JP2002328621A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make mountable a front cover without scratching a metallic foil section of a printed wiring board and to secure the contact between the earth mounting section of the cover and the metallic foil section of the board. SOLUTION: The tip portion 17b of an opening section side having a U shaped cross section of a front cover 17 is bent in a slanted manner to the external side from the middle section. When a panel mounting part 16 is taken in with an illuminating unit 15 from an opening section 9 of the cover 17 and are to be mounted, an earth mounting section 17a is made so that the section 17a does not contact with a metallic foil section 12a of a printed wiring board 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device such as a liquid crystal display device mounted on, for example, video equipment such as a television receiver, a monitor and car navigation, and information equipment such as a computer.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have been developed using fine processing technology,
AV equipment with the progress of material technology and high-density packaging technology,
It is used for various purposes such as OA equipment and in-vehicle communication equipment, and is attracting attention in the electronics industry as a new display device replacing a CRT (Cathode Ray Tube). Under such circumstances, the liquid crystal display device includes:
In response to the increasing demand for thinner, lighter, smaller, and narrower frames, the semiconductor device for driving electrodes is directly mounted on the glass substrate on which the active elements are formed, thereby achieving compactness in the thickness direction. It is becoming common to employ a COG (chip-on-glass) mounting method that has been developed. In this COG mounting method, a flexible wiring board is used to transmit power and signals to each electrode driving semiconductor element. When assembling a liquid crystal display device, the flexible wiring board is made of an anisotropic conductive sheet (Anisotro.
pic Conductive Film = hereinafter referred to as ACF) and connected to a glass substrate and a printed wiring board.

FIG. 3 is a block diagram of a general panel mounted product 16. The panel mounted product 16 is also called a liquid crystal module, and is a liquid crystal display panel 1 in which the signal electrodes 2 and the scanning electrodes 3 are arranged in a grid corresponding to liquid crystal cells (not shown) provided in a matrix. On a glass substrate 1A, which is one of the substrates, a signal electrode driving semiconductor element 4 for driving the signal electrode 2, a scan electrode driving semiconductor element 7 for driving the scanning electrode 3, and each of the signal electrode driving semiconductor elements 4 and One end of each of the plurality of flexible wiring boards 8 that supplies drive power to the scan electrode drive semiconductor element 7 and transmits signals is mounted.

That is, the semiconductor element 4 for driving the signal electrode,
The scanning electrode driving semiconductor element 7 and the flexible wiring board 8 are arranged and mounted on the peripheral portion of the glass substrate 1A, and the flexible wiring board 8 includes the signal electrode driving semiconductor element 4 and the scanning electrode driving semiconductor element. 7 is connected via a signal wiring group 10 and a power supply wiring 11.
Further, the printed wiring board 12 on which the driving semiconductor elements for supplying power and signals to the signal electrode driving semiconductor elements 4 and the scanning electrode driving semiconductor elements 7 through the flexible wiring board 8 are arranged is a flexible wiring board 8. The end is connected using an ACF or the like.

The signal electrode driving semiconductor element 4 processes the supplied signal to drive the signal electrode 2, and the scanning electrode driving semiconductor element 7 processes the supplied signal to cause the scanning electrode 3 to operate. Drive. Thereby, characters or images are displayed on the display area of the liquid crystal display panel 1.

FIG. 4 is an exploded perspective view of a general liquid crystal display device. This liquid crystal display device uses an illumination unit 15 for introducing a light source 13 such as a cold-cathode fluorescent tube from the side of the light guide plate 14 and emitting light from the surface to uniformly guide the light to the entire liquid crystal display panel. The panel mounted product 16 is attached to the metal front cover 17 together with the lighting unit 15. When mounting the panel mounted product 16 having the printed wiring board 12 mounted on the liquid crystal display panel 1 via the flexible wiring board 8 to the front cover 17, the flexible wiring board 8 is bent by 180 ° and the liquid crystal display panel 1 and the printed wiring are connected. The lighting unit 15 is sandwiched between the substrates 12, and taken into the front cover 17 from the opening on the rear surface side and attached to the front cover 17 in order to protect the panel mounted product 16, thereby forming a liquid crystal display device. At this time, the printed wiring board 12 is bent so as to reach the back surface of the lighting unit 15 and is arranged along the back surface of the lighting unit 15.

FIG. 5 is an external view of a case where the liquid crystal display device is assembled. FIG. 5A is a view from the side where the liquid crystal display panel 1 can be seen. The liquid crystal display panel 1 is attached so as to cover a peripheral portion of the panel with a frame-shaped front cover 17.
FIG. 5B is a view seen from the opposite side of FIG. 5A and is a view from the side where the lighting unit 15 is visible. The printed wiring board 12 is attached to the lighting unit 15 with screws or the like.

By the way, as described above, the lighting unit 15
(E.g., a display monitor or a car navigation system) that incorporates a liquid crystal display device having a printed circuit board 12 or a printed wiring board 12 therein, may cause interference with a fluorescent tube such as a cold cathode tube as the light source 13. A malfunction may occur in the semiconductor element portion. In order to prevent this malfunction, the front cover 17 must be made of metal and grounded to the ground of the printed circuit board 12 to shield the interference. There are the following methods for connecting the front cover 17 on the front surface side of the liquid crystal display panel 1 to the power ground of the printed wiring board 12 on the back surface of the panel (FIGS. 6, 7, and 8).

FIG. 6 shows a lead wire 18 soldered to a ground pattern portion of a printed wiring board 12 connected to a front cover 17 by soldering. Means other than soldering, such as screwing, may be used, but in any case, the lead wire 18 goes outside, which hinders the incorporation into a device as a liquid crystal display device and increases the number of attached parts, thereby reducing material cost and cost. Production costs increase.

FIG. 7 shows an example in which a grounding metal fitting 19 for grounding, instead of the lead wire 18, is attached to the outer periphery (back side) of the front cover 17 by screws. However, unlike the case of connection by the lead wire 18, it is possible to improve the obstruction when the liquid crystal display device is incorporated in a device, but the material cost and the production cost are similarly increased. For this reason, as shown in FIG. 8, the incorporation of the ground metal 19 and the front cover 17 is intended to reduce inconvenience in assembling and cost.

[0011]

In the conventional liquid crystal display device, as shown in FIG. 8, the shape of the front cover 17 is changed so that screws can be directly screwed to the printed wiring board 12 on the back surface of the panel. Easy to ground, has been improved. However, as shown in FIG. 9, when the front cover 17 is mounted from a state where the lighting unit 15 and the panel mounted product 16 are assembled, the ground mounting portion 17a hits and becomes difficult to mount. Attempting to forcibly attach the printed wiring board 12 may damage a metal foil portion such as a copper foil on the pattern surface of the printed wiring board 12 and cause a disconnection of the metal foil portion.

For this reason, as shown in FIG. 10, if the whole ground mounting portion 17a is widened outward, the above-mentioned difficulty in mounting is improved, but on the contrary, since the stress is applied to the outside, the ground mounting portion 17a is exposed. A gap between the printed wiring board 17a and the printed wiring board 12 is likely to be formed, and there is a possibility that the contact of the ground connection portion 12a may be completely lost.

SUMMARY OF THE INVENTION It is an object of the present invention to mount a front cover without damaging a metal foil portion of a printed wiring board. An object of the present invention is to provide a display device that ensures contact with a foil portion.

[0014]

In order to solve the above problems and achieve the above object, a display device according to the present invention is provided with a driving semiconductor element arranged on the outer periphery of the display panel for displaying the display panel. A printed circuit board, a panel mounted product comprising a flexible wiring board disposed between the display panel and the printed wiring board and electrically connecting the semiconductor element for driving the display panel and the semiconductor element for driving the printed wiring board; It has a lighting unit provided on the back side, and a front cover for fixing the lighting unit so as to cover them. The front cover has an opening for taking in the panel mounted product and the lighting unit on the back side, and the side face has a cross section. The U-shaped lower side inner surface has a ground mounting portion, and the flexible wiring board of the panel mounted product is bent to make the printed wiring board a lighting unit. In a display device which is attached so as to be sandwiched between the back surface side and the back surface side of the front cover, and the ground mounting portion of the front cover is fixed so as to be in contact with the metal foil portion of the printed wiring board provided on the back surface, The front end of the opening with a U-shaped cross section is bent obliquely outward from the middle of the opening, and the ground mounting part is connected to the printed wiring board when the panel mounting product is taken in with the lighting unit from the opening of the front cover and mounted. Is characterized in that it does not come into contact with the metal foil portion.

According to the present invention, when the front cover is mounted so as to cover the printed wiring board and the panel mounted product obtained by folding the flexible wiring board and the lighting unit,
The front panel is attached by inserting it through the opening of the front cover.Because the front end of the opening on the opening side is bent outward, the display panel and the lighting unit are obliquely inserted from the opening into the U-shaped part of the front cover. , The metal foil portion of the printed wiring board is attached without contact with the ground attachment portion of the front cover. After the front cover is attached, the part of the front cover that is not bent outside the ground attachment part comes into contact with the metal foil part of the printed wiring board. The contact can be reliably ensured without generating a gap between the foil portion.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the display device of the present embodiment is a liquid crystal display device in which a panel mounted product 16 is mounted on a metal front cover 17 together with a lighting unit 15.

The panel mounted product 16 drives the liquid crystal display panel 1 having a liquid crystal layer sandwiched between a pair of substrates, and the signal electrode 2 and the scanning electrode 3 formed on one substrate 1A of the liquid crystal display panel 1, respectively. Liquid crystal display panel 1 provided with a semiconductor element 4 for driving signal electrodes and a semiconductor element 7 for driving scanning electrodes
A printed wiring board 12 on which a display panel driving semiconductor element for displaying the liquid crystal display panel 1 is provided; and a signal electrode driving semiconductor element 4 and a scanning electrode driving semiconductor element 7 of the liquid crystal display panel 1, respectively. And a flexible wiring board 8 for electrically connecting the driving semiconductor elements of the wiring board 12 (see FIGS. 3 and 4). The panel mounted product 16 is attached to the front cover 17 so that the printed wiring board 12 and the flexible wiring board 8 are folded and the lighting unit 15 is sandwiched therebetween.

The illumination unit 15 is arranged on the back side of the liquid crystal display panel 1, and introduces a built-in light source from the side surface of the light guide plate and emits light from the surface, and is also called a backlight unit.

The front cover 17 has a metal frame shape, and has an opening 9 formed on the back surface thereof for receiving and mounting a panel mounted product 16 with the lighting unit 15 interposed therebetween. Further, the side surface has a U-shaped cross section, and has a ground mounting portion 17a on the lower inner surface of the U shape (the upper inner surface having the U-shaped cross section in FIG. 1).

The ground mounting portion 17a of the front cover 17 is superimposed on the metal foil portion 12a of the printed wiring board 12 screwed to the corner of the front cover 17 with respect to the lighting unit 15, and the screws B are used for screwing. Fixed. A front end portion 17b of the front cover 17 on the side of the opening 9 having a U-shaped cross section is bent outward from a middle portion thereof. In other words, additional components are eliminated by simply bending the screw slightly obliquely outward at the center S of the screw fixing hole Ba of the ground mounting portion 17a. In the present embodiment, the inclination angle θ of the tip portion 17b is about 20 degrees to 35 degrees, but is not limited thereto. However, with such an inclination angle θ, the shape does not particularly protrude outward and no stress is applied. Although the screw is used in this embodiment, the screw need not always be used.

Next, the case of assembling the liquid crystal display of the present embodiment will be described. First, the liquid crystal display panel 1
Printed wiring board 12 via flexible wiring board 8
When mounting the panel mounted product 16 on which the flexible wiring board 8 is mounted to the front cover 17,
° Bend the LCD panel 1 and the printed circuit board 1
2 and the front cover 1 sandwiching the lighting unit 15
7 (see FIG. 3). At this time, the printed wiring board 12 is bent to reach the back surface of the lighting unit 15 and is arranged along the back surface of the lighting unit 15, and the printed wiring board 12 is attached to the lighting unit 15 with screws or the like.

As shown in FIG. 2A, the lighting unit 1
5 with the front cover 17
From the opening 9 toward the side having a U-shaped cross section. At this time, the front end portion 17b of the front cover 17 on the side of the opening having the U-shaped cross section is bent outward from the middle portion at the center portion S of the screw hole of the ground mounting portion 17a, so that the ground mounting portion 17a is formed. Can be attached without scratching the metal foil portion 12a on the printed wiring board 12.

With this mounting, as shown in FIG. 2B, the metal foil portion 12a of the printed wiring board 12 and the ground mounting portion 17a of the front cover 17 are securely fixed with the screw B in a state where they are in contact with each other. Therefore, electrical connection can be reliably performed. As a result, since the entire front cover 17 is grounded to the ground, it is possible to prevent the interference from the light source of the lighting unit 15 from leaking to the outside.

The above embodiment of the present invention is an example, and is applicable to an active matrix type liquid crystal panel, a simple matrix type liquid crystal panel, and other types of liquid crystal display devices using a matrix type display panel. .

[0026]

According to the display device of the present invention, the front end portion of the front cover fixed in contact with the metal foil portion of the printed wiring board on the opening side having the U-shaped cross section is inclined from the middle thereof. By bending outwards, it is possible to eliminate the addition of components and prevent the metal foil part of the printed circuit board from hitting when attaching the front cover. After the front cover is attached, it is possible to reliably ensure the contact between the printed wiring board and the ground connection portion of the front cover.

[0027]

[Brief description of the drawings]

FIG. 1 is a plan view of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a sectional view of the liquid crystal display device of the embodiment.

FIG. 3 is a block diagram of a panel mounted product.

FIG. 4 illustrates a liquid crystal display device.

FIG. 5 is an exploded perspective view of a liquid crystal display device.

FIG. 6 is a cross-sectional view showing an example of a mounting form of a panel-mounted product to a front cover.

FIG. 7 is a cross-sectional view showing an example of a mode of mounting a panel-mounted product to a front cover.

FIG. 8 is a cross-sectional view showing an example of a mounting mode of a panel-mounted product to a front cover.

9 is a cross-sectional view of the liquid crystal display device mounted by the mounting method according to FIG.

FIG. 10 is a cross-sectional view showing a mounting mode of a panel-mounted product to a front cover.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display panel 2 ... Signal electrode 3 ... Scan electrode 4 ... Semiconductor element for signal electrode drive 7 ... Semiconductor element for scan electrode drive 8 ... Flexible wiring board 9 ... Opening 10: Signal wiring group 11: Power supply wiring 12: Printed wiring board 15: Illumination unit 16: Panel mounted product 17: Front cover 17a: Earth mounting part 17b ..End portions on the opening side with a U-shaped cross section 18 Lead wire 19 Grounding bracket

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H089 HA40 KA17 QA10 QA12 TA03 TA09 TA18 TA20 5G435 AA07 AA17 BB12 BB15 CC09 EE05 EE08 EE13 EE27 EE32 EE36 EE37 EE40 EE47 FF08 FF12 GG42 HH12 HH14 KK

Claims (1)

[Claims] 1. A printed wiring board provided on a periphery of a display panel and provided with a driving semiconductor element for displaying the display panel, and a driving semiconductor element of the display panel provided between the display panel and the printed wiring board. A panel mounting product comprising a flexible wiring board for electrically connecting a driving semiconductor element of a printed wiring board, a lighting unit provided on the back side of the display panel, and a front cover for fixing these to cover the front, The cover has an opening on the back side to take in the panel mounted product and the lighting unit,
The side surface has a U-shaped cross section, and a ground mounting portion is provided on the lower inner surface of the U-shape. The flexible wiring board of the panel mounted product is bent, and the printed wiring board is bent between the back side of the lighting unit and the back side of the front cover. In a display device which is attached so as to be sandwiched between the front cover and the ground attachment portion of the front cover to be fixed so as to be in contact with the metal foil portion of the printed wiring board provided on the back surface, the front end of the front cover on the opening side having a U-shaped cross section is provided. Part,
It is bent obliquely outward from the middle part, so that the ground mounting part does not contact the metal foil part of the printed wiring board when taking in and mounting the panel mounted product together with the lighting unit from the opening of the front cover. A display device.