JP2000338486A - Back light device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a back light device of a simple structure constituted to make LCD(liquid crystal device) illumination shine uniformly without the hindrance of the attaching and detaching manipulation on a light source side to be carried out in order to exchange the light source even if circuitry to drive the LCD is complicated. SOLUTION: This back light device allows the exchange of the light source 3 for illuminating the LCD 1 from behind with the attaching and detaching manipulation by the movement in a direction along the plane of the LCD 1. The light source 3 side is arranged in approximate alignment to the center of the plane of the LCD 1 and the power feed routes from wiring boards 2 and 2A to the LCD l are formed by a flexible printed circuit board 6 arranged to go around a lamp cover 4 in which the light source 3 is housed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight device for illuminating a liquid crystal device (hereinafter referred to as an LCD) from the back and making it easy to see an image projected on the surface of the LCD, and more particularly to a circuit configuration for driving the LCD. The present invention relates to a backlight device that uniformly illuminates LCD illumination without hindering a light source attaching / detaching operation for replacing a light source even when the backlight becomes complicated.

[0002]

2. Description of the Related Art Generally, this type of backlight device is
The light source is placed almost in line with the center of the LCD plane,
It illuminates the illumination uniformly.

FIG. 2 shows an example of a conventional backlight device. As shown in FIG. 1, in this conventional backlight device, a wiring board 102 for driving an LCD is arranged in parallel with the LCD 101 on the rear side of the LCD 101, and
A light source 104 is inserted and arranged in an opening 103 formed at the center of the plane of the LCD 02.
It is designed to be illuminated from behind.

In this case, the LCD 101 and the wiring board 102 are attached via a lamp cover 105 for protecting the light source.
And is held by being pinched.

In this configuration, the light source 104 inserted and arranged in the opening 103 can be replaced by the attachment / detachment operation of the light source 104 by moving the LCD 101 in a direction perpendicular to the plane.

However, when the circuit configuration for driving the LCD 101 becomes complicated, as shown in FIG.
2A is required.

However, with the configuration shown in FIG. 3, the light source 104 cannot be replaced. In this case, if the device is forcibly disassembled, the light source 104 can be replaced. However, the light source 104 may not be able to be repaired.
It becomes impossible to perform the attachment / detachment operation of the light source 104 required for replacement of the light source.

Therefore, in the conventional backlight device proposed above, as shown in FIG.
An opening 108 is formed on the side of the lamp cover 105A.
The light source 102 illuminating the LCD 101 from the back can be replaced with the light source 104 by attaching and detaching the light source 102 by moving the light source 102 in a direction along the plane of the LCD 101.

[0009]

However, as in the conventional example shown in FIG. 4 described above, there is provided a backlight device capable of attaching and detaching the light source 102 for illuminating the LCD 101 from the back by moving the light source 102 in the direction along the plane of the LCD 101. In the case of the configuration, although the light source 104 can be easily exchanged, the opening 108 is formed on the side of the lamp cover 105A without any change in the position of the light source. From light source 1
There is a problem that the position of No. 04 is shifted, and the illumination of the LCD 101 becomes non-uniform.

In addition, the wiring boards 102, 102A
Since the power supply path to D101 is formed as it is in the related art, there is a problem that the backlight device cannot have a simpler structure.

In view of the above circumstances, the present invention does not hinder the operation of attaching and detaching the light source for replacing the light source, even if the circuit configuration for driving the liquid crystal device becomes complicated.
It is an object of the present invention to provide a backlight device having a simple structure devised so as to uniformly illuminate the brightness of a liquid crystal device.

[0012]

According to a first aspect of the present invention, there is provided a light source for illuminating a liquid crystal device from a back surface, and the liquid crystal device is moved in a direction along a plane of the liquid crystal device. A backlight device in which the light source is replaceable by an attaching / detaching operation by the light source. It is formed by a printed circuit board which is arranged so as to be wrapped around a lamp cover to be formed.

According to the first aspect of the present invention, since the light source is arranged so as to be substantially coincident with the center of the plane of the liquid crystal device, it is possible to meet the condition of uniform illumination of the liquid crystal device.

Further, since the light source can be replaced by an attaching / detaching operation by moving the liquid crystal device in a direction along the plane of the liquid crystal device, for example, two circuit boards are required to cope with a complicated circuit configuration for driving the liquid crystal device. Even if they are arranged, they do not hinder the operation of attaching and detaching the light source.

According to a second aspect of the present invention, in the backlight device according to the first aspect, the printed circuit board is provided on a lamp cover of the light source by extending one end of a flexible printed circuit board connected to the liquid crystal device. It is characterized by being arranged in a wraparound along.

According to the second aspect of the present invention, the power supply path from the wiring board to the liquid crystal device simply extends from one end of the flexible printed circuit board extending from the liquid crystal device and extends around the lamp cover of the light source. Therefore, the work of wiring the power supply path is extremely easy as compared with the case where the wiring is formed by the conventional method.

In addition, when the flexible printed circuit board is disposed so as to be wrapped around the lamp cover of the light source,
Since it is not necessary to form a power supply path from the wiring board to the liquid crystal device by the conventional method, the entire device can be made to have a simple structure.

According to a third aspect of the present invention, in the backlight device according to any one of the first and second aspects, a power supply path from the wiring board to the light source is provided by the printed circuit board. .

According to the third aspect of the present invention, a power supply path for driving the LCD and a power supply path for driving the light source are provided on the flexible printed circuit board, so that the entire apparatus can have a simpler structure. it can.

According to a fourth aspect of the present invention, in the backlight device according to any one of the first to third aspects, the printed board is held in the wraparound state by a reinforcing board.

According to the fourth aspect of the present invention, since the state in which the flexible printed circuit board is wrapped along the lamp cover of the light source is held by the reinforcing substrate, the wrapped state can be shielded from the outside.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a side sectional view showing a main portion of a backlight device according to an embodiment of the present invention.

As shown in FIG. 1, this backlight device has the following structure in a configuration in which two wiring boards 2 and 2A for driving the LCD are arranged in parallel with the LCD 1 on the back side of the LCD 1. Measures are taken.

An LCD is provided on the lamp cover 4 for protecting the light source.
An opening 5 through which the light source 3 can be inserted and arranged is formed on the side of the cover so that the light source 3 can be replaced by an attachment / detachment operation by moving in a direction along the plane of the LCD 1. The opening 5 is provided so that the light source 3 can be arranged.
Is set.

A power supply path from the two wiring boards 2 and 2A to the LCD 1 is formed by a flexible printed circuit board (FPC) 6 which is disposed so as to extend around the lamp cover 4 of the light source 3.

The flexible printed circuit board 6 has a power supply path 6a from the two wiring boards 2 and 2A to the LCD 1 and a power supply path 6b from the two wiring boards 2 and 2A to the light source 3. Is held by the reinforcing substrate 7 in a state of being turned around along the lamp cover 4.

The LCD 1 and the wiring boards 2 and 2A are arranged with the lamp cover 4 interposed therebetween, and the whole of them is held by sandwiching the case 8 and the panel 9.

With such a configuration, the lamp cover 4
The state where the light source 3 is inserted into the opening 5 of the
Since the light source 3 is arranged so as to be substantially coincident with the center of the plane 1, the condition conforms to the condition for uniformizing the LCD illumination.

The two wiring boards 2 and 2A are arranged in response to the complexity of the circuit configuration for driving the LCD 1, but the light source 3 is moved by moving in the direction along the plane of the LCD 1. Since the two wiring boards 2 and 2A can be replaced by the attaching / detaching operation, the two wiring boards 2 and 2A do not hinder the attaching / detaching operation of the light source 3.

Further, the LCD 1 is connected to the two wiring boards 2 and 2A.
A power supply path to the lamp cover 4 of the light source 3 extends from one end of the flexible printed circuit board 6 protruding from the LCD 1.
It is only necessary to dispose them along the route, so that the work of wiring the power supply path is extremely easy as compared with the case where the wiring is formed by the conventional method.

In addition, when the flexible printed circuit board 6 is arranged so as to be wrapped around the lamp cover 4 of the light source 3, the two wiring boards 2, 2A can be connected to the LCD by a conventional method.
Since it is not necessary to form a power supply path to the power supply 1, the entire apparatus can have a simple structure. In particular, as in the present embodiment, by providing the power supply path 6a for driving the LCD 1 and the power supply path 6b for driving the light source 3 on the flexible printed circuit board 6 together, the entire apparatus can have a simpler structure. it can.

Further, since the state in which the flexible printed circuit board 6 is wrapped along the lamp cover 4 of the light source 3 is held by the reinforcing substrate 7, the wrapped state can be shielded from the outside. Note that a normal hard printed board can be used as the reinforcing board 7.

[0033]

As described above, according to the present invention,
Even if the circuit configuration for driving the LCD becomes complicated,
It is possible to provide a backlight device having a simple structure that is devised so as to uniformly illuminate the LCD illumination without hindering a light source attaching / detaching operation for replacing the light source.

[Brief description of the drawings]

FIG. 1 is a sectional side view of a main part showing a configuration of an embodiment of a backlight device according to the present invention.

FIG. 2 is a sectional side view showing a main part of an example of a conventional backlight device.

FIG. 3 is a side sectional view showing a main part of another example of a conventional backlight device.

FIG. 4 is an explanatory diagram of a conventionally proposed measure for improving a backlight device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal device (LCD) 2, 2A wiring board 3 Light source 4 Lamp cover of light source 5 Opening 6 Flexible printed board (FPC) 7 Reinforcement board 8 Case 9 Panel

Claims (4)

[Claims] 1. A backlight device comprising: a light source for illuminating a liquid crystal device from a back surface; and a light source that can be replaced by an attachment / detachment operation by moving the liquid crystal device in a direction along a plane of the liquid crystal device. The light source is arranged so as to be substantially coincident with the center, and a power supply path from the wiring board to the liquid crystal device is formed by a printed circuit board arranged around the lamp cover in which the light source is accommodated. Backlight device. 2. The backlight device according to claim 1, wherein the printed circuit board is arranged so as to extend around one end of a flexible printed circuit board connected to the liquid crystal device and to extend along a lamp cover of the light source. Backlight device. 3. The backlight device according to claim 1, wherein a power supply path from the wiring board to the light source is provided by the printed circuit board. 4. The backlight device according to claim 1, wherein the printed board is held by the reinforcing board in the wraparound state.