JP2001021881A - Illumination unit and liquid crystal display device using the same - Google Patents

Abstract

(57) [Problem] To provide a uniform illumination unit by dividing a point light source into a light guide plate having a V groove and entering the light. SOLUTION: As a lighting unit, a reflector 8 for guiding light from a point light source 3 is provided with a concave and convex portion, and the light source 3 has a V-groove 2 and a reflection sheet 6 provided on the point light source 3.
By dividing the light from the light source, a linear light source can be replaced to obtain a low power consumption and uniform illumination unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination unit used for a transmission type or reflection type display device, and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have been widely used in display devices for information devices such as laptop and notebook type word processors and personal computers, taking advantage of features such as light weight, thinness and low power consumption. became.

Further, as a recent trend, a liquid crystal display device capable of performing color display has become the majority, and an illumination unit having high luminance and high light uniformity is indispensable for this. This lighting unit is roughly classified into a direct type using a uniforming means such as a lighting curtain and an edge light (side light) type using a light guide plate. Recently, a notebook type word processor and a personal computer have been used. With the spread, the edge light type increased.

[0004] Further, since notebook type and portable information terminals of transmissive liquid crystal display devices are sometimes used outdoors, it has been desired to increase the brightness of the backlight. There is a need for a reflective liquid crystal device. However, in the reflective liquid crystal display device, the display cannot be seen at night when there is no external light. For this reason, a transparent light guide plate is installed on the front of the liquid crystal panel, and during the daytime, external light is illuminated without being blocked by the transparent light guide plate. Front lights for illuminating panels have been developed. As the transparent light guide plate used for these, those having a V-groove formed without improving the luminance efficiency and without printing have begun to be used. Further, as a light source, low power consumption is required like a portable information terminal device, and a lamp having an inverter generates noise, so that an LED light source is required.

FIG. 5 is a perspective view showing a partial configuration of a lighting unit used in a conventional portable information terminal device or the like. As shown in FIG. 5, a V-groove 2 is formed on the surface of the light guide plate 1 to form a waveform, and light from a plurality of point light sources 3 (for example, LEDs or light bulbs) is directed in the direction of arrow a through the reflector 4. Light. This gives a bright line 5.

[0006]

However, in the configuration of the illumination unit shown in FIG. 5, if the LED light source, which is the point light source 3, is used for the light guide plate 1 in which the V-groove 2 is formed, the bright line 5 has no spread. There was a problem that light could not be used effectively. For this reason, there has been proposed a light guide plate 1 in which a diffraction grating is formed and divided into planar shapes, but there is a problem that processing is difficult due to the fine shape.

The present invention has been made in view of the above points, and divides the light of a point light source and replaces it with a linear light source before the LED light source enters the light guide plate, thereby generating noise with low power consumption. It is an object of the present invention to provide a lighting unit having no light source and a liquid crystal display device using the same.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is to reduce the power consumption by constructing a point light source of an LED light source by reflecting it on an uneven portion of a reflector, dividing the light source, and bringing the point light source closer to a line light source. Lighting unit.

According to the present invention, an inexpensive lighting unit having low power consumption, high light uniformity, and a liquid crystal display device using the lighting unit can be provided by simply replacing a point light source with a line light source.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

(Embodiment 1) FIG. 1 is a sectional view showing a configuration of a lighting unit according to Embodiment 1 of the present invention.
This is a case where the reflector 8 is provided so as to extend from the backlight side. It should be noted that cross-sectional display diagonal lines of some members are omitted in relation to the light ray direction display.

As shown in FIG. 1, a large number of V-grooves 2 are formed at predetermined intervals on the back surface of the light guide plate 1 at predetermined intervals to form a wave. The reflection sheet 6 is disposed on the lower surface of the V groove (on the right side in the drawing). A point light source 3 such as an LED light source or a light bulb is disposed on a light incident surface 7 of the light guide plate 1 at a position surrounded by a reflector 8, and light from the point light source 3 is transmitted through a diffusion sheet 9 to a light transmitting plate. 1 reflection sheet 6
Light.

FIG. 2 is an enlarged sectional view showing the structure of a reflector 8 used in FIG. 1 and FIG. 3, which will be described later, and has an uneven portion 8a for dividing light from the point light source 3 and approaching a line light source.
Are formed in large numbers.

Next, the operation of the above configuration will be described with reference to FIGS. 1 and 2. The light from the point light source 3 shown in FIG. 1 is reflected and reflected by the concave and convex portions 8a of the reflector 8 shown in FIG. The light is guided to the light incident surface 7. A diffusion sheet 9 is disposed on the light incident surface, and the divided point light sources are
The light is incident on the light guide plate 1 (in the direction of the arrow a), is reflected by the V-groove 2, and is reflected by the reflection sheet 6.
Is emitted to the direction substantially perpendicular to the surface (in the direction of the arrow b), transmitted through the transmissive liquid crystal panel 10 and the reflective liquid crystal panel 11, and displayed.

With this configuration of the lighting unit, the bright line by the point light source is diffused, and the liquid crystal panel can be uniformly illuminated. The illumination unit is applied to the back panel (rear surface) of the liquid crystal display device and is extremely effective as low power consumption illumination. .

(Embodiment 2) FIG. 3 is a sectional view showing a configuration of a lighting unit according to Embodiment 2 of the present invention.
This is a case where the reflector 8 is provided so as to extend from the front light side. It should be noted that the cross-section display diagonal lines of some members are omitted in relation to the light ray direction display. In the second embodiment, the light guide plate 1 (having the V-groove 2 and the reflection sheet 6) and the reflector 8 having the same structures as those described in the first embodiment are used.
(Including the uneven portion 8a) and the like, and the arrangement of the point light source 3, the reflector 8 and the diffusion sheet 9 with respect to the light entrance surface 7 of the light guide plate 1 is also substantially the same as that of FIG.

Therefore, also in the second embodiment, the light from the point light source 3 is diffused by the diffusion sheet 9 and the light incident surface 7 of the light guide plate 1
Diffused light (in the direction of arrow a) is reflected by the reflection sheet 6 provided on the V-groove 2, emitted to a direction substantially perpendicular to the surface of the light guide plate 1 (in the direction of arrow b), and transmitted through the reflective liquid crystal panel 11. Light enters the liquid crystal panel 10 and is displayed. In other words, the illumination unit having this configuration diffuses the bright line by the point light source and can uniformly illuminate the liquid crystal panel, and is very effective as low power consumption illumination implemented on the front panel (front surface) of the liquid crystal display device.

(Embodiment 3) FIG. 4 is a perspective view of a main part showing a configuration of a lighting unit according to Embodiment 3 of the present invention. In the third embodiment, the reflector 8 used in the first embodiment (FIGS. 1 and 2) and the second embodiment (FIG. 3) is replaced with a strip-shaped light guide plate 12.
A point light source 3 such as an LED is disposed on the end faces 12a and 12b of the light guide plate, and the light source is reflected by the V-shaped groove 12c of the strip-shaped light guide plate 12 and emitted to the light incident surface 7 of the light guide plate 1. Thus, the liquid crystal panel becomes a linear light source and can uniformly irradiate the liquid crystal panel.

[0019]

As described above, according to the present invention,
With a simple configuration, a point light source such as an LED is replaced with a line light source, and a light guide plate having a V-groove can be uniformly irradiated with light, and a lighting unit with high luminance efficiency and low power consumption can be realized. In addition, by manufacturing a liquid crystal display device using the lighting unit of the present invention, it is possible to realize a liquid crystal display device with high display quality that is compact and has little unevenness in brightness. Thus, it is possible to provide a transmission type and reflection type liquid crystal display device with low power consumption.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a backlight configuration of a lighting unit according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of a reflector of a lighting unit according to Embodiments 1 and 2 of the present invention.

FIG. 3 is a sectional view showing a front light configuration of a lighting unit according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view of a main part showing a configuration of a lighting unit according to Embodiment 3 of the present invention.

FIG. 5 is a perspective view showing a partial configuration of a conventional lighting unit.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light guide plate 2, 12 c V-groove 3 point light source 4, 8 reflector 8 a uneven portion 6 reflection sheet 7 light incident surface 9 diffusion sheet 10 transmission liquid crystal panel 11 reflection liquid crystal panel 12 strip-shaped light guide

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H091 FA14Z FA23Z FA45Z LA11 LA18 5G435 AA00 AA02 AA03 AA18 BB12 BB15 BB16 EE23 EE27 FF03 FF06 FF08 GG23 GG26 LL07 LL08 LL09

Claims (3)

[Claims] 1. A light guide plate having light equalizing means on a front surface of a liquid crystal panel, at least one or more point light sources arranged on at least one side surface of the light guide plate, and reflecting light from the point light source. And a reflector for guiding the light of the point light source, wherein the light of the point light source is divided by forming a reflection surface of the reflector for guiding the light of the point light source into an uneven shape. 2. The lighting unit according to claim 1, wherein the reflector is a strip-shaped light guide having a V-groove, and a point light source is disposed on an end face thereof. 3. A light guide plate having light equalizing means on a front surface of a liquid crystal panel, at least one or more point light sources disposed on at least one side surface of the light guide plate, and reflecting light from the point light source. And a reflector for guiding the light of the point light source. The illumination unit for dividing the light of the point light source by forming a reflection surface of the reflector for guiding the light of the point light source into an uneven shape is disposed on the rear or front surface of the liquid crystal display element. A liquid crystal display device characterized by the above-mentioned.