JPH0654037U - Backlight unit - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a backlight unit capable of improving the luminance uniformity ratio without unnecessarily reducing the brightness. [Structure] Reference numeral 4 denotes a housing having a reflective layer on the inner surface thereof, in which a fluorescent lamp 2 is arranged. A diffusion plate 3 and a Fresnel lens sheet 1 are sequentially arranged in the opening of the housing 4. Especially, the Fresnel lens sheet 1 has its groove 1a.
Are arranged so as to substantially coincide with the axial direction of the fluorescent lamp 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention particularly relates to a backlight unit used as a backlight unit of a liquid crystal display device.

[0002]

[Prior art]

 A conventional backlight unit of this type is configured, for example, by arranging a fluorescent lamp in a lamp house having a reflecting plate on the bottom and by arranging a diffusion plate on the opening side of the lamp house.

According to this structure, the light emitted from the fluorescent lamp is directly and directly reflected by the reflection plate and indirectly incident on the diffusion plate, so that the liquid crystal display device has relatively little uneven brightness. Is irradiated.

However, since the thickness of the backlight unit is thin, even if a diffuser plate is used, the uniformity of luminance distribution is low, and good liquid crystal display cannot be expected.

Therefore, in order to improve the uniformity of the brightness distribution, an adjusting method is adopted in which the brightness of the bright part is suppressed and the brightness is adjusted to the dark part.

[0006]

[Issues to be solved by the device]

 With such a configuration, the uniformity of the luminance distribution can be improved, but the brightness becomes insufficient. On the other hand, if the distance between the diffuser and the fluorescent lamp is increased, the brightness can be reduced and the brightness unevenness can be reduced.

Therefore, an object of the present invention is to provide a backlight unit that can maintain the uniformity of the brightness distribution relatively with a simple structure and can improve the brightness.

[0008]

[Means for Solving the Problems]

 Therefore, in order to achieve the above-mentioned object, the present invention has a Fresnel lens sheet arranged on a diffuser plate, and further, the direction of the groove forming the lens of the lens sheet is directed to the axis of the fluorescent lamp. It is almost the same as the direction.

[0009]

【Example】

 Next, an embodiment of the present invention will be described with reference to FIGS. In the figure, 1 is a Fresnel lens sheet. This sheet 1 is arranged on the opening side of a housing (lamp house) 4. A fluorescent lamp 2 is arranged in this housing 4, and a diffusion plate 3 is arranged between the fluorescent lamp 2 and the Fresnel lens sheet 1. In particular, the Fresnel lens sheet 1 is arranged so that the direction of the groove 1a forming the lens is substantially aligned with the axial direction of the fluorescent lamp 2. An example of the inside of the housing 4, for example, the bottom is formed as an anti-slope.

[0010]

[Effect of device]

 As described above, according to the present invention, by arranging the Fresnel lens sheet on the diffusion plate, the direction of light collection is made to coincide with the direction of the lamp, and the unevenness of light and darkness of the light is noticed. It is possible to improve the brightness uniformity without using a lighting curtain or the like even with a thin backlight unit.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view of a Fresnel lens sheet according to the present invention.

FIG. 3 is an enlarged perspective view of a main part of FIG.

[Explanation of symbols]

 1 Fresnel lens sheet 2 Fluorescent lamp 3 Diffuser 4 Housing

Claims (2)

[Scope of utility model registration request] 1. A direct-type backlight unit having a fluorescent lamp, a reflection plate for reflecting the light of the fluorescent lamp, and a diffusion plate for diffusing and transmitting the light of the fluorescent lamp, wherein a Fresnel lens shield is provided on the diffusion plate. The backlight unit is characterized in that 2. The backlight unit according to claim 1, wherein the direction of the groove forming the lens of the Fresnel lens sheet is substantially aligned with the axial direction of the fluorescent lamp.