JP2003167263A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve prevention of malfunction caused by light leakage and a measure against static electricity from the backlight of a bear chip mounted on a flexible substrate by one member. <P>SOLUTION: When connecting the flexible substrate (a chip on film substrate) 2 having the bear chip 2a mounted thereon to the terminal part of a liquid crystal panel, and in the case of turning up and disposing the flexible substrate 2 at the rear surface side of the backlight 3, a shield plate 21 to be disposed on the rear surface of the mounting surface of the bear chip 2a is arranged succesively to the flexible substrate 2 by bending it. A mask electrode 22 connected to the grand terminal of the flexible substrate 2 and consisting of a solid pattern covering the whole rear face of the bear chip mounting surface is formed on the shield plate 21. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having a backlight, and more particularly, to a flexible substrate on which a bare chip for driving a liquid crystal is mounted. The present invention relates to a technique for protecting a bare chip when it is arranged to be folded on the rear side. 2. Description of the Related Art As shown in FIG. 3, a terminal portion 1a of a liquid crystal panel 1 has, for example, a COF as a liquid crystal driving circuit board.
The substrate 2 is connected. What is COF? Chip on fi
Im is an abbreviation for lm, which is a board on which a chip component 2a such as an IC or LSI is mounted on a flexible board. When the liquid crystal panel 1 is of a transmissive type or a transflective type, a back light 3 is provided on the back side (non-observation side) of the panel. When assembled as a product, the liquid crystal panel 1 is stored together with the backlight 3 in a housing (not shown) called a metal case or an outer case. At this time, the COF substrate 2 is disposed so as to be folded back on the back side of the backlight 3, but when the chip component 2a is a bare chip that is not packaged,
Light leakage from the backlight 3 may cause a malfunction. Therefore, conventionally, the bare chip 2a
A light-shielding tape is stuck on the side opposite to the mounting surface to prevent malfunction due to light leakage from the backlight 3. In addition to the malfunction due to light leakage, as a countermeasure against static electricity of the bare chip 2a, for example, a ground electrode made of a solid pattern is formed on a COF substrate. However, the application of the light-shielding tape requires a cost for the tape and a labor for attaching the light-shielding tape, so that the cost increases accordingly. Even if a ground electrode is provided as a countermeasure against static electricity, a large space is required. For example, a COF substrate used for a small model such as a mobile phone cannot afford such a large space. It makes the design difficult. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a liquid crystal display device in which a single member can shield a bare chip from light and can prevent static electricity. . [0009] In order to achieve the above object, the present invention provides a liquid crystal panel, a flexible substrate on which a bare chip for driving a liquid crystal is mounted, and which is connected to a terminal portion of the liquid crystal panel. A backlight disposed on the back side of the liquid crystal panel, wherein the flexible substrate is disposed on the back side of the backlight by folding back, on a predetermined side of the flexible substrate,
A shielding plate arranged on the back surface of the bare chip mounting surface by bending is connected in series, and the shielding plate is connected to a ground terminal of the flexible substrate,
A mask electrode composed of a solid pattern covering the entire back surface of the bare chip mounting surface is formed. Usually, since the electrodes of the flexible substrate are made of copper foil, the mask electrodes for countermeasures against static electricity also function as light-shielding films for bare chips. In addition, since the mask electrode is disposed inside the flexible substrate in a folded state, the storage area of the flexible substrate is not increased. Next, an embodiment of the present invention will be described with reference to FIGS. The liquid crystal display device according to this embodiment also includes a liquid crystal panel 1 and a backlight 3 located on the back side thereof, as in the conventional example described with reference to FIG. A terminal section 1a is connected to a COF substrate 2 as a flexible substrate for driving a liquid crystal. FIGS. 1 and 2 are plan views viewed from the backlight 3 side. It is hidden underneath and cannot be seen. When the COF substrate 2 is stored in a case (not shown) called a metal case or an outer case, the COF substrate 2 is folded over the backlight 3 (back side). Bare chip 2a is CO
It is mounted on the back side of the F board 2. According to the present invention, as shown in FIG.
The shielding plate 21 is pulled out from the F substrate 2. The shielding plate 21 may be continuously provided on a side that does not hinder the design,
It is preferable to be pulled out from the side near the mounting surface of a. As shown in FIG. 2, the shielding plate 21 is located on the back side of the mounting surface of the bare chip 2a (in FIG.
The upper surface of the bare chip 2a is formed in such a size that the rear surface of the mounting surface of the bare chip 2a can be covered in this bent state. On the shielding plate 21, a mask electrode 22 of a solid pattern covering at least the entire back surface of the mounting surface of the bare chip 2a is formed. The mask electrode 22
It is connected to a ground terminal (not shown) of the COF board 2 via the lead wire 22a. The mask electrode 22 is made of copper foil like the other wiring portions of the COF substrate 2, and the mask electrode forming surface is
In order to effectively prevent the wraparound of light or static electricity to the bare chip 2a, the back surface opposite to the mounting surface of the bare chip 2a is preferable, but it is formed on the same surface as the mounting surface of the bare chip 2a. Is also good. Further, it may be formed on both sides. In any case, after the shielding plate 21 is bent toward the back side of the mounting surface of the bare chip 2a, the COF substrate 2
Is folded over the backlight 3 and fixed by a predetermined fixing means. As a result, the mask electrode 22 serves as a light-shielding film of the bare chip 2a when viewed from the backlight 3 side, and static electricity existing around the bare chip 2a also dissipates the mask electrode 22
And dropped to ground. In the case of a liquid crystal display device for a small and thin device typified by a portable telephone, a sidelight type backlight is preferably employed, but the present invention relates to a liquid crystal having a direct type backlight. The present invention is also applicable to a display device. As described above, according to the present invention,
When connecting a flexible board with a bare chip mounted to the terminal of the liquid crystal panel, and folding the flexible board on the back side of the backlight, arranging it on a predetermined side of the flexible board, bending it to the back side of the bare chip mounting surface The shielding plate to be arranged is connected in series, and the shielding plate is connected to the ground terminal of the flexible substrate, and by forming a mask electrode composed of a solid pattern covering the entire back surface of the bare chip mounting surface, one member is formed. Thus, light shielding and static electricity countermeasures for the bare chip can be performed.

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 as viewed from a backlight side. FIG. 2 is a plan view of the liquid crystal display device viewed from the backlight side in a state where a shielding plate is bent. FIG. 3 is an exploded perspective view schematically showing a liquid crystal display device as a conventional example. [Description of Signs] 1 Liquid crystal panel 1a Terminal 2 COF substrate 2a Bare chip 21 Shielding plate 22 Mask electrode 3 Backlight

Claims (1)

Claims: 1. A liquid crystal panel, a flexible substrate on which a bare chip for driving liquid crystal is mounted, and connected to a terminal portion of the liquid crystal panel, and a backlight disposed on the back side of the liquid crystal panel. In the liquid crystal display device, wherein the flexible substrate is folded back on the back side of the backlight, a shielding plate disposed on the back side of the bare chip mounting surface by bending the flexible substrate on a predetermined side of the flexible substrate And a shield electrode connected to a ground terminal of the flexible substrate and formed of a solid pattern covering the entire back surface of the bare chip mounting surface is formed on the shielding plate. apparatus.