KR100454824B1 - The back light for LCD - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight for an LCD, and more particularly, to a backlight for an LCD that maintains uniformity of brightness by disposing a fluorescent lamp in a light guide plate and a diffuser plate in a direct or edge shape.

In order to achieve the above object, the present invention is a reflection plate including a projection, a flat portion formed horizontally on both ends of the projection, a groove disposed on the reflecting plate, the groove and the flat surface disposed corresponding to the projection A light guide plate having a second planar portion disposed corresponding to the portions; a diffuser plate disposed on the light guide plate and uniformly distributing light passing through the light guide plate; a fluorescent lamp disposed above the protrusion of the reflecting plate; It is disposed on the diffusion plate, characterized in that it comprises a protective sheet to prevent the external impact of the backlight.

According to the present invention having the above-described configuration, by placing a fluorescent lamp inside the light guide plate (or diffuser plate) to minimize the loss of the amount of light has the advantage of reducing the increase in brightness and the external impact applied to the backlight.

Description

Backlight for LCD {The back light for LCD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight for an LCD, and more particularly, to a backlight for an LCD that maintains uniformity of brightness by disposing a fluorescent lamp in a light guide plate and a diffuser plate in a direct or edge shape.

The present invention is a supplementary application of Patent Application No. 1999-0053193 entitled "Fluorescent Lamp Flat Panel LCD Backlighter" and Patent Application No. 2001-0011486 entitled "Integrated Backlight with Light Guide Panel".

Generally, backlight for LCD is divided into edge type backlight and direct type backlight. Edge type backlight is placed at the edge of the light guide plate, and the fluorescent lamp is placed on the edge of the light guide plate to transmit the light of the fluorescent lamp to the edge of the light guide plate. .

On the other hand, the direct type backlight is arranged in a plurality of fluorescent lamps on the reflecting plate at a predetermined interval as disclosed in Patent Application No. 2001-0011486 (hereinafter referred to as' 11486) to direct the light of the fluorescent lamp directly directed to the diffusion plate of the top plate In this way, the technical focus is placed on the uniformity of brightness over the entire panel and the thinning of the panel.

The present invention has been made to solve the above problems, an object of the present invention is to place a fluorescent lamp inside the light guide plate (or diffuser plate) to increase the brightness and reduce the external impact applied to the backlight backlight To provide.

Another object of the present invention is to provide a backlight for an LCD that can maintain uniformity in brightness by printing a specific pattern on the light guide plate and the diffusion plate.

Still another object of the present invention is to provide a backlight for an LCD that can minimize light loss by eliminating light scattering at the light guide plate interface by injecting fluid between the fluorescent lamp and the fluorescent lamp insertion hole.

Still another object of the present invention is to provide a thin LCD backlight by removing the empty space between the light guide plate and the diffusion plate.

1A is a cross-sectional view of an LCD backlight according to a first embodiment of the present invention.

Figure 1 (b) is an exploded perspective view of the LCD backlight according to the first embodiment of the present invention.

2 is a cross-sectional view of a direct type backlight according to a second embodiment of an LCD backlight according to the present invention;

3 is a cross-sectional view of a direct type backlight according to a third embodiment of an LCD backlight according to the present invention;

4 is a sectional view of an edge type backlight according to a fourth embodiment of an LCD backlight according to the present invention;

5 is a cross-sectional view of an edge type backlight according to a fifth embodiment of an LCD backlight according to the present invention;

6 is a conceptual view of a direct type and an edge type backlight in the form of a liquid injection between the fluorescent lamp and the fluorescent lamp insertion opening according to the present invention.

7 is a view showing the results of experiments when and when the liquid is injected between the fluorescent lamp and the fluorescent lamp insertion opening according to the present invention.

<Description of the symbols for the main parts of the drawings>

10 fluorescent lamp 20 reflector

30: light guide plate 40: diffuser plate

50: protective sheet 60: edge reflective layer

70 fluid 16 fluorescent lamp insertion hole

22: protrusion part 24: flat part

32: groove 34: second flat portion

121, 122, 123: printing pattern 72: air layer

In order to achieve the above object, the present invention is a reflection plate including a projection, a flat portion formed horizontally on both ends of the projection, a groove disposed on the reflecting plate, the groove and the flat surface disposed corresponding to the projection A light guide plate having a second planar portion disposed corresponding to the portions; a diffuser plate disposed on the light guide plate and uniformly distributing light passing through the light guide plate; a fluorescent lamp disposed above the protrusion of the reflective plate; And a protective sheet disposed on the upper plate and protecting the backlight surface.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 (a) is a cross-sectional view of the LCD backlight according to the first embodiment of the present invention, a direct type backlight.

As shown, the backlight is composed of a reflector 20, a light guide 30, a diffuser 40, and a protective sheet 50.

The reflector plate 20 is formed of a protrusion part 22 and a flat part 24 formed horizontally at both ends of the protrusion part 22. An inclined surface having a predetermined angle is formed at the end of the planar portion 24 to improve the reflectance. In addition, the fluorescent lamp 10 is disposed on the protrusion 22 of the reflecting plate 20. Here, the fluorescent lamp 10 may be a cold cathode fluorescent lamp or an external cathode fluorescent lamp, which is disclosed in Patent Application No. 2000-0083512.

The light guide plate 30 is provided on the reflective plate 20, and the light guide plate 30 is provided with a groove 32 and a second planar portion 34 at predetermined intervals on a lower surface thereof. Here, the groove 32 is disposed to correspond to the protrusion 22 of the reflective plate 20, and the second planar portion 34 is disposed to correspond to the plane portion 24 of the reflective layer 20.

The diffusion plate 40 is disposed above the light guide plate 30 and serves to uniformly distribute the light passing through the light guide plate 30. The protective sheet 50 is disposed above the diffusion plate 40 and serves to protect the backlight surface. Here, the diffusion plate 40 and the protective sheet 50 is a flat plate.

In particular, unlike the air layer formed between the light guide plate and the diffusion plate of the '11486, the present invention can be implemented because the light guide plate 30 and the diffusion plate 40 are closely arranged so that no air layer is formed to implement a thin LCD backlight.

The light directed from the fluorescent lamp 10 to the top passes through the light guide plate 30 and then diffuses by the diffuser plate 40, and the light directed from the fluorescent lamp 10 toward the bottom is reflected by the reflector 20. The light is directed to the top.

Figure 1 (b) is an exploded perspective view of the LCD backlight according to the first embodiment of the present invention, a direct type backlight. As described with reference to FIG. 1A, the reflective plate 20, the light guide plate 30, the diffusion plate 40, and the protective sheet 50 are formed. The light guide plate 30 and the diffuser plate 40 are made of polymethyl methacrylate (PMMA). In general, the light guide plate 300 employs a transparent PMMA, and the diffuser plate 40 is a diffuser PMMA. To employ.

Reflective paints are printed on the upper surface of the light guide plate 30 above the fluorescent lamp 10 and the lower surface of the light guide plate 30 with constant patterns 121 and 122, and also on the lower surface of the diffuser plate 40 with the reflective paint. It is printed with the pattern 123.

The printed patterns 121, 122, and 123 serve to attenuate the light on the top of the fluorescent lamp 10 and to disperse the light from side to side to make the luminance uniform. In addition, the printing material uses a white paint with good reflectivity, and the pattern of the pattern is a fine dot or a pattern such as linear. The patterns 121, 122, and 123 densify the central portion of the upper end of the fluorescent lamp 10, and decrease the density toward the left and right, densely away from the fluorescent lamp 10 on the inclined surface 113 at the bottom of the light guide plate, The portion close to the fluorescent lamp 10 weakens the density.

2 is a cross-sectional view of a direct type backlight according to a second embodiment of an LCD backlight according to the present invention.

FIG. 2A illustrates a flat plate-shaped structure, which includes a protrusion 22, a flat portion 24 horizontally formed at both ends of the protrusion 22, and a reflection plate 20. The light guide plate 30 having an upper portion and a groove 32 corresponding to the protrusion 22 of the reflective plate 20 and a second flat portion 34 disposed corresponding to the flat portion 24. And a diffuser plate 40 disposed above the light guide plate 30 to uniformly distribute the light passing through the light guide plate 30, and a fluorescent lamp disposed above the protrusion 22 of the reflective plate 20. 10 and the diffusion plate 40, the protective sheet 50 to prevent the external impact of the backlight is formed.

FIG. 2B has the same shape as that of FIG. 1A, and the groove 32 formed in the light guide plate 30 may be formed on the light guide plate 30.

FIG. 2 (c) shows a reflecting plate 20 including a protrusion 22, a flat portion 24 horizontally formed at both ends of the protrusion 22, and an inclined portion having a predetermined angle of inclination from the flat portion 24. ) And a groove 32 disposed above the reflector 20, a groove 32 disposed corresponding to the protrusion 22 of the reflector 20, and a second planar portion 24 corresponding to the plane 24. A diffusion plate 40 having a 34, a fluorescent lamp 10 disposed between the protrusion 22 of the reflecting plate 20 and the groove 32 of the diffusion plate 40, and the diffusion plate 40. It is disposed on the top, and formed of a protective sheet 50 to prevent the external impact of the backlight. Here, the light guide plate 30 is not used, but only the diffusion plate 40 is used.

3 is a cross-sectional view of a direct type backlight according to a third embodiment of an LCD backlight according to the present invention.

3 (a) shows a fluorescent lamp 10 that emits light by discharge of an electrode, a reflecting plate 20, and a fluorescent lamp 10 disposed above the reflecting plate 20, into which the fluorescent lamp 10 is inserted. A light guide plate 30 including an insertion hole 16, a diffuser plate 40 disposed above the light guide plate 30 to uniformly distribute light passing through the light guide plate 30, and the diffusion plate 40. It is disposed on the top, and consists of a protective sheet 50 to prevent the external impact of the backlight. Here, fluid may be injected between the fluorescent lamp 10 and the fluorescent lamp insertion hole 16 to prevent light scattering.

3 (b) has the same structure as that of FIG. 1 (a) except that the light guide plate 30 further includes a fluorescent lamp insertion hole 16, and thus a detailed description thereof will be omitted.

3 (c) has the same structure as that of FIG. 2 (c) except that the fluorescent plate insertion hole 16 is further included in the diffusion plate 40, and thus a detailed description thereof will be omitted.

4 is a cross-sectional view of the edge type backlight according to the fourth embodiment of the LCD backlight according to the present invention.

FIG. 4A shows a second lamp having a fluorescent lamp 10 emitting light by discharge of an electrode, a first light guide part 30a, and a fluorescent lamp insertion hole 16 into which the fluorescent lamp 10 is inserted. The light guide plate 30 including the light guide portion 30b and the edge reflective layer 60 disposed on the outer circumferential surface of the second light guide portion are formed.

4 (b) shows the shape separated into the first light guide portion and the second light guide portion, and FIG. 4 (c) shows that the second light guide portion 30b has the fluorescent lamp insertion hole 16 in the edge reflecting layer 60. The shape of the third light guide portion 30b cut to and detachably coupled thereto is shown. 4 (d) is a shape in which the third light guide portion 30b is separated into a V shape.

In the present invention, by placing the fluorescent lamp 10 inside the light guide plate, all of the light of the fluorescent lamp 10 propagated to the light guide plate 30, thereby achieving a luminance increase effect of 20% or more than the conventional edge type. Here, the lower surface of the first light guide portion 30a is tapered.

5 is a cross-sectional view of an edge type backlight according to a fifth embodiment of an LCD backlight according to the present invention.

5 (a) to 5 (d) are FIGS. 4 (a) to 5 except that the lower surface of the light guide portion 30a is formed in a flat plate shape and has a predetermined number of fluorescent lamps 10 and 10a. Since it is the same shape as 4 (d), detailed description is omitted.

6 is a conceptual diagram of a direct type and an edge type backlight in which a liquid is injected between a fluorescent lamp and a fluorescent lamp insertion hole according to the present invention.

In order to prevent light scattering, a fluid is injected between the fluorescent lamp 10 and the fluorescent lamp insertion hole 16, and both ends of the fluorescent lamp insertion hole 16 are sealed using a bonding material for acrylic bonding. Here, it is preferable to use water, oil, transparent liquid silicone, transparent liquid chromium, or the like having the same refractive index as that of the light guide plate (about 1.5).

FIG. 6 (a) shows an edge type backlight and FIG. 6 (b) shows a fluid injection into a direct backlight.

7 is a view showing the results of experiments when and when the liquid is injected between the fluorescent lamp and the fluorescent lamp insertion opening according to the present invention.

FIG. 7 (a) is a diagram showing scattering due to diffuse reflection of light by the air layer 72 at the fluorescent lamp insertion hole, and FIG. 7 (b) is a diagram showing the propagation of light when the fluid is injected. In the present invention, water was injected into the fluorescent lamp insertion hole 16 and both ends of the fluorescent lamp insertion hole 16 were sealed.

Although the present invention has been described in detail above, those of ordinary skill in the art to which the present invention pertains may variously modify the present invention without departing from the spirit and scope of the present invention as defined in the appended claims. It is apparent that the present invention may be modified or modified. Therefore, a simple change according to an embodiment of the present invention will not be possible without departing from the technology of the present invention.

According to the present invention having the above-described configuration, by placing a fluorescent lamp inside the light guide plate (or diffuser plate) to minimize the loss of the amount of light has the advantage of reducing the increase in brightness and the external impact applied to the backlight.

In addition, there is an advantage that the uniformity of the brightness can be maintained by printing a specific pattern using a white paint having good reflectivity on the light guide plate and the diffusion plate.

In addition, by injecting a fluid between the fluorescent lamp and the fluorescent lamp insertion hole there is an advantage that can minimize the amount of light loss by removing the scattering of light at the light guide plate interface.

In addition, by removing the empty space between the light guide plate and the diffuser plate can implement a thin LCD backlight, there is an advantage that can increase the brightness by minimizing the loss of light.

Claims (18)

delete delete delete delete delete delete delete delete delete delete delete delete delete A fluorescent lamp emitting light by the discharge of the electrode; A light guide plate including a first light guide part and a second light guide part including a fluorescent lamp insertion hole into which the fluorescent lamp is inserted; And An edge reflective layer disposed on one side of the second light guide part, And the first and second light guide portions are separated. 15. The backlight of claim 14, wherein the second light guide portion further comprises a third light guide portion that is cut and detachably coupled from the edge reflecting layer to the fluorescent lamp insertion opening. The backlight for the LCD of claim 15, wherein the third light guide portion has a V shape. 15. The backlight of claim 14, wherein a fluid for preventing scattering of light is injected between the fluorescent lamp and the fluorescent lamp insertion opening. 15. The backlight for an LCD according to claim 14, wherein the fluorescent lamp is plural.