JP2009284145A - Liquid crystal television - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal television that eliminates breakage of an audio amplifier IC by preventing static electricity from being aerially discharged from a front cabinet to a cone portion of a speaker. <P>SOLUTION: The liquid crystal television having a liquid crystal module 2, a speaker 4, a wiring board 3, etc., equipped in a front cabinet 1a and a rear cabinet 1b is constituted having a ground-potential metal piece 5 interposed between the front cabinet 1a and the speaker 4. Static electricity charged in the front cabinet 1a is aerially discharged to the ground-potential metal piece 5 disposed in front of the speaker 4 to prevent aerial discharge to the cone portion of the speaker 4, thereby eliminating breakage of the audio amplifier IC due to aerial discharge. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal television, and more particularly to an improved liquid crystal television that prevents static electricity from being discharged in the air from a front cabinet to a cone portion of a speaker.

  As is well known, a liquid crystal module, a speaker, a wiring board, and the like are built in the front cabinet and rear cabinet of a liquid crystal television. In such a liquid crystal television, when static electricity is discharged from the front cabinet into the speaker cone in the air, a Zener diode for preventing the audio amplifier IC mounted on the wiring board from being destroyed is a signal output line of the audio amplifier IC. Is provided.

On the other hand, various proposals have conventionally been made as ESD countermeasures in electronic devices. For example, a semiconductor component connected to a wiring member is discharged from a statically charged human body or other article to a wiring member inside the electronic device through a heat radiating hole provided in the casing of the electronic device such as a thin display device. In order to prevent the occurrence of defective dielectric breakdown, a thin plate-like partition that protrudes in the normal direction of the inner surface of the housing is formed in the vicinity of the heat radiation hole of the inner surface of the housing where a wiring member such as FPC or FFC is adjacent. And the electronic device housing | casing which maintained the space distance of a heat radiating hole and a wiring member is proposed (patent document 1).
In addition, the circuit board and circuit components in the housing are prevented from being destroyed by static electricity that has entered the housing from openings such as button holes, ventilation openings, and gaps in the joints of the housing. For this purpose, an exposed portion of the ground circuit pattern is formed on the circuit board so as to face the opening formed in the housing, and solder is provided on the exposed portion so that the distance from the opening to the solder is the opening. There has also been proposed an electrical device that is shorter than the distance from the terminal part of the switch component to lead the static electricity that has entered from the opening to the ground circuit pattern from the solder (Patent Document 2).

  In order to effectively ground the metal cabinet while suppressing the impact caused by static electricity and suppressing the generation of high voltage, a specific discharge path is provided between the metal front cabinet on the front of the CRT and the ground portion. There has also been proposed an electric device that is provided to ground the front cabinet (Patent Document 3).

Furthermore, in order to prevent the static electricity from staying on the grill net and to eliminate the deterioration of the product value due to the adhesion of dust, the electrostatic breakdown of electronic parts, the malfunction of the product, etc. There has also been proposed a speaker grill in which a conductive plate is disposed so as to be in contact with the back surface of the grill net and the plate is connected to a ground terminal of a household outlet via an electric cord or the like (Patent Document 4).
JP 2007-73790 A JP 2006-302544 A JP 2001-157142 A JP 2003-9269 A

  In the above-described conventional liquid crystal television, even if static electricity is discharged from the front cabinet to the cone portion of the speaker, the audio amplifier IC is not destroyed because it is discharged to the ground by the Zener diode. Since the cost is increased by providing a Zener diode in the signal output line, it is difficult to say.

  On the other hand, as in the ESD countermeasure disclosed in Patent Document 1, a device that maintains the spatial distance between the heat radiation hole and the wiring member using a partition wall has an uncertain effect of preventing air discharge. As described above, the distance from the opening to the solder is made shorter than the distance from the opening to the terminal part of the switch part, and the static electricity that enters from the opening to the ground circuit pattern is restricted to the circuit design. Therefore, it is difficult to say that all of them are good measures, and these ESD countermeasures are not specifically applicable as means for preventing air discharge from the front cabinet of the liquid crystal television to the speakers.

  Further, the ESD countermeasure of Patent Document 3 is expensive because it provides a specific discharge path incorporating a resistor, a discharge tube, a high-voltage capacitor, and the like. Further, like the ESD countermeasure of Patent Document 4, a grill is provided. What prevents a static electricity from staying by bringing a conductive plate into contact with the net is not suitable as a means for preventing air discharge from the front cabinet of the liquid crystal television to the speaker.

  The present invention has been made under the above circumstances, and the problem to be solved is to prevent static electricity from being discharged in the air from the front cabinet to the cone portion of the speaker, thereby eliminating the destruction of the audio amplifier IC. An object of the present invention is to provide a liquid crystal television which can reduce the cost by omitting a Zener diode for protecting the IC.

  In order to achieve the above object, a liquid crystal television according to the present invention includes a ground potential between a front cabinet and a speaker in a liquid crystal television in which a liquid crystal module, a speaker, a wiring board, and the like are built in a front cabinet and a rear cabinet. The metal piece is interposed.

  The metal piece may be attached to the metal frame of the liquid crystal module, or may be a protruding piece integrally formed by processing the metal frame of the liquid crystal module. Moreover, it is preferable that the said metal piece has a comb shape.

  When the ground potential metal piece is interposed between the front cabinet and the speaker as in the liquid crystal television of the present invention, static electricity staying in the front cabinet is in the air in the ground potential metal piece located in front of the speaker. Since the electric discharge occurs and the air does not discharge to the cone portion of the speaker, the concern that the audio amplifier IC is destroyed by the air discharge is eliminated. Accordingly, it is not necessary to provide a Zener diode for protecting the audio amplifier IC in the output signal line of the audio amplifier IC, and the Zener diode can be omitted, so that the cost can be reduced accordingly.

  Since the above metal piece must be at ground potential, it is convenient to attach the metal piece to the metal frame of ground potential of the liquid crystal module adjacent to the speaker. However, when the metal piece is attached to the metal frame later, it is economically disadvantageous because the number of parts increases and it is necessary to increase the metal piece attachment process. On the other hand, if the metal piece is integrally formed by processing the metal frame of the liquid crystal module, there is no need to increase the number of parts or increase the metal piece attachment process, and the metal frame is manufactured from sheet metal. In this case, the metal piece can be formed only by adding a simple process such as cutting and raising, which is economically advantageous.

  In addition, if the metal piece has a comb shape, air discharge is easily performed on the sharp comb-tooth portion, and sound interference by the metal piece does not substantially occur.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

  1 is a schematic cross-sectional view of a liquid crystal television according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a main body of the liquid crystal television, FIG. 3 is a front view of the liquid crystal module of the liquid crystal television, and FIG. It is a disassembled partial perspective view of a metal frame and a bezel.

  As shown in FIGS. 1 and 2, this liquid crystal television has a liquid crystal module 2 built in a front cabinet 1a and a rear cabinet 1b made of synthetic resin, and a liquid crystal panel 2a of the liquid crystal module 2 is a front cabinet 1a. It is exposed at the front opening.

  A plurality of convex portions 2c are formed on the metal frame 2b (rear frame) of the liquid crystal module 2 by drawing, and the main wiring board 3 is supported by these convex portions 2c and attached to the back side of the metal frame 2b. It has been. On the main wiring board 3, a tuner (not shown), an audio amplifier IC, and other various electronic components (not shown) are mounted.

  As shown in FIGS. 1 to 3, a pair of left and right speakers 4 is provided on the lower side of the liquid crystal module 2, and the wires 4 a of the respective speakers 4 are connected to connectors of the main wiring board 3. A ground potential metal piece 5 is interposed between the speaker 4 and the front cabinet 1a. The metal piece 5 will be described in detail later.

  As shown in FIG. 2, the liquid crystal module 2 includes a liquid crystal panel 2a, a metal frame 2b (rear frame), a light reflecting sheet 2d, a cold cathode tube 2e, a lamp frame 2f, optical sheets 2g and 2h, a cell guide 2i, and a bezel 2j. It is comprised by the main members. More specifically, the rear metal frame 2b is obtained by processing a sheet metal into a shallow box shape, and the upper and lower side plates 2k are bent into a U shape to form double side plates. A light reflecting sheet 2d bent in a trapezoidal shape is stacked inside the metal frame 2b, and a plurality of cold cathode tubes 2e bent into a U shape are disposed on the front side thereof. It is fixed with a lamp holder (not shown).

  A lamp frame 2f that also serves as a reflector is attached to the left and right side wall portions of the metal frame 2b. By this lamp frame, the end portion on which the lamp socket of the U-shaped cold cathode tube 2e is attached is opposite to the end portion. The U-shaped bent part is covered.

  The four peripheral edges of the two optical sheets 2g and 2h are placed on the upper and lower double side plates 2k and the left and right lamp frames 2f of the metal frame 2b, and are held by a cell guide 2i made of synthetic resin. These optical sheets 2g and 2h are light diffusing sheets that diffuse the direct light from the U-shaped cold cathode fluorescent lamp 2d and the reflected light reflected by the light reflecting sheet 2d and uniformly irradiate the liquid crystal panel 2a. The optical sheet 2h is a thin light reflecting sheet, but the rear optical sheet 2g is a thick panel-like light diffusing sheet (light diffusing plate) that is difficult to bend. Then, four peripheral edges of a liquid crystal panel 2a (liquid crystal cell) are placed on the cell guide 2i and pressed by a sheet metal bezel 2j having an L-shaped cross-sectional shape, and the liquid crystal module 2 is assembled.

  As shown in FIG. 3, a pair of left and right metal pieces 5, 5 having a comb shape protrudes below the liquid crystal module 2, and these metal pieces 5, 5 are connected to the pair of left and right speakers 4, 4. Located just in front of the cone. As shown in FIG. 4, the metal piece 5 is formed by cutting and raising the outer plate 2m of the double side plate 2k on the lower side of the metal frame 2b into a comb shape, and the notch formed in the bezel 2j. It protrudes downward through the part 2n. Since the metal frame 2b of the liquid crystal module 2 is at the ground potential, the comb-shaped metal piece 5 formed by cutting and raising as described above is also at the ground potential.

  The shape of the metal piece 5 is not limited to the comb shape as in this embodiment, and may be various shapes such as a square, a triangle, and a lattice shape. There is an advantage that air discharge is easily performed on the comb teeth portion, and sound interference by the metal piece 5 does not substantially occur, which is preferable.

  In this embodiment, the metal plate 5 is formed by cutting and raising the outer side plate 2m of the double side plate 2k of the metal frame 2 into a comb shape. For example, when the speaker 4 is positioned slightly forward It is preferable to cut and raise the sheet metal bezel 2j to form the metal piece 5 at a slightly more forward position. Even in this case, the bezel 2j is screwed to the metal frame 2 and is at the ground potential, so the metal piece 5 is at the ground potential.

  Further, a metal piece 5 is manufactured separately, and is attached to the metal frame 2b or bezel 2j of the liquid crystal module 2 with a screw or the like, and the metal piece 5 having a ground potential is interposed between the speaker 4 and the front cabinet 1a. Good. However, this case is economically disadvantageous because the number of parts increases and an additional metal piece mounting process is required. On the other hand, when the metal frame 2b is processed and the metal piece 5 is integrally formed as in the present embodiment, it is not necessary to increase the number of parts or increase the metal piece attachment process, and the metal frame is made from sheet metal. Since a metal piece can be formed only by adding a simple process such as cutting and raising when manufacturing, it is economically advantageous.

  As described above, when the metal piece 5 having the ground potential is interposed between the speaker 4 and the front cabinet 1a and is positioned immediately before the cone portion of the speaker 4, the static electricity staying in the front cabinet 1a becomes the ground potential. Since the air discharge occurs in the metal piece 5 and the air discharge does not occur in the cone portion of the speaker 4, the audio amplifier IC can be sufficiently prevented from being destroyed by the air discharge. Accordingly, it is not necessary to provide a Zener diode for protecting the audio amplifier IC in the output signal line of the audio amplifier IC, and the Zener diode can be omitted, so that the cost can be reduced accordingly.

It is a schematic sectional drawing of the liquid crystal television concerning one Embodiment of this invention. It is sectional drawing of the main-body part of the liquid crystal television. It is a front view of the liquid crystal module of the liquid crystal television. It is a disassembled partial perspective view of the metal frame and bezel of the liquid crystal module.

Explanation of symbols

1a front cabinet 1b rear cabinet 2 liquid crystal module 2a liquid crystal panel 2b metal frame (rear frame)
3 Wiring board 4 Speaker 5 Metal piece of ground potential

Claims (4)

  A liquid crystal television having a liquid crystal module, a speaker, a wiring board and the like built in a front cabinet and a rear cabinet, wherein a ground potential metal piece is interposed between the front cabinet and the speaker.   2. The liquid crystal television set according to claim 1, wherein the metal piece is attached to a metal frame of the liquid crystal module.   2. The liquid crystal television according to claim 1, wherein the metal piece is integrally formed by processing a metal frame of the liquid crystal module.   4. The liquid crystal television set according to claim 1, wherein the metal piece has a comb shape.

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