JPS6218986Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a television tuner device, and by integrating a tuning inductor and a tuning capacitance element used in a tuned resonance circuit with a resin mold, a resonance element with good dimensional accuracy can be created. It is an object of the present invention to improve the characteristics of a television tuner device and to simplify the assembly work.

One example of a television tuner device is one that has a resonant circuit with an equivalent circuit as shown in FIG. 1, and this equivalent circuit is constructed as shown in FIGS. 2A and 2B. First, Figure 1 and Figure 2 A,
B will be explained.

FIG. 1 shows a λ/4 type resonant circuit, in which one end of an inductor 1 is connected to a variable capacitance diode 2 and grounded via a DC cut capacitor _CD . Rs indicates the sum of high-frequency direct current resistance in the resonance system, and Cs indicates the stray capacitance formed at the connection between the inductor 1 and the variable capacitance diode 2. An operating voltage is applied to the variable capacitance diode 2 via a resistor 3.

FIG. 2A shows an actual configuration of the circuit shown in FIG. 1, in which a U-shaped inductor 21 is placed on the substrate 4 and soldered to the pattern on the back side.
In relation to the circuit shown in FIG. 1, a variable capacitance diode 22 and a resistor 23 are soldered to the back surface. According to this, inductor 21 and variable capacitance diode 2
A large stray capacitance is formed between the connection part with the diode 22 on the board 4 and the ground pattern located nearby, and this stray capacitance is connected in parallel with the capacitance of the diode 22, which makes it possible to change the frequency. This will reduce the range. In addition, the inductor 21
By soldering the diode 22 and the diode 22, the junction resistance is increased and the Q of the circuit is lowered. It is necessary to assemble the inductor 21 and the variable capacitance diode 22 in separate steps.

FIG. 2B also shows an actual configuration of the circuit shown in FIG. is soldered to. A resistor 23 is soldered to the connection portion with the variable capacitance diode 22. According to this, the stray capacitance generated between the connection between the inductor 21 and the variable capacitance diode 22 and the ground pattern can be reduced, but the junction resistance is still large and the Q of the circuit is lowered. The inductor 21 and the variable capacitance diode 22 are connected in advance and attached to the board 4. One end of the inductor 21 (the part to be soldered directly to the pattern on the board 4) and the pattern on the board 4 of the variable capacitance diode 22 are Because the dimensional accuracy with the part to be soldered is not constant,
Difficult to assemble.

In this way, no matter which configuration of FIG. 2 A or B is used to make a television tuner, in the television tuner device, these resonant circuits are connected to each stage (usually an antenna input stage, an RF amplification stage, Since the oscillator stage is used as a tuned resonant circuit, the above-mentioned drawbacks occur in each stage.

Next, an embodiment of a television tuner device that solves the conventional drawbacks will be described with reference to FIGS. 3A and 3B regarding the key point of the television tuner device, which is a resonant element consisting of an inductor and a capacitive element in a resonant circuit.

FIG. 3A shows the manufacturing process of a resonant element (consisting of an inductor and a variable capacitance element) before FIG. 3B is assembled. The resonant element 30 includes an inductor 31, an auxiliary plate 31A, and a variable capacitance diode 3.
It consists of 2. A chip of the variable capacitance diode 32 is attached to a predetermined portion of the auxiliary plate 31A, a wire is connected from the chip to the inductor 41, and the resin mold 32A (shown by a dotted line) is formed. The inductor 31 and the auxiliary plate 31A before the chip is attached are each integrated with the connecting part main body 5 by the connecting part 5A, and the inductor 31 and the auxiliary plate 31A for forming adjacent resonant elements are connected to the connecting part 5B ( (shown with diagonal lines). Although the connecting portion 5B is not necessarily necessary, it is effective for pairing (preparing diodes with the same characteristics) for each set. Resin mold 32
After finishing A, it is cut by X--X rays to form the insertion part _5A1 into the board. For those cut by X-X rays, connect several resonant elements as a set, apply a voltage to the inductor located at the end and the auxiliary plate, check the continuity of the diode, and then connect the connecting part 5B. to be excised. Inductor 3
1, a signal extraction section 31B and a trimmer capacitance forming section 41C are formed.

FIG. 3B shows the checked resonant element 30 mounted on the board 4. The insertion part _5A1 of the auxiliary board 31A into the board 4 is soldered to the pattern, and the resistor 33 and capacitor C _D are connected. Ru. The trimmer capacitance forming section 31C faces the trimmer movable plate 31D, and the capacitor 6 is connected to the signal extraction section 31B. With this configuration, the variable capacitance diode 32 in chip form is directly connected to the inductor, so the high frequency DC resistance Rs is extremely low, so the Q of the circuit is high. Since there is almost no stray capacitance that occurs in parallel, the frequency can be varied over a wide range. Since the inductor 31 and variable capacitance diode 32 of the resonant element 30 are integrated with high dimensional accuracy in separate steps, mounting on the substrate 4 is extremely simple, suitable for automation, and has uniform characteristics. By providing the signal extraction section 31B, the signal can be extracted at a fixed position, so that characteristics can be further made uniform.

In Figures 3A and 3B, diodes in the form of chips are used, but the invention is not limited to this, and variable capacitance diodes that have lead terminals and have been molded in resin in advance can be used in accordance with the method shown in Figure 3A. In this case as well, the inductor and variable capacitance diode as the resonant elements are integrated in separate steps with good dimensional accuracy (because the inductor and the auxiliary plate are integrated by the connecting portion 5A). It has the effects described above.

The television tuner device of the present invention has a capacitor arranged between a first conductor and a second conductor, connected to each conductor, and connected to the capacitor and each conductor. Since the element and the connection part are integrally formed by resin molding and have a resonant element using the first conductor as the main inductor, as already mentioned, a resonant element with good dimensional accuracy is used. Another advantage is that the characteristics can be improved and assembly work can be simplified, making it suitable for automation.

[Brief description of the drawings]

Figure 1 is an equivalent circuit diagram of a resonant circuit used in a conventional television tuner device.
Figures A and B each show a resonant section of a conventional television tuner device constructed using the equivalent circuit shown in Figure 1. FIGS. 3A and 3B are diagrams for explaining the process of forming a resonant element, and a resonant section of a television tuner device configured using the formed resonant element, respectively. 30... Resonant element, 31... Inductor, 3
1A... Auxiliary board, 32... Variable capacitance diode,
32A...Resin mold.

Claims (1)

[Scope of utility model registration request] A capacitive element is disposed between the first conductor and the second conductor, connected to each of the conductors, and the capacitive element and the connection portion between each of the conductors and the capacitive element are molded with resin. What is claimed is: 1. A television tuner device comprising a resonant element integrally constructed with a first conductor as a main inductor.