KR100879948B1 - Edge type backlight unit of using micro rectangular lens pattern - Google Patents

Abstract

The present invention discloses a side dimming backlight device in which a micro square lens pattern (MICRO RECTANGULAR LENS PATTERN) is formed on a lower surface of a light guide plate to improve brightness and screen quality. The apparatus of the present invention includes a light source, a light guide plate which is located on the side of the light source and converts the light incident from the light source into a surface light source and exits upward, and is located below the light guide plate and is incident to the rear of the light guide plate. In the side-illumination type backlight device comprising a reflector plate for reflecting the forward light to the front and a prism sheet positioned on the exit surface of the light guide plate, the micro-rectangle lens pattern on the lower surface of the light guide plate half the incident surface from which the line light source is incident Randomly embossed or engraved and arranged at different densities in the incident plane direction. Therefore, in the present invention, the diffused light is uniformly radiated to the image side, so that the diffusion sheet is unnecessary, and the interference fringe generation can be suppressed by randomizing the arrangement of the micro square lens patterns. In addition, the present invention can improve the screen quality than the screen using scattering by using total reflection and refraction rather than scattering.

Backlight, Light Guide Plate, Micro Rectangular Lens Pattern, Prism Pattern

Description

Side dimming backlight unit using micro square lens pattern {EDGE TYPE BACKLIGHT UNIT OF USING MICRO RECTANGULAR LENS PATTERN}

1 is a cross-sectional view showing the overall structure of a side-illuminated backlight according to the prior art,

Figure 2 is a cross-sectional view showing a light guide plate according to the prior art,

Figure 3a is a perspective view showing the lower surface of the light guide plate of the side-illuminated backlight according to the present invention,

3B is a plan view of the light guide plate lower surface pattern shown in FIG. 3A;

3C is a side view of the light guide plate lower surface pattern shown in FIG. 3A;

FIG. 3D is a view for explaining the lower surface pattern of the light guide plate shown in FIG. 3A;

Figure 4a is a perspective view showing the upper surface of the light guide plate of the side-illuminated backlight device according to the present invention,

4B is a view for explaining the pattern of the upper surface of the light guide plate shown in FIG. 4A;

FIG. 4C is a diagram illustrating various pattern examples of the upper surface of the LGP shown in FIG. 4A;

5 is a view showing a light path by the lower pattern of the light guide plate according to the present invention;

6 is a view showing a light path by the lower and upper patterns of the light guide plate according to the present invention;

7 is a graph illustrating a comparison of left and right viewing angles of a light guide plate (LGP) according to a pattern of a lower surface;

FIG. 8 is a graph illustrating a comparison between upper and lower viewing angles of light guide plates (LGPs) according to patterns of a lower surface.

** Explanation of symbols for main parts of drawings **

1: reflector 2,20: light guide plate

3: diffuser plate 4: prism sheet

5: protective sheet 6: light source

7: light source reflector 20d: light guide plate lower surface

20u: upper surface of the light guide plate 20i: incident surface

20r: Carousel 22: Micro Rectangular Lens Pattern

24: Prism pattern

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit, and more particularly, to a side dimming backlight device in which a micro square lens pattern (MICRO RECTANGULAR LENS PATTERN) is formed on a lower surface of a light guide plate to improve brightness and screen quality. .

In general, a backlight device of a liquid crystal display is a cylindrical light source such as a Cold Cathode Fluorescent Lamp (CCFL), a Hot Cathode Fluorescent Lamp (HCFL), an External Electrode Fluorescent Lamp (EEFL), or a Light Emitting Diode (LED). Devices, EL (Electro Luminescence) devices, etc. are mainly used, and are classified into side-lighting and direct-lighting backlight devices according to the manner in which the light sources are arranged. In general, side dimming backlight devices are mainly used in LCDs for notebooks or computer monitors because of their relatively thin thickness, and direct dimming backlight devices are mainly used in LCDs for large screens such as TVs due to high light efficiency.

In the conventional side-illuminated backlight device, as shown in FIG. 1, the fluorescent lamp 6, which is a linear light source, is positioned on the side of the light guide plate 2 that scatters the light of the linear light source and converts the light into a surface light source, and the fluorescent lamp 6 is It is enclosed with the lamp reflector 7 so that the light emitted from the fluorescent lamp 6 is directly or reflected by the lamp reflector 7 to be incident on the light guide plate 2. A reflecting plate 1 is positioned below the light guide plate 2, and a diffusion sheet 3 for scattering light emitted from the light guide plate 2 to equalize luminance by refraction of the light guide plate 2 and refracting the diffused light. Various sheets, such as the prism sheet 4 and the protective sheet 5, which condense and improve brightness, are located. The prism sheet 4 is divided into a vertical prism sheet 4-1 and a horizontal prism sheet 4-2, and the two prism sheets 4 overlap each other.

In the side-illumination type backlight device having such a structure, light emitted from the fluorescent lamp 6 is incident on the side incident surface of the light guide plate 2, and the light guide plate 2 scatters and equalizes the light of the fluorescent lamp received as a linear light source. The reflection plate 1 reflects the light from the light guide plate 2 downward to the upper side of the light guide plate 2 to increase the light efficiency. The diffusion sheet 3 located above the light guide plate 2 scatters the light emitted from the light guide plate 2 to improve brightness and appearance, and the prism sheet 4 refracts and condenses the diffused light to improve brightness. Let's do it.

However, in the conventional side-illuminated backlight device, as shown in FIG. 2, light is scattered due to an etching or printed pattern formed on the lower surface of the light guide plate 2 and emitted to the upper side of the light guide plate, so that the light collecting effect is increased. There is a problem of deterioration. That is, in the conventional light guide plate 2, as shown in FIG. 2, the emission directing angle is significantly laid out in the normal direction, and is emitted in a wide spread form, so that the light collecting effect in the normal direction is lowered on the upper prism sheet, and the large-sized etching on the lower side is performed. There is a problem that a diffusion sheet is required as a pattern. Referring to FIG. 2, it can be seen that the vertical angle θ _V1 of the light beam by the etching pattern is about 55 ° with respect to the normal line, and the horizontal angle θ _H1 is largely scattered by about 55 °.

The present invention has been proposed to solve the above problems, and an object of the present invention is to form a micro rectangular lens pattern (MRL) on the lower surface of the light guide plate rather than an etching or a print pattern, so that brightness and screen It is to provide a side light type backlight device with improved quality.

The present invention for solving the above problems, a line light source, a light guide plate which is located on the side of the line light source and converts the light incident from the line light source to the surface light source and exits to the upper side, and located below the light guide plate In the side-illumination type backlight device including a reflecting plate for reflecting the light incident to the rear of the light guide plate forward, and a prism sheet located on the exit surface of the light guide plate,

On the lower surface of the light guide plate, a micro-rectangle lens pattern is formed and arranged in a randomly embossed or intaglio direction by varying the density from the incident surface to which the line light source is incident to the semi-incident surface direction, thereby improving the brightness and screen quality. It is done.

The upper surface of the light guide plate may be any one of a general prism pattern, a prism pattern having curvature only on a mountain, a discontinuous intaglio prism pattern, a discontinuous embossed prism pattern, a discontinuous embossed prism pattern having a curvature formed on a mountain, or a discontinuous embossed prism pattern having a flat acid. The prism pattern is formed in an embossed or intaglio to condense light emitted from the lower side by the micro-rectangle lens pattern to be further concentrated.

In addition, the micro-rectangle lens pattern has a horizontal (H) and vertical (V) of the size of 20㎛ to 100㎛, the depth (or height) (D) is 1/4 (H / 4) of the horizontal size, the curvature Radius R has a size of 1/4 to 1/2 of the horizontal size, the prism pattern, the angle of the angle (θ _T ) or the angle of the valley (θ _B ) of the prism pattern is 120 ° to 160 °, The width W is 10 µm to 60 µm, and the curvatures R _T and R _B of the peaks or valleys of the prism are 1/2 or less of the width.

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

Figure 3a is a perspective view showing a lower surface of the light guide plate of the side-illuminated backlight according to the present invention, Figure 3b is a plan view of the light guide plate lower surface pattern shown in Figure 3a, Figure 3c is a side view of the light guide plate lower surface pattern shown in Figure 3a, Figure 3d FIG. 3A is a diagram for describing a lower surface pattern of the light guide plate illustrated in FIG. 3A.

As shown in FIGS. 3A to 3D, the micro-rectangle lens pattern (MRL) 22 has a density from the incident surface 20i toward the incident surface 20r on the lower surface 20d of the side-illuminated backlight according to the present invention. In addition, it is arranged randomly to improve the brightness and screen quality of the backlight unit.

3A to 3D, the micro-rectangle lens patterns 22 are randomly arranged at a small density near the incident surface 20i, and are gradually arranged at a denser density toward the incident surface 20r so that the side light source ( Even if the luminance decreases as the distance from 6) increases, uniform light can be emitted to the upper surface 20u. In addition, the light guide plate 20 according to the present invention can suppress the interference pattern generated by the regular pattern because the micro rectangular lens pattern 22 is randomly arranged, the micro rectangular lens pattern 22 is the lower surface (20d) of the light guide plate Can be embossed or embossed concave, and the planar size of the micro-rectangle lens pattern 22 has a horizontal (H) and vertical (V) of 20 μm ≦ H or V ≦ 100 μm. , The depth (or height) D is 1/4 (H / 4) of the horizontal size, and the radius of curvature R has a size of H / 4≤R≤H / 2.

FIG. 4A is a perspective view illustrating an upper surface of a light guide plate of the side-illuminated backlight device according to the present invention. FIG. 4B is a view for explaining a pattern of the upper surface of the light guide plate shown in FIG. 4A, and FIG. 4C shows various views of the upper surface of the light guide plate shown in FIG. 4A. It is a figure which shows a pattern example.

As shown in FIG. 4A, a prism pattern 24 is uniformly formed on the light guide plate 20u of the side-illuminated backlight device according to the present invention, perpendicular to the incidence surface 20i, so that the bottom surface of the light guide plate 20u is formed on the micro-rectangle lens pattern 22 from the lower side. The light emitted upward is further focused.

Referring to FIGS. 4A to 4B, the prism pattern 24 is continuously arranged in an embossed or intaglio pattern on the upper surface 20u of the light guide plate, and the angle of the peak (θ _T ) or the angle of the bone (θ _B ) of the prism pattern is arranged. Is 120 ° to 160 °, the width W is 10 µm to 60 µm, and the curvature R _T and R _B of the peak or valley of the prism is 1/2 or less of the width W.

The shape of the prism pattern 24 can be modified in a wide variety of shapes, as shown in FIG. 4C. (A) is an example of a general prism pattern, and (B) is a shape of a prism pattern having only a curvature in a mountain. (C) is an example of a discontinuous embossed prism pattern, (d) is an example of a discontinuous embossed prism pattern, (e) is an example of a discontinuous embossed prism pattern with curvature formed on the mountain, and (b) is an acid An example of a flat discrete embossed prism pattern.

5 is a view showing a light path by the lower pattern of the light guide plate according to the present invention, Figure 6 is a view showing a light path by the lower and upper pattern of the light guide plate according to the present invention.

As described above, in the structure in which the micro rectangular lens pattern 22 is formed on the bottom surface 20d of the light guide plate according to the present invention, the path of the light incident from the light source 6 on the side surface is shown in FIG. 5. It can be seen that the vertical angle θ _V2 of the light beam reflected by and reflected upwards is approximately 44 ° with respect to the normal and the horizontal angle θ _H2 is also approximately 44 °.

In addition, according to the present invention, in the structure in which the micro-rectangle lens pattern is formed on the lower surface of the light guide plate and the prism pattern is formed in the upper surface, the path of the light incident from the light source 6 on the side surface is shown in FIG. 6. 22) the vertical angle θ _V3 of the light beam reflected by the light toward the upper side and exiting through the upper prism pattern 24 is about 46 ° with respect to the normal, and the horizontal angle θ _H3 is also about 20 °. It is understood that it is degree.

FIG. 7 is a graph illustrating a left and right viewing angle of the LGP according to the lower surface pattern, and FIG. 8 is a graph showing the upper and lower viewing angles of the LGP according to the lower surface pattern.

Referring to FIG. 7, the K1 graph is a graph showing left and right viewing angle characteristics of a light guide plate (LGP) of a pattern according to a conventional etching, and K2 is a case where the micro-rectangle lens pattern 22 is formed on the bottom surface 20d of the light guide plate according to the present invention. Is a graph showing the LGP left and right viewing angle characteristics, and K3 is the LGP in the case where the micro rectangular lens pattern 22 is formed on the lower surface 20d of the light guide plate and the prism pattern 24 is formed on the upper surface 20u of the light guide plate according to the present invention. A graph showing left and right viewing angle characteristics.

Referring to FIG. 8, the G1 graph is a graph showing the LGP upper and lower viewing angle characteristics of the pattern according to the conventional etching, and G2 is the upper and lower LGP when the micro-rectangle lens pattern 22 is formed on the lower surface 20d of the light guide plate according to the present invention. G3 is a graph showing viewing angle characteristics, and G3 shows the upper and lower viewing angle characteristics of LGP when the micro-rectangle lens pattern 22 is formed on the lower surface 20d of the light guide plate and the prism pattern 24 is formed on the upper surface 20u of the light guide plate according to the present invention. It is a graph.

According to the graph characteristic shown, it can be seen that the viewing angle characteristic of the light guide plate on which the patterns 22 and 24 according to the present invention are formed is improved than the viewing angle characteristic of the light guide plate according to the conventional etching pattern.

Although the present invention has been described in detail through specific embodiments, the present invention is not limited to the above-described embodiments, and various changes may be made by those skilled in the art to which the present invention pertains without departing from the spirit and scope of the present invention. It may be changed and implemented.

As described above, in the present invention, by applying a fine micro square lens pattern to the lower side of the light guide plate, the light is uniformly diffused to the upper side, thereby eliminating the need for a diffusion sheet, and randomly arranging the micro square lens patterns. It can suppress occurrence. In addition, the present invention can improve the screen quality than the screen using the scattering by using total reflection and refraction rather than scattering, and by first condensing the first focused light in the lower micro rectangular lens pattern from the upper prism pattern to the left and right again Dual brightness can be improved.

Claims (4)

A light guide plate positioned at a side of the light source and converting light incident from the line light source into a surface light source and exiting upward; a light guide plate positioned below the light guide plate to the rear of the light guide plate to the front In the side-illumination type backlight device comprising a reflecting plate for reflecting, and a prism sheet positioned on the exit surface of the light guide plate, The lower surface of the light guide plate The horizontal (H) and the vertical (V) have a size of 20 μm to 100 μm, the depth (or height) D is 1/4 (H / 4) of the horizontal size, and the radius of curvature R is the horizontal size. The micro square lens patterns having a size of 1/4 to 1/2 of are randomly embossed or engraved with different densities in the direction of the incidence plane from the plane of incidence from which the line light source is incident. On the upper surface of the light guide plate The prism pattern of any one of the prism pattern or the prism pattern having curvature only on the mountain, the discontinuous intaglio prism pattern, the discontinuous embossed prism pattern, the discontinuous embossed prism pattern having the curvature formed on the mountain, or the discontinuous embossed prism pattern having the flat surface is the incident surface. In addition to being formed perpendicular to the prism pattern has a peak angle (θ _T ) or valley angle (θ _B ) of 120 ° to 160 °, the width (W) is 10㎛ to 60㎛, the peak or valley of the prism The curvature of R _T , R _B becomes 1/4 to 1/2 of the width, and the light is condensed from the lower side by the micro-rectangle lens pattern and further condenses the light emitted to the upper side. Side dimming backlight device, characterized in that to improve the brightness and screen quality. delete delete delete

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