Patent Grant
7388545
The present application is based on, and claims priority from, Taiwan Application Serial Number 94217923, filed Oct. 17, 2005, the disclosure of which is hereby incorporated by reference herein in its entirety.
1. Field of Invention
The invention relates to a shielding device and, in particular, to a shielding device that prevents the antenna signal of a notebook computer from interference.
2. Related Art
Notebook computers have limited volumes. However, there are more and more devices to be integrated into a single notebook computer. The work frequency is also getting higher. Therefore, it is necessary to provide good shielding to prevent interference among devices. Modem notebook computers are already integrated with antennas for wireless communication functions. The antenna is usually integrated in the panel bracket of the display panel. The antenna transmits signals via electromagnetic (EM) waves. However, the panel itself has a liquid crystal display (LCD) driver that generates a video clock with the frequency about 65 MHz. Some high frequency components of the video clock overlap with the frequencies of the antenna operating in the 802.11 b/g band, thus interfering with the antenna signals. Therefore, how to design a shielding device to prevent the antenna of a notebook computer from interference with the video signals is very important.
An objective of the invention is to provide a shielding device to prevent the antenna signals of a notebook computer from interference.
Another objective of the invention is to provide a notebook computer that can prevent the antenna signals from interference.
Yet another objective of the invention is to provide a shielding device that can prevent the high frequency components of the LCD driver from interfering with other devices.
In accord with the above-mentioned objectives, the invention provides a shielding device to prevent the antenna signals of a notebook computer from interference. According to a preferred embodiment of the invention, the shielding device includes a grounding component and a shielding plate. The shielding plate is made of conductive material. The shielding plate has a first portion and a second portion. The first portion is electrically connected to a grounding device via the grounding component. The second portion is disposed between an antenna and a display controller. The shielding plate prevents the frequency components of the display controller from interfering with the antenna. The antenna is located in the panel bracket of the display panel. The display controller is a LCD driver. The grounding component is a metal foil. The metal foil attaches the first portion of the shielding plate to the grounding device. The metal foil and the grounding device are connected electrically.
The invention provides a notebook computer that can prevent the antenna signals from interference. According to a preferred embodiment of the invention, the notebook computer includes a host part, a panel part, and a shielding device.
The panel part is connected to the host part. The panel part has a grounding device. The panel bracket of the panel part contains an antenna. The shielding device includes a grounding component and a shielding plate. The shielding plate is made of a conductive material. The shielding plate has a first portion and a second portion. The first portion is electrically connected to the grounding device via the grounding component. The second portion is disposed between the antenna and a display controller. The shielding plate prevents the frequency components of the display controller from interfering with the antenna frequencies. The display controller is a LCD driver. The grounding component is a metal foil. The metal foil and the grounding device are connected electrically.
The invention has at least the following advantages, wherein each embodiment has one or many of the advantages. The disclosed shielding device can prevent the antenna signals of a notebook computer from interference. The disclosed shielding device can prevent the high frequency components of a display driver from interference. The invention provides a notebook computer that can prevent its antenna signals from interference.
These and other features, aspects and advantages of the invention will become apparent by reference to the following description and accompanying drawings which are given by way of illustration only, and thus are not limitative of the invention, and wherein:
The antenna 112 of the notebook computer is located in the panel bracket 110. The LCD panel 102 contains a display controller 114, such as a LCD driver. The LCD driver 114 generates a video clock. Since the video clock is a periodic square wave (or close to a periodic square wave), some high frequency components in the video clock may overlap with the antenna frequencies, thus interfering with the antenna signals. When the antenna 112 and the LCD driver 114 are close to each other, the interference phenomena become more prominent.
The grounding component 204 may be a metal foil, such as the aluminum foil. The metal foil attaches the first portion 208 of the shielding plate 206 to the grounding device 212. The metal foil and the grounding device 212 are electrically connected.
The grounding component 204 may also be a conductive tape, such as the aluminum tape. The conductive tape attaches the first portion 208 of the shielding plate 206 to the grounding device 212. The conductive tape and the grounding device 212 are electrically connected.
With simultaneous reference to
SE=R+A+B(in dB)
where SE is the shielding effectiveness, R is the reflection loss, A is the absorption loss, and B is the conditional correction factor. The threshold of the shielding effectiveness is computed as follows:
The threshold of the shielding effectiveness=λ/20,
where λ is the wavelength of the EM wave to be shielded. The span d between the grounding points 602a, 602b, . . . , 602j is preferably smaller than 0.625 cm, if the antenna 214 operates in the frequency band of 802.11 b/g where the frequency and the wavelength are about 2.4 GHz and 12.5 cm respectively.
The invention has at least the following advantages, wherein each embodiment has one or many of the advantages. The disclosed shielding device can prevent the antenna signals of a notebook computer from interference. The disclosed shielding device can prevent the high frequency components of a display driver from interference. The invention provides a notebook computer that can prevent its antenna signals from interference.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 94217923 U | Oct 2005 | TW | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 6724348 | Fang | Apr 2004 | B2 |
| 6937205 | Chou et al. | Aug 2005 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| 20070085753 A1 | Apr 2007 | US |
