JP3488790B2 - Display device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal, a plasma,
The present invention relates to a display device in which a display substrate made of L or the like and a wiring substrate on which a driving IC is provided are covered with a metal housing. 2. Description of the Related Art FIG. 4 shows a liquid crystal display device 1 as a display device.
4 to FIG. 6, FIG. 4 is a perspective view thereof, and FIG. 5 and FIG. 6 are cut line BB and cut line CC shown in FIG. 4, respectively.
FIG. [0003] The liquid crystal display device 1 comprises a liquid crystal panel 2 and a surface light source body 3.
A liquid crystal (not shown) is sealed between the glass substrate 4 and the second glass substrate 5, and display electrodes (not shown) are arranged on their respective inner surfaces so as to be orthogonal to each other to form a display screen 6. Make up. Further, a wiring board 7 such as a printed board is arranged in parallel with the second glass substrate 5 such that respective end faces thereof face each other, and the second glass substrate 5 is placed on a metal plate 8 made of stainless steel or the like. The wiring board 7 is fixed with an adhesive resin 9 made of a heat-resistant adhesive. The driving ICs 10 are arranged on the wiring board 7, and the driving ICs 10 are covered with a protective resin layer 11. [0004] As for the surface light source body 3, reference numeral 12 denotes a light guide plate, 1
Reference numeral 3 denotes a fluorescent tube, and reference numeral 14 denotes a reflecting member. Further, the surface light source body 3 is fixed together with the liquid crystal panel 2 in a metal housing 15. To fix the liquid crystal panel 2, a metal plate 8 is used.
It is fixed to the metal housing 15 with the adhesive 16 provided above. Then, as shown in FIG. 5, the wiring board 7 is fixed to the metal housing 15 with screws 17. At that time, screw 17
Is electrically connected to the ground electrode 18 provided on the wiring board 7, so that the ground electrode 18 is also electrically connected to the metal housing 15 through the screw 17. Further, as shown in FIG. 6, there is also a configuration in which the ground electrode 18 is electrically connected to the metal housing 15 through a metal spring 20 fixed by solder 19. Thus, according to the liquid crystal display device 1 having the above configuration, even if the electromagnetic waves generated from the wiring board 7 and the like are radiated to the metal casing 15, the ground electrode 1
8 to prevent electromagnetic wave energy from being radiated through the metal housing 15 into the air. That is, in recent years, leakage of electromagnetic waves from electronic devices such as televisions, radios, and mobile phones has become a problem. However, a display unit such as a liquid crystal display, a plasma display, an EL display, and an external circuit such as a printed wiring board for the display unit are provided. In such display devices, it is important to take measures against such electromagnetic interference.
Therefore, as described above, the electromagnetic wave energy is
5 from the air. [0007] However, in the liquid crystal display device 1 having the above configuration, the screw 1 as shown in FIG.
7 or the metal housing 15 as shown in FIG. 6 is in contact and conduction with the metal housing 15 having a large area. There is a problem in that it reacts sensitively to the generated electromagnetic wave, so that the potential of the metal housing 15 fluctuates, and electromagnetic wave radiation from the metal housing 15 is likely to occur. Further, when the screw 17 is used, there is a problem that a screw tightening step is added, and the workability of the assembly is deteriorated. In the case where the metal spring 20 is used, a wiring board 7 on which the metal spring 20 is mounted is prepared in advance, and after the step of fixing the wiring board 7 together with the second glass substrate 5 on the metal plate 8, In addition, there is a problem that the metal spring 20 hits the manufacturing device or the transport device and is damaged before the step of disposing the metal spring 15 in the metal housing 15. Furthermore, by providing the screw 17 and the metal spring 20, it is necessary to process the metal housing 15 suitable for the screw 17 and the metal spring 20, and there is a problem that the cost of the metal housing 15 increases due to the complexity. Accordingly, it is an object of the present invention to provide a display device in which electromagnetic wave radiation from a metal housing is prevented. Another object of the present invention is to provide a display device with reduced manufacturing cost. [0010] In the display device of the present invention, a wiring substrate is provided in parallel with a display substrate having a display screen so that end faces thereof are opposed to each other, and one main surface of the wiring substrate is provided. A metal plate extending from the display substrate is provided thereon, a driving IC is provided on the other main surface of the wiring substrate, and the display substrate and the wiring substrate are covered with a metal housing. A conductive adhesive is applied and formed on both main surfaces of the metal plate, and one conductive adhesive is electrically connected to the ground electrode provided on the wiring board, and the other conductive adhesive is electrically connected to the metal housing. It is characterized by having. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A display device according to the present invention will be described by taking a liquid crystal display device as an example. 1 is a perspective view of the liquid crystal display device 1a, FIG. 2 is an enlarged cross-sectional view taken along a line AA in FIG. 1, and FIG. 3 is an exploded (expanded) perspective view. The same parts as those of the conventional liquid crystal display device 1 are denoted by the same reference numerals. This liquid crystal display device 1a comprises a liquid crystal panel 2a and a surface light source body 3. In the liquid crystal panel 2a, the display substrate is constituted by a first glass substrate 4 and a second glass substrate 5, and is sealed. A liquid crystal (not shown) is sealed with a stopper (not shown) to constitute the display screen 6. Further, a wiring board 7 such as a printed board is arranged in parallel with the second glass substrate 5 such that respective end faces thereof are opposed to each other, and the wiring board 7 is connected to the second glass substrate 5 on a metal plate 8 made of stainless steel or the like. Adhesive resin 9 made of a heat-resistant adhesive (for example, double-sided tape 8625k manufactured by Dainippon Ink) with substrate 7
It is fixed by. The driving ICs 10 are arranged on the wiring substrate 7 or the second glass substrate 5, and the driving ICs 10 are covered with a protective resin layer 11 (for example, KH2520 resin manufactured by Hitachi Chemical Co., Ltd.). The liquid crystal display device 1a according to the present invention comprises a liquid crystal panel 2a and a surface light source 3. In the liquid crystal panel 2a, compared to the conventional liquid crystal display device 1, the liquid crystal display device 1a is disposed on both main surfaces of the metal plate 8. By providing conductive adhesives 21 and 22 (for example, a conductive double-sided tape manufactured by Teraoka Seisakusho) is provided.
One conductive adhesive 21 is brought into conductive contact with the ground electrode 18 disposed on the wiring board 7 and the other conductive adhesive 22 is brought into conductive contact with the metal housing 15a. The surface light source body 3 is composed of a light guide plate 12, a fluorescent tube 13, a reflection member 14, and the like, and the surface light source body 3 is fixed together with a liquid crystal panel 2a in a metal housing 15a. The wiring board 7 has, for example, 1 inside the board.
A bus line group having a multilayer wiring structure in which one or two or more wiring layers can be formed and / or a structure in which a wiring layer is formed on both main surfaces and having a power supply and a signal line necessary for driving the driving IC 10 Is wired. Further, if necessary, each system such as a power supply and a logic may be wired for each layer, or a circuit for processing various power supplies and signals supplied from the outside may be mounted. According to the liquid crystal display device 1a having the above structure, the ground electrode 18 can be disposed on the wiring board 7 over a wide area,
By arranging a large number, such a ground electrode 18 can be made conductive with the metal housing 15a through the conductive adhesive 21. Furthermore, such conductivity can be provided by the conductive pressure-sensitive adhesive 21, but the bonding strength is increased by the bonding resin 9 made of the other heat-resistant pressure-sensitive adhesive.
The reliability of both conductivity and adhesive strength is enhanced. Thus, in the above embodiment, since the conductive adhesives 21 and 22 are provided on both main surfaces of the metal plate 8 widely and in many places, the electromagnetic waves generated from the wiring board 7 and the like are not affected by the metal casing. Even if the conductive adhesives 21 and 22 are radiated to the body 15a, the conductive adhesives 21 and 22 are widely distributed from the metal housing 15a.
Through the ground electrode 18. It should be noted that the present invention is not limited to the above-described embodiment, and various changes and improvements may be made without departing from the scope of the present invention. For example, in this embodiment, a liquid crystal display device has been described as an example, but the same operation and effect can be obtained with other display devices including plasma, EL, and the like. As described above, according to the display device of the present invention, the display substrate having the display screen on the metal plate and the wiring substrate are juxtaposed such that both end surfaces thereof face each other. , The display board and the wiring board are covered with a metal housing, and a conductive adhesive is applied and formed on both main surfaces of the metal plate, and one conductive adhesive is provided on the wiring board. Ground electrode and the other conductive adhesive are made to make conductive contact with the metal housing, so even if electromagnetic waves generated from the wiring board are radiated to the metal housing, It flows into the ground electrode through the conductive adhesive disposed over a wide area, thereby reducing or eliminating electromagnetic radiation from the metal housing, and as a result, it is possible to provide a highly reliable display device that prevents electromagnetic radiation. . Further, in the display device of the present invention, the conventional screw tightening step is not required, the metal spring is not damaged, and the display device has a simple metal housing structure.
There is also an advantage that manufacturing yield is improved and manufacturing cost is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a liquid crystal display device which is a display device of the present invention. FIG. 2 is an enlarged cross-sectional view taken along line AA of FIG. 1; FIG. 3 is an exploded (expanded) perspective view of a liquid crystal display device which is a display device of the present invention. FIG. 4 is a perspective view of a conventional liquid crystal display device. FIG. 5 is an enlarged sectional view taken along the line BB of FIG. 4; FIG. 6 is an enlarged cross-sectional view taken along line CC of FIG. 4; DESCRIPTION OF THE SYMBOLS 1, 1a Liquid crystal display device 2, 2a Liquid crystal panel 3 Surface light source 4 First glass substrate 5 Second glass substrate 6 Display screen 7 Wiring substrate 8 Metal plate 9 Adhesive resin 10 Driving IC 11 Protective resin layer 16 Adhesive 15, 15a Metal housing 18 Ground electrodes 21, 22 Conductive adhesive

Claims (1)

(57) [Claim 1] A wiring board is arranged on a display board having a display screen so that end faces thereof are opposed to each other, and extends from one side of the wiring board to the other main surface from the display board. A display device comprising a metal plate to be disposed, a driving IC disposed on the other main surface of the wiring substrate, and the display substrate and the wiring substrate covered by a metal housing. A conductive adhesive is applied and formed on the main surface, and one conductive adhesive is made to conduct to the ground electrode provided on the wiring board, and the other conductive adhesive is made to conduct to the metal housing. Display device.