JPH0429548Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) The present invention relates to a composite component used in a trap circuit of a color television receiving circuit.

(Prior Art) In a color television receiving circuit, as shown in FIG. 4, an audio IF (intermediate frequency) trap circuit 3 is provided between a video detection circuit 1 and a video amplification circuit 2. This audio IF trap circuit 3 is used to remove the IF signal (4.5MHz) mixed into the video detection output. If the mixed IF signal component increases, color beat interference will occur in the color signal processing circuit at the subsequent stage, making it difficult to reproduce normal color video, so the IF signal must be sufficiently attenuated. This audio IF trap circuit 3 is often constructed using a ceramic filter or LC element.

FIG. 5 shows a conventional composite component used in such an audio trap circuit 3. On the printed circuit board 4, there are first, second and third parts insulated from each other.
Conductive layers 5, 6, 7 are formed, each conductive layer 5, 6,
A three-terminal trap element 8 is connected by soldering terminals 8a, 8b, and 8c to conductive layers 6 and 7, respectively, and an inductor element 9 is connected by soldering terminals 9a and 9b to conductive layers 6 and 7, respectively. It is connected. T ₁ , T ₂ , T ₃ are each conductive layer 5,
These are lead terminals connected to terminals 6 and 7.

In this way, the composite component has an equivalent circuit as shown in Figure 6, and the video detection signal input between T ₁ and _{T 2} is trap-processed and then output from between T ₁ and _{T 2} . The image is amplified.

However, such a composite component has the disadvantage that the attenuation bandwidth obtained by trap processing varies due to variations in the characteristics of the three-terminal trap element 8 and variations in the inductance of the inductor element 9 that constitute it. . Attenuation bandwidth is 4.5M
It is desirable that the frequency bands before and after the Hz audio IF signal are maintained at a constant attenuation width with reproducibility.

If the attenuation bandwidth is narrow, the audio IF signal cannot be removed sufficiently, resulting in beat interference on the color video. Conversely, if the attenuation bandwidth is wide, not only the audio IF signal but also the high frequency portion of the video signal will be removed, resulting in a reduction in video resolution.

(Problems to be Solved by the Invention) As described above, conventional composite components have a problem in that the attenuation bandwidth fluctuates because variations in the characteristics of the constituent elements directly affect the trap operation.

The present invention was developed in response to the above problems, and aims to provide a composite component that keeps the attenuation bandwidth constant by using capacitor elements whose characteristics can be adjusted as constituent elements. be.

[Structure of the invention] (Means for solving the problems) In order to achieve the above object, the invention provides a first conductive layer, a second conductive layer, and a third conductive layer that are insulated from each other on the surface of a dielectric substrate. is formed, and a fourth conductive layer is formed on the back surface thereof, each terminal of the three-terminal trap element is connected to each of the first, second, and third conductive layers, and the second and third conductive layers are connected to each terminal of the three-terminal trap element. Each terminal of an inductor element is connected to each terminal, and a capacitor element is formed by the second and third conductive layers, the dielectric substrate, and the fourth conductive layer.

(Function) The second layer formed on the front and back surfaces of the dielectric substrate
By changing the opposing areas of the third conductive layer and the fourth conductive layer via the dielectric substrate, the capacitance characteristic (value) of the capacitor element can be adjusted. This allows the attenuation bandwidth of the composite component to be held constant.

(Embodiment) FIGS. 1a and 1b are a plan view and a side view showing an electronic component according to an embodiment of the present invention. Reference numeral 11 denotes a conductive substrate made of barium titanate ceramic, for example, and a surface 11a of this dielectric substrate 11. A first conductive layer 12, a second conductive layer 13, and a third conductive layer 14 which are insulated from each other are formed on the back surface 11b of the dielectric substrate 11. Fourth conductive layer 15 is formed such that at least a portion of conductive layers 13 and 14 are opposed to each other. Each of the conductive layers 12, 13, 14, and 15 can be easily formed at a predetermined location and in a predetermined area by using a well-known screen printing method, sputtering method, etching method, or the like. The first, second and third conductive layers 12, 13 and 14 are provided with a three-terminal trap element 16 made of a ceramic filter at each terminal 16a, 16.
They are connected by soldering b and 16c. Similarly, an inductor element 17 is connected to the second and third conductive layers 13 and 14 by soldering respective terminals 17a and 17b. Further, the second conductive layer 13 and the fourth conductive layer 15 facing each other with the dielectric substrate 11 interposed
Similarly, the third conductive layer 14 and the fourth conductive layer 15 constitute a capacitor element 18b. The capacitance of each capacitor element 18a, 18b is determined by the facing area of the constituent conductive layers, and the capacitance can be adjusted by changing the facing area. The opposing area can be changed by using the above-mentioned processing means and adjusting the area of each conductive layer 13, 14, 15 by so-called trimming.

FIG. 2 shows an equivalent circuit of the composite component obtained in this example. The video detection signal is
Input between T ₁ − T ₂ and after trap processing T _1
-T2 is output and the image is amplified.

FIG. 3 shows the damping characteristics obtained by the composite component of this example.

The vertical axis shows the degree of attenuation (dB), and the horizontal axis shows the frequency (MHz). Characteristics A, B, and C show cases in which the capacitances of capacitor elements 18a and 18b are changed, respectively.

As is clear from the figure, in both characteristics, the 4.5MHz audio IF signal is reliably attenuated, and the attenuation bandwidth centered around this audio IF signal is maintained at a constant value W. . This allows only the audio IF signal to be removed without affecting the video signal.

[Effects of the Invention] As is clear from the above description, according to the present invention, by using a capacitor element whose characteristics can be adjusted as a component, the attenuation bandwidth can be kept constant.

[Brief explanation of the drawing]

1a and 1b are plan and side views showing an electronic component according to an embodiment of the present invention, FIG. 2 is an equivalent circuit diagram of the electronic component of the present invention, and FIG. 3 is an attenuation characteristic of the electronic component of the present invention.
FIG. 4 is a block diagram for explaining the present invention, and FIGS. 5 and 6 are a plan view and an equivalent circuit diagram of a conventional example. 11...Dielectric substrate, 12, 13, 14, 15
... Conductive layer, 16 ... Three-terminal trap element, 17
...Inductor element, 18a, 18b...Capacitor element.

Claims (1)

[Scope of utility model registration request] A first conductive layer, a second conductive layer, and a third conductive layer insulated from each other are formed on the front surface of the dielectric substrate, and a fourth conductive layer is formed on the back surface thereof, and the first conductive layer,
Each terminal of a three-terminal trap element is connected to each of the second and third conductive layers, and each terminal of an inductor element is connected to each of the second and third conductive layers. A composite component characterized in that a capacitor element is constituted by a substrate and a fourth conductive layer.