DE29905435U1 - Low-noise block-down receiver with improved housing construction - Google Patents

Description

77 199 p7/bn

MICROELECTRONICS TECHNOLOGY, INC. Hsinchu, Taiwan, R.O.C.

LOW NOISE BLOCK-DOWN RECEIVER WITH IMPROVED HOUSING CONSTRUCTION BACKGROUND OF THE INVENTION

1. Technical area

The invention relates to a low noise block-down receiver (LNB), and in particular to a low noise block-down receiver with an improved housing structure that can be manufactured at low cost.

2. Description of the state of the art

In general, a satellite television signal is transmitted to, for example, a television set via a number of devices, such as a horn, a waveguide, an orthogonal mode converter and a low-noise processing circuit. However, these devices are separate from each other. Consequently, they are cumbersome to use and result in higher manufacturing costs. To solve these problems, a low-noise block-down receiver (LNB) has been introduced as shown in Fig. 1. The low-noise block-down receiver comprises a processing circuit (not shown), a signal output connector 14, a horn 11 for collecting electromagnetic microwave radiation, a waveguide

12 connected to the horn 11 and a container 13 connected to the waveguide 12 for accommodating the processing circuit and preventing microwave leakage and/or extraneous noise interference. Furthermore, the horn 11, the waveguide 12 and the container 13 are formed in a metal case from a mold. In addition, a case made of plastic 20 is provided which comprises two parts 20a and 20b and is formed to enclose the metal case so that the metal case is protected from corrosion caused by severe external climatic conditions. Generally, a plastic cover is used to shield a signal input just above the horn 11.

However, during the manufacturing process for the LNB summarized above, the molds for the plastic and plastic cases must be prepared individually. Furthermore, during assembly, the processing circuit must first be placed in the metal case, and then the plastic case is used to enclose the metal case. In order to reduce the cost and simplify the structure of the LNB, it is desirable to develop a low-noise block-down receiver with a simple structure and low manufacturing cost, and one that requires less material for its construction.

DESCRIPTION OF THE INVENTION

In view of the above, it is an underlying technical problem of the invention to provide a low-noise block-down receiver which has a simple structure and with which the manufacturing costs can be reduced considerably.

_t ⁰ * ₉ J ·····*

To solve the above technical problem, the low-noise block-down receiver includes a

signal processing circuit and a housing used to house the processing circuit and acts as a horn and waveguide. The low noise block-down receiver is characterized in that the housing is made of plastic material and its inner surface is covered with a metal film coating, which can conduct microwaves and prevent both signal leakage and extraneous noise interference.

Due to the cost saved on molds, assembly, and manufacturing materials, the overall manufacturing cost can be reduced significantly. Furthermore, the plastic housing can be easily modified and controlled so that there is no gap between the metal film and the plastic housing. Consequently, not only can the plastic housing be made stronger to prevent damage, but the variable shape, small size, and light weight of the plastic housing can also meet the requirements of a wide variety of installation spaces.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will become more apparent from the following detailed description and the accompanying drawings which are given by way of example only and are not limitative of the present invention. In the drawings:

Fig. 1 is a schematic side view showing portions of a conventional low noise block-down receiver;

Fig. 2 is a schematic sectional view showing a low-noise block-down receiver according to a preferred embodiment of the invention; and

Fig. 3 is a schematic and perspective view showing a socket for the signal output of a low-noise block-down receiver according to a preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Fig. 2 is a schematic cross-sectional view showing a low noise block-down receiver (LNB) according to a preferred embodiment of the invention. Referring to Fig. 2, the LNB includes a signal processing circuit 40, a horn ¹¹ , a waveguide 12', and a container 13' used to house and enclose the processing circuit 40. The horn 11', the waveguide 12', and the container 13' are made in a mold from plastic material such as ABS and form a plastic housing 10'. The inner surface of the plastic housing 10' is coated with a metal film 31, for example a copper-nickel alloy, copper-silver alloy, or copper-gold alloy. To facilitate assembly, the container 13' has a bottom cover 13a' which is used to seal the container 13' after the low noise signal processing circuit 40 is placed therein, thereby preventing extraneous noise interference. To prevent short circuit, a spacer 50 is further installed between the processing circuit 40 and the bottom cover 13a'.

Fig. 3 is a schematic and perspective view showing a socket 14' for the signal output of an LNB according to a preferred embodiment of the invention arranged in the container 13'. The socket 14' has an internal structure which is spirally toothed and coated with a metal film (not shown) or formed in a mold together with the socket 14'. Furthermore, a signal output connector (not shown) similar to that shown in Fig. 1 is inserted into the socket 14'. The output terminal of the output connector is electrically connected to the processing unit 40 to transmit a processed signal to, for example, a television set.

In general, the metal film 31 can be formed by any known coating method. In addition, constant amounts of an anti-UV agent and an anti-oxidant can be previously filled on the inside of the plastic housing 10'. The plastic housing is then coated with the metal film 31 (for example, a cupronickel film with a suitably selected composition) which can conduct microwaves and preferably has a conductivity of less than 0.31 ohm/cm-^ (2 ohm/US in^) to meet the requirements of a high frequency microwave protocol.

In an LNB based on the invention, the manufacturing cost can be reduced considerably because it is not necessary to manufacture a metal case and the metal film coating can be mass-produced at high speed. Furthermore, the plastic case can withstand mechanical stress and corrosion and has higher strength. Consequently, a low-noise block-down receiver with a simple structure and low cost is achieved.

While the invention has been described by way of example and with reference to the preferred embodiment, it is to be understood that the invention is not limited to the embodiment disclosed. On the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Accordingly, the appended claims should be given the broadest interpretation so as to encompass all such modifications and similar arrangements.

Claims (3)

PROTECTION CLAIMS 1. Low-noise block-down receiver (I) with a
improved housing construction, comprising a
Signal processing circuit (40) and a housing
(10 ¹ ) for receiving the processing circuit which functions as horn (II ¹ ) and waveguide (12'), characterized in that: the housing (10 ¹ ) is made of plastic material and has an inner surface designed to conduct microwaves and prevent both signal leakage and external noise interference with a
metal film coating (31). 2. Receiver according to claim 1, characterized in that the metal film (31) is an electrically conductive alloy. 3. Receiver according to claim 1, characterized in that the output signal of the processing circuit (40) is output via a connector (14) which is plugged into a socket (14') provided in the housing, the surface of the socket being coated with a metal film (31).