduced. From this, the following effects can be obtained.

  In other words, the interval between the differential signal transmission lead pins cannot often be reduced due to, for example, the reason that it is determined by the standard, and for this reason, the differential impedance between the differential signal transmission lead pins is In many cases, it is larger than the differential impedance between the differential signal transmission lines provided on the circuit board. Therefore, there arises a problem that the impedance matching state between the differential signal transmission lead pin and the differential signal transmission line on the circuit board is not good.

  On the other hand, in the present invention, since the dielectric is provided between the differential signal transmission lead pins, the capacitance between the differential signal transmission lead pins can be increased by this dielectric. By reducing the differential impedance between the dynamic signal transmission lead pins, the differential impedance between the differential signal transmission lead pins can be brought close to the differential impedance between the differential signal transmission lines of the circuit board. Thereby, the impedance matching state between the differential signal transmission lead pin and the differential signal transmission line of the circuit board can be improved.

  In addition, the dielectric provided between the adjacent differential signal transmission lead pins provides a differential impedance between the adjacent differential signal transmission lead pins between the adjacent differential signal transmission lines of the connection circuit board. By providing a configuration made of a dielectric material having a dielectric constant for matching to the differential impedance, impedance matching between the differential signal transmission lead pin and the differential signal transmission line of the circuit board is improved. be able to. As a result, reflection of the differential signal due to impedance mismatch can be suppressed, so that the performance of information transmission using the differential signal can be improved, and the circuit with high reliability for differential signal transmission Modules can be provided.

  Furthermore, since the structure is very simple, such as a configuration in which a dielectric is interposed between adjacent pairs of differential signal transmission lead pins, the manufacturing is easy. Thus, the cost of the circuit module can be reduced by the ease of manufacture and the simple structure.

  Furthermore, the module case, the lead pin, and the dielectric provided between the adjacent differential signal transmission lead pins are integrally formed by a molding technique, thereby providing the module case with a differential signal transmission lead pin. The manufacturing process for attaching the capacitor and the manufacturing process for providing the dielectric between the adjacent differential signal transmission lead pins are not required, and the manufacturing process can be simplified. Thereby, further cost reduction of a circuit module can be achieved.

  Furthermore, if the gap between the lead pins for differential signal transmission deviates from the design value or if there is a gap between the lead pins for differential signal transmission, the differential impedance between the lead pins for differential signal transmission tends to deviate from the design value. The module case, lead pins, and dielectric provided between adjacent differential signal transmission lead pins are integrally molded using molding technology, so that the distance between the differential signal transmission lead pins is as designed. In addition, the dielectric can be formed without gaps between the differential signal transmission lead pins. For this reason, it becomes easy to manufacture so that the differential impedance between the differential signal transmission lead pins is as designed, and the differential signal transmission lead pins are connected to the differential signal transmission line on the circuit board with high impedance. Can be matched. Thereby, the reflection of the differential signal due to the impedance mismatch can be prevented more reliably, and the reliability of information transmission of the differential signal can be further improved.

  Further, between the other lead pins other than between the differential signal transmission lead pins adjacent to each other, by providing a configuration in which no dielectric is interposed in a portion protruding from the case wall, between the adjacent differential signal transmission lead pins Since the gap between the other lead pins is a gap, electrical coupling between the lead pins can be weakened by the gap. Thereby, for example, it can suppress that the electric current which each conducts to an adjacent lead pin through a space | gap causes mutual interference, and noise arises in each other's electric current, and various problems resulting from noise can be prevented.

  Another specific configuration of the present invention, that is, each lead pin is covered with a dielectric on the protruding tip side portion from the circuit board except for the protruding tip portion, and between at least one adjacent lead pin, When the gap for adjusting the electrical coupling degree between the adjacent lead pins is provided, a dielectric without gap is not provided between the adjacent differential signal transmission lead pins. To improve the impedance matching state between the differential signal transmission lead pin and the differential signal transmission line of the circuit board, and to solve the problem caused by the impedance mismatch. The effect that it can be avoided) can be obtained.

  In addition, since unnecessary electrical coupling can be suppressed between the lead pins adjacent to each other via the gap, currents respectively conducted to the adjacent lead pins via the gap cause mutual interference to generate mutual currents. Generation of noise can be suppressed, and various problems caused by noise can be prevented.

  Further, each lead pin has a configuration in which the portion on the protruding tip side from the circuit board is covered with a dielectric except for the protruding tip portion, so that the dielectric around each lead pin, and all the lead pins It becomes easy to integrally mold the module case by a molding technique. For this reason, it is possible to greatly simplify the manufacturing process of the circuit module, thereby reducing the cost of the circuit module. In addition, as described above, this configuration can easily make the interval between the differential signal transmission lead pins as designed, and can form a dielectric between the differential signal transmission lead pins without any gap. Therefore, the impedance matching between the differential signal transmission lead pin and the differential signal transmission line of the circuit board can be made better, and the problem caused by the impedance mismatch can be avoided more reliably. Can be obtained.

  By the way, for example, when the interval between adjacent differential signal transmission lead pins is not determined by the standard, the interval between the differential signal transmission lead pins can be provided without providing a dielectric between the differential signal transmission lead pins. It is conceivable to reduce the differential impedance between the differential signal transmission lead pins by increasing the capacitance between the differential signal transmission lead pins. However, narrowing the interval between the lead pins for differential signal transmission is limited due to manufacturing problems and the like, so if there is a gap between the lead pins for differential signal transmission, differential signal transmission It is difficult to match the differential impedance between the differential signal transmission lead pins to the differential impedance between the differential signal transmission lines on the circuit board by adjusting the distance between the lead pins for transmission. In contrast, in the present invention, a dielectric is provided between the differential signal transmission lead pins, and the capacitance between the differential signal transmission lead pins is increased by the dielectric to increase the difference between the differential signal transmission lead pins. It is possible to easily match the dynamic impedance to the differential impedance between the differential signal transmission lines on the circuit board, and obtain an effect that cannot be obtained when there is a gap between the differential signal transmission lead pins. Can do.

  Embodiments according to the present invention will be described below with reference to the drawings. In the description of the embodiment described below, the same components as those of the circuit module shown in FIG.

  FIG. 1A shows a simplified schematic cross-sectional view of the circuit module of the first embodiment. The module case 3 constituting the circuit module 1 includes an upper case 5 and a lower case 6, and the lower case 6 includes a plurality of cases in a manner of penetrating the case wall from the inside of the case to the outside. Lead pins 4 are arranged. FIG. 1B shows a plan view of the plurality of lead pins 4 and the lower case 6 viewed from the upper side of FIG. 1A is a cross-sectional view corresponding to the AA portion shown in FIG.

In the first embodiment, among the plurality of lead pins 4 provided in the circuit module 1, adjacent paired lead pins 4A ₁ and 4A ₂ form differential signal transmission lead pins on the signal input side, and The adjacent lead pins 4B ₁ and 4B ₂ forming a pair form a differential signal transmission lead pin on the signal output side.

Around between adjacent signal input side of the differential signal transmission lead pin 4A _1, 4A ₂ and for their differential signal transmission lead pin 4A _1, 4A _2, projecting distal end from the circuit board 2 except for the projecting distal portion P A dielectric 12A is provided in a side portion (hereinafter referred to as a mold designated portion) M. Similarly, also around the differential signal transmission signal output side adjacent lead pins 4B _1, and between the lead pin 4B ₁ thereof differential signal transmission 4B _2, 4B _2, the dielectric 12B in the mold specified site M Is provided. Note that the protruding tip portions P of the differential signal transmission lead pins 4A ₁ , 4A ₂ , 4B ₁ , 4B ₂ (that is, the portions exposed from the dielectrics 12A, 12B) are provided on the motherboard 8, for example. It is a site | part inserted by the through-hole 10 for pin insertion. Further, in the first embodiment, the portions protruding inward and outward from the case wall in the lead pins 4 other than the differential signal transmission lead pins 4A ₁ , 4A ₂ , 4B ₁ , 4B ₂ are covered with a dielectric. Not. In other words, between the differential signal transmission lead pins 4A ₁ and 4A ₂ on the signal input side and between the lead pins 4 other than between the differential signal transmission lead pins 4B ₁ and 4B ₂ on the signal output side, Dielectric material is not interposed at the portion protruding outward.

Dielectric 12A between the differential signal transmission lead pin 4A _1, 4A ₂ controls the capacitance between the differential signal transmission lead pin 4A _1, 4A ₂ by the dielectric constant, the differential signal transmission lead pin The differential impedance between 4A ₁ and 4A ₂ is adjusted. In the first embodiment, the dielectric 12A has a differential impedance between the differential signal transmission lead pins 4A ₁ and 4A ₂ between the differential signal transmission lines of the connection partner provided on the circuit board 2. It is comprised with the dielectric material which has the dielectric constant for becoming the same as that of the differential impedance. The same applies to the dielectric 12B between the differential signal transmission lead pins 4B ₁ and 4B ₂ .

In the first embodiment, the module case 3 is made of the same dielectric material as the dielectrics 12A and 12B (for example, a resin such as PPS (polyphenylene sulfide resin)). The module case 3, the dielectrics 12A and 12B, and the differential signal transmission lead pins 4A ₁ , 4A ₂ , 4B ₁ and 4B ₂ are integrally formed by an insert molding technique. In this way, the differential signal transmission lead pins 4A ₁ , 4A ₂ , 4B ₁ , 4B ₂ are integrally formed on the module case 3 and the dielectrics 12A, 12B by the insert molding technique, so that these differential signal transmission lead pins. 4A ₁ , 4A ₂ , 4B ₁ , 4B ₂ can be accurately fixed to the module case 3 at the designed positions (in other words, the distance between the differential signal transmission lead pins 4A ₁ , 4A ₂ The distance between the differential signal transmission lead pins 4B ₁ and 4B ₂ can be set as designed. In addition, the dielectrics 12A and 12B can be interposed between the differential signal transmission lead pins 4A ₁ and 4A _{2 and} between the differential signal transmission lead pins 4B ₁ and 4B ₂ without a gap. Thus, the differential signal transmission lead pins 4A ₁ and 4A ₂ and the differential signal transmission lead pins 4B ₁ and 4B ₂ can be provided with a differential impedance almost as designed so that the differential signal transmission can be performed. The differential impedance between the lead pins 4A ₁ and 4A ₂ for use and the differential signal transmission lead pins 4B ₁ and 4B ₂ can be matched to the differential impedance between the differential signal transmission lines connected to the circuit board 2 it can.

For example, lead pins 4 having a diameter of 0.51 mm are used, the distance d between the lead pins 4 is 1.78 mm, and there is a gap between adjacent differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ). In this case, the differential impedance between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) is about 200Ω. Normally, the differential impedance between the differential signal transmission lines on the circuit board 2 is 100Ω, so that the gap between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) is a gap. The differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) are impedance mismatched with the differential signal transmission line to which the circuit board 2 is connected.

On the other hand, the dielectric constant is 4.7 as the dielectric 12A (12B) between the adjacent differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) as in the first embodiment. For example, when a PPS is provided, the differential impedance between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) is about 100Ω, and the differential signal transmission lead pins 4A ₁ and 4A ₂ ( 4B ₁ , 4B ₂ ) can be impedance-matched with the differential signal transmission line to which the circuit board 2 is connected.

In the first embodiment, the differential signal transmission lead pins 4A ₁ , 4A ₂ , 4B ₁ , 4B ₂ are integrally provided on the module case 3 and the dielectrics 12A, 12B by an insert molding technique. Because of the configuration, the differential signal transmission lead pins 4A ₁ , 4A ₂ , 4B ₁ , 4B ₂ do not have a gap S as shown in FIG. 2 between the module case 3 and the dielectrics 12A, 12B. That is, the dielectric 12A (12B) can be provided without a gap between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ).

On the other hand, for example, when the differential signal transmission lead pins 4A ₁ , 4A ₂ , 4B ₁ , 4B ₂ are not integrally formed with the dielectrics 12A, 12B and the module case 3, for example, they are integrally formed with the module case 3. Through holes for inserting the differential signal transmission lead pins 4A ₁ , 4A ₂ , 4B ₁ , and 4B ₂ are formed in the dielectrics 12A and 12B, and each of the through holes has a differential signal transmission. The lead pins 4A ₁ , 4A ₂ , 4B ₁ , 4B ₂ for insertion are inserted. In this case, due to problems such as processing accuracy, the differential signal transmission lead pins 4A ₁ , 4A ₂ , 4B ₁ , 4B ₂ are provided in the dielectrics 12A and 12B. Therefore, a gap S is generated between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) and the dielectric 12A (12B). It becomes.

For example, lead pins 4 having a diameter of 0.51 mm are used, the distance d between the lead pins 4 is 1.78 mm, and there is a dielectric between the adjacent differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ). When the dielectric 12A (12B) having a ratio of 4.7 is provided without a gap, the differential impedance between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) is calculated. 98Ω. As a result, the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) can be impedance-matched with the differential signal transmission line having a differential impedance of 100Ω, for example, which is connected to the circuit board 2. it can.

On the other hand, as shown in FIG. 2, differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) even when the distance d between the lead pins 4 having a diameter of 0.51 mm is 1.78 mm, as described above. If there is a gap S on the differential signal transmission lead pin 4A ₁ (4B ₁ ) side and a gap S on the differential signal transmission lead pin 4A ₂ (4B ₂ ) side, When the gap D between the air gaps S is 0.05 mm, the differential impedance between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) is calculated to be 128Ω. That is, the differential impedance between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) deviates from the differential impedance between the differential signal transmission lines to which the circuit board 2 is connected. .

As described above, even if a slight gap S exists between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ), the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) While the differential impedance between the _two is deviated from the set value, in the first embodiment, there is no gap between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ). Since the dielectric 12A (12B) can be provided, such a problem can be prevented.

In the first embodiment, the mold designation portion M of the differential signal transmission lead pins 4A ₁ , 4A ₂ , 4B ₁ , 4B ₂ is covered with dielectrics 12A, 12B. Therefore, as compared with the case around each differential signal transmission lead pin _{4A 1, 4A 2, 4B 1} , 4B 2 is air, the differential signal transmission lead pin _{4A 1, 4A 2, 4B 1} , 4B 2 Although the dielectric loss (tan δ) of the differential signal energizing the current increases, the harmonics of the differential signal are attenuated by the dielectric losses due to the dielectrics 12A and 12B. The aperture is improved, that is, the differential signal transmission performance can be improved.

  The second embodiment will be described below. In the description of the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and duplicate descriptions of common portions are omitted.

FIG. 3A shows a simplified schematic cross-sectional view of the circuit module of the second embodiment, and FIG. 3B shows a lower case 6 constituting the circuit module 1 and the lower case 6. The lead pin 4 is schematically shown by a plan view seen from the upper side of FIG. As shown in FIGS. 3A and 3B, in the second embodiment, as in the first embodiment, differential signal transmission lead pins 4A ₁ , 4A ₂ (4B ₁ , 4B ₂ ) And around the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ), a dielectric 12A (12B) is provided.

In the second embodiment, the lead pins 4 other than the differential signal transmission lead pins 4A ₁ , 4A ₂ , 4B ₁ , 4B ₂ are connected to the mold designated portion M (that is, the circuit excluding the protruding tip portion P). A portion protruding from the substrate on the leading end side) is covered with a dielectric 13. Further, a gap K is provided between the adjacent lead pins 4 to avoid the gap between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ).

Configurations other than the configuration unique to the second embodiment described above are the same as those of the first embodiment. By providing a unique configuration in the second embodiment, the following effects can be obtained. That is, when the configuration of the first embodiment described above is provided, the differential signal transmission lead pins 4A ₁ , 4A ₂ , 4B ₁ , 4B ₂ are integrally formed with the lower case 6 by, for example, an insert molding technique. However, it is difficult to integrally mold the other lead pins 4 with the lower case 6. For this reason, the other lead pins 4 are provided, for example, in the through holes 7 for inserting lead pins provided in the circuit board 2 and the lower case 6 after the circuit board 2 is installed in the lower case 6. It is attached to the circuit module 1 by passing through the through-hole for inserting the pin, and being connected and fixed to the circuit board 2 with, for example, solder.

  On the other hand, in the second embodiment, since the dielectrics (12A, 12B, 13) are provided around the mold designated portion M of all the lead pins 4, the dielectrics 12A, 12B, 13 are provided. Is made of the same dielectric material as that of the lower case 6, and the dielectrics 12A, 12B, 13 are formed integrally with the lower case 6, so that all the lead pins 4 are integrated with the lower case 6 by insert molding technology. It becomes possible to mold. Thereby, the manufacturing process of the circuit module 1 can be greatly simplified.

By the way, as shown in the schematic cross-sectional view of FIG. 4, all the lead pins 4 can be formed by the insert molding technique even when the dielectrics 14 are provided between all the lead pins 4 arranged close to each other without a gap. It is possible to integrally mold with the lower case 6. However, in this case, since the dielectric 14 is provided between the lead pins 4, the distance between the lead pins 4 is smaller than when the dielectric 14 is not provided (when the gap between the lead pins 4 is a gap). The capacitance increases and the degree of electrical coupling increases. By providing a dielectric between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ), the effects described in the first embodiment can be obtained. If the electrical coupling degree between the four lead pins increases, mutual interference occurs between the other lead pins 4 and adversely affects each other, which is not preferable.

Considering this, in the configuration of the second embodiment, there is a gap between the adjacent lead pins 4 avoiding the gap between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ). K is provided. The gap K is adjusted in the direction in which the capacitance between the lead pins 4 is reduced and the electrical coupling degree is reduced as compared with the case where a dielectric is provided between the lead pins 4. Therefore, unnecessary electrical coupling between the lead pins 4 can be suppressed by providing such a coupling degree adjustment gap K.

In the configuration of the second embodiment, the gap K is provided between all the lead pins 4 avoiding the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ). For example, when the lead pin 4D shown in FIG. 3 (b) is configured such that no electrical signal is passed through, no electrical coupling occurs between the lead pin 4D and the adjacent lead pin 4E. There is no need to worry about problems caused by such electrical coupling. Therefore, the dielectric 13 may be interposed between the lead pins 4D and 4E. Thus, a dielectric may be interposed between the predetermined lead pins 4 that avoid the gap between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ). However, a gap K for suppressing (adjusting) electrical coupling between the lead pins 4 is provided between at least one adjacent lead pin 4.

  The third embodiment will be described below. In the description of the third embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and duplicate descriptions of the common portions are omitted.

  In the third embodiment, an optical module that is one of circuit modules will be described. FIG. 5 shows the optical module of the third embodiment in an exploded state. The optical module 20 of the third embodiment has a module case 23 composed of a base side case 21 and a lid side case 22, a circuit board 24 accommodated in the module case 23, and an optical connector 25. Configured.

  The circuit board 24 is provided with an optical-electrical converter (not shown) having one or both of a function of converting an electrical signal into an optical signal and a function of converting an optical signal into an electrical signal. In addition, an electric circuit electrically connected to the photoelectric conversion unit is provided. A plurality of lead pins 26 are connected and fixed to the circuit board 24 by, for example, solder. Each of the lead pins 26 penetrates the circuit board 24 from the front side to the back side of the circuit board 24, and further penetrates the case wall of the base side case 22 from the inside of the base side case 22 to the outside. Thus, the leading end portion of each lead pin 26 is formed to protrude outside the base side case 22 (module case 23). The electric circuit formed on the circuit board 24 can be electrically connected to an external electric circuit by the lead pin 26.

  The optical connector 25 is for fitting with the optical connector of the connection partner and optically connecting the optical fiber of the optical connector of the connection partner to the optical fiber provided in the optical-electrical conversion part of the circuit board 24. It is.

  In the third embodiment, the plurality of lead pins 26 connected and fixed to the circuit board 24 includes a pair of adjacent differential signal transmission lead pins. The most characteristic feature of the third embodiment is that a configuration related to the lead pin, which is unique to the first embodiment or the second embodiment, is provided.

  In the third embodiment, since the configuration unique to the first or second embodiment is provided, the same effects as those of the first embodiment and the second embodiment can be obtained.

In addition, this invention is not limited to the form of each 1st-3rd embodiment, Various embodiments can be taken. For example, in each of the first to third embodiments, the dielectric provided without a gap between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) is the differential signal transmission lead pin 4A _1. , 4A ₂ , 4B ₁ , 4B ₂ and the lower case 6 are formed at the same time when they are integrally formed by the insert molding technique. In contrast, for example, when the differential signal transmission lead pins 4A ₁ , 4A ₂ , 4B ₁ , 4B ₂ and the lower case 6 are integrally formed by the insert molding technique, FIGS. 6 (a) and 6 (b). The gap Z is formed between the differential signal transmission lead pins 4B ₁ , 4B ₂ (4A ₁ , 4A ₂ ), and a dielectric material is injected into the gap Z to be filled later. motion signal transmission lead pin _{4A 1, 4A 2 (4B 1} , 4B 2) may be configured to be interposed without gaps dielectric in between.

In this case, the dielectric formed by later injection between the differential signal transmission lead pins 4A ₁ , 4A ₂ (4B ₁ , 4B ₂ ) is made of a dielectric material different from the dielectric material of the lower case 6. May be. The dielectric material constituting the lower case 6 is determined in consideration of various conditions such as durability and strength, and cannot be said to have a high degree of freedom in material selection. Therefore, when the dielectric provided between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) is the same dielectric material as the constituent material of the lower case 6, That is, the dielectric provided between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) is limited.

In contrast, the dielectric provided between the differential signal transmission lead pins 4A ₁ , 4A ₂ (4B ₁ , 4B ₂ ) can be formed of a dielectric material different from the dielectric material of the lower case 6. The degree of freedom in selecting a dielectric material constituting the dielectric provided between the differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) can be increased. This makes it easier to impedance-match the differential signal transmission lead pins 4A ₁ , 4A ₂ (4B ₁ , 4B ₂ ) with the differential signal transmission lines of the circuit board 2.

In addition, although the configuration in which two pairs of differential signal transmission lead pins 4A ₁ and 4A ₂ (4B ₁ and 4B ₂ ) are provided is shown, the pair of differential signal transmission lead pins may be a pair or three or more pairs. A differential signal transmission lead pin may be provided.

It is a figure for demonstrating the circuit module of the example of 1st Embodiment. It is a figure for demonstrating the effect acquired from the structure of 1st Embodiment. It is a figure for demonstrating the circuit module of the example of 2nd Embodiment. It is a figure showing the example of a state which interposed the dielectric material between all the closely arranged lead pins. It is an exploded view for demonstrating an example of an optical module. It is a figure for demonstrating other example embodiments. It is a figure for demonstrating the example of 1 form of a circuit module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Circuit module 2,24 Circuit board 3,23 Module case 4,26 Lead pin 12A, 12B, 13 Dielectric

Claims (6)

  A plurality of lead pins project from the inside of the module case to the outside through the case wall, and the electric circuit formed on the circuit board accommodated in the inside of the module case becomes an external circuit by a predetermined lead pin. In a circuit module having an electrically connected configuration, a plurality of lead pins include adjacent differential signal transmission lead pins that form a pair for transmitting a differential signal, and adjacent to each other. Between the lead pins for differential signal transmission, a dielectric is provided without a gap at the protruding tip side part from the circuit board except for the protruding tip part, and between the other lead pins, the part protruding from the case wall is provided. A circuit module characterized in that no dielectric is interposed.   A plurality of lead pins project from the inside of the module case to the outside through the case wall, and the electric circuit formed on the circuit board accommodated in the inside of the module case becomes an external circuit by a predetermined lead pin. In the circuit module having a configuration of being electrically connected, the plurality of lead pins include adjacent differential signal transmission lead pins that form a pair for transmitting a differential signal. In each case, the portion on the protruding tip side from the circuit board excluding the protruding tip is covered with a dielectric, and between at least one adjacent lead pins, the electrical coupling degree between the adjacent lead pins is adjusted. A circuit module characterized in that an air gap is provided.   3. The circuit module according to claim 2, wherein the gap for adjusting the coupling degree provided between the lead pins is formed so as to avoid between the differential signal transmission lead pins which form adjacent pairs.   The circuit board is formed with differential signal transmission lines forming adjacent pairs for transmitting differential signals, and the differential signal transmission lead pins forming adjacent pairs are the differential signals of the circuit board. The dielectric provided between the differential signal transmission lead pins that are in the configuration connected to the transmission line and adjacent to each other is connected to the differential impedance between the adjacent differential signal transmission lead pins. 3. The circuit board according to claim 1, wherein the circuit board is made of a dielectric material having a dielectric constant for matching a differential impedance between adjacent lines for differential signal transmission. 3. The circuit module according to 3.   The module case is made of a dielectric material, and the dielectric provided between the lead pins is made of the same dielectric material as the dielectric material of the module case, and the module case, the lead pins, and the dielectric are formed by a molding technique. The circuit module according to any one of claims 1 to 4, wherein the circuit module is integrally formed.   6. The circuit module according to claim 1, wherein the circuit module is an optical module having a function of converting an optical signal and an electric signal.

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