KR100879949B1 - Edge type backlight unit of using micro cylindrical pattern - Google Patents

Abstract

The present invention discloses a side dimming type backlight device in which a microcylindrical pattern MCP and a micro lens pattern MLA are formed on a lower surface of a light guide plate to improve light brightness and screen quality. The present invention provides a light source, a light guide plate which is located on the side of the light source and converts the light incident from the line light source into a surface light source and exits to the upper side, and the light that is located below the light guide plate to the rear of the light guide plate In the side-illumination type backlight device comprising a reflecting plate for reflecting forward and a prism sheet positioned on the exit surface of the light guide plate, a micro cylindrical pattern (MCP) is carried on the lower surface of the light guide plate from the incident surface where the line light source is incident It is formed and arranged in an embossed or intaglio with different densities in the slope direction. The micro cylindrical pattern (MCP) has a long front shape left and right when viewed from the incident surface and is hemispherical when viewed from the side, and viewed from the front. The parallel length L _y at the time is gradually widened from the incident surface to the incident surface.

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

Description

Side illuminated type backlight unit using micro cylindrical pattern {EDGE TYPE BACKLIGHT UNIT OF USING MICRO CYLINDRICAL 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,

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

4 is a front and side view of the light guide plate cylindrical pattern shown in FIG.

5 is a view of a light guide plate lower surface micro lens pattern shown in FIG. 3;

6 is a light distribution plate vertical pattern application distribution chart according to the present invention,

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

FIG. 8 is a graph illustrating a comparison of left and right viewing angles of a light guide plate LGP according to a pattern of a bottom surface thereof;

9 is a graph illustrating a comparison of upper and lower viewing angles of the light guide plate (LGP) according to the lower surface pattern.

** 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: inclined plane 22: micro cylindrical pattern

24: micro lens pattern

The present invention relates to a backlight unit, and more particularly, a microcylindrical pattern (MICRO CYLINDRICAL PATTERN: MCP) and a micro lens pattern (MLA) are formed on a lower surface of the light guide plate to improve light brightness and screen quality. It relates to a dimming backlight device.

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). ) And EL (Electro Luminescence) devices are mainly used, and are classified into edge-lighting and direct-lighting backlight devices according to the way 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, an object of the present invention is to form a micro-cylindrical pattern (MCP) and a micro lens pattern (MLA), not the etching or print pattern on the lower surface of the light guide plate It is to provide a side-illuminated backlight device with improved brightness and screen 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-cylindrical pattern (MCP) is formed and arranged in an embossed or intaglio direction with different densities in the direction of incidence from the incident surface to which the line light source is incident, so as to improve the brightness and screen quality. do.

The micro-cylindrical pattern (MCP) has a long front shape left and right when viewed from the incident surface and is hemispherical when viewed from the side, and the parallel length (L _y ) when viewed from the front is increased from the incident surface to the incident surface. L _y = L ₁ + [x ₁ × (y _i × S)] + [x ₂ × (y _i × S) ² ] + [x ₃ × (y _i × S) ³ ] (where L ₁ is 0.01㎛≤L ₁ ≤0.06㎛ parallel as an initial length in the vicinity of the entrance surface of the cylindrical micro-pattern (MCP) (L _1), the scale (S) factor S≤ ± 0.005, and each coefficient (X _1, X ₂ , X ₃ ) is gradually widened according to X ₁ ≤ ± 0.05, X ₂ ≤ ± 0.01, X ₃ ≤ ± 0.005), the height (H ₁ ) of the micro-cylindrical pattern (MCP) is 2㎛≤ H ₁ ≦ ₂₀ μm, and the radius of curvature R ₁ is ₅ μm ≦ R ₁ ≦ ₃₀ μm.

On the lower surface of the light guide plate, the micro-curve has a radius of curvature R _{2 of 5} μm ≦ R ₂ ≦ ₃₀ μm and a height H _{2 of 2} μm ≦ H ₂ ≦ ₂₀ μm between the micro cylindrical patterns MCP. A lens pattern (MLA) is additionally arranged between the micro cylindrical patterns (MCPs) at the same embossment or intaglio as the micro cylindrical patterns (MCPs) to form an interference pattern (Moire) by the micro cylindrical patterns (MCPs). To improve screen quality.

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

3 is a perspective view showing a lower surface of the light guide plate of the side-illuminated backlight according to the present invention, FIG. 4 is a front view and a side view of the lower surface of the light guide plate cylindrical pattern shown in FIG. 3, and FIG. Drawing.

As shown in FIGS. 3 to 5, a microcylindrical pattern (MCP) 22 and a microlens pattern (MLA) 24 are incident on the lower surface 20d of the side-illuminated backlight according to the present invention. It is formed and arranged in an embossed or intaglio pattern with different densities in the direction from the surface 20i to the incident surface 20r to improve the brightness and screen quality of the backlight unit BLU.

As shown in FIG. 4, the micro-cylindrical pattern (MCP) 22 has a long front-to-left shape when viewed from the entrance surface 20i and is hemispherical when viewed from the side, and parallel when viewed from the front. The length L _y is gradually widened from the incidence plane 20i to the incidence plane 20r as shown in Equation 1 below.

L _y = L ₁ + [x ₁ × (y _i × S)] + [x ₂ × (y _i × S) ² ] + [x ₃ × (y _i × S) ³ ]

In Equation 1 L ₁ is 0.01㎛≤L ₁ ≤0.06㎛ parallel as an initial length in the vicinity of the entrance surface of the cylindrical micro-pattern (MCP) (L _1), the scale (S) factor S≤ ± 0.005 and, respectively, of coefficients _{(X 1, X 2, X} 3) is _{X 1 ≤ ± 0.05, X 2} ≤ ± 0.01, X 3 ≤ ± surface incident on the condition of 0.005 (20i) structure changing the parallel length to bring surface (20r) in to be. In addition, the height H ₁ of the micro cylindrical pattern (MCP) 22 is ₂ μm ≦ H ₁ ≦ ₂₀ μm, and the radius of curvature R ₁ is ₅ μm ≦ R ₁ ≦ ₃₀ μm.

On the other hand, the lower surface 20d pattern of the light guide plate according to the present invention may be formed only with the micro-cylindrical pattern (MCP) 22 described above, but as shown in FIG. As shown in FIG. 5, the microlens pattern (C) has a curvature radius R _{2 of 5} μm ≦ R ₂ ≦ ₃₀ μm and a height H _{2 of 2} μm ≦ H ₂ ≦ ₂₀ μm. The Micro Lens Pattern (MLA) 24 is further arranged between the Micro Cylindrical Pattern (MCP) 22 by the same embossment or intaglio as the Micro Cylindrical Pattern (MCP) 22 to be formed by the Micro Cylindrical Pattern (MCP) 22. It can be configured to prevent moire and improve screen quality.

In addition, according to the present invention, the density in which the microcylindrical pattern (MCP) 22 and the micro lens pattern (MLA) 24 are arranged is low in the vicinity of the incident surface 20i, as shown in FIG. 6. The distribution increases toward the incoming entrance surface 20r.

7 is a view showing a light path by the bottom pattern of the light guide plate according to the present invention.

First, when the microlens pattern MLA is used on the lower surface of the light guide plate and the prism pattern is used on the upper surface of the light guide plate, the light condensed by the microlens pattern MLA is uniformly diffused to the upper side to be stacked on the upper side of the light guide plate LGP. One sheet of diffusion sheet may be removed in place of the diffusion sheet. The light condensed from the lower micro lens pattern MLA is once again condensed from the left and right by an upper prism. However, due to the diffusion of the lower micro lens pattern MLA, the viewing angle distribution is broadly formed. The manufacturing cost of the light guide plate LGP is increased due to the additional processing of the upper prism pattern.

In the present invention, a composite pattern of the micro cylindrical pattern (MCP) 22 and the micro lens pattern (MLA) 24 is applied to the lower surface 20d of the light guide plate so that the prism pattern is not required to be formed on the upper surface 20u of the light guide plate. It is. That is, the present invention is to improve the condensing ability than the conventional LGP by applying a fine micro-cylindrical pattern (MCP) (22) on the lower surface of the light guide plate (20P) to focus the central exit angle of the upper and lower viewing angle within 19 degrees. .

Referring to FIG. 7, in the composite pattern structure in which the microcylindrical pattern 22 and the micro lens pattern 24 are formed on the lower 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. 7. As shown in FIG. 9, the vertical angle θ _V2 of the light beam reflected by the composite patterns 22 & 24 on the lower surface and emitted upward is about 19 ° with respect to the normal line, and the horizontal angle θ _H2 is also shown. It can be seen that it is about 16 °.

FIG. 8 is a graph showing a left and right viewing angle of the LGP according to the lower surface pattern, and FIG. 9 is a graph showing the upper and lower viewing angles of the LGP according to the lower surface pattern.

Referring to FIG. 8, a K1 graph is a graph showing left and right viewing angle characteristics of a light guide plate LGP having a microlens pattern MLA formed on a lower surface of a light guide plate 20d and a prism pattern formed on an upper surface thereof, and K2 according to the present invention. It is a graph which shows the left-right viewing angle characteristic of the light guide plate (LGP) 20 in which the microcylindrical pattern 22 and the micro lens pattern (MLA) 24 were formed in the light guide plate lower surface 20d.

Referring to FIG. 9, the G1 graph is a graph showing top and bottom viewing angle characteristics of a light guide plate LGP having a microlens pattern MLA formed on a lower surface of the light guide plate 20d and a prism pattern formed on the top surface, and G2 is in accordance with the present invention. It is a graph which shows the up-down viewing angle characteristic of the light guide plate (LGP) 20 in which the microcylindrical pattern 22 and the micro lens pattern (MLA) 24 were formed in the light guide plate lower surface 20d.

According to the graph characteristics shown, it can be seen that the viewing angle characteristics of the light guide plate 20 in which the composite patterns 22 and 24 according to the present invention are improved than the viewing angle characteristics of the light guide plate according to the conventional 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, the present invention applies a micro-cylindrical pattern (MCP) to the lower side of the side-illuminated backlight LGP where the light source is located on the side, and the light incident on the incident surface and totally reflected in the incident surface is directed to the incident surface. Due to the micro-cylindrical pattern (MCP) that is parallel in the vertical direction and randomly arranged in the direction parallel to the incident surface, light is emitted uniformly upwards, and is located between the micro-cylindrical patterns (MCP). By diffusing light by the micro lens pattern (MLA) it is possible to secure a pattern technology different from the conventional, it is possible to provide a high-brightness backlight product with improved screen quality.

In particular, according to the present invention, the parallel length of the micro-cylindrical pattern (MCP) is varied from the incident surface of the light guide plate to the incident surface so that uniform light can be emitted to the upper side of the light guide plate, and the random arrangement and the micro lens pattern (MLA) By adding, it is possible to eliminate the occurrence of interference fringes due to the pattern.

Therefore, according to the present invention, even if the prism pattern is not formed on the upper surface of the light guide plate, the existing prism sheet may be partially changed to a diffusion sheet due to the improvement of the light collecting ability.

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 and a prism sheet positioned on the exit surface of the light guide plate, The lower surface of the light guide plate When viewed from the entrance face, the frontal shape is long left and right, and when viewed from the side, it is hemispherical, and the parallel length (L _y ) when viewed from the front face increases from the entrance face to the entrance face. Equation L _y = L ₁ + [x ₁ × (y _i × S)] + [x ₂ × (y _i × S) ² ] + [x ₃ × (y _i × S) ³ ] (Where, L ₁ is a 0.01㎛≤L ₁ ≤0.06㎛ parallel as an initial length in the vicinity of the entrance surface of the cylindrical micro-pattern (MCP) (L _1), the scale (S) is a factor S≤ ± 0.005, respectively, the coefficients (X ₁ , X ₂ , X ₃ ) is gradually widened according to X ₁ ≤ ± 0.05, X ₂ ≤ ± 0.01, X ₃ ≤ ± 0.005, and the height (H ₁ ) is 2㎛≤H ₁ ≤ The micro cylindrical pattern MCP having a curvature radius R _{1 of 5} μm ≦ R ₁ ≦ ₃₀ μm is embossed or engraved with different densities in the incident plane from the incident plane to which the linear light source is incident. Parallel length Ly is arranged in a direction parallel to the incident surface, A micro lens pattern having a shape of a radius of curvature R _{2 of 5} μm ≦ R ₂ ≦ ₃₀ μm and a height H _{2 of 2} μm ≦ H ₂ ≦ ₂₀ μm between the micro cylindrical patterns MCP. Pattern: MLA is arranged between the micro-cylindrical pattern (MCP) in the same embossed or intaglio with the micro-cylindrical pattern (MCP) to prevent the moire caused by the micro-cylindrical pattern (MCP) and improve the screen quality To be made Side dimming backlight device, characterized in that to improve the brightness and screen quality. delete delete delete

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