JPH0621717A - Picture receiving antenna - Google Patents

Abstract

PURPOSE:To effectively prevent the production of a multiple image (ghost) even in an area having lots of reflection waves such as midtown area. CONSTITUTION:The incidence of a reflecting wave causing a multiple image is prevented by dispersing conductive particles or glass particles 11 in a weather- proof film 10 of an antenna element 3 so as to reflect irregularly most of the reflecting waves made incident in the antenna element 3 with the conductive particles or eliminating the reflecting wave with the filter effect of the glass particles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image receiving antenna for receiving VHF waves or UHF waves, which is formed by combining a plurality of antenna elements each made of a metal pipe coated with a weather resistant film. The present invention relates to an image receiving antenna capable of preventing the generation of an image (ghost) as much as possible.

[0002]

2. Description of the Related Art Conventionally, as a television antenna for receiving VHF and UHF waves, a combination of antenna elements (aluminum pipes covered with a weather resistant film) is generally used. Is generally an antenna having the structure shown in FIG.

That is, the horizontal boom 2 is attached to the mast 1,
A plurality of antenna elements 3 are juxtaposed on one end side of the lateral boom 2 to form a director 4, and a radiator 5 made of a flat ring-shaped antenna element is attached behind the director 4. A reflector 7 is formed by the antenna elements 3 attached to both ends of a vertical boom 6 attached at a right angle to the horizontal boom 2 and to the other end of the horizontal boom behind the radiator 5.

In this image receiving antenna, the main wave A is guided to the radiator 5 by the director 4, and the reflected wave B from the rear or the upper side is prevented from entering the radiator 5 by the reflector 7. ing. Then, the radio wave incident on the radiator 5 is introduced into the image receiving device (TV) by the feeder line 8 and is visualized.

[0005]

The important performance required for the image receiving antenna is that it has high sensitivity, multiple images (ghost), and little noise. Regarding sensitivity and noise among these performances, antennas having extremely high performance have been supplied in recent years.
For multiple images (ghosts), sufficient performance may not be obtained depending on the usage environment of the antenna.

That is, the conventional antenna is, as described above,
A reflector 7 formed behind the radiator 5 prevents reflected waves from above and behind from entering the radiator 5, thereby preventing generation of a ghost. In such a case, in most cases Can prevent the generation of multiple images (ghosts), but in urban areas where buildings such as buildings are lined up, a large number of reflected waves reach the antenna from all angles, and with conventional reflectors alone, It is difficult to sufficiently prevent the reflected wave from entering.

The present invention has been made in view of the above circumstances, and provides a novel image receiving antenna capable of preventing the occurrence of multiple images (ghosts) as much as possible even in an area such as an urban area where there are many reflected waves. The purpose is to

[0008]

In order to achieve the above object, the present invention provides, as a first invention, an image receiving antenna comprising a combination of an antenna element having a surface of a metal rod-shaped substrate coated with a weather resistant film. Provided is an image-receiving antenna characterized in that conductive particles are dispersed in a weather-resistant film of an antenna element.

Further, as a second invention, in an image receiving antenna comprising a combination of an antenna element in which the surface of a metal rod-shaped substrate is covered with a weather resistant film, glass particles are dispersed in the weather resistant film of the antenna element. An image receiving antenna is provided.

[0010]

According to the antenna of the first aspect of the present invention, the conductive particles dispersed in the weather resistant coating of the antenna element diffusely reflect and attenuate most of the reflected wave incident on the antenna element, The incidence of reflected waves that cause the multiple image phenomenon is prevented.

According to the antenna of the second aspect of the invention, the glass particles dispersed in the weather resistant film of the antenna element have a filter effect, and most of the reflected waves incident on the antenna element are irregularly reflected. The reflected wave that is attenuated and causes the multiple image (ghost) phenomenon is prevented from entering.

Here, although the main wave is naturally attenuated by the conductive particles and glass particles dispersed in the weather resistant film of the antenna element, the reflected wave and the main wave have greatly different strengths. While most of the main wave of high intensity is incident, the reflected wave of low intensity can be attenuated so that it hardly affects the image, and due to the high performance of the image receiving device (TV) in recent years, Even if the incident intensity of the main wave is attenuated to some extent, a clear image can be reproduced.

Further, since the antenna of the present invention is devised to attenuate the incident intensity of the reflected wave on the antenna element itself constituting the antenna, it effectively acts on the reflected wave coming from all directions. Therefore, it is possible to very effectively prevent the generation of a multiple image (ghost) even in the central area where many reflected waves are incident from all angles.

[0014]

EXAMPLES The present invention will be described more specifically by showing examples. 1 and 2 show an image-receiving antenna for VHF waves according to an embodiment of the present invention. This antenna shows an antenna element 3 constituting a director 4, a radiator 5 and a reflector 7. The configuration shown in FIG. The other configurations are as described above.

FIG. 2 shows an antenna element 3 which constitutes the antenna of FIG. 1 described above. The outer surface of a base body 9 made of a metal pipe is covered with a weather resistant film 10 and the weather resistant film 10 is In addition, dispersed particles 11 made of conductive particles or glass particles are uniformly dispersed.

Here, conductive particles or glass particles are used as the dispersed particles 11, and as the conductive particles, VHF is used.
Anything can be used as long as it diffuses the waves,
Although not particularly limited, specifically, aluminum, titanium,
Carbon and the like are mentioned. Among them, aluminum is preferably used because it is lightweight and has excellent durability. The particle diameters of the conductive particles and the glass particles are not particularly limited, but can be usually about 0.01 to 0.1 mm.

The amount of the dispersed particles 11 dispersed is not particularly limited, but is preferably 50% by volume or less, particularly 20 to 30% by volume of the weather resistant coating. In this case, if the amount of dispersed particles exceeds 50% by volume, the incident intensity of the main wave may be greatly attenuated and a clear image may not be obtained. On the other hand, if the amount of dispersed particles is extremely small, incident of reflected waves may be well prevented. Sometimes you can't.

The weather resistant film 10 may be a film made of an ordinary material such as a vinyl chloride resin film and having a thickness of about 0.5 to 1.5 mm. Further, the base body 9 may be the same as a normal antenna element such as an aluminum pipe. Further, depending on the case, a rod-shaped substrate having no hollow portion may be used, but from the viewpoint of lightweight, it is usually a pipe-shaped substrate.

According to this image receiving antenna, the conductive particles 11 dispersed in the weather resistant film 10 of the antenna element 3 diffusely reflect most of the reflected waves incident on the antenna element, or the weather resistant film. The glass particles 11 dispersed in the inside 10 have a filter effect, and most of the reflected waves incident on the antenna element 3 are diffusely reflected or absorbed to be attenuated to cause a multiple image phenomenon. Is prevented from entering.

In this case, the main wave is naturally attenuated by the conductive particles and the glass particles 11 dispersed in the weather resistant coating 10 of the antenna element 3, but the intensity of the reflected wave and the main wave is large. Since they are different, it is possible to make most of the main wave of high intensity incident and attenuate the reflected wave of low intensity so as to have almost no effect on the image. In addition, the high performance of recent image receiving devices (TVs) Due to
Even if the incident intensity of the main wave is attenuated to some extent, a clear image can be reproduced.

Further, according to the antenna of this embodiment, since the antenna element 3 itself is devised to attenuate the incident intensity of the reflected wave, it effectively acts on the reflected wave coming from all directions, Therefore, it is possible to very effectively prevent the generation of multiple images (ghosts) even in the city center where many reflected waves are incident from all angles.

The image-receiving antenna of the present invention is not limited to the above embodiment, but the number and combination of the antenna elements 3 forming the director 4 and the reflector 7 and the antenna element forming the radiator 5 are not limited thereto. The shape and the like can be changed as appropriate, and the antenna for VHF wave is shown in the above-mentioned embodiment. However, by using the antenna element having the structure shown in FIG.
It is also possible to configure an HF antenna. Further, in the above-described embodiment, all the antenna elements have the structure shown in FIG. 2, but only the antenna element of the radiator 5 can have the structure shown in FIG. Unless you change it, you can change it.

[0023]

As described above, according to the image receiving antenna of the present invention, the incident intensity of reflected waves can be reduced as much as possible even in the central area where many reflected waves are generated from any angle. It is possible to obtain a clear image by preventing the occurrence of an image (ghost) as much as possible.

[Brief description of drawings]

FIG. 1 is a perspective view showing an image receiving antenna according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an antenna element that constitutes the image receiving antenna.

[Explanation of symbols]

 1 Mast 2 Horizontal boom 3 Antenna element 4 Waveguide 5 Radiator 6 Vertical boom 7 Reflector 8 Feeder wire 9 Metal pipe (base) 10 Weather resistant film 11 Conductive particles or glass particles

Claims (2)

[Claims] 1. An image receiving antenna comprising a combination of an antenna element having a surface of a metal rod-shaped substrate coated with a weather resistant coating, wherein conductive particles are dispersed in the weather resistant coating of the antenna element. For antenna. 2. An image receiving antenna comprising a combination of an antenna element in which a surface of a metal rod-shaped substrate is covered with a weather resistant coating, wherein glass particles are dispersed in the weather resistant coating of the antenna element. antenna.