Electronic device having bezel structure

An electronic device having a bezel structure includes a case, an installation element, part of which is installed to the case, a conductive bezel having a loop shape to fixedly couple the installation element to the case, and an electronic unit provided in the case. The conductive bezel includes a support portion to directly support a circumference of the installation element, and a separation portion formed at one or more positions of the support portion to separate the support portion by a predetermined interval to restrict formation of an electrical loop.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of Korean Patent Application No. 2003-68318, filed on Oct. 1, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic device having a bezel structure to fix constituent elements, and more particularly, to an electronic device having a bezel structure which can restrict radiation of an electromagnetic field from a loop formed by the bezel.

2. Description of the Related Art

In general, electronic devices, such as screen incorporated projectors or LCD monitors, use a metal bezel to firmly support constituent elements, such as a screen. The bezel has a loop shape because a central portion of one of the constituent elements must not be blocked by the bezel.

FIG. 1is a perspective view illustrating a general projection television as an example of an electronic device. Referring toFIG. 1, the projection television includes a case1, a screen3installed to the case1, a loop shaped bezel5to fix the screen3to the case1, and an electronic unit7provided in the case1. The case1and the screen3are formed of an insulation material such as plastic while the bezel5is formed of a conductive material, such as aluminum. The electronic unit7includes an optical projection unit, such as an optical system for projection, and an electronic circuit to drive the optical projection unit.

In the electronic device having the above structure, the electronic unit7including the electronic circuit is arranged close to the bezel5as a size of the electronic device decreases. When the electronic unit7is arranged close to the bezel5, as shown inFIG. 2, a near field9generated by the electronic unit7is electronically coupled to the bezel5having a loop shape. Thus, the bezel5forms a loop antenna at and around a resonance frequency.

Assuming that a total length of a loop formed by the bezel5is L1, the following Equation 1 is satisfied.
L1=k×λ0[Equation 1]

Here, the total length of the loop “L1” is twice a sum of a width W and a height H of the bezel5. That is, L1=2×(H+W). “k” denotes an expansion rate of a wavelength and is not less than 1.0 in a free space. The expansion rate “k” changes according to a size of the bezel5and the electronic circuit7arranged around the bezel5. “λ0” denotes a resonance wavelength.

When the bezel5having the above structure is employed, the bezel5resonates at the resonance wavelength “λ0” and a minimum resonance frequency f is about 300/λ0MHz. Accordingly, the near field9generated by the electronic unit7at and around the resonance frequency increases so that the increased near field9causes problems in that electronic field radiation and electro-magnetic interference (EMI) increase.

In order to solve the above problems, a conventional electronic device has been suggested to shield the electronic circuit or the electronic unit and to form the bezel supporting the screen with an insulation material. Also, in order to solve a problem in the strength of the bezel5, an additional metal plate to reinforce the bezel5is provided in the conventional electronic device. The above solutions, however, have drawbacks, such as an increase in weight, deterioration in assembly, lowering in mechanical strength, and an increase in manufacturing cost.

SUMMARY OF THE INVENTION

In order to solve the above and/or other problems, it is an aspect of the present invention to provide an electronic device having an improved bezel structure to maintain a mechanical strength and an appearance and simultaneously reduce an electronic field radiation and EMI.

The foregoing and/or other aspects and advantages of the present general inventive concept may be achieved by providing an electronic device having a bezel structure including a case, an installation element, part of which is installed to the case, a conductive bezel having a loop shape to fix the installation element to the case, and an electronic unit provided in the case, wherein the conductive bezel may comprise a support portion to directly support an outside of the installation element, and a separation portion formed at one or more positions of the support portion to separate the support portion by a predetermined interval to restrict formation of an electrical loop.

In an aspect of the present general inventive concept, the electronic device having a bezel structure may further comprise a resistor and/or an inductor which is electrically connected to the support portion at one or more separation portions.

The foregoing and/or other aspects and advantages of the present general inventive concept may also be achieved by providing a bezel used with an electronic and/or electrical device having a case and an electronic unit disposed in the case, the bezel comprising a support portion having a loop shape to be fixedly coupled to a circumference of an installation element, and having both ends separated by a predetermined interval, and a separation portion formed between the both ends of the support portion to restrict formation of an electric loop.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 3shows a projection television as an example of an electronic and/or electrical device according to an embodiment of the present general inventive concept. Referring toFIG. 3, the electronic device may include a case11, an installation element13, such as a screen, installed in the case11, a bezel20to fixedly couple the installation element13to the case11, and an electronic unit17provided inside the case11.

The installation element13can be fixedly coupled to the case11by the bezel20to be exposed outside with respect to the case11.

The bezel20may have a loop shape to encompass the installation element13and can be made of a conductive material, such as metal, to firmly support the installation element13.

Referring toFIG. 4, the bezel20may include a support portion21to directly support a circumference of the installation element13, and a separation portion25separated from the support portion21. The separation portion25, as shown inFIG. 4, can be formed to electrically disconnect both ends of the supporting portion21by a predetermined width at a portion of the support portion21. The width of the separation portion25can be formed not to generate an electrical loop.

By providing the separation portion25, a loop current in a high frequency range generated due to an electrostatic capacity formed between both ends of the support portion21disposed at both sides of the separation portion25can be prevented. Thus, an increase in radiation of an electronic (or electromagnetic) field can be restricted (prevented).

An insulation reinforcing member29can be installed in a position corresponding to the separation portion25. The insulation reinforcing member29can be coupled to the support portion21by screws to reinforce the support portion21. The insulation reinforcing member29can be exposed outside and can prevent the separation portion25from being exposed so that an aesthetic outer appearance of the electronic device can be maintained.

Referring toFIG. 5, a width of a separation portion26provided between both ends of a support portion22of a bezel20. When the width of the separation portion26decreases, it causes a problem in that a loop antenna is formed in the bezel20having the decreased width. That is, the loop antenna formed inFIG. 5can be represented by an equivalent circuit as shown inFIG. 6.

Referring toFIGS. 5 and 6, the support portion22can form a closed circuit23and the separation portion26functions as a capacitor27, so that charges are accumulated in the separation portion26.

Since the capacitor27maintains a short-circuit state in a high frequency range, a function of the bezel20as the loop antenna can be maintained when the separation portion26is not provided. An embodiment to reduce an effect by the electrostatic capacity when the width of the separation portion is narrow, will be described with reference toFIG. 7.

FIG. 7is a perspective view illustrating a loop shaped conductive bezel20used with an electronic device to remove an effect generated due to the electrostatic capacity by lowering the electrostatic capacity while decreasing the width of the separation portion26according to another embodiment of the present general inventive concept. Referring toFIGS. 3 and 7, in order to reduce the electrostatic capacity, the separation portion26can be provided at four corners of the support portion22of the bezel20that has a rectangular shape in the electronic device. An equivalent circuit of this connection is shown inFIG. 8.

Referring toFIG. 8, since the equivalent circuit has four capacitors28connected in series, assuming that the electrostatic capacity of each of the capacitors28is C, the equivalent electrostatic capacity is C/4 so that a loop current decreases. That is, when the separation portion26is provided at “n” number of positions, the electrostatic capacity can be reduced to 1/n.

Although inFIGS. 7 and 8, the separation portions26are formed at four positions, however, the present general inventive concept is not limited thereto. In setting the number and position of the separation portions26, a variety of modifications can be available according to a type of the electronic device.

That is, the formation of the loop antenna can be restricted (prevented) by setting the number and position of the separation portions according to the type of the electronic device, for example, a total length of the bezel, a closeness (distance) between the electronic circuit and the bezel, and a strength of an electronic wave radiated from the electronic circuit.

Referring toFIG. 9, an electronic device according to another embodiment of the present general inventive concept may include a resistor31which is installed at one or more positions where separation portions26of a bezel are installed (provided). The resistor31can be electrically connected to both ends of the support portion22through each separation portion26. In the electronic device, since a width of the separation portion26is relatively smaller, when the separation portion functions as a stray capacitor27, a loop current flowing through the bezel20can be reduced.

Since a Q factor of a circuit formed by the bezel is inversely proportional to a resistance, the loop current can be reduced by electrically connecting the resistor31between both ends of the separation portion26to lower the Q factor. Thus, the radiation of an electronic field can be reduced.

Referring toFIG. 10, an electronic device according to another embodiment of the present general inventive concept may include an inductor35which is installed at one or more positions where separation portions26of a bezel are installed (provided). The inductor35can be electrically connected to both ends of support portion22through the separation portion26to form a parallel resonance circuit with a capacitor27between the electrostatic capacity of the separation portion26and the inductor35. That is, in an equivalent circuit of the bezel having the above structure, the capacitor27and the inductor35can be connected in parallel to form the parallel resonance circuit. An inductance of the inductor35can be set such that a resonance frequency generated by the inductor35and the capacitor27is the same as that of the bezel20.

By including the above inductor35to the bezel, an impedance of a circuit around the resonance frequency range increases, and accordingly the loop current decreases. As a result, radiation of an electronic field can be restricted (prevented).

Referring toFIG. 11, an electronic device according to another embodiment of the present general inventive concept may include both a resistor31and an inductor35which are installed at one or more positions where separation portions26of a bezel are installed (provided). The resistor31and the inductor35can be electrically connected in parallel to both ends of the support portion22through the separation portion26to form a parallel resonance circuit between the electrostatic capacity of the separation portion26and a combination of the resistor31and the inductor35.

FIG. 12is a perspective view illustrating a state of the loop shaped conductive bezel in which a resistor31and an inductor35are installed. Referring toFIG. 12, a lug41can be provided in an inner space of a support portion22and coupled to the support portion22using a plurality of screws45. The screws45can be provided at the support portion22at either side of the separation portion26and made of a conductive material. The resistor31and the inductor35can be connected between the screws45separately disposed at either side of the support portion22. Thus, both ends of the resistor31and the inductor35are electrically connected to the support portion22.

FIG. 13is a view illustrating an equivalent circuit of the loop shaped conductive bezel ofFIG. 11. Referring toFIGS. 11 and 13, the capacitor27formed by the separation portion26ofFIG. 11, the resistor31, and the inductor35are connected in parallel to form an RLC parallel resonance circuit. Values of the inductor35and the capacitor27can be used to determine the resonance frequency. The value of the inductor35can be set to be the same as that of an overall resonance frequency generated by the RLC circuit formed by the bezel. Accordingly, an impedance of an overall equivalent circuit can be increased and consequently, a current can be decreased so that the radiation of an electronic field around that resonance frequency is reduced.

A structure of a portion of the electronic device shown inFIG. 11can be provided at either one of the separation portions or a plurality of the separation portions.

Although the embodiments includes a bezel used to fixedly couple the installation element, such as a screen, to the case, the present general inventive concept is not limited thereto and can be applied to loop shaped conductive support frames to keep and maintain electronic devices including an electronic circuit with the restricted (prevented) radiation of the electronic or electrical field. Also, the present general inventive concept can be applied to an aperture stop which is employed to prevent an unnecessary light radiation generated by optical parts, such as an optical modulator.

In the electronic device having the above-described bezel, a current flowing through the support portion can be restricted (prevented) by providing the separation portion at one or more positions of the support member, the resistor, and/or the inductor at the separation portion. Thus, the bezel can be prevented from functioning as an antenna so that the radiation of the electronic or electrical field can be reduced.

FIG. 14is a graph illustrating a result of comparison between levels of radiation of electromagnetic waves generated in a conventional bezel of an electronic device and a bezel according to the embodiment of the present general inventive concept, respectively. The graph ofFIG. 14illustrates data obtained by applying the embodiment of present general inventive concept to an LCD projection television with a 50 inch screen.

In the graph, a letter “A” indicates a waveform generated from the conventional bezel, which shows a higher decibel of radiation of the electromagnetic wave than other waves. A letter “B” indicates a waveform generated from the bezel provided with both a resistor and an inductor at each of three separation portions according to the embodiment shown inFIG. 11. A letter “C” indicates a waveform generated from an electronic device in which a bezel structure is not adopted. The waveform indicated by the letter “B” shows that the electromagnetic wave can be radiated at a relatively lower decibel than the waveform indicated by the letter “B,” and that the waveform can be similar to that of the electronic device without the bezel structure.

According to an aspect of the present general inventive concept, the electronic device may comprises a television apparatus having the case11, the installation element13, such as a screen, installed in the case11, and the electronic unit17provided inside the case11as shown inFIGS. 1 and 3. The case11may have a wall defining an opening in which the installation element13is disposed while the bezel is coupled between the wall of the case11and the installation element13. An image generated using the electronic unit17is produced on the installation element13through the opening of the case11.