JPH0996799A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the circuit board area on the peripheries of threaded holes as far as possible and to facilitate the drawing around of wirings in the circuit board by increasing the area of the circuit board without forming the relief parts of the circuit board on the periphery of the threaded holes in the recessed parts of a metallic frame in the interposing parts of the circuit board. SOLUTION: The circuit 2 bored with the holes of the size exactly needed for passing screws 5 therethrough is interposed between the rear surface of the recessed part of the metallic frame which do not project the head parts of the screws forward and to which the pressing force by the head parts of the screws is surely transmitted and the mounting surface on the side of the apparatus to be used at the time of mounting the liquid crystal display device to the apparatus to be used by screwing via the metallic frame 1. The circuit board area is increased without providing the interposing parts of the circuit board 2 with the relief parts of the circuit board 2 on the peripheries of the screw holes of the recessed parts. As a result, the drawing around of the wiring near the connecting parts between the circuit board 2 and the circuit board 6 for display signals housed in the rear side on the side in the transverse direction of the metallic frame 1 is facilitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention increases the area of a circuit board around a screw hole as much as possible when a liquid crystal display device is mounted on a device to be used via a metal frame by screwing, and the wiring within the circuit board is laid out. Regarding technology to facilitate.

[0002]

2. Description of the Related Art In order to display a large amount of liquid crystal display with high definition, a so-called matrix display system using horizontal scanning lines (electrodes) and vertical display signal lines (electrodes) is usually used. . In general, the circuits required for that purpose are stacked and stored on a multilayer circuit board on the backside of the vertical side of a frame-shaped metal frame that surrounds the display screen of the liquid crystal display device, and the backside of the top and bottom sides of the display screen of the metal frame is stored. Is provided with a display signal line board for transmitting a display signal from the circuit board to the vertical signal electrodes.

An example of the conventional liquid crystal display device as described above is shown in FIG. 3A shows the metal frame 1a directly visible to the user of the liquid crystal display device, and FIG. 3B shows the circuit board 2 housed on the back surface thereof, and a number of signal electrodes arranged in parallel in the vertical direction from the circuit board. 3 shows a display signal line substrate 6 for transmitting a display signal to the liquid crystal display element 4, and FIG.
(C) is a resin molded product (so-called mold) which is a part to which the display device is mounted on the side of the device using this liquid crystal display device.
3 is shown. When the metal frame 1a is fastened to the device to be used with screws, the frame-shaped portion of the metal frame 1a presses and fixes the periphery of the display portion of the liquid crystal display element 4 to the device to be used. 3 (a), FIG. 3 (b), and FIG.
The vertical chain line drawn in each figure of (c) shows the center position of the mounting screw.

At a place where the metal frame 1a is mounted on a device using a liquid crystal display device by screwing, the screw head is prevented from protruding forward, and the mounting and fixing pressure by the screw head is surely secured over a wide area. A recess having a flat bottom is formed around the screw hole of the metal frame 1a so as to be transmitted. A top view of the recess is shown in FIG.
FIG. 4B shows a cross-sectional view taken along the line BB around the recessed portion in FIG. As can be seen from FIG. 4 (b) and FIG. 3 (b), there is an escape portion around the screw hole of the circuit board 2 so that the bottom surface around the recessed screw hole of the metal frame 1a is in contact with the mounting surface on the device side to be used. Because of this, the wiring from the circuit board 2 to the display signal line board 6 is severely restricted. Although the width (area) of the escape portion is not so large, the entire width is narrow, and therefore the formation of the escape portion having a small area severely restricts the wiring layout.

Further, the metal frame 1a must be grounded, but conventionally, soldering is performed for that purpose.
However, there has been a problem that a region for that purpose must be secured in the product, and the workability of assembling the liquid crystal display device as the product is deteriorated.

Further, the liquid crystal display device has a fate that it is necessary to reduce the overall size, that is, the outermost shape of the metal frame, while ensuring the same display area. The structure was disadvantageous. If the outer shape of the metal frame is forcibly narrowed down with the conventional structure, EMI (electromagnetic noise interference) with respect to nearby electronic devices may eventually increase.

[0007]

As described above, the conventional liquid crystal display device has various problems in the mounting and fixing method using the screws, but the present invention solves these problems. An object of the present invention is to provide a liquid crystal display device that can be easily attached and fixed with screws.

[0008]

In order to solve the above problems, in the present invention, a metal frame surrounding a rectangular display portion of a liquid crystal display element in a frame shape is provided, and the back side of the vertical side of the metal frame is provided. A circuit for sequentially applying the scanning signal to the scanning electrodes of the display element extending in the horizontal direction and applying the display signal to the vertical signal electrodes of the display section orthogonal to the scanning electrodes to which the scanning signal is applied. In a liquid crystal display device in which a substrate is installed and a signal line substrate for transmitting a display signal to the above-mentioned signal electrode is installed on the back side of the lateral side of the metal frame, the liquid crystal display device is used as a device through the metal frame. When installing by tightening the screw, the screw head does not project forward, and the back surface of the metal frame recessed portion that is provided so that the pressing pressure by the screw head can be transmitted reliably and the mounting surface on the equipment side Between the above, the above-mentioned circuit board having a hole of a size just necessary for passing a screw is interposed, and in the intervening portion of the circuit board, a relief portion of the circuit board is provided around the screw hole of the metal frame concave portion. Instead, it was decided to increase the circuit board area.

In practice, the circuit board is installed only on the back side of one side in the vertical direction of the metal frame, and the display board is provided on the back side of each of the two sides in the horizontal direction of the metal frame located above and below the display section. A track board is often installed. Also, when attaching the metal frame to the device using screws,
When connecting the grounding circuit connection pads to the metal frame and the circuit board at locations where they are opposite to each other and where the screw tightening pressure is surely applied, and when mounting the liquid crystal display device to the device by screwing through the metal frame In addition, the grounding circuit for the metal frame is automatically formed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS By taking the above-mentioned means, the area of the circuit board at the portion necessary for arranging the wiring from the circuit board in the vertical direction to the line board for display signal in the horizontal direction is significantly increased. As a result, the wiring can be easily routed. In addition, in the past, it was necessary to perform extremely troublesome work such as soldering in order to ground the metal frame, but simply by tightening the screw to fix the metal frame to the device to be used, it will automatically Since the ground circuit is formed, the workability of assembling the liquid crystal display device is greatly improved. Obviously, if a reliable ground circuit is formed, EMI will be greatly improved.

The area allowance of the circuit board produced by the present invention can be utilized for reducing the outermost dimension of the board, that is, for proportionately reducing the frame portion. Not a few.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of an embodiment of the present invention, and FIG.
A metal frame that directly touches the eyes of the user of the liquid crystal display device 1
1B shows a circuit board 2 housed on the back surface of the metal frame 1, and a display signal line board 6 for transmitting a display signal from the circuit board to a large number of signal electrodes arranged in parallel in the vertical direction of the display unit. , And a liquid crystal display element 4, and FIG. 1 (c) shows a resin molded product (so-called mold) 3 which is a part to which the display device is mounted on the side of the equipment using this liquid crystal display device. When the metal frame 1 is fastened to the device to be used with screws, the frame-shaped portion of the metal frame 1 presses and fixes the periphery of the display portion of the liquid crystal display element 4 to the device to be used. The vertical chain line drawn in each of FIGS. 1 (a), 1 (b), and 1 (c) indicates the center position of the mounting screw. In FIG. 1 (b), a shaded portion around the screw hole is a portion where the substrate area is increased by the present invention. However, in the case shown in the figure, in order to show the effect of the present invention, the circuit board is advanced to be interposed between the flat bottom surface of the recessed portion of the metal frame and the mounting portion on the utilization device side, and all portions other than the screw holes are connected to the circuit. It is used to increase the area of the substrate. In this embodiment, a circuit board having eight layers is used, and even a slight increase in the area is very useful for facilitating the wiring layout. However, in actuality, there is a strong tendency to use the wiring for reducing the outermost dimension of the liquid crystal display device rather than enjoying the margin for wiring.

Also in this embodiment, as in the case of the conventional example, at the place where the metal frame 1 is attached to the device using the liquid crystal display device by screwing, the screw head does not protrude forward, and A concave portion having a flat bottom surface is formed around the screw hole of the metal frame 1 so that the mounting and fixing pressure by the screw head is surely transmitted through a wide area. A top view of the recess is shown in FIG. 2 (a), and a sectional view taken along the line AA around the recess is shown in FIG. 2 (b). FIG.
As can be seen from (b) and FIG. 1 (b), the circuit board 2 does not have a clearance portion around the screw hole. Wiring such as wiring up to 6 becomes easy. In other words, it means that a margin for reducing the outermost dimension of the circuit board and therefore the liquid crystal display device is gained.

It should be noted that grounding circuit connection pads (not shown) are respectively provided at positions near the screws for mounting and fixing the liquid crystal display device, on the back surface of the metal frame 1 and on the circuit board 2 so as to face each other. Then, the grounding circuit of the metal frame is automatically formed at the same time when the display device is screw-fastened. This eliminates the need for soldering work for grounding the metal frame as in the conventional case, and the workability of assembling the liquid crystal display device is greatly improved.
Of course, it contributes to the reduction of EMI.

[0015]

As described above, according to the present invention, the circuit board housed on the back surface of the vertical side of the metal frame and the display signal line housed on the back surface of the lateral side of the metal frame. Wiring around the connection portion with the substrate is facilitated, and the ground circuit of the metal frame is automatically formed at the same time as the liquid crystal display device is screwed, fixed and fixed, thereby improving the assembly productivity of the liquid crystal display device and the EMI. Contribute to reduction,
Furthermore, there is an effect that the outermost dimension of the circuit board and therefore the liquid crystal display device may be reduced.

[Brief description of drawings]

FIG. 1 is an embodiment diagram of the present invention, in which FIG. 1 (a) shows a metal frame, and FIG. 1 (b) shows a circuit board, a display signal line board, and a liquid crystal display device housed on the back surface of the metal frame. FIG. 1C shows the display device mounting portion of the device to be used.

FIG. 2 shows a recess having a flat bottom surface formed around a screw hole of a metal frame, and FIG. 2 (a) is a top view of the recess.
FIG. 2B shows a sectional view taken along the line AA around the recessed portion.

FIG. 3 is a diagram showing an example of a conventional liquid crystal display device.
3A shows a metal frame, FIG. 3B shows a circuit board, a display signal line board, and a liquid crystal display element housed on the back surface of the metal frame, and FIG. 3C shows a display device of a device to be used. Shows the mounting part.

FIG. 4 shows a recess having a flat bottom surface formed around a screw hole of a metal frame, and FIG. 4A is a top view of the recess.
FIG. 4B shows a sectional view taken along the line BB around the recessed portion.

[Explanation of symbols]

1, 1a ... Metal frame, 2 ... Circuit board, 3 ... Resin molded product, 4 ... Liquid crystal display element, 5 ... Screw, 6 ... Display signal line board.

Claims (3)

[Claims] 1. A metal frame which surrounds a rectangular display portion of a liquid crystal display element in a frame shape, and is provided on the back side of a vertical side of the metal frame to a scanning electrode of a display element extending in the horizontal direction.
A circuit board for sequentially providing a scanning signal and for providing a display signal to a vertical signal electrode of the display section orthogonal to the scanning electrode to which the scanning signal is applied is installed, and a horizontal side of the metal frame is provided. On the back side, in a liquid crystal display device having a signal line substrate for transmitting a display signal to the signal electrode,
When this liquid crystal display device is attached to a device to be used via a metal frame by screwing, a metal frame provided so that the screw head does not project forward and the pressing pressure by the screw head is reliably transmitted. Between the back surface of the recessed portion and the mounting surface on the side of the device to be used, the circuit board having a hole of a size just required for threading the screw is interposed, and the metal frame is provided in the intervening portion of the circuit board. A liquid crystal display device, characterized in that a circuit board area is increased by not providing an escape portion of a circuit board around a screw hole of a recess. 2. The circuit board is concentrated and installed only on the back side of one vertical side of the metal frame, and the display signal line board is provided on the back side of each of the two horizontal sides of the metal frame located above and below the display section. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is installed. 3. When a metal frame is attached to a device using a screw, a ground circuit connection pad is provided at each of the metal frame and the circuit board at a position facing each other and to which a screw tightening pressure is reliably applied. 2. The liquid crystal display device according to claim 1, wherein a grounding circuit for the metal frame is automatically formed when the liquid crystal display device is attached to a device using the metal frame.