The present disclosure relates to a back cover of an image display apparatus such as a plasma display television (TV).
In the field of plasma display TVs or liquid crystal TVs, a reduction in the thickness of image display apparatuses is remarkably progressing by virtue of employing a thin power circuit, a thin panel or the like. In these days, for example, even a TV having a 26 inch screen size generally has a thickness of 40 mm or less.
Patent Document 1: JP 2010-271441 A
In TVs which have been becoming thinner and thinner as described above, particularly in a plasma display TV in which a metal plate is used as a back cover, there is a problem of noise generated from the vicinity of the back cover.
One non-limiting and exemplary embodiment provides a thin-screen TV capable of suppressing the generation of noise from a back cover.
In a conventional plasma display TV before being thinned down, noise from the vicinity of a back cover is not particularly annoying. However, the inventor of the present application has noticed that, in a recent plasma display TV which has been sufficiently thinned down, noise from the vicinity of a back cover is noticeable. Further, the inventor of the present application has assumed that the cause of the noise is a magnetic flux generated by a toroidal coil in an internal circuit. More specifically, a conventional plasma display TV has a reasonable thickness. Therefore, even if toroidal coils are provided in an internal circuit, there is a sufficient distance between the toroidal coils and a back cover. On the other hand, in a recent thin-screen plasma display TV, a toroidal coil in an internal circuit and a back cover are arranged close to each other. Therefore, the inventor of the present application has assumed that, in a recent thin-screen plasma display TV, a back cover vibrates due to the influence of a magnetic flux generated by a toroidal coil in an internal circuit, and noise is generated from the back cover as a result of the vibration, and has invented an image display apparatus having the following configuration.
The image display apparatus according to the present disclosure is an image display apparatus including a circuit board on which a toroidal coil is mounted, and a back cover covering a back face,
wherein the back cover has at least one hole configured to reduce the influence of a magnetic flux generated by the toroidal coil, the hole being provided in a region including a region facing the toroidal coil on the circuit board.
According to the present disclosure, the influence of the magnetic flux generated by the toroidal coil is reduced by the holes formed on the metallic back cover of the thin-screen TV. Therefore, vibration of the metallic back cover of the thin-screen TV in which the toroidal coil in the internal circuit and the metallic back cover are arranged close to each other is significantly reduced. That is, noise is not substantially generated from the metallic back cover of the thin-screen TV in which the toroidal coil in the internal circuit and the metallic back cover are arranged close to each other.
Hereinbelow, a preferred embodiment according to the present disclosure will be described with reference to the drawings.
In this manner, the holes 6 in the back cover 8 of the present embodiment is formed in the region (of the back cover 8) that faces the toroidal coils 2 on the circuit board 4. Further, the diameter of the holes 6 and the interval between the holes 6 can be appropriately set. For example, the diameter of the holes 6 can be set to a predetermined value within the range of 4 to 10 mm, and the interval between the holes 6 can be set to a predetermined value within the range of 1 to 5 mm.
In the partial region 8a of the back cover 8, an insulation plate 10 which is made of an insulating resin or the like is provided on the inner side of the region of the holes 6 arranged in a grid pattern. The insulation between the toroidal coils 2 and the back cover 8 is ensured by the insulating plate 10. Further, the insulating plate 10 makes it possible to prevent minute objects from entering the inside of the thin-screen TV 20. As will be described below, the insulating plate 10 itself cannot be the factor of the generation of vibration.
As described above, the inventor of the present application has assumed that the cause of noise generated from the vicinity of the back cover 8 is the influence of a magnetic flux generated by toroidal coils. Therefore, in order to reduce the influence of the magnetic flux, the many holes 6 are formed on the back cover 8 of the thin-screen TV 20. In this manner, a metal part of the back cover 8 affected by the magnetic flux is reduced.
That is, as illustrated in
In the present embodiment, the many holes 6 arranged in a grid pattern are formed in the partial region 8a which includes at least a part of the back cover 8 of the thin-screen TV 20, the part facing the toroidal coils 2 in an internal circuit, so that vibration of the back cover 8 caused by the influence of the magnetic flux generated by the toroidal coils 2 is reduced to thereby prevent the generation of noise from the back cover 8.
The inventor of the present application has experimentally confirmed that noise is generated from the back cover 8 when the back cover 8 is made of metal, and, further, that the noise substantially disappears by utilizing the present embodiment. Further, the inventor of the present application has experimentally confirmed that, even when the toroidal coils 2 have gaps, vibration of the back cover 8 is reduced, and noise generated from the vicinity of the back cover 8 substantially disappears by utilizing the present embodiment.
Further, the inventor of the present application has also confirmed that a back cover that is made of a material other than metal (an insulating resin, for example) hardly vibrates. This fact indicates that a back cover made of a material other than metal (an insulating resin, for example) is not affected by the influence of a magnetic flux generated by toroidal coils 2 in an internal circuit. Therefore, in the present embodiment, the insulating plate 10 (see
Hereinabove, it has been described that the present embodiment can be applied to a plasma display TV. The present embodiment can also be applied to another kind of TV, for example, a liquid crystal TV as long as a toroidal coil is mounted in an internal circuit and a back cover is made of metal.
The present invention is utilized in a thin image display apparatus such as a plasma display TV and a liquid crystal TV that has a back cover made of metal.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2012/000540 | 1/27/2012 | WO | 00 | 7/18/2014 |