JPH11133394A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the degree of design freedom of electric parts arrangement of a liquid crystal driving circuit board of a thin type by using a lead frame having terminals at both ends for electrical connection of a LED back light and the liquid crystal driving circuit board. SOLUTION: Fixing of the LED packaging substrate 1 is executed by the clip type terminal 3a of the lead frame 3, by which the sepn. of the LED packaging substrate 1 and a light transmission plate 7 is made possible and, therefore, the width size of the LED packaging substrate 1 is reduced and the thickness size of the back light is made smaller. The length side of the pin parts of the lead frame 3 and foaming may be changed at need and, therefore, the position of the back light input land 6 of the liquid crystal driving circuit board 5 is optimized and the degree of design freedom of the electric parts arrangement is enhanced. In addition, the shape of the flat planar terminal 3b is formed to a flat plate shape, by which the electrical connection on the back light mounting surface side of the liquid crystal driving circuit board 5 is made possible and the electrode soldering height of the back light is made lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a liquid crystal display device using an LED backlight.

[0002]

2. Description of the Related Art In recent years, a backlight of a liquid crystal display device required for electronic musical instruments, electric components, information terminal equipment, and the like is required to have low power consumption and a long life.
The adoption of backlight is increasing. In the LED backlight configuration, an edge backlight configuration that can realize low cost and thinness has become mainstream. Further, in the LED mounting mode, a type in which LED elements are mounted on a printed circuit board is used because various kinds of LED elements can be mounted for brightness and emission color.

Hereinafter, a liquid crystal display device using a conventional LED backlight having an edge light configuration will be described.

FIG. 2 is an exploded perspective view of a main part showing the structure of a conventional liquid crystal display device. In FIG. 2, reference numeral 21 denotes a liquid crystal display panel, 22 denotes a liquid crystal drive circuit board formed of a printed circuit board on which a drive circuit for driving the liquid crystal display panel 21 is mounted, and 23 denotes the liquid crystal display panel 21 and the liquid crystal drive circuit board 22.
Conductive rubber for electrically connecting the
24 is a metal frame that compresses and holds the conductive rubber 23 and holds the liquid crystal display panel 21 and the liquid crystal drive circuit board 22; 25 is an LED element; and 26 is an LED on which an LED circuit pattern is laid and the LED element 25 is mounted. It is a mounting board. A backlight electrode land 27 for inputting a backlight power supply is laid on the LED mounting board 26. Reference numeral 28 denotes a light guide plate on which a reflection plate 29 is attached on the back surface. The light guide plate 28 is fixed to the LED mounting board 26 to constitute a backlight and emit light from the back surface of the liquid crystal display panel 21. The electrical connection between the backlight and the liquid crystal drive circuit board 22 is made by the LED mounting board 2 as shown by the white arrow.
6 is inserted into a hole 30 provided in the liquid crystal drive circuit board 22, and a backlight electrode land 27 and a backlight input land 31 laid on the back side of the liquid crystal drive circuit board 22 are inserted.
Is soldered on the back side.

Next, the operation will be described. First, when the power of the LED is input from the back side of the liquid crystal drive circuit board 22 through the backlight input land 31, the LED element 25 emits light and enters from the side surface of the light guide plate.
The light entering the light guide plate 28 is reflected by the reflection plate 29 and emitted from the upper surface of the backlight.

[0006]

However, in the above-mentioned conventional configuration, the backlight electrode is mounted on the LED mounting board 26.
Since the backlight electrode land 27 is provided on the LED mounting board 26 and the light guide plate 28,
It is necessary to provide a hole for welding and connecting the light guide plate 28 to the ED mounting board 26, and an increase in the width of the LED mounting board 26 results in an increase in the thickness of the entire backlight. In order to input power to the light, the liquid crystal drive circuit board 22 is disposed in a portion immediately below the backlight electrode, and the backlight electrode land 27 is provided.
It is necessary to provide a backlight input land on the back surface side with the insertion hole 30 and to make electrical connection by soldering on the opposite surface side of the backlight mounting surface, which increases the overall thickness of the liquid crystal display device. . In addition, the liquid crystal drive circuit board 22
In this case, the degree of freedom in designing the arrangement of the electric components in the above-mentioned method is reduced, and the liquid crystal drive circuit board 22 is also enlarged.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a liquid crystal display device which is thin and can increase the degree of freedom in designing electric components on a liquid crystal drive circuit board.

[0008]

In order to achieve this object, a liquid crystal display device according to the present invention comprises an electric connection between an LED backlight and a liquid crystal drive circuit board, which is fixed at one end with an LED mounting board therebetween. And a lead frame having a terminal connected to the backlight input land of the liquid crystal drive circuit board at the other end.

With this configuration, the LED mounting board is sandwiched between the terminals at one end of the lead frame and fixed, so that the LED mounting surface of the LED mounting board and the liquid crystal display surface can be vertically fixed. Can be separated, the size of the LED mounting board can be reduced, and the overall thickness of the backlight can be reduced. Also, by performing the lead forming on the lead portion of the lead frame, it is possible to configure the backlight input lands other than directly below the LED mounting board, thereby increasing the degree of freedom in designing the layout of electric components in the liquid crystal driving circuit board. it can. In addition, by making the portion of the lead frame that is electrically connected to the liquid crystal drive circuit board into a flat plate shape, electrode connection on the backlight mounting surface side of the liquid crystal drive circuit board becomes possible, and the electrode soldering height of the backlight is increased. Can be lowered.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention can be embodied concretely by adopting the constitutions described in the respective claims. However, in order to facilitate its implementation, the following functions are described in addition to the constitutions. And

The invention according to claim 1 is characterized in that the LED mounting board is fixed to a predetermined position by being fixed to an LED mounting board on which an LED element is mounted, and electrically connected to an input electrode land of the LED mounting board. A lead frame having a terminal to be connected at one end is provided, and the other end of the lead frame is used as a backlight input electrode of the liquid crystal drive circuit board, and the lead frame electrically connects the LED mounting board and the liquid crystal drive circuit board. It can be fixed at a predetermined position mechanically as well as mechanically. In particular, it is not necessary to install the backlight input electrode of the liquid crystal drive circuit board directly below the input electrode land of the LED mount board by forming the lead frame, and the design position of the LED mount board and the liquid crystal drive circuit board can be made arbitrary. Can be.

According to the second aspect of the present invention, the backlight input electrode at the other end of the lead frame is a flat terminal fixed to the backlight input land provided on the liquid crystal drive circuit board, so that the lead frame can be easily manufactured. Can be formed.

According to a third aspect of the present invention, an LED
A lead frame having a terminal fixed to one end of an LED mounting board on which an element is mounted and fixed to a predetermined position of a liquid crystal driving circuit board, and having one end electrically connected to an input electrode land of the LED mounting board. The other end is electrically connected and fixed to the backlight input land of the liquid crystal drive circuit board, and has both functions of the invention according to claim 1 and the invention according to claim 2. .

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing a configuration in which an LED backlight is mounted on a liquid crystal drive circuit board of a liquid crystal display device. In FIG. 1, reference numeral 1 denotes an LED mounting board in which an LED element 2 is mounted on a printed board. Reference numeral 3 denotes a flat plate for fixing the LED mounting board 1 and electrically connecting the clip-shaped terminal 3 a having an electric connection function with the input electrode land 4 to the backlight input land 6 provided on the liquid crystal drive circuit board 5. It is a lead frame having a terminal 3b. Reference numeral 7 denotes a light guide plate on which a reflection plate 8 is attached on the back surface,
It is separated from the mounting substrate 1. Also, lead frame 3
The electrical connection between the clip-shaped terminal 3a and the input electrode land 4 is performed by fixing with an ultraviolet curable resin or by soldering. The electrical connection between the flat terminal 3b and the backlight input land 6 is as follows. This is performed by soldering.

As described above, according to the present embodiment, since the LED mounting board 1 can be fixed by the clip-shaped terminals 3a of the lead frame 3, the LED mounting board 1 and the light guide plate 7 can be separated. 1 is reduced in width, and the thickness of the backlight can be reduced. Also,
By changing the length and forming of the pin portion of the lead frame 3 as necessary, the position of the flat terminal 3b can be optimized, and thus the position of the backlight input land 6 on the liquid crystal drive circuit board 5 is optimized. It is possible to increase the degree of freedom in designing the arrangement of electric components. Further, by making the shape of the flat terminal 3b flat, electrical connection on the backlight mounting surface side of the liquid crystal drive circuit board 5 becomes possible, and the electrode soldering height of the backlight can be reduced.

[0017]

As described above, according to the present invention, the electric connection between the LED backlight and the liquid crystal driving circuit board can be made by using a lead frame having terminals at both ends, and the liquid crystal driving circuit board is thin. An excellent liquid crystal display device having a high degree of design freedom can be realized.

[Brief description of the drawings]

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

FIG. 2 is an exploded perspective view of a main part showing a configuration of a conventional liquid crystal display device.

[Explanation of symbols]

 1,26 LED mounting board 2,25 LED element 3 lead frame 3a clip-shaped terminal 3b flat terminal 4 input electrode land 5,22 liquid crystal drive circuit board 6,31 backlight input land 7,28 light guide plate 8,29 reflector 30 holes

Claims (3)

[Claims] 1. An LED mounting board on which an LED element is mounted, the LED mounting board being fixed at a predetermined position, and having a terminal at one end for electrically connecting the LED mounting board with an input electrode land interposed therebetween. A liquid crystal display device comprising a lead frame, wherein the other end of the lead frame is used as a backlight input electrode of a liquid crystal drive circuit board. 2. The liquid crystal display device according to claim 1, wherein the backlight input electrode at the other end of the lead frame is a flat terminal fixed to a backlight input land provided on the liquid crystal drive circuit board. 3. A terminal which is fixed to an LED mounting board on which an LED element is mounted, fixes the LED mounting board at a predetermined position on a liquid crystal driving circuit board, and electrically connects to an input electrode land of the LED mounting board. A liquid crystal display device having a configuration in which the other end of a lead frame provided at one end is electrically connected to and fixed to a backlight input land of a liquid crystal drive circuit board.