JPH0764084A - Illumination device, liquid crystal display device, back light and display device - Google Patents

Abstract

PURPOSE:To prevent a sheet for controlling light from being hung down and to prevent the uniformity ratio of luminance from being lowered caused by the hanging-down of the sheet for controlling light by supporting the sheet for controlling light which is not made to adhere to the inside surface of a diffusion plate but merely superposed on it by a transparent supporting member from the inside surface side thereof. CONSTITUTION:This illumination device is provided with light sources 13a and 13b, a reflecting plate 12 constituted by forming the inside surface thereof to be a reflecting surface and disposing the light sources 13a and 13b on the inside bottom surface thereof, the diffusion plate 15 disposed on the light outgoing end of the plate 12 and the sheet for controlling light 14 superposed on the inside surface of the plate 15. Besides, the transparent supporting member 16 supporting at least the sheet 14 from the inside surface thereof is provided on the inside bottom surface of the plate 12. Then, both of the bottom surface of the member 16 and the inside bottom surface of the plate 12 brought into contact with the bottom surface are formed to be flat. Since the sheet 14 is supported from the inside surface of the intermediate part in the width direction in such a manner, it is prevented from being hung down inside caused by vibration, impact, secular change or the like and the uniformity ratio of the luminance is prevented from being lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device, a backlight, a liquid crystal display device and a display device suitable for a large backlight for illuminating the back surface of a relatively large liquid crystal display panel, and more particularly to a uniform brightness. The present invention relates to an illuminating device, a liquid crystal display device, a backlight, and a display device that improve the degree of support and the supporting strength of a diffusion plate or the like.

[0002]

2. Description of the Related Art Conventionally, an example of this type of illumination device is shown in FIG. This illuminating device 1 is of a so-called direct-lighting type. For example, a pair of right and left fluorescent lamps 3a having a straight shape are provided on the inner bottom surface of a bottomed rectangular tubular reflecting plate 2 whose inner surface is formed as a reflecting surface 2a. , 3b are arranged in parallel. As shown in FIG. 7, the reflection plate 2 is integrally formed with an auxiliary reflection portion 2b protruding inwardly in a mountain shape at an intermediate portion in the width direction.

Then, on the light exit opening end of the reflection plate 2,
A rectangular diffusion plate 5 having a light control sheet 4 superimposed on the inner surface is placed and fixed, and an object to be illuminated such as a liquid crystal display panel disposed on the diffusion plate 5 is illuminated in a planar manner. It is like this.

[0004]

However, in the conventional lighting device 1 as described above, the light control sheet 4 is simply laminated on the inner surface of the diffusion plate 5 without adhering the light control sheet 4, and the light control sheet 4 is also stacked. Since it does not support the inner surface of 4 at all,
There is a possibility that the light control sheet 4 hangs inward due to vibrational shock, secular change, etc., and the brightness uniformity is lowered.

Therefore, the present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an illuminating device, a liquid crystal display device, which can prevent the light control sheet from sagging and enhance the brightness uniformity. It is to provide a backlight and a display device.

[0006]

The present invention is configured as follows in order to solve the above-mentioned problems.

The invention according to claim 1 of the present application (hereinafter, referred to as the first
Invention), the light source and the inner surface are formed into a reflective surface,
An illuminating device comprising: a reflection plate on the inner bottom surface of which the light source is arranged, a diffusion plate arranged at a light emitting end of the reflection plate, and a light control sheet which is superposed on the inner surface of the diffusion plate. A transparent support member that supports at least the light control sheet from the inner surface is provided on the inner bottom surface of the reflection plate.

Further, in the invention according to claim 2 of the present application (hereinafter referred to as the second invention), the bottom surface of the supporting member and the inner bottom surface of the reflecting plate in contact with the bottom surface are both formed to be flat. Characterize.

Further, in the invention according to claim 3 of the present application (hereinafter referred to as the third invention), the light control sheet is provided with a plurality of dot-shaped reflective films on the transparent sheet body in the vicinity of the light source. It is characterized in that it is formed so as to become denser and gradually becomes sparser as it goes away from the light source.

The invention according to claim 4 of the present application (hereinafter referred to as the fourth invention) is characterized in that a diffusion sheet is superposed on the inner surface of the light control sheet.

Further, in the invention according to claim 5 of the present application (hereinafter referred to as the fifth invention), the reflection plate has a stepped portion which supports at least an end portion of the diffusion plate and the light control sheet at its end portion. Is formed.

Further, the invention according to claim 6 of the present application (hereinafter referred to as the sixth invention) is any one of claims 1 to 5.
The illumination device according to the item (1) is configured to illuminate the object to be illuminated from the back surface.

The invention according to claim 7 of the present application (hereinafter referred to as the seventh invention) is characterized in that the illuminated object is a liquid crystal display panel.

The invention according to claim 8 of the present application (hereinafter referred to as the eighth invention) is characterized in that the illuminated object is an evacuation guidance display board or a display board such as a signboard.

[0015]

[Action]

<First to Fifth Inventions> The light control sheet is simply laminated on the inner surface of the diffusion plate without adhering the light control sheet. However, the light control sheet is supported from the inner surface side by a transparent supporting member. Therefore, it is possible to prevent the light control sheet from hanging down. As a result, it is possible to prevent the reduction of the brightness uniformity degree due to the hanging of the light control sheet, and it is possible to increase the support strength of the diffusion plate or the like.

Further, since the support member is transparent, it is possible to prevent the light from the light source from being blocked by this support member and the luminous flux to be reduced, thereby preventing the brightness from being lowered.

<Second Invention> Since the bottom surface of the support member and the inner bottom surface of the reflection plate contacting the bottom surface are both formed to be flat, the joint surface between the bottom surface of the support member and the inner bottom surface of the reflection plate is formed. The support member can be expanded to stabilize the uprightness of the support member, and its support strength can be increased.

<Third Invention> In the light control sheet, a plurality of dot-shaped reflective films are densely formed in the vicinity of the light source on the transparent sheet main body to reduce the amount of transmitted light, while moving away from the light source. According to this, since it is formed so as to gradually become sparse and the amount of transmitted light is increased, it is possible to improve the luminance uniformity.

<Fourth Invention> Since the light from the light source is doubly diffused by the diffusing plate and the diffusing sheet, the diffusivity can be increased and the luminance uniformity can be increased.

<Fifth Invention> Since the reflecting plate can support at least the diffusion plate and the end of the diffusion sheet by the supporting step, the diffusion plate and the diffusion sheet can be reliably and firmly supported. it can.

<Sixth to Eighth Inventions> Since the illuminating device according to any one of the first to fifth inventions having a high degree of luminance uniformity is incorporated in a backlight, a liquid crystal display device or a display device, these backlights can be used. It is possible to improve the brightness uniformity as a light, a liquid crystal display device, or a display device.

[0022]

Embodiments of the present invention will be described below with reference to FIGS. The same or corresponding parts in FIGS. 1 to 5 are designated by the same reference numerals.

FIG. 1 is a vertical cross-sectional view of an embodiment of the present invention. In the figure, an illuminating device 11 is a so-called direct-lighting type, and a bottomed corner in which almost the entire inner surface is formed as a reflecting surface 12a. On the inner bottom surface of the tubular reflecting plate 12, for example, a pair of right and left linear fluorescent lamps 13a and 13b are arranged in parallel. As shown in FIG. 2, the reflection plate 12 is an intermediate portion in the width direction thereof, and is integrally formed with an auxiliary reflection portion 12b protruding inwardly in a mountain shape between the pair of fluorescent lamps 13a and 13b. ing.

A rectangular plate-shaped diffusing plate 15 having a light control sheet 14 superposed on the inner surface is placed and fixed on the light exit opening end of the reflecting plate 12, and the light diffusing plate 15 is placed on the diffusing plate 15. An object to be illuminated such as a liquid crystal display panel provided is illuminated in a planar manner.

The light control sheet 14 includes, for example, a plurality of dot-shaped reflective films on the transparent sheet body, and the fluorescent lamp 13 is provided.
While forming densely in the vicinity of a and 13b to reduce the amount of transmitted light, the fluorescent lamps 13a and 13b are formed so as to become sparser as they move away from the pair of fluorescent lamps 13a and 13b to increase the amount of transmitted light to improve the brightness uniformity. I am trying.

Then, as shown in FIG. 1 and FIG.
2 has both ends in the width direction bent into L-shapes to integrally form a pair of left and right support steps 12c and 12d, respectively, and diffuses with the light control sheet 14 by these support steps 12c and 12d. Both ends of the plate 15 in the width direction are supported.

The chevron-shaped auxiliary reflecting portion 12b of the reflecting plate 12 is also provided.
On the inner surface of each of the flat portions 1e, a flat portion 12e that makes the chevron projection a flat surface with a required width is formed at a required pitch in the axial direction.
Mounting holes 12f are formed in the center of 2e. As shown in FIG. 3, for example, a cylindrical leg portion 16a of a support rod 16 made of a transparent resin is tightly fitted into each of the mounting holes 12f, and each support rod 16 is attached to the inner bottom surface of each flat portion 12e. It stands on top. Each of the support rods 16 is located at the lower end of a substantially frustoconical main body 16b having a diverging downward diameter in the figure, and a large-diameter frustoconical end portion 16 having a slightly larger diameter and diverging downward.
The bottom surface 16d of the large-diameter end portion 16c is formed into a flat surface so that c is integrally coupled and is closely seated on the flat bottom surface of the auxiliary reflection portion 12b. The legs 16a are integrally coupled.

The upper end surface of each support rod 16 which is a flat surface contacts the inner surface of the light control sheet 14 to support the light control sheet 14 and the diffusion plate 15 as shown in FIG. There is.

Therefore, according to the present embodiment, since the light control sheet 14 and the diffusion plate 15 are supported by the plurality of transparent support rods 16 from the inner surface of the light control sheet 14 in the width direction, the vibration control and It is possible to prevent the light control sheet 14 from hanging down inward due to aging or the like and lowering the brightness uniformity, and also to ensure that the light control sheet 14 and the diffusion plate 15 are provided in the middle portion in the width direction. Since they are firmly supported, these 14 and 15 can be increased in size.

Further, since the bottom surface 16d of each support rod 16 and the inner bottom surface of the flat portion 12f with which the bottom surface 16d is in contact are both formed into flat surfaces, the area of the surface in contact with both bottom surfaces 16d and 12f is increased. The uprightness of each support rod 16 can be stabilized, and the support strength by each support rod 16 can be increased.

Furthermore, since each support bar 16 is transparent,
It is possible to prevent light from the pair of fluorescent lamps 13a and 13b from being blocked and reduce the luminous flux.

Note that, for example, like a lighting device 11a shown in FIG. 4, a radiator 1 made of silicon resin, metal or the like is provided between each fluorescent lamp 13a, 13b and the inner bottom surface of the reflector 12.
You may interpose 7a, 17b. According to this, the heat generated by the fluorescent lamps 13a, 13b is generated by the radiators 17a, 17b.
Since the heat is dissipated by b and the temperature rise in the reflector 12 can be suppressed, the space in the reflector 12 can be effectively used.

FIG. 5 is a perspective view showing a partial cross-section of another embodiment of the present invention. This is one example when the illumination device 11 shown in FIG. 1 is assembled as a backlight of a liquid crystal display (LCD) 21. An example is shown.

That is, in this liquid crystal display device 21, an LCD (liquid crystal display device) panel 22 in the form of a horizontally long rectangular plate is brought into close contact with the light exit surface of the diffusion plate 15 of the illuminating device 11 shown in FIG.
It is characterized in that it is held by a pair of left and right supporting step portions 12c and 12d of the reflection plate 12, and a diffusion sheet 23 having substantially the same shape and size is superposed on the inner surface of the light control sheet 14.

Therefore, according to this embodiment, since the diffusion sheet 23 is added, the diffusivity can be increased to further enhance the brightness uniformity, and the high brightness and high brightness on the light emitting surface of the diffusion plate 15 can be achieved. LCD panel 2 due to uniform light emission
The back side of 2 can be illuminated entirely and evenly.

It should be noted that the LCD panel 22 may be replaced with a display board such as a guide board or a signboard, etc., on which a desired display is made by characters or figures so as to form a thin evacuation guide light or a light guide board signboard. .

In each of the above embodiments, the case where a pair of straight fluorescent lamps 13a and 13b are used as the light source has been described, but the present invention is not limited to this, and the type and number of light sources, The shape is not limited.

[0038]

As described above, according to the first to fifth inventions of the present application, the light control sheets which are simply stacked without being adhered to the inner surface of the diffusion plate are supported from the inner surface side by the transparent supporting member. Therefore, the light control sheet can be prevented from hanging down. As a result, it is possible to prevent the reduction of the brightness uniformity due to the hanging of the light control sheet, and also to firmly support the diffuser plate and the light control sheet, and thus to increase the size of these. You can

Further, since the supporting member is transparent, it is possible to prevent the light from the light source from being blocked by the supporting member and to prevent the luminous flux from decreasing and the luminance from decreasing.

In the second invention of the present application, since the bottom surface of the supporting member and the inner bottom surface of the reflecting plate contacting the bottom surface are both formed to be flat, the bottom surface of the supporting member and the inner bottom surface of the reflecting plate are joined together. The surface can be enlarged to stabilize the uprightness of the support member.

In the third invention of the present application, the light control sheet has a plurality of dot-shaped reflective films densely formed in the transparent sheet main body in the vicinity of the light source, and gradually becomes sparse as the distance from the light source increases. Since it is formed as described above, it is possible to improve the brightness uniformity.

According to the fourth aspect of the present invention, the light from the light source is doubly diffused by the diffuser plate and the diffuser sheet, so that it is possible to enhance the diffusivity and enhance the luminance uniformity.

In the fifth invention of the present application, at least the diffusion plate and the end portion of the diffusion sheet can be supported by the supporting step portion of the reflection plate, so that the diffusion plate and the diffusion sheet are reliably and firmly supported. Therefore, it is possible to increase the size of the diffusion plate and the diffusion sheet.

In the sixth to eighth inventions of the present application, the illuminating device according to any one of the first to fifth inventions having high luminance uniformity is incorporated in a liquid crystal display device, a backlight, or a display device. It is possible to enhance the luminance uniformity as a liquid crystal display device, a backlight, or a display device.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an embodiment of a lighting device according to the present invention.

FIG. 2 is a perspective view of the reflector shown in FIG.

FIG. 3 is a perspective view of essential parts showing a state in which the support member shown in FIG. 1 is erected on a flat portion of a reflection plate.

FIG. 4 is a vertical sectional view of another embodiment of the present invention.

5 is a vertical sectional view of an embodiment of a liquid crystal display device in which the lighting device shown in FIG. 1 is assembled as a backlight.

FIG. 6 is a vertical cross-sectional view of a conventional lighting device.

FIG. 7 is a perspective view of the conventional reflector shown in FIG.

[Explanation of symbols]

 11, 11a Illuminating device 12 Reflecting plate 12a Reflecting surface 12b Auxiliary reflecting part 12c, 12d Supporting step part 12e Flat part 12f Mounting hole 13a, 13b Pair of fluorescent lamps 14 Light control sheet 15 Diffusing plate 16 Supporting rod 16a Leg part 16b Supporting Rod main body 16d Support rod bottom 17 Diffusion sheet 21 Liquid crystal display device 22 Liquid crystal display panel 23 Diffusion sheet

Claims (8)

[Claims] 1. A light source, a reflection plate having an inner surface formed as a reflection surface and having the light source disposed on the inner bottom surface thereof, a diffusion plate disposed at a light emitting end of the reflection plate, and the diffusion plate. In a lighting device having a light control sheet that is superposed on the inner surface of, a transparent support member that supports at least the light control sheet from the inner surface is provided on the inner bottom surface of the reflector. Characteristic lighting device. 2. The illuminating device according to claim 1, wherein the bottom surface of the support member and the inner bottom surface of the reflection plate in contact with the bottom surface are both flat. 3. A light control sheet, in which a plurality of dot-shaped reflective films are densely formed in the vicinity of a light source on the transparent sheet body, and gradually become sparse as the distance from the light source increases. 3. The method according to claim 1 or 2, wherein
Illumination device described. 4. The lighting device according to claim 1, wherein a diffusion sheet is superposed on the inner surface of the light control sheet. 5. The reflection plate is formed with a stepped portion which supports at least an end portion of the diffusion plate and the light control sheet at an end portion thereof. The lighting device according to. 6. A backlight comprising the illumination device according to claim 1 configured to illuminate an object to be illuminated from the back side. 7. The liquid crystal display device according to claim 6, wherein the illuminated body is a liquid crystal display panel. 8. The display device according to claim 6, wherein the illuminated body is an evacuation guidance display board or a display board such as a signboard.