KR100619397B1 - Backlight apparatus - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention provides a backlight device in which luminance unevenness due to change over time is less likely to occur, longer life of the lamp is achieved, and deterioration of display quality due to the spacer is prevented.

A backlight device having a plurality of linear light sources 3 and a reflecting plate 2 for reflecting light of the light source 3, wherein the distance between the light source 3 and the reflecting plate 2 is determined by the linear light source ( In the spacer 6 which is kept constant along the longitudinal direction of 3), the axial direction position is shifted between adjacent light sources 3 and 3.

Reflector, light source, lamp

Description

Backlight apparatus

1 is a cross-sectional view showing an embodiment of the present invention.

2 is a plan view showing an embodiment of the present invention.

3 is a front view of the circular spacer for supporting the lamps individually.

4 is a front view of a rectangular spacer for individually supporting lamps.

5 is a front view of a triangular spacer that individually supports lamps.

6 is a front view of a spacer integrally supporting two lamps.

7 is a front view of a spacer integrally supporting three lamps in a straight line shape.

8 is a front view of a spacer integrally supporting three lamps in a triangular configuration.

9 is a front view of a spacer that supports two lamps so as to be mountable from a radial direction.

It is a schematic diagram which arrange | positioned the spacer in sinusoidal shape.

<Brief description of the main parts of the drawing>

2 reflector 3 linear light sources

5 lamp

The present invention relates to a backlight device used in a liquid crystal display device.

A liquid crystal display device is used as a television or a super-large monitor, and the backlight device is required to have a wide viewing angle, high brightness and light weight. In order to achieve these demands, a so-called direct backlight device is used.

The structural feature of the direct backlight device is that there is a linear light source underneath the light emitting surface (diffusion plate). The light emitted from the linear light source is irradiated from the light emitting surface (diffusion plate) as the light reflected by the reflector formed of a layer having a high reflectance and the combined light of the direct light. In order to efficiently obtain the reflected light, the linear light source and the reflecting plate form a predetermined clearance.

In recent years, as the size of the backlight increases, it is required to increase the linear light source. However, when the linear light source becomes long, the linear light source is bent by its own weight or the like, and the clearance between the linear light source and the reflecting plate becomes uneven. Therefore, the reflected light cannot be obtained uniformly, resulting in deterioration of display quality.

Here, Japanese Patent Laid-Open No. Hei 11-329040 discloses a lamp support for fixing both ends of a light source. However, when the lamp support is formed in the axial middle portion of the linear light source to prevent the linear light source from bending, the shadow of the lamp support is generated on the light emitting surface of the backlight, which adversely affects the display quality.

An object of the present invention is to provide a backlight device which avoids the adverse influence caused by the installation of a lamp support and prevents the bending of the linear light source.

In order to achieve the above object, the present invention takes the following means. That is, the present invention is characterized in that a backlight device having a plurality of linear light sources and a reflecting plate for reflecting light of the light source, wherein the distance between the light source and the reflecting plate is fixed along the longitudinal direction of the linear light source. The spacer to be kept securely is formed so that the position in the axial direction is shifted between adjacent light sources.

According to the present invention, the bending of the linear light source can be prevented by the spacer. In addition, since the positions of the spacers are not the same between adjacent light sources, even when the spacers are formed, the shadows are hardly noticeable and do not adversely affect the display quality.

When the distance between adjacent linear light sources is P and the amount of displacement in the axial direction of the spacer is L, it is preferable that L is in a relationship proportional to the inverse of P.

It is preferable that the spacer maintains a distance of 1 to 2 mm between the linear light source and the reflecting plate.

The spacer is preferably transparent or white.

In the linear light source, two or more lamps may be paired to constitute one linear light source. In this case, the spacer may individually support a plurality of lamps constituting one linear light source, and the spacer may integrally support a plurality of lamps constituting one linear light source.

Embodiment of the Invention

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on drawing.

1 and 2, the backlight device has a case 1 having an upper side opened, a reflecting plate 2 is formed on an inner surface of the case 1, and a plurality of backlights are disposed at predetermined intervals from the reflecting plate 2. The linear light sources 3 are arranged in parallel with each other, and the light diffusing plate 4 is formed so as to close the opening of the case 1. And a liquid crystal display (not shown) is arrange | positioned at the upper surface side of this diffuser plate 4.

The one linear light source 3 is composed of two lamps 5. As the lamp 5, a cold cathode fluorescent lamp or a hot cathode fluorescent lamp is used, and in particular, a cold cathode tube is preferable. Of course, the number of lamps 5 constituting one linear light source 3 is not limited to two, but may be composed of two or more lights. In the case of three or more, the arrangement | positioning to be equalized (equal spaced arrangement) is preferable. In addition, one linear light source 3 may be constituted by one lamp 5.

The lamp 5 has a thin tube shape having a tube diameter of about 3 mm, but has a length of several hundred mm, and therefore, the lamp 5 has a structure that is easily bent. Electrodes (not shown) are formed at both ends of the lamp 5 in the axial direction, and because of these electrodes, both ends of the lamp axial direction are ineffective light emitting regions with lower luminance than the middle part of the lamp axis direction. In addition, the ineffective light emitting area is generally in the range of about 10 mm at both ends of the lamp axial direction, and the axial middle portion excluding these ineffective light emitting areas is an effective light emitting area having high luminance. In addition, both ends of the lamp 5 are supported by the case 1 in the axial direction.

When each linear light source 3 is comprised by the some lamp | ramp 5, the thing of the same optical characteristic of each lamp | ramp 5 is used. For example, if the tube current when one lamp is conventionally used as one linear light source is 6 mA, the tube current when two lamps 5 are used as one linear light source 3 in this embodiment. Becomes 3mA.

It is preferable that the several lamp 5 which comprises one linear light source 3 is arrange | positioned close to each other, grouping, and it is preferable to be accommodated in the width within 15 mm specifically ,. The smaller the interval between the lamps 5 is, the better, but it is not preferable to contact each other. In order to avoid contact between the lamps 5, a spacer (not shown) such as an O-ring can be inserted.

The distance between the linear light sources 3 is preferably 15 to 50 mm. If it falls more than 50mm, the brightness tends to be uneven.

It is preferable that the distance between the linear light source 3 and the diffuser plate 4 is 40 mm or less. As the diffuser plate 4, a plate formed of a material in which light-diffusing fine particles are mixed with a transparent resin such as acryl is used.

The reflector 2 is not particularly limited as long as the reflector 2 has a high reflectance. The reflector 2 is covered with a reflecting surface of a resin layer or a metal layer. The reflecting plate 2 is preferably white. In order to efficiently obtain the reflected light, the linear light source 3 and the reflecting plate 2 have a clearance of 1 to 2 mm.

In order to prevent the clearance from being uneven over the longitudinal direction (axial direction) of the linear light source 3 due to the warp caused by its own weight or the like, the linear light source 3 and the reflecting plate 2 and The spacer 6 is formed in between.

The color and material of this spacer 6 are not specifically limited, Resin, such as transparent or white acrylic, glass, and a silicone rubber are used. By making the spacer 6 transparent or white, shadows of the spacer 6 are less likely to occur. As shown in Figs. 3 to 5, the spacer 6 is formed by drilling the lamp insertion hole 7 in a member whose outer shape is circular, rectangular, triangular or the like.

By inserting the lamp 5 into the lamp insertion hole 7 of these spacers 6 and arranging it on the reflecting plate 2, the distance between each lamp 5 and the reflecting plate 2 is kept constant individually. . Moreover, the said spacer 6 is formed so that the space | interval of the linear light source 3 and the reflecting plate 2 may be kept constant in the range of 1-2 mm.

The spacer 6 inserted into the lamp 5 is positioned at an arbitrary position in the lamp axial direction by friction between the lamp insertion hole 7 and the surface of the lamp 5, but the spacer 6 is positioned in the lamp axial direction. When the external force is applied, the spacer 6 is movable in the ramp axial direction. Therefore, the position of the spacer 6 can be easily changed as needed.

The spacer 6 can be formed in the effective light emitting area which is the axial middle part of the lamp 5. Formed in the axial middle portion, it is possible to effectively prevent the warping of the lamp. In addition, although two spacers 6 are formed in one lamp 5 in FIG. 2, three or more spacers may be formed and one may be formed.

As shown in the drawing, when one linear light source 3 is constituted by a plurality of lamps 5, the spacer 6 maintains an interval between the respective lamps 5 in one linear light source 3. Each lamp 5 is made into non-contact. In other words, the spacer 6 is also an inter-lamp spacer for non-contacting a plurality of lamps constituting one linear light source. Therefore, it is not necessary to separately form the O-ring or the like for avoiding contact between the lamps 5.

6-8 are the spacers 6 which integrally support the several lamp | ramp 5 of one linear light source 3. As shown to FIG. 9 shows that the spacer 6 can be mounted in the radial direction of the lamp 5, and the cutout 8 is formed in the lamp insertion hole 7, and the cutout 8 The lamp 5 is mountable. In the case shown in Fig. 9, one lamp insertion hole 7 may be provided. The spacer 6 or other spacers shown in FIGS. 3 to 9 may be integrally formed with respect to the reflecting plate.

When the spacers 6 are formed at the same positions of the linear light sources 3, the shadows have the same shape and affect the display quality. However, in the present invention, the spacers 6 are arranged so as to be shifted in the axial direction. Thus, the display quality is not affected.

That is, when the space | interval of the adjacent linear light source 3 is called P, and the shift amount of the axial direction of the spacer 6 is called L, when the space | interval P of the linear light source 3 is narrow, it is necessary to widen the shift | offset amount L. On the contrary, when P is wide, L may be narrow. In other words, L is in proportion to the inverse of P (L ∝ k / P, k is an integer). This relationship can also be applied to the arrangement of the spacers 6 in each lamp 5 constituting one linear light source 3.

As shown in FIG. 10, the spacer 6 may be arranged in a sine wave shape (in this case, L is amplitude and P is 1/4 wavelength).

According to embodiment of this invention of the said structure, a luminance nonuniformity by a time-dependent change hardly arises. That is, in the case where one linear light source is composed of one conventional lamp, if there is a deviation in deterioration of each lamp, the luminance unevenness is very noticeable. In this embodiment, the plurality of lamps 5 are grouped. Because of this arrangement, variations due to deterioration of each one are alleviated, and as a result, luminance unevenness in the light emitting surface is less likely to occur.

That is, when the light emission amount deteriorates and the light emission amount is 1/2 ＇in the related art, in the present embodiment, the light emission amount＇ 1/2 + 1/2 ＇is＇ 1/2 + 1/4 = 3/4 ＇ By this, it becomes ＇3/4＇ compared with the ＇1/2 의 of conventional deterioration, and the variation in deterioration is alleviated.

In addition, since the lamp 5 is used more conventionally, the load acting on each of the lamps required to achieve the required luminance may be smaller than that of the conventional art. Specifically, since the tube current flowing through the lamp 5 becomes smaller, the lamp Longer lifespan

That is, the tube current required for one lamp may be half or less of the conventional art. Basically, in a stable atmosphere exceeding the discharge stable voltage, the smaller the tube current value flowing through the lamp 5, the longer the life is. Therefore, longer life can be achieved in the present embodiment.

In addition, by using a plurality of lamps constituting one linear light source, the diameter of the lamp can be made thin. When the taper becomes thin, the warpage is increased by its own weight, but the warpage is prevented by the spacer.

In addition, this invention is not limited to what is shown to the said embodiment.

According to the present invention, since the spacer which maintains the space | interval between a light source and a reflecting plate uniformly along the longitudinal direction of a linear light source is formed so that the axial direction may shift | deviate between adjacent light sources, the conventional thing formed in the same position In comparison, deterioration of display quality by the spacer is prevented.

When two or more lamps are paired to form one linear light source, luminance unevenness due to change over time is hardly generated, and the life of the lamp is extended.

Claims (7)

A backlight device having a plurality of linear light sources and a reflector for reflecting light of the light sources, The backlight device which maintains the space | interval between the said light source and a reflecting plate uniformly along the longitudinal direction of the said linear light source is formed so that the axial position may shift | deviate between adjacent light sources. The backlight device according to claim 1, wherein when the distance between adjacent linear light sources is called P and the amount of displacement in the axial direction of the spacer is referred to as L, L is in proportion to the inverse of P. The backlight device of claim 1, wherein the spacer maintains a distance of 1 to 2 mm between the linear light source and the reflecting plate. The backlight device of claim 1, wherein the spacer is transparent or white. 2. The backlight device according to claim 1, wherein the linear light source comprises two or more lamps in pairs to constitute one linear light source. The backlight device of claim 5, wherein the spacers individually support a plurality of lamps constituting one linear light source. The backlight device according to claim 5, wherein the spacers integrally support a plurality of lamps constituting one linear light source.

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