JPH11259002A - Planar display device and attachment structure therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce electromagnetic wave noise in a planar display device used for a notebook personal computer or the like and the attachment structure. SOLUTION: At a projection part 16 for attachment provided with a screw hole, the layer 3 of ferrite which is an electromagnetic noise adsorption material is disposed between the shelf-like extension part of a metallic frame 12 and the shelf-like extension part of a bone structure frame 13 made of resin. Also, on the boss 21 for the attachment of an external case body 2, a ring 31 made of the ferrite is put. Thus, common mode noise by a feedback current from this planar display device to an external driving system is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display with reduced electromagnetic noise and a mounting structure thereof. In particular, the present invention relates to a liquid crystal display device used for a notebook computer, a car navigation device, a liquid crystal monitor, or the like, in which transmission of electromagnetic noise to connected devices and radiation of electromagnetic noise to the outside are reduced.

[0002]

2. Description of the Related Art In recent years, flat display devices replacing CRT displays have been actively developed. Among them, liquid crystal display devices have attracted particular attention because of their advantages such as light weight, thinness, and low power consumption.

In particular, TFT-type liquid crystal display devices capable of displaying fine moving images on a large screen have been rapidly expanding in applications and markets as large-screen high-quality images have been developed.

[0004] The improvement of the large screen and the high image quality of the flat-panel display device causes the clock of the drive circuit system to cope with this, leading to an increase in the amount of generation of electromagnetic noise. However, on the other hand, in order to improve the display performance of the flat panel display, interference / interference (EMI, electromagnetic interference) caused by electromagnetic noise transmitted from the flat panel display to an external driving device is required.
terference) is required to be further reduced.

[0005] Further, with the expansion of applications and markets of flat panel display devices, it is required to further reduce interference and interference caused by electromagnetic noise with respect to other electronic and electric devices that can be arranged nearby.

[0006] The reduction of electromagnetic wave noise in a conventional flat panel display device will be described with reference to a liquid crystal display module (called a liquid crystal module) which is assembled as a display on the lid side of a notebook computer.

[0007] A general notebook personal computer is a bivalve close-open type, and has a bottom portion on which a keyboard is disposed on an upper surface, and a lid side portion connected to the keyboard via a hinge mechanism. A liquid crystal display device is disposed on the lid side portion with the inner side surface as a display surface.

In the case where the housing of the lid side portion of such a notebook personal computer is made of plastic, a conductive paint is applied to the surface to reduce electromagnetic wave noise, or the housing is made of plastic. Conductive particles such as carbon black are kneaded into a plastic material constituting a body.

On the other hand, a liquid crystal display module is usually
A liquid crystal display panel having a light modulation layer is held by a frame-shaped metal frame (called a bezel) on the display surface side and a frame on the back side, and a backlight mechanism and a printed board are assembled on the back side. The frame-shaped frame on the display surface side is made of metal in order to prevent radiation of electromagnetic noise from the periphery of the display panel connected to the drive system to the display surface side.

In the liquid crystal display module, a frame, a backlight, and a printed circuit board on a display surface side and a back surface side are fixed to each other by screwing using metal screws. At the four corners of the substantially rectangular liquid crystal display module, mounting portions having holes for inserting screws are provided, and are screwed to nut portions provided at corresponding positions inside the lid side housing of the notebook computer. You. This nut is
Usually, it is formed in a substantially short columnar projection (mounting boss).

[0011]

With the above-described structure, noise electromagnetic waves generated in a drive system or the like inside the liquid crystal display module in a direction substantially parallel to the display surface of the liquid crystal display module. The generation of the components is suppressed by the conductivity of the outer surface of the lid-side housing. However, for the component in the direction substantially perpendicular to the liquid crystal display module, the structure is such that the mounting screw hole of the liquid crystal display module and the boss of the notebook computer lid side are connected only through metal screws. Therefore, generation is hardly suppressed.

Further, in the liquid crystal display module, since the printed wiring board on the back side and the metal bezel on the display side are joined by metal screws, the electromagnetic noise generated on the printed wiring board is reduced. Is transmitted to the metal bezel and radiated to the outside from here. That is,
The metal bezel functions as an antenna that radiates electromagnetic noise outside.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a flat display device and a structure for mounting the flat display device with reduced electromagnetic wave noise.

[0014]

According to a first aspect of the present invention, there is provided a flat panel display device comprising: a display panel having a light modulation layer; and a metal frame frame disposed to cover a peripheral portion on a display surface side of the display panel. A skeletal structure frame on the back side for holding the display panel together with the metal frame-shaped frame, an internal drive system for driving the display panel, and a part or extension of the metal frame-shaped frame or the skeleton structure frame And a mounting screw hole portion provided with a screw hole through which a mounting screw is inserted, the electromagnetic noise absorbing material comprising a ferromagnetic non-conductive material at or near the mounting screw hole portion. It is characterized by having.

According to the above configuration, it is possible to substantially eliminate the common mode noise caused by the feedback current from the flat panel display to the external drive system. Further, it is possible to suppress generation of electromagnetic wave noise of a component in a direction substantially perpendicular to the flat display device and radiation to the outside.

According to a second aspect of the present invention, there is provided a flat panel display mounting structure, comprising: a display panel having a light modulating layer; a metal frame-shaped frame arranged to cover a peripheral portion on a display surface side of the display panel; A skeletal structure frame on the back side that holds the display panel together with the frame-shaped frame, an internal drive system for driving the display panel, and a part or extension of the metal frame-shaped frame or the skeleton structure frame In a mounting structure for mounting a flat panel display device having an installation screw hole portion provided with a screw hole through which a screw is inserted to an external housing, a ferromagnetic non-magnetic member is provided at or near the mounting screw receiving portion of the external housing. An electromagnetic noise absorbing material made of a conductive material is provided.

According to the above configuration, the common mode noise due to the feedback current from the flat panel display to the external drive system can be reduced. Further, it is possible to suppress generation of electromagnetic wave noise of a component in a direction substantially perpendicular to the flat display device and radiation to the outside.

According to a third aspect of the present invention, there is provided a flat panel display device, comprising: a display panel having a light modulation layer; a metal frame-shaped frame arranged to cover a peripheral portion on a display surface side of the display panel; In a flat display device including a back-side skeletal structure frame that holds the display panel together with a frame, and a drive printed board that drives the display panel, a frame that joins the drive printed board and the metal frame-shaped frame An electromagnetic noise absorbing material made of a ferromagnetic non-conductive material is provided in contact with or near the joining metal screw.

According to the above configuration, the electromagnetic noise radiated from the metal frame-shaped frame of the flat display device can be greatly reduced.

According to a fourth aspect of the present invention, there is provided a flat panel display mounting structure comprising: a display panel having a light modulation layer; a metal frame for holding the display panel; a driving printed board for driving the display panel; In a mounting structure for mounting a flat display device having a metal frame and a mounting screw hole portion provided with a screw hole for inserting a mounting screw into a part or an extended portion of the drive printed circuit board to an external housing, An electromagnetic noise absorbing material made of a ferromagnetic non-conductive material is disposed on the mounting screw receiving portion of the external housing, the mounting screw hole portion, or in the vicinity thereof.

According to the above configuration, the electromagnetic noise radiated from the metal frame of the flat panel display can be greatly reduced.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described.
A liquid crystal display module in which a backlight is integrally formed with a resin skeleton frame is attached to a lid housing of a notebook computer as an example, which will be described with reference to FIGS.

FIG. 1 is a schematic cross-sectional perspective view showing a state in which a substantially rectangular liquid crystal display module 1 is fixed to an external housing 2 by screws. FIG. 2 is an exploded perspective view showing an enlarged part of the mounting structure in FIG.

The liquid crystal display module 1 has a metal frame in which a display panel 11 having a light modulation layer between two transparent insulating substrates is arranged so as to cover a peripheral portion of the display panel 11 on a display surface side. It is housed in a frame structure 15 consisting of a metal frame 12 and a resin frame 13 on the back side that holds the display panel 11 together with the metal frame 12. Here, the resin frame 13 is configured as a backlight unit integrally including a backlight including a fluorescent tube and a light guide plate.

In the frame structure 15, a driving printed board 14 is arranged along one end of the display panel.

At each of the four corners of the liquid crystal display module 1, mounting projections 16 projecting from the frame structure 15 to the outer peripheral side for screwing the liquid crystal display module 1 to the outer casing 2 are provided. . The mounting projection 16 is configured such that the shelf-like extension of the metal frame 12 and the shelf-like extension of the resin frame 13 are overlapped via the ferrite layer 3 that is an electromagnetic absorption layer.
It has a structure in which a screw hole 17 penetrating these is provided.

On the other hand, the external housing 2 is provided with a mounting boss 21 having a nut portion 22 corresponding to the mounting projection 16 and the screw hole 17 of the liquid crystal display module 1. A bead-shaped ferrite ring 31 is fitted into the mounting boss 21.

The metal mounting screw 4 is inserted through the screw hole 17 of the mounting projection 16 and the mounting boss 21
Is screwed to the nut portion 22 of the main body.

As in the above embodiment, when the ferrite layer 3 and the ferrite ring 31 are arranged at the joint of the liquid crystal display module 1 and the external housing 2 by screws, the liquid crystal display module 1 The transmission of electromagnetic noise to the external drive system via the external housing 2 is greatly suppressed. Therefore, common mode noise due to the feedback current to the external drive system can be substantially removed. Further, it is possible to suppress generation of electromagnetic wave noise of a component in a direction substantially perpendicular to the liquid crystal display module and radiation to the outside.

When the level of the electromagnetic noise in the above embodiment was measured in an anechoic chamber, the level was 100 to 200 M
At Hz, an electromagnetic noise reduction effect of 10 dBμV or more was observed as compared with the case where the ferrite layer 3 and the ferrite ring were not provided.

A liquid crystal display device according to a second embodiment of the present invention will be described with reference to an exploded perspective view of a joint portion of a frame structure shown in FIG.

The liquid crystal display device according to the second embodiment has the structure shown in FIG.
In almost the same configuration as the liquid crystal display module of
The driving printed board 14 is disposed on the back side of the resin frame 13, and the printed board 14 and the metal frame 12 are directly joined by metal screws 41 for joining the frames. Here, a metal screw 41 for joining the frame is used.
Is screwed into the nut portion 19 provided on the metal frame 12 by inserting the screw hole 18 of the drive printed board 14 and the ferrite ring 31 in this order. That is, the screw rod 4 at the portion where the metal screw 4 also electrically connects the drive printed board 14 and the metal frame-shaped frame 12
2, a ferrite ring 31 is arranged.

As described above, the ferrite ring 31 that absorbs electromagnetic noise is arranged around the screw rod 42 that joins the drive printed board 14 and the metal frame 12 and also electrically connects the frame. Therefore, the transmission of electromagnetic noise from the drive printed circuit board 14 to the metal frame 12 and radiation to the outside is greatly suppressed.

The mounting structure of the liquid crystal display device according to the third embodiment of the present invention will be described with reference to an exploded perspective view of the mounting projection shown in FIG.

The liquid crystal display according to the third embodiment has the structure shown in FIG.
In the configuration substantially similar to the liquid crystal display module shown in FIGS. 1 to 2, a driving printed board 14 is disposed on the back side of a resin frame 13 and is fixed integrally with the metal frame 12 and the resin frame 13. Also in the mounting overhang portion 16, the metal frame-shaped frame 12,
The resin frame 13 and the drive printed circuit board 14 are stacked in this order from above.

In the same manner as in the first embodiment shown in FIG.
A mounting boss 21 having a nut portion 22 is provided corresponding to the screw hole 17 of FIG. On the mounting boss 21,
A bead-shaped ferrite ring 31 is fitted.

In the above embodiment, since the ferrite ring 31 is disposed at a place where the drive printed circuit board 14 and the outer casing 2 where electromagnetic noise is generated are directly screwed, the ferrite ring 31 is provided.
Transmission of electromagnetic noise from the drive printed circuit board 14 to the external drive system via the external housing 2 is greatly suppressed. Therefore, common mode noise due to the feedback current to the external drive system can be substantially removed.

[0038]

According to the first and second aspects of the present invention, it is possible to reduce the common mode noise due to the feedback current from the flat display device to the external drive system.

According to the third and fourth aspects of the invention, the electromagnetic noise radiated from the metal frame of the flat panel display can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional perspective view showing a liquid crystal display device and a structure for attaching the liquid crystal display device to an external housing according to a first embodiment.

FIG. 2 is an exploded perspective view showing a main part of the mounting structure of FIG. 1 in an enlarged manner.

FIG. 3 is an exploded perspective view similar to FIG. 2, showing a mounting structure of a liquid crystal display device according to a second embodiment.

FIG. 4 is an exploded perspective view similar to FIG. 2, showing a mounting structure of a liquid crystal display device according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display module 12 Metal frame 13 Resin frame 14 Driving printed circuit board 15 Frame structure 16 Mounting overhang 17 Screw hole 2 External housing (notebook PC lid) 21 Mounting boss 22 Nut 3 Ferrite layer 31 Ferrite ring 4 Metal screw for mounting 41 Metal screw for frame connection

Claims (4)

[Claims] 1. A display panel having a light modulating layer, a metal frame-shaped frame arranged to cover a peripheral portion on a display surface side of the display panel, and the display panel is held together with the metal frame-shaped frame. A frame structure frame on the back side, an internal drive system for driving the display panel, and a screw hole for inserting a mounting screw into a part or extension of the metal frame-shaped frame or the frame structure frame are provided. A flat panel display device comprising: a mounting screw hole portion; and an electromagnetic noise absorbing material made of a ferromagnetic non-conductive material is provided at or near the mounting screw hole portion. 2. A display panel having a light modulating layer, a metal frame-shaped frame arranged to cover a peripheral portion on the display surface side of the display panel, and the display panel is held together with the metal frame-shaped frame. A frame structure frame on the back side, an internal drive system for driving the display panel, and a screw hole for inserting a mounting screw into a part or an extension of the metal frame-shaped frame or the frame structure frame are provided. In a mounting structure for mounting a flat panel display device having a mounting screw hole portion to an external housing, an electromagnetic noise absorbing material made of a ferromagnetic non-conductive material is provided at or near the mounting screw receiving portion of the external housing. A flat display device characterized by the above-mentioned. 3. A display panel having a light modulating layer, a metal frame-shaped frame arranged to cover a peripheral portion on a display surface side of the display panel, and the display panel is held together with the metal frame-shaped frame. In a flat display device including a back-side skeleton structure frame and a drive printed circuit board for driving the display panel, the drive printed circuit board is in contact with a frame joining metal screw for joining the metal frame-shaped frame or A flat display device, wherein an electromagnetic noise absorbing material made of a ferromagnetic non-conductive material is disposed near the metal screw for frame joining. 4. A display panel having a light modulation layer, a metal frame for holding the display panel, a driving printed board for driving the display panel, and a part of the metal frame and the driving printed board. Or, in a mounting structure for mounting a flat display device provided with a mounting screw hole portion provided with a screw hole through which a mounting screw is inserted in an extending portion to an external housing, the mounting screw receiving portion of the external housing, Alternatively, an electromagnetic noise absorbing material made of a ferromagnetic non-conductive material is disposed at or near the mounting screw holes, and the mounting structure for a flat panel display device.