JP3427041B2 - Up-down tuner - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a home terminal, a CATV device for multimedia, a TV and a VTR.
Up-down tuner used for 2. Description of the Related Art Generally, an up-down tuner is constructed as shown in FIG.
As shown by 0, unlike a general tuner, there are two local oscillation circuit sections, and leakage of an oscillation frequency and spurious interference due to an input signal and two local oscillation signals are likely to occur. Spurious interference refers to radio waves radiated from a transmitter or other electronic devices into space via an antenna, radiating radio waves having unnecessary frequencies in addition to a required bandwidth (occupied bandwidth). This unnecessary radiated radio wave is called spurious, and the spurious includes harmonics, subharmonics of the transmission frequency, fundamental waves of the modulation frequency, and higher-order sideband frequencies, and is used for tuning the output stage of the transmitter for tuning. When the characteristics are insufficient, a considerable amount is often radiated from the antenna and interferes with other communication lines, and this is called spurious interference. That is, in an up-down tuner, spurious interference mainly refers to interference between two local oscillation signals inside the up-down tuner. In FIG. 10, BPF is a band pass filter (band pass filter), AMP is a high frequency amplifier, MIX is a mixer (mixer), OSC is a local (local oscillator), and PLL is a phase Lock·
It is a loop. FIG. 10A is a block diagram of an up-down tuner, and FIG. 10B is a block diagram of a general tuner. For this reason, countermeasures have been taken by increasing the number of shields inside the metal chassis, dividing the circuit into individual circuits, and increasing the number of grounding points (soldering points). More specifically, as shown in FIG. 11A, a conventional up-down tuner includes a printed wiring board 1 in a high-frequency component and the like, and a slit 2 formed in the printed wiring board 1. The printed wiring board 1 is incorporated into the metal chassis 3, and the printed wiring board is soldered with a soldering iron in order to improve the reliability of a soldering portion between the metal chassis 3 and the printed wiring board 1. 1. A structure in which a sufficient amount of solder is provided between the copper foil portion and the like and the metal chassis 3 (strong soldering), a discarded chip is mounted to increase the amount of solder, and the printed wiring board 1 and the metal chassis 3 are joined by soldering. It is. In the figure, 3a is a shield part of the metal chassis 3. In FIG. 11A, 11 is an RF (high frequency) unit, 12 is a first local unit, 13 is a first local amplifier unit, and 14 is a first local PLL (phase locked loop). ) Section, 15 is a first mixer section, 16 is a first IF (intermediate frequency) section, 17 is a second mixer section, 18 is a second local section, 1
Reference numeral 9 denotes a second local PLL unit, and reference numeral 20 denotes a second IF unit. These units are separated by the shield portion 3a of the metal chassis 3 and increase the number of solder joints between the printed wiring board 1 and the metal chassis 3. By doing so, countermeasures against spurious interference are taken. These circuit configurations are shown in FIG.
0 (a). FIG. 11B shows a configuration diagram of a conventional general tuner for comparison. FIG. 12 is a view for explaining the soldering of a conventional up-down tuner. (A) shows the result of solder joining by solder dipping. In the solder dipping, the solder 4 was thin and cracks were easily generated. (B) shows a case in which a part of the metal chassis 3 is bent to perform solder joining. According to this joining, a certain amount of solder can be secured, but the solder 4 may still be thin and cracks may occur. Further, (c) is for performing solder bonding by soldering (strong solder) using a soldering iron, and according to this bonding, cracks can be prevented.
In addition, (d) shows the case where soldering is performed using the discarded chip 5, and according to this bonding, the chip 5 can be mounted to secure the amount of solder and prevent cracks.
Therefore, a solder pile, a discarded chip, or the like is mounted to increase the amount of solder, and the printed wiring board 1 and the metal chassis 3 are joined by soldering. As described above, the conventional up-down tuner mounts the solder pile and the discarded chip 5 in order to improve the reliability. The cost of chips) has led to significant cost increases. The printed wiring board 1 of the metal chassis 3
Is formed in a portion for supporting the spur, and the notch is not shielded, thereby affecting spurious interference characteristics. In view of the above problems, it is an object of the present invention to provide an up-down tuner which secures an amount of solder, reduces spurious interference, and can reduce the cost by developing an integrated earth plate. And An up-down tuner according to the present invention is an up-down tuner in which a printed wiring board and a metal chassis penetrating a slit formed in the printed wiring board are joined by soldering. A ground plate provided on both sides of the metal chassis for holding the metal chassis from both sides and soldering the printed wiring board and the metal chassis in a substantially L-shape when viewed from the side; The plate is sandwiched from both sides of the metal chassis, and a part thereof is connected. At a portion where the metal chassis intersects, the metal chassis is partially fitted to only one side of the metal chassis, thereby avoiding the metal chassis, The sheet is spread over almost the entire soldering area, and the soldering portion of the ground plate is halfway between
Storing the field and connecting the printed wiring board and the metal chassis
From two split nails to improve the reliability of solder joints
And an approximately L-shaped oblique angle or an acute angle
Between the nail and the printed wiring board.
A gap is formed in the gap, and the solder is stored in the gap . According to the up-down tuner of the present invention,
Since the metal chassis is sandwiched from both sides, and an earth plate having a substantially L-shaped soldering portion in side view for soldering the printed wiring board and the metal chassis is provided, soldering is performed on the front and back surfaces of the metal chassis. Even if there is a part, it can easily cope with it, and partly attach the ground plate to only one side of the metal chassis to dodge the metal chassis and expand it, and one ground plate will cover almost the entire area of soldering Is to be developed. In addition, since the soldering portion is substantially L-shaped when viewed from the side, the printed wiring board and the metal chassis can be soldered with high reliability. In addition, the soldering part of the earth plate is two
Divided claw shape, and approximately L shape in side view of this claw
The obtuse or acute angle makes the nail and printed wiring
A structure that creates a gap between the board and solder in this gap
The area of the soldered area and the amount of solder
Increased strength of solder between printed wiring board and metal chassis
Of solder cracks due to thermal cycle
it can. FIG. 1 is a configuration diagram of an up-down tuner according to an embodiment of the present invention. FIG.
It is a block diagram of the earth plate used for the said up-down tuner. In this embodiment, in order to minimize the cost increase, instead of mounting a solder pile or a discarded chip as in the conventional example, as shown in FIGS. It is formed by using an earth plate 6 that can be incorporated in three structures. The earth plate 6 is sandwiched from both sides of the shield portion 3a inside the metal chassis 3, a part thereof is connected, and further extends from the shield portion 3a of the metal chassis 3 to the surface of the printed wiring board 1. It comprises a soldering portion 6a for soldering the metal chassis 3 and the printed wiring board 1. The soldering part 6a
Is formed in a substantially L-shape in a side view, as shown in FIG. By providing the ground plate 6 as described above, the area of the soldered portion and the amount of solder are greatly increased, and the bonding strength of the solder between the printed wiring board 1 and the metal chassis 3 can be improved. The earth plate 6 is formed of a single earth plate and is spread over almost the entire soldering area. Here, in order to spread the earth plate 6 over the entire area, it is necessary to solder both the front and back surfaces of the metal chassis 3 or to avoid a portion where the metal chassis 3 intersects. . When soldering is required on both the front and back surfaces of the metal chassis 3, as shown in FIG.
Can be dealt with by providing a soldering portion 6 a corresponding to each of the front and back surfaces of the metal chassis 3. Also, when it is necessary to avoid a portion where the metal chassis 3 intersects, as shown in FIG. 5, the ground plate 6 is partially attached to only one side of the metal chassis 3 to avoid the metal chassis 3. Can be expanded. The material of the earth plate 6 is not particularly limited as long as it has good adhesion to solder and good workability, and is formed, for example, of tinplate. According to this configuration, even if there is a soldering portion on the front and back surfaces of the metal chassis 3, it is possible to easily cope with the problem. The metal chassis 3 can be deployed in a dodging manner, and can be deployed in almost the entire area of soldering with one ground plate 6. As shown in FIG. 6, the metal chassis 3 has a notch 3b such as a notch for holding the printed wiring board 1 in a shield portion 3a of the metal chassis 3, and a ground plate. 6 is provided with a shield portion 6b corresponding to the cutout portion 3b so as to cover the cutout portion 3b, whereby it is possible to close a place where no shield is conventionally provided, and the shielding effect can be greatly improved. . Further, by providing the shield portion 6b in a place where the chassis could not be deployed conventionally, the shielding effect can be greatly improved. Thereby, as shown in FIG. 7, for example, the spurious interference characteristics are improved by 5 to 10 dB in the S / I ratio. Specifically, as shown in FIG. 8, each unit is almost completely partitioned. In the figure, 11 is an RF (high frequency) unit, 12 is a first local unit, 13 is a first local amplifier unit, and 14 is a first local PLL.
(Phase locked loop) section, 15 is a first mixer section, 16 is a first IF (intermediate frequency) section,
Reference numeral 17 denotes a second mixer unit, reference numeral 18 denotes a second local unit, reference numeral 19 denotes a second local PLL unit, and reference numeral 20 denotes a second I / O unit.
Section F. Each of these parts is shielded by a shield part 6b at a place where there is no conventional shield, and is almost completely partitioned. As a result, the spurious interference characteristics are conventionally taken up for a long time, and the spurious interference characteristics have been improved to the extent that some other performance is sacrificed. . Further, the soldering portion 6a of the earth plate 6 is constructed as shown in FIG. 9 and is composed of two claws 7 as shown in FIG. The solder can be stored in the gap between the printed wiring boards 7 to improve the reliability of the solder joint between the printed wiring board 1 and the metal chassis 3. Also, as shown in (b) and (c), a gap is formed between the claw 7 and the printed wiring board 1 by making the substantially L-shape in a side view obtuse or acute, so that the solder is accumulated in the gap. Thereby, the reliability of the solder joint can be improved. In addition, as shown in (d) and (e), a through hole 8 made of a circle or a rectangle including an ellipse is formed substantially at the center of the soldering portion 6a.
May be provided, and the solder may be stored in the through-hole 8 to improve the reliability of the solder joint. According to this configuration, in the result of the long-term reliability test for 500 hours, the rate of occurrence of cracks at the soldered portion can be improved from 50% or more when no countermeasures are taken to 5% or less. Here, the long-term reliability test is a thermal shock test, and the thermal shock test is a cycle of −20 ° C. and 80 ° C. in a cycle of 30 minutes, and whether a solder crack has occurred after 168 cycles or 500 cycles. It is a test to confirm whether or not. From the above, high reliability at relatively low cost,
High-performance up-down tuners can be produced. As described above , according to the present invention ,
Claw shape with the soldering part of the earth plate divided into two
And an approximately L-shaped oblique angle or an acute angle
The gap between the nail and the printed wiring board.
It is designed to store solder in this gap.
The area of the attachment area and the amount of solder have increased significantly,
Improves the bonding strength of the solder between the wire plate and the metal chassis,
Generation of solder cracks due to
You. As a result, even when used for a long time,
Generation can be greatly reduced. [0034]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram showing an up-down tuner according to an embodiment of the present invention. FIG. 2 is a configuration diagram of an earth plate used in the up-down tuner shown in FIG. FIG. 3 is a cross-sectional view for explaining a solder bonding state between a printed wiring board and a metal chassis. FIG. 4 is a perspective view illustrating a case where both sides of a metal chassis are sandwiched between ground plates. FIG. 5 is a perspective view for explaining a case in which an earth plate is deployed while avoiding a crossing metal chassis. FIG. 6 is a perspective view illustrating a shield provided on an earth plate. FIG. 7 is a comparison diagram of spurious interference characteristics between the embodiment and the conventional example. FIG. 8 is a plan view showing a specific configuration of an up-down tuner. FIG. 9 is a perspective view showing an example of a soldering portion of an earth plate. FIG. 10A is a block diagram of an up-down tuner, and FIG. 10B is a block diagram of a general tuner. 11A is a configuration diagram of a conventional up-down tuner, and FIG. 11B is a configuration diagram of a conventional general tuner. FIG. 12 is a cross-sectional view for explaining a conventional solder joint between a printed wiring board and a metal chassis. [Description of Signs] 1 Printed wiring board 2 Slit portion 3 Metal chassis 3a Shield portion 3b Notch portion 4 Solder 6 Ground plate 6a Solder portion 6b Shield portion 7 Claw 8 Through hole

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H05K 9/00

Claims (1)

(57) An up-down tuner in which a printed wiring board and a metal chassis penetrating through a slit formed in the printed wiring board are joined by soldering. L for holding the printed wiring board and the metal chassis by soldering while holding the same.
A grounding plate provided on both sides of the metal chassis for holding the U-shaped soldering portion, wherein the grounding plate is sandwiched from both sides of the metal chassis, a part thereof is connected, and at a portion where the metal chassis intersects, by infested only one side of the part on the metal chassis, home to the metal chassis, it is expanded to the soldering portion of substantially the entire region in one piece, the soldering portions of the ground plate, while Pool the solder
Solder joint between the printed wiring board and the metal chassis
It consists of two split nails to improve reliability.
The substantially L-shape of the claw in a side view is made obtuse or acute.
With this, a gap is formed between the nail and the printed wiring board.
An up-down tuner, characterized in that solder is stored in the gap .