JP2000011724A - Back light, liquid crystal display and lighting system using this - Google Patents

Abstract

PROBLEM TO BE SOLVED: To narrow and thin an architrave of a back light, a liquid crystal display and a lighting system using this back light by changing an arranging place of a circuit device. SOLUTION: A reflecting means 8 is inclined in the direction for approaching a light diffusing means 4 as it becomes more distance from a light source 6, and the clearance part 9 is formed between the reverse side of the reflecting means 8 and the bottom surface part 3a of a main body case 3 in a position separate from the light source 6. There is no need to arrange a space for housing a circuit device 10 in the peripheral edge part of a back light 1 and on the reverse side of the back light 1 by housing the circuit device 10 in this clearance part 10. Thus, an architrave of the back light can be narrowed and thinned, and an architrave of a liquid crystal display and a lighting system using this back light 1 can be narrowed and thinned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight, a liquid crystal display using the same, and a lighting device.

[0002]

2. Description of the Related Art There are three types of backlights used in lighting devices such as liquid crystal display devices and guide lights, a direct type, a light guide plate type, and a hollow type.

[0003] Since the direct type backlight is a system in which a light source is arranged on the back side of a transmissive liquid crystal display element or a display unit, an image of the light source is reflected on the display surface of the transmissive liquid crystal display element or the display unit. , The uniformity (brightness uniformity) of the display surface is low.

[0004] Light guide plate type backlights are currently the mainstream of backlights, and since an acrylic resin light guide plate is used as a light transmission path, light use efficiency and uniformity are high. However, since the acrylic resin has a large specific gravity, the weight of the backlight increases significantly when the light guide plate is enlarged in accordance with an increase in the display area of the transmissive liquid crystal display element and the display unit.

[0005] A hollow type backlight is a type in which a hollow region is used as an optical transmission path without using a light guide plate as described in, for example, Japanese Patent Application Laid-Open No. 8-171806. Significantly lighter than the backlight.

[0006]

In the case of a hollow backlight, as in the case of other backlights,
Circuit devices such as a lighting circuit of a light source and a driving circuit of a transmissive liquid crystal display element are arranged on the periphery of the backlight (around the light emitting surface of the backlight) or on the back side of the backlight.

When the circuit device is arranged on the periphery of the backlight, the size of the frame around the backlight becomes large. When the circuit device is arranged on the back side of the backlight, the thickness of the backlight becomes large.

Accordingly, an object of the present invention is to provide a hollow backlight having a narrower frame and a reduced thickness by changing the location of the circuit device, a liquid crystal display device and a lighting device using the same. And

[0009]

According to a first aspect of the present invention, there is provided a backlight having a bottom surface portion, and a main body case having an open surface facing the bottom surface portion; A light diffusing unit disposed to emit light incident from the back surface side facing the bottom surface unit from the light emitting surface on the front surface side; a hollow region formed between the bottom surface unit and the light diffusing unit; A long light source disposed at an edge of the hollow region; a reflector for reflecting light emitted from the light source toward the hollow region; and a light source disposed in the hollow region so as to face the light diffusing unit. A reflecting means inclined toward the light diffusing means as moving away from the light source; and a gap formed between the back side of the reflecting means and the bottom face at a position distant from the light source; Circuit device housed in the gap When; comprises a. The circuit device referred to here mainly means a lighting circuit device for a light source, but may include a circuit for driving another device, or may mainly include a circuit device for another device. Good.

Therefore, the reflecting means is inclined so as to approach the light diffusing means as the distance from the light source increases.
A gap is formed between the back surface of the reflection means and the bottom surface of the main body case at a position away from the light source. By housing the circuit device in this gap, there is no need to provide a space for housing the circuit device on the peripheral portion of the backlight or on the back side of the backlight. Is achieved.

According to a second aspect of the present invention, in the backlight according to the first aspect of the present invention, the circuit device includes a spacer portion which is in contact with a back surface of the reflection means.

Therefore, since the spacer portion is in contact with the back surface of the reflection means, the deflection and deformation of the reflection means are prevented, and the state in which the light reflected by the reflection means is most appropriately incident on the light diffusion means is maintained. As a result, the uniformity of the light emitting surface of the light diffusing means is maintained at a high level.

According to a third aspect of the present invention, in the backlight according to the first aspect of the present invention, the circuit device is also used as a spacer portion which is in contact with a back surface of the reflection means. The double use of the spacer means that the circuit device freely performs the function of the spacer.

Therefore, since the circuit device is in contact with the back surface of the reflecting means, the bending and deformation of the reflecting means are prevented,
The state in which the light reflected by the reflection means enters the light diffusion means best is maintained, and the uniformity of the light emitting surface of the light diffusion means is maintained high.

According to a fourth aspect of the present invention, there is provided a liquid crystal display device comprising: the backlight according to any one of the first to third aspects; and a transmissive liquid crystal display element disposed on the light emitting surface.

Therefore, also in this liquid crystal display device, narrowing of the frame and reduction in thickness are achieved. In this liquid crystal display device, the circuit device housed in the gap portion of the backlight includes a driving circuit of a transmission type liquid crystal display element in addition to a lighting device of a light source.

A lighting device according to a fifth aspect of the present invention includes the backlight according to any one of the first to third aspects; and light control means disposed on the light emitting surface.

The light control means includes optical means such as a prism for controlling light distribution, and light transmitting display means.

Therefore, also in this lighting device, narrowing of the frame and reduction in thickness are achieved.

[0020]

FIG. 1 shows a first embodiment of the present invention.
It will be described based on. FIG. 1 is a vertical sectional front view showing a liquid crystal display device using a hollow backlight 1. This liquid crystal display device is formed by a backlight 1 and a transmission type liquid crystal display element 2. The transmission type liquid crystal display element 2
It is arranged on a light emitting surface of a prism sheet of the backlight 1 described later.

The backlight 1 has a main body case 3 whose one surface is open and the other five surfaces are closed. In this main body case 3, the surface facing the open surface is a bottom surface 3a.

At an open surface of the main body case 3, a prism sheet 4 serving as a light diffusing means is disposed so as to be opposed to the bottom surface 3a in parallel. The prism sheet 4 has a function of diffusing and transmitting the light incident from the back surface side facing the bottom surface portion 3a to the light emitting surface 4a on the front surface side and emitting the light from the light emitting surface 4a. A hollow region 5 is formed between the prism sheet 4 and the bottom surface 3a.

At the edge of the hollow area 5, a fluorescent lamp 6 as a long light source is disposed. Around the fluorescent lamp 6, light emitted from the fluorescent lamp 6 is
There is provided a reflecting plate 7 which is a reflecting member for reflecting light toward.

In the hollow area 5, a reflection sheet 8 serving as a reflection means for reflecting light emitted directly from the fluorescent lamp 6 or reflected by the reflection plate 7 toward the prism sheet 4.
Is arranged. This reflection sheet 8 is used for the fluorescent lamp 6.
Is arranged so as to be in contact with the bottom surface portion 3a at a position near the fluorescent lamp 6, and is inclined away from the bottom surface portion 3a toward the prism sheet 4 as the distance from the fluorescent lamp 6 increases.

A gap 9 is formed between the back surface of the reflection sheet 8 and the bottom surface 3a. In this gap 9,
A circuit device 10 such as a lighting circuit of the fluorescent lamp 6 and a driving circuit of the transmission type liquid crystal display element 2 is housed therein. Circuit device 10
The outer peripheral cover 10a which is a part of the outer peripheral cover 10a also serves as a spacer portion, and the outer peripheral cover 10a is in contact with the back surface of the reflection sheet 8.

In such a configuration, the reflection sheet 8 disposed in the hollow area 5 is inclined so as to approach the prism sheet 4 as the distance from the fluorescent lamp 6 increases, so that the light emitted from the fluorescent lamp 6 can be emitted from the prism sheet. 4, the light is evenly applied to the entire surface of the prism sheet 4, and the uniformity of the light emitting surface 4a of the prism sheet 4 is increased.

Then, the reflecting sheet 8 is inclined so that the back side of the reflecting sheet 8 and the bottom surface 3a of the main body case 3 are formed.
The space for accommodating the circuit device 10 is provided in the gap 9 formed between the main body case 3 and the back surface of the main body case 3 which is the peripheral portion of the backlight 1 and the back surface of the backlight 1. , And the backlight 1 can be made narrower and thinner. Further, the entire liquid crystal display device using the backlight 1 can also achieve a narrower frame and a reduced thickness.

Since the outer peripheral cover 11 of the circuit device 10 housed in the gap 9 is in contact with the back surface of the reflection sheet 8,
The deflection and deformation of the reflection sheet 8 are prevented. By preventing the deflection and deformation, the state where the light reflected by the reflection sheet 8 is most appropriately incident on the prism sheet 4 is maintained, and the uniformity of the light emitting surface 4a of the prism sheet 4 is maintained high. .

In this embodiment, the case where the backlight 1 is used in a liquid crystal display device in which the transmission type liquid crystal display element 2 is disposed on the light emitting surface 4a of the prism sheet 4 in the backlight 1 has been described. However, instead of the transmissive liquid crystal display element 2, the backlight 1 can also be used in a lighting device in which various display units are arranged on the light emitting surface 4a of the prism sheet 4. By using the backlight 1 in such a lighting device, a narrower frame and a thinner lighting device can be achieved.

Further, in the present embodiment, the case where the outer peripheral cover 10a of the circuit device 10 also serves as the spacer portion has been described, but as shown in FIG.
The spacer section 11 made of a separate member may be attached to a.

Next, a second embodiment of the present invention will be described with reference to FIG.
It will be described based on. The same parts as those described in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. FIG.
FIG. 1 is a vertical sectional front view showing a liquid crystal display device using a hollow backlight 12. This liquid crystal display device includes a backlight 12 and a transmission type liquid crystal display element 2. The transmissive liquid crystal display element 2 is disposed on the light emitting surface 4 a of the prism sheet 4 of the backlight 12.

In the backlight 12, two fluorescent lamps 6 are arranged so as to be opposed in parallel to two edges of the hollow area 5. In the hollow region 5, a reflection sheet 8 that directly emits light from the fluorescent lamp 6 or reflects light reflected by the reflection plate 7 toward the prism sheet 4 corresponds to each of the two fluorescent lamps 6. Are arranged one by one.

Each of the reflection sheets 8 is arranged so as to be in contact with the bottom surface 3a of the main body case 3 in the vicinity of the corresponding fluorescent lamp 6, and moves away from the bottom surface 3a and approaches the prism sheet 4 as the distance from the fluorescent lamp 6 increases. It is inclined in the direction. For this reason, a gap 13 is formed between the back surface of the reflection sheet 8 and the bottom surface 3a at the center position of the main body case 3. The gap 13 accommodates a circuit device 10 such as a lighting circuit for the fluorescent lamp 6 and a drive circuit for the transmission type liquid crystal display element 2. The circuit device 10 is provided with an outer peripheral cover 10 a serving as a spacer portion, and the outer peripheral cover 10 a is in contact with the back surface of the reflection sheet 8.

In such a configuration, the reflection sheet 8 disposed in the hollow area 5 is inclined so as to approach the prism sheet 4 as the distance from the fluorescent lamp 6 increases, so that the light emitted from the fluorescent lamp 6 is reduced to the prism sheet. 4, the light is evenly applied to the entire surface of the prism sheet 4, and the uniformity of the light emitting surface 4a of the prism sheet 4 is increased.

Then, the reflecting sheet 8 is inclined so that the back side of the reflecting sheet 8 and the bottom surface 3a of the main body case 3 are formed.
The space for accommodating the circuit device 10 is provided in the gap 13 formed between the main body case 3 and the back surface of the main body case 3 which is the peripheral portion of the backlight 1 and the back surface of the backlight 1. , And the backlight 1 can be made narrower and thinner. Further, also in the liquid crystal display device using the backlight 1, a narrower frame and a thinner display can be achieved.

Since the outer peripheral cover 10a of the circuit device 10 accommodated in the gap 13 is in contact with the back surface of the reflection sheet 8, the deflection and deformation of the reflection sheet 8 are prevented. By preventing the deflection and deformation, the state where the light reflected by the reflection sheet 8 is most appropriately incident on the prism sheet 4 is maintained, and the uniformity of the light emitting surface 4a of the prism sheet 4 is maintained high. .

[0037]

According to the backlight according to the first aspect of the present invention, the circuit device is provided in the gap between the back surface of the reflection means formed by inclining the reflection means and the bottom surface of the main body case. Since the circuit device is housed, it is not necessary to provide a space for housing the circuit device on the periphery of the backlight or on the back surface side of the backlight, so that the frame of the backlight can be made narrower and thinner.

According to the backlight according to the second aspect of the present invention, the reflecting portion can be prevented from being bent or deformed by bringing the spacer portion of the circuit device into contact with the back surface of the reflecting portion. For this reason, it is possible to maintain the reflection unit in a state where the light reflected by the reflection unit is most appropriately incident on the light diffusion unit, and maintain a high uniformity of the light emitting surface of the light diffusion unit. be able to.

According to the backlight of the third aspect of the present invention, since the circuit device also serves as the spacer portion, the circuit device is brought into contact with the back surface of the reflection device to prevent the deflection and deformation of the reflection device. Can be prevented. For this reason, it is possible to maintain the reflection unit in a state where the light reflected by the reflection unit is most appropriately incident on the light diffusion unit, and maintain a high uniformity of the light emitting surface of the light diffusion unit. be able to.

According to the liquid crystal display device of the fourth aspect of the present invention, since the backlight according to any one of the first to third aspects is used, the frame width and the thickness of the entire liquid crystal display device can be reduced. Can be achieved.

According to the lighting device of the fifth aspect of the present invention,
Since the backlight according to any one of claims 1 to 3 is used, the frame width and the thickness of the entire lighting device can be reduced.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view showing a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional front view showing a modification of the first embodiment.

FIG. 3 is a vertical sectional front view showing a liquid crystal display device according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1,12 Backlight 2 Transmissive liquid crystal display element 3 Main body case 3a Bottom part 4 Light diffusing means 4a Light emitting surface 5 Hollow area 6 Light source 7 Reflector 8 Reflecting means 9, 13 Gap 10 Circuit device 10a, 11 Spacer section

Claims (5)

[Claims] 1. A main body case having a bottom surface portion, and a surface facing the bottom surface portion is open; and a main body case is disposed on the open surface of the main body case, and is incident from a back surface side facing the bottom surface portion. A light diffusing means for emitting light from a light emitting surface on the front surface side; a hollow region formed between the bottom surface and the light diffusing means; a long light source disposed at an edge of the hollow region; A reflector that reflects light emitted from the light source toward the hollow area; disposed in the hollow area so as to face the light diffusing means, and is arranged to approach the light diffusing means as the distance from the light source increases. A backlight comprising: an inclined reflecting means; a gap formed between the rear surface side of the reflecting means and the bottom face at a position distant from the light source; and a circuit device housed in the gap. . 2. The backlight according to claim 1, wherein the circuit device includes a spacer portion abutting on a back surface of the reflection means. 3. The backlight according to claim 1, wherein the circuit device also serves as a spacer portion that is in contact with a back surface of the reflection unit. 4. A liquid crystal display device comprising: the backlight according to claim 1; and a transmissive liquid crystal display element disposed on the light emitting surface. 5. The backlight according to claim 1, further comprising: a light control means disposed on the light emitting surface;
A lighting device comprising: