JPS5855682Y2 - UHF Chu-nano Kiyoshin Kairo Kotai - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resonant circuit structure of a UHF tuner used for receiving UHF electromagnetic waves in a television receiver, for example.

In recent television receivers, there is a trend to use electronic tuners as a means for selecting channels, and it has become possible to block and downsize the channel selection section.

Furthermore, the electronic tuning tuner is expected to be versatile in its operation as it can be used as a tuning operation means, such as automatic tuning based on memory and tuning using a touch switch that turns on and off by touching an electrode.

Broadly speaking, this electronic tuner consists of a tuning section for receiving radio waves and a tuning section for changing the tuning frequency.

Various circuit configurations have been considered for the channel selection section, and some have been implemented, resulting in improved performance.

Furthermore, in the tuning section, as shown in FIG. 1, a DC voltage (tuning voltage) VE is applied to the varactor diode VD in the opposite direction
is applied to vary the junction capacitance and operate together with the fixed inductor L to vary the tuning frequency.

Therefore, the tuning voltage applied from the tuning section is required to be accurate so that the predetermined frequency can be received, and circuits have been devised to meet this requirement. The tuning section shown in FIG. 1 must also operate accurately and meet expectations.

However, in the conventional circuit structure that forms the circuit shown in Figure 1 above, the positions of the components (varactors, diodes, inductors, etc.) differ depending on the product, and it is extremely difficult to create a circuit with uniform characteristics. Have difficulty.

In particular, since the frequencies handled by this circuit are high, the tuning frequency will change even if there is a minute misalignment of the components.

Therefore, in order to adjust the stray capacitance of the inductor and set the circuit resonance frequency, an adjustment plate is usually provided close to the inductor, and the distance between this plate and the capacitor that the inductor constitutes can be adjusted. If the adjustments were made in a timely manner, the adjustment work would be complicated and difficult.
The structure was such that it was easy to accidentally touch other parts.

The present invention was developed in response to the above-mentioned circumstances, and the purpose is to provide a resonant circuit structure for a UHF tuner that makes it easier to adjust the tuning frequency to make it more accurate. be.

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 2 and 3.

First, to explain the outline of the resonant circuit structure, 11 in Fig. 2
is, for example, a box-shaped external conductor, and the base end of an inductor 12 is fixed to one side wall 111 of the external conductor 11, and this inductor 12 is arranged parallel to the bottom wall 11□ of the external conductor and is connected to the side wall 111. It extends toward the opposing side wall 113.

The inductor 12 is a flat, substantially rod-shaped single piece made of metal, and is formed, for example, as shown in FIG. 3a.

That is, a flat rod-shaped portion 12□ on the proximal end side, an electrode portion 123 that is bent in a direction substantially perpendicular to the rod-shaped portion 12 on the distal end side and has a wider width, and the rod-shaped portion 12□ of this electrode portion 123. and a positioning part A for attaching the diode formed between.

This positioning part A is formed by connecting the end part of the rod-shaped part [2], the electrode part 123, and the corner part by an L-shaped continuous part 122, and has a rectangular cutout a. become.

Further, a positioning piece B is integrally formed in the lower corner portion of the electrode portion 123 in the drawing corresponding to the cutout a in the direction in which the electrode portion 123 expands.

Therefore, when the base end of the inductor 12 is fixed to the external conductor side wall 11□ as shown in FIG.
The wide surface of the external conductor is disposed substantially perpendicular to the bottom wall 112 of the external conductor.

Then, one terminal 13□ of a varactor diode 13 as a variable capacitance element is soldered to the inductor 12, and the other terminal 13□ of this diode is connected to a grounding terminal 13□, for example, in a circular shape provided on the bottom wall 11□ of the external conductor. capacitor 1
It is stably installed and connected to one electrode of 4.

In this case, the main body of the diode 13 is placed against a positioning piece B formed on the electrode portion 123 to perform its positioning.

Furthermore, the circuit structure is provided with an adjustment element 15 attached to the fixed part.

Therefore, an adjustment capacitor is formed between the electrode part 123 and the adjustment element 15, and this adjustment element 15 is connected to the electrode part 123.
Fixed capacitance such as stray capacitance and ground capacitance of this circuit can be adjusted by placing the capacitance close to or apart from the capacitance, and the resonant frequency can be variably adjusted.

In this case, the adjusting element 15 is constructed with an adjusting means as shown in FIGS. 3a and 3l to facilitate the adjustment work.

That is, the first flat part 15 facing the electrode part 123,
and a second flat portion 152 that constitutes an adjustment tool and extends in a perpendicular direction from the second flat portion 152.

In this case, the second flat portion 152 is disposed opposite the cutout a of the inductor and is disposed away from the inductor.

Furthermore, the second flat portion 15° has a locking portion 1 cut out from the side thereof, as shown in FIG. 3, for example.
53 is formed.

According to the resonant circuit structure of the UHF tuner of the present invention constructed as described above, the adjustment work of the adjustment element 15 becomes extremely easy, and there is no possibility of accidentally touching the inductor 12 or the like and disturbing the adjustment. do.

That is, in the circuit structure, after the arrangement of each component is fixed, the resonant frequency is set.

In this case, the adjustment element 15 is adjusted with a driver 16 or the like in the direction of the arrow X or Y in FIG. When driven, the first flat portion 15□ is pushed in the direction of the arrow X in the drawing, and when the second flat portion 152 is driven in the direction of the arrow X, the vicinity of the locking portion of the second flat portion 152 is pushed in the directions of the arrows for adjustment.

During this adjustment, the adjustment element 15 is bent into an L shape, so adjustment can be easily performed without touching the inductor 12 with an adjustment rod such as a driver.

In particular, when pushing the adjustment element 15 in the direction of the arrow X shown in the figure, if this plate does not have the second flat part 152, the adjustment rod will be inserted between the first flat part 151 and the electrode part 123 and the inductor will be forced to adjust. 12, the position may be misaligned or the soldering to the diode terminal may become detached, making accurate adjustment impossible. However, with the present invention, such problems are eliminated.

Furthermore, in the circuit configuration of the present invention, a metal lid 17 (shown in FIG. 3) is provided over the opening of the external conductor 11, but since it is easy to adjust the adjustment element 15 as described above,
By providing a through hole in the lid 17 as shown in the figure, adjustments can be made through the through hole without having to remove the lid each time.

In the above embodiment, the adjustment element 15 is provided with the second flat part so that the adjustment is made through this, but the invention is not limited to this, and the adjustment is performed at a position away from the condenser forming part of the adjustment element 15. If a tool is provided, the above purpose can be remotely achieved. For example, a triangular adjustment tool 154 can be formed as shown in FIG.
The configuration may be such that the capacitance is variably adjusted from .

Further, to describe another effect of the above embodiment, first, in the circuit structure as described above, after the components are arranged, the parts indicated by broken circles in FIG. 2 are soldered.

In this case, in mass production at a factory or the like, a plurality of the circuit structures, external conductors, etc. are assembled into a larger chassis and transported by a conveyor or the like.

This large chassis also incorporates a tuning circuit and other components to form a single tuner body, and when this tuner body is being transported in large quantities, the soldering work at the points indicated by the circles above is extremely hectic. becomes.

In the case of such work, the above circuit structure makes it easy to determine the placement position of the diode, and the soldering position of the terminal to the inductor is also the same for each product, so the length l of the inductor part is constant. .

As a result, the inductance in this circuit can be brought very close to the designed value, and the same is true for each mass-produced product.

Therefore, not only is the reliability of the product improved, but the subsequent adjustment of the circuit is also facilitated, and the resonant frequency is made more accurate.

Furthermore, by providing the positioning portion and the positioning piece, it acts as a holder for the diode, making wiring soldering work easier and preventing positional shift until the solder hardens, which is extremely effective in improving work efficiency and circuit performance.

As described above, the present invention can provide a resonant circuit structure for a UHF tuner that makes it easier to adjust the tuning frequency to make it more accurate.

[Brief explanation of the drawing]

Fig. 1 is a principle diagram of the tuning circuit, Fig. 2 is a side sectional view and a plan view showing the resonant circuit structure of the UHF tuner of the present invention, and Fig. 3 a and l) are perspective views showing the main parts of the circuit structure of the present invention. 4 are perspective views showing other embodiments of the main parts of the circuit structure of the present invention. 11...Outer conductor, 12...Inductor, 12□...Inductor section, 123...
...Electrode part, 13...Varactor diode (
variable capacitance diode), 15...adjustment element, 1
52...Second flat part (adjustment tool).

Claims (1)

[Scope of utility model registration request] A plate-shaped inductor part whose base end is fixed to the side wall of the external conductor and whose other end has a notch in which a variable capacitance diode is housed, and an electrode part which is bent and extended at the tip of this inductor part. The adjustment element includes an inductor, a flat part fixed to the bottom wall of the external conductor and forming an adjustment capacitor together with the electrode part, and an adjustment tool integrally formed extending from one end of the flat part in the direction of the electrode part. A UHF tuner resonant circuit structure characterized by the following.