JP3016945U - LCD backlight reflection structure - Google Patents

Abstract

(57) [Summary] [Object] Regarding a reflective structure of a backlight of a liquid crystal display device, even when a top-illuminated LED is used, LC
An object of the present invention is to provide a reflective structure of a liquid crystal backlight, which can secure the amount of light applied to the D panel and can also secure a sufficient actual display area of the LCD panel. In a reflective structure of a liquid crystal backlight having a configuration in which the LCD panel 1 is uniformly illuminated from the back side by light condensed from a light source to a light guide 2 on the back side of the LCD panel 1,
The top-illuminated LED 3 is used as the light source, and the reflection film 24 is formed on the surface of the light guide 2 near the top-illuminated LED. As the surface of the light guide 2 near the light source, both upper surfaces and both side surfaces of the light guide 2 can be considered. As a result, it is possible to obtain a liquid crystal display device which has a small space and has a large actual display area.

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a reflective structure of a backlight of the liquid crystal display device.

[0002]

2. Description of the Related Art In recent years, the needs for portable transceivers have been required to be more compact and compact, and various work has been done such as elimination of extra space and circuit integration. In addition, a space-saving and efficient structure is also required for a lighting device for an LCD panel which has been conventionally used as a display device for a portable transceiver.

FIG. 4 is a central cross-sectional view showing an example of a conventional liquid crystal display device. The LCD panel 1 and the light guide 2 which will be described below are housed in the housing 10 and fixed to the printed circuit board P, and the surface of the LCD panel 1 is exposed through the opening on the upper surface of the housing 10. To form a display portion.

A light guide 2 is arranged on the back surface of the LCD panel 1, a notch 22 is provided at the center of both side surfaces of the light guide 2, and a light source protruding from the printed circuit board P is arranged in the notch 22. Be touched. An LED 30 is normally used as this light source, and light is emitted toward the center of the light guide 2 from the entire side surface in the thickness direction (side irradiation type).

A reflection film 21 is formed on the back surface of the light guide body 2, and when the side surface of the light guide body 2 is illuminated by the LED 30 as described above, light is transmitted through the light guide body 2 to the back surface of the LCD panel 1. It will be irradiated more. At this time, the light applied to the bottom surface of the light guide 2 is reflected by the reflective film 21 and guided to the back surface of the LCD panel 1.

When the side-illuminated light source is used, the light guide 2 needs to have a considerable thickness (for example, about 2 mm 2), which is against the request for space saving. Therefore, as shown in FIG. 5, the top-illuminated LED 3 may be used.

That is, the top-illuminated LEDs 3 are arranged on the bottom surface (front surface of the printed circuit board P) of the notches 22 provided on both sides of the light guide 2 so that the light from the light source faces upward, and the LCD The edge of the panel 1 is directly irradiated with light, and the center of the LCD panel 1 is guided through the light guide 2. According to this configuration, there is an effect that the light guide 2 can be made thin (for example, about 0.9 mm).

[0008]

[Problems to be solved by the device]

 However, when the above-mentioned top-illuminated LED 3 is used, the back surface of the LCD panel 1 above the top-illuminated LED 3 is directly irradiated with light from the top-illuminated LED 3, and the other parts are exposed via the light guide 2. Since the light is emitted by reflected light, the brightness of the LCD panel 1 becomes uneven when viewed from the surface.

Therefore, the width W of the front cover of the housing 10 is set to be large, and the relatively bright parts of both ends of the LCD panel 1 are covered with the covers, so that only the uniform brightness part is displayed in the display area. The configuration used as is adopted. However, this structure has a drawback that the actual display area of the LCD panel 1 is narrowed. Further, in the structure using the conventional top-illuminated LED 3, the light-guide 2 as a whole emits light from the top-illuminated LED 3. Since it does not receive light, it tends to lack the amount of light.

The present invention has been proposed in view of the above-mentioned conventional circumstances, and even when a top-illuminated LED is used, it is possible to secure the amount of light emitted to the LCD panel, and further It is an object of the present invention to provide a reflective structure of a liquid crystal backlight that can sufficiently secure an actual display area.

[0011]

[Means for Solving the Problems]

 The present invention adopts the following means to achieve the above object. That is, as shown in FIG. 1, a reflection structure of a liquid crystal backlight configured to uniformly illuminate the LCD panel 1 from the back side by the light condensed from the light source to the light guide 2 on the back side of the LCD panel 1. In the above configuration, the top-illuminated LED 3 is used as the light source, and the reflective film 24 is formed on the surface of the light guide 2 near the top-illuminated LED 3.

As the surface of the light guide 2 near the light source, the upper surface and the both side surfaces of both ends of the light guide 2 can be considered.

[0013]

[Action]

 With the above configuration, most of the light emitted from the top-illuminated LED 3 as a light source is radiated toward the back surface (or side surface) of the light guide 2, and once the upper surface (or side surface) of both ends of the light guide 2 is radiated. The light is reflected by the reflective film 24, then illuminated by the reflective film 21 on the bottom surface of the light guide 2, and then illuminated on the back surface of the LCD panel 1. At this time, since the emission angle of the top surface irradiation type LED 3 extends in all directions, the reflected light from the reflection film 21 is evenly applied to the entire area of the LCD panel 1. Further, a part of the light from the top-illuminated LED 3 is directly guided to the light guide 2 and is evenly applied to the back surface of the LCD panel 1.

[0014]

【Example】

 FIG. 1 is a central cross-sectional view of an LCD device according to an embodiment of the present invention. A light guide 2 made of a transparent synthetic resin plate or the like is arranged on the back surface of the LCD panel 1, and a reflection film 21 is formed on the back surface of the light guide 2 by vapor deposition of aluminum or application of white paint. A notch 22 is provided at the center of both sides of the light guide 2.

On the other hand, on the printed circuit board P corresponding to the cutout portion 22, an LED serving as a light source is provided so that the light from the LED directly illuminates the rear surface of the end portion of the LCD panel 1, that is, the top-illuminated LED 3 Is placed as. Further, the LCD panel 1 and the light guide 2 arranged as described above are mounted on the printed circuit board P by the housing 10.

The shape of the notch 22 is, for example, as shown in FIG. 2, a shape in which a central portion of both ends of the light guide 2 is cut in a U shape over the thickness direction, or as shown in FIG. A shape in which the center bottom of both ends of the light guide body 2 is engraved with a predetermined depth can be considered.

A reflective film 24 is formed on the end of the light guide 2 provided with the cutout 22. In the embodiment shown in FIG. 2, the reflection film 24 is made of, for example, aluminum vapor-deposited or white-coated synthetic resin sheet on the entire upper surface and side surface of the end portion of the light guide 2, and It is attached so as to cover the U-shaped notch 22. In the embodiment shown in FIG. 3, for example, aluminum vapor deposition is directly applied to the upper surface and side surface of the end of the light guide 2, or white coating is applied directly to the upper surface and side surface of the light guide 2. .

As a result, most of the light emitted from the top-illuminated LED 3 is first reflected by the reflection film 24 and further reflected by the reflection film 21 on the lower surface of the light guide body 2 so that the back surface of the LCD panel 1 is covered. And a part of it is directly irradiated to the back surface of the LCD panel 1 through the light guide 2. At this time, since the emission angle of the top-illuminated LED 3 extends in all directions, the reflected light from the reflective film 21 is evenly applied to the entire area of the LCD panel 1.

Therefore, the light from the top-illuminated LED 3 reaches the center of the LCD panel 1 to the full, and it is possible to display without any difference in brightness and contrast, and the area of the display part of the LCD panel 1 can be effectively used. It becomes possible to use.

[0020]

[Effect of device]

 As described above, according to the present invention, the light guide and the vicinity of the light source are sealed with the reflection film. Therefore, even if a top-illuminated light source is used, the light from the light source is emitted from the edge of the LCD panel. It has the effect of reaching the center sufficiently and forming a uniformly bright screen.

[Brief description of drawings]

FIG. 1 is a central cross-sectional view of the present invention.

FIG. 2 is a partially enlarged perspective view of the present invention.

FIG. 3 is a partially enlarged perspective view of the present invention.

FIG. 4 is a sectional view of an LCD panel using a side-illuminated LED.

FIG. 5 is a sectional view of an LCD panel using a top-illuminated LED.

[Explanation of symbols]

 1 LCD panel 2 Light guide 24 Reflective film

Claims (2)

[Scope of utility model registration request] 1. In a reflective structure of a liquid crystal backlight, which is configured to uniformly illuminate the LCD panel from the back side with light condensed from a light source on a light guide body on the back side of the LCD panel, a top-illuminated LED is used as the light source. , The top irradiation type LE
A reflective structure for a liquid crystal backlight, characterized in that a reflective film is formed on the surface of the light guide near D. 2. The reflective structure for a liquid crystal backlight according to claim 1, wherein surfaces of the light guide near the light source are upper surfaces and both side surfaces of both ends of the light guide.