KR20100026632A - Direct type backlight module and diffuser - Google Patents

Abstract

PURPOSE: A direct type backlight module and a diffuse sheet are provided to reduce pass of an optical ray and diffuse light uniformly through a light transmitting substrate using a light transmitting fabric. CONSTITUTION: A light penetration fabric(506) is attached to the lower part of a light projecting board to reduce the penetration of the light ray. A light penetration fabric controls a density between chambers according to a location of a cool cathode(502). The density of a part corresponding to the upper of the cold cathode ray tube is highest. The density of the middle position of two cool cathode ray tubes is lowest.

Description

Direct Type Backlight Module and Diffuser}

The present invention relates to a diffusion sheet and a direct type backlight module using the diffusion sheet, and more particularly, a diffusion sheet and a diffusion sheet for uniformly scattering the light while simultaneously reducing the transmission of light using a light-transmitting fabric and a light-transmitting substrate. It relates to a direct type backlight module using a sheet.

Currently, the use of liquid crystal displays is becoming more and more common, and general liquid crystal displays use a backlight module as a light source. In this case, the backlight module is classified into an edge type and a direct type based on the immovability of the internal structure, and its application range is also different from each other. For example, the edge type is mainly used for small liquid crystal displays mainly used in notebooks, PDAs or desktop computers, but the direct type is mainly used for large liquid crystal displays such as large TVs.

The present invention is an improvement on the diffusion sheet portion in the direct type backlight module, hereinafter, the prior art of the direct type backlight module will be described in detail.

As shown in FIG. 1, the direct backlight module 10 according to the related art includes a frame 102, a reflective sheet 104, a plurality of light generators 106, a light guide plate 105, and a lower portion. The diffusion sheet 110, the prism lens 112, the upper diffusion sheet 114 and the liquid crystal panel 116. In this case, the reflection sheet 104 having a function of reflecting light rays generated by the light generator 106 is installed in the frame 102 and positioned at the bottom of the direct type backlight module 10, and the light generator 106 is provided. ) Is used as the light source of the backlight module. In addition, the light guide plate 108 for guiding and passing the light beam is installed on the reflective sheet 104 in the form of covering the light generator 106, and shields the light generator 106 on the upper surface thereof, The lower diffusion sheet 110 that serves to scatter, the prism lens 112 that concentrates light rays and raises the brightness thereon, and the upper diffusion sheet 114 that increases the shielding effect and brightness on the upper surface. And the liquid crystal panel 116 having a display function on the uppermost layer is sequentially provided.

In particular, in the structure of such a direct type backlight module, a technique of increasing light shielding effect and brightness has become a focus of research and development of the diffusion sheet.

For example, the Republic of China Patent No. 538211 describes a diffusion sheet structure having a groove 208 to enhance the light diffusion effect, as shown in FIG. That is, the direct type backlight module 20 collects the light rays emitted from the lamp 204 through the transparent sheet 202 through the reflective sheet 206 and then uniformly diffuses them. In this case, the transparent sheet 202 is provided with a plurality of grooves 208 having various shapes, and as the approach is closer, the inclined angle of the grooves 208 is made smaller so that the light rays are refracted to uniformly diffuse the light rays. To do that. However, since different light source arrangements and different molds have to be developed, not only the productivity of the diffusion sheet is low, but also the burden caused by the standardized production process is severe.

In addition, the Republic of China Patent No. 588149 describes a diffusion sheet structure in which a wave pattern is formed on the arc surface as shown in FIG. Here, the direct backlight module 30 includes a reflective sheet 302, a plurality of light sources 304, and a diffusion sheet 306. At this time, the portion corresponding to the diffusion sheet 306 and the light source 304 in a straight line is the thickest portion, the thickness thereof becomes thinner toward both sides, and the center portion of the light source 304 is formed the thinnest. The direct type backlight module 30 having such a configuration has an advantage in that a strong light beam of a portion approaching a light source can be diffused using a large amount of diffusing agent included in a thick portion. However, similar to the Republic of China Patent No. 538211, there is a problem in that a mold must be developed separately according to different light source structures.

In addition, Republic of China Patent No. M261716 describes a diffusion sheet structure having a different structure, as shown in FIG. Here, the direct type backlight module 40 includes a plurality of light sources 402, a transmissive sheet 404, and a plurality of cylindrical lenses 406 positioned above the light source 402. In this case, the interval between the cylindrical lenses 406 is formed as half (S / 2) of the interval S between two consecutive light sources 402. In addition, the refraction of the light beam is controlled using the change in curvature of the cylindrical lens 406 to uniformly diffuse the light beam. That is, since the physical phenomenon of indirectly shielding the strong light is used, there is an advantage that the light can be uniformly diffused. However, there is a problem in that the design of the curvature is not limited so that a lot of manpower is consumed as compared with the design of the wave structure or the surface structure of the groove state.

An object of the present invention is to provide a diffusion sheet having a low cost while controlling the diffusion of a light source effectively. In addition, an object of the present invention is to provide a diffusion sheet for reducing the passage of light rays and at the same time spreading the light beams uniformly, and a direct type backlight module using the diffusion sheet.

In order to achieve the above object, the diffusion sheet according to the present invention is a light-transmitting substrate for uniformly diffusing light rays, and formed of a light-transmitting fabric of at least one layer which serves to reduce the transmission of light rays formed on the bottom of the light-transmitting substrate. It is composed.

In the diffusion sheet according to the present invention, the light transmitting substrate may be made of polycarbonate (PC), polymethylmethacrylate (PMMA), polystyrene (PS), acrylonitrile butadiene styrene copolymer (Acrylonitrile) Butadiene Styrene (ABS), polyethylene terephthalate glycol (PET), glycol modified polyethylene terephthalate glycol (PETG), MS resin or glass.

In addition, in the diffusion sheet according to the present invention, the light transmitting substrate includes light diffusing particles.

In addition, in the diffusion sheet according to the present invention, the light diffusing particles are polymethyl methacrylate (PMMA), MS resin, acrylonitrile butadiene styrene copolymer (Acrylonitrile Butadiene Styrene, ABS), polystyrene (Polystyrene, PS), silicon dioxide powder (SiO ₂ ), barium hydrate powder (BaSO ₄ ), aluminum oxide powder (Al ₂ O _{3 )} , titanium oxide powder (TiO ₂ ) or a mixture thereof.

In addition, in the diffusion sheet according to the present invention, the permeable fabric is composed of polyamide fiber (Polyamide Fiber), polyester fiber (Polyester Fiber), polyethylene fiber (Polyethylene Fiber) or metal wire.

In addition, in the diffusion sheet according to the present invention, the transparent fabric is manufactured by knitting single yarn or plywood, the light-transmitting hole is formed in a triangle, a square, a circle or an oval.

On the other hand, the direct type backlight module according to the present invention comprises at least one light generator for generating light rays, a reflection sheet positioned below the light generator to reflect light rays, a light transmitting substrate for uniformly diffusing light rays, and the light transmitting substrate. A diffuser sheet positioned at a lower side of the diffuser sheet and having at least one layer of light-transmitting fabric to reduce the transmission of light rays, the diffuser sheet positioned above the light generator to diffuse the light beam, and positioned at an upper side of the diffuser sheet; And at least one layer of exit sheet for controlling the direction of the outgoing light rays.

In addition, in the direct type backlight module according to the present invention, the light generator is composed of a cold cathode tube, a light emitting diode, or an external electrode fluorescent lamp.

In addition, in the direct type backlight module according to the present invention, the light-transmitting substrate is made of polycarbonate (PC), polymethylmethacrylate (PMMA), polystyrene (PS), acrylonitrile butadiene styrene copolymer (Acrylonitrile Butadiene Styrene, ABS), polyethylene terephthalate (PET), glycol-modified polyethylene terephthalate glycol (PETG), MS resin or glass.

In addition, in the direct type backlight module according to the present invention, the light transmitting substrate includes light diffusing particles.

In addition, in the direct type backlight module according to the present invention, the light diffusing particles are polymethyl methacrylate (PMMA), MS resin, acrylonitrile butadiene styrene copolymer (Acrylonitrile Butadiene Styrene, ABS), polystyrene ( Polystyrene, PS), silicon dioxide powder (SiO ₂ ), barium hydrate powder (BaSO ₄ ), aluminum oxide powder (Al ₂ O _{3 )} , titanium oxide powder (TiO ₂ ) or a mixture thereof.

In addition, in the direct type backlight module according to the present invention, the light transmitting fabric is composed of polyamide fiber (Polyamide Fiber), polyester fiber (Polyester Fiber), polyethylene fiber (Polyethylene Fiber) or metal wire.

In addition, in the direct type backlight module according to the present invention, the light-transmitting fabric is manufactured by knitting single yarn or plywood, and the light-transmitting hole is formed in a triangular, square, circular or oval shape.

In addition, in the direct type backlight module according to the present invention, the exit sheet is composed of a prism lens, an antireflective transparent sheet, or a planar transparent sheet.

 In addition, in the direct type backlight module according to the present invention, the exit sheet is polycarbonate (PC), polymethylmethacrylate (Polymethylmethacrylate, PMMA), polystyrene (Polystyrene, PS), acrylonitrile butadiene styrene copolymer (Acrylonitrile Butadiene Styrene, ABS), polyethylene terephthalate (PET), glycol-modified polyethylene terephthalate glycol (PETG), MS resin or glass.

According to the direct backlight module and the diffusion sheet according to the present invention having the configuration as described above, there is an advantage that it is possible to provide a direct backlight module and a diffusion sheet having a low cost while effectively controlling the diffusion of the light source.

In addition, according to the direct backlight module and the diffusion sheet according to the present invention, there is an advantage that can be uniformly diffused light while reducing the passage of light.

Hereinafter, four embodiments will be described, so that the direct type backlight module and the diffusion sheet according to the present invention will be described in detail.

[First Embodiment]

As shown in FIG. 5, the direct type backlight module 50 includes a plurality of cold cathode tubes 502, a reflective sheet 504, a continuous light-transmitting fabric 506 formed by knitting polyamide fibers, and a diffusion sheet ( 508 and prism lens 510.

At this time, the interval between the yarn and the yarn of the light-transmitting fabric 506 can be adjusted according to the actual use situation, the smaller the interval is lower the light transmittance, the larger the interval is higher the light transmittance. That is, the light-transmitting fabric 506 is the density between the yarn is controlled according to the position of the cold cathode tube 502, the portion corresponding to the upper side of the cold cathode tube 502 is the highest density is formed of a high density portion, Since the density is low in the intermediate position of two consecutive cold cathode tubes 502, it is formed as a low density part. That is, as shown in Fig. 6, the spacing between the yarns gradually increases as it moves from the low density portion to the high density portion. In addition, the high-density portion of the translucent fabric 506 shields a portion of the light beam so that the light beam passing through the diffusion sheet 508 becomes uniform. In this embodiment, there is a change in density between the yarn in one direction (direction parallel to the cold cathode tube 502).

The diffusion sheet 508 is made of polycarbonate (PC), and the diffusion sheet 508 includes silicon dioxide powder (SiO ₂ ), which is a light diffusing agent for diffusing light rays. In addition, the diffusion sheet 508 is manufactured by pressing the light-transmitting fabric 506 and the polycarbonate raw material by an extrusion molding machine. In addition, the prism lens 510, which is positioned above the diffusion sheet 508 and is substantially perpendicular to the emission plane to the direction of the light emitted from the diffusion sheet 508, is made of polycarbonate. do.

The above embodiment having such a configuration can adjust the distance between the corresponding yarn and the yarn according to the different luminance requirements of the different light source products. In addition, the transparent fabric 506 can be ordered to the manufacturer of the transparent fabric according to the gap between the yarn and the yarn, there is no need to manufacture a mold separately, the cost is reduced. In addition, it is also possible to use a fabric having a fixed interval, but if necessary cut to a suitable width may be formed by compression molding on polycarbonate.

Second Embodiment

In the direct type backlight module 70 according to the present invention, the density of the continuous knitted formed transparent fabric 506 is not limited to one direction.

That is, as shown in FIG. 7, the direct type backlight module 70 includes a plurality of light emitting diodes 702, a reflective sheet 704, a light-transmitting fabric 706 continuously formed of polyester fiber, and diffusion. It consists of a sheet 708 and a plurality of anti-reflective sheet 710.

At this time, the interval between the yarn and the yarn of the light-transmitting fabric 706 can be adjusted as needed, the smaller the interval is lower the light transmittance, the larger the interval is higher the light transmittance. That is, the light transmission fabric 706 is the density between the yarn is controlled according to the position of the light emitting diode 702, the density corresponding to the upper side of the light emitting diode 702 is the highest density is formed as a high density portion In the middle portion of the two consecutive light emitting diodes 702, the density is low, and thus the low density portion is formed. That is, as shown in Fig. 8, the distance between the yarn and the yarn gradually increases as it moves from the low density portion to the high density portion. In addition, the knitting method of the warp and weft yarn of the light-transmitting fabric 706 is the same as the above-described method, and the intersection of the high-density portion in the orthogonal direction of the yarns constituting the light-transmitting fabric 706 is the position of the light emitting diode 702. Overlaps with In addition, the high density portion of the light-transmitting fabric 706 shields a part of the light beam, so that the light beam passing through the diffusion sheet 708 becomes uniform.

The diffusion sheet 708 is made of polymethyl methacrylate (PMMA), and the diffusion sheet 708 includes polystyrene (PS) particles, which are light diffusing agents for light diffusion. In this case, the light-transmitting fabric 706 and the polymethyl methacrylate raw material may be manufactured by compressing the extrusion sheet 708 to be used. In addition, a plurality of the anti-reflective transparent sheet 710 which is positioned above the diffusion sheet 708 and serves to reduce the luminance of the emitted light by shielding the light emitted from the diffusion sheet 708 is also polymethyl. It consists of methacrylate.

Third Embodiment

The direct type backlight module 90 according to the present invention may be applied to the design of a light source in which the light sources are located on different planes and the incident light intensity is different according to the design of the panel or the indicator.

That is, as shown in FIG. 9, the direct type backlight module 90 includes a plurality of external electrode fluorescent lamps 902 (located on a flat plane, and the light incident from the lamp close to the diffusion sheet is strong, and the diffusion sheet is provided. Light incident from a lamp farther away from the lamp is a weak fluorescent lamp), a reflective sheet 904, a translucent fabric 906 formed by continuous knitting of polyethylene fibers, a diffusion sheet 908, and a plurality of planar transmissive sheets 910. It consists of.

At this time, the interval between the yarn and the yarn of the light-transmitting fabric 906 can be adjusted as needed, the smaller the interval is lower the light transmittance, the larger the interval is higher the light transmittance. That is, the light transmission fabric 906 has a density between the yarn and the yarn is adjusted according to the position of the external electrode fluorescent lamp 902, the portion corresponding to the upper side of the external electrode fluorescent lamp 902 is relatively high density, The upper side of the external electrode fluorescent lamp 902, which is closest to the diffusion sheet 908, is formed to have the highest density since the density is highest, and between two consecutive external electrode fluorescent lamps 902. The located part has the lowest density, so each part is formed as a low density part. That is, as shown in FIG. 10, the gap between the yarn and the yarn increases gradually as it moves from the low density portion to the high density portion or the ultra high density portion. In addition, by shielding a portion of the light rays in the high density portion of the light-transmitting fabric 906, and the most light rays in the highest density portion, the light rays passing through the diffusion sheet 908 is uniform.

On the other hand, the diffusion sheet 908 is composed of polyethylene terephthalate glycol, the diffusion sheet 908 includes a barium sulphate powder (BaSO ₄ ) as a light diffusing agent for diffusing light. In this case, the light-transmitting fabric 906 and the polyethylene terephthalate glycol raw material may be pressed to an extrusion molding machine to manufacture the diffusion sheet 908. In addition, the plurality of planar translucent sheets 910 positioned above the diffusion sheet 908 to guide light rays emitted from the diffusion sheet 908 may be made of polymethylmethacrylate.

[Example 4]

In the direct type backlight module 110 according to the present invention, when the light source is uniform and concentrated, by directly attaching a uniform fabric to the light source, the effect of reducing the incident amount of light and making the emitted light uniform is obtained. Can be.

That is, as shown in FIG. 11, the direct type backlight module 110 includes a plurality of external electrode fluorescent lamps 1102, a reflective sheet 1104, a light-transmitting fabric 1106 formed of a continuous knitted polyethylene fiber, The diffusion sheet 1108 and a plurality of planar transmissive sheets 1110 are formed. At this time, as shown in Figure 12, the gap between the yarn and the yarn of the light-transmitting fabric 1106 is formed at a fixed interval, it can be adjusted based on the intensity of the light beam of the exit surface.

In addition, the diffusion sheet 1108 is composed of polyethylene terephthalate glycol, the diffusion sheet 1108 includes a barium sulphate powder (BaSO ₄ ) as a light diffusing agent for light diffusion. In this case, the light-transmitting fabric 1106 and the polyethylene terephthalate glycol raw material may be prepared by pressing the extrusion sheet 1108 to be used. In addition, the plurality of planar transmissive sheets 111 positioned above the diffusion sheet 1108 and guiding light rays emitted from the diffusion sheet 1108 may be made of polymethylmethacrylate.

The embodiments of the present invention described above and illustrated in the drawings should not be construed as limiting the technical idea of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can change and change the technical idea of the present invention in various forms. Therefore, such improvements and modifications will fall within the protection scope of the present invention, as will be apparent to those skilled in the art.

1 is a view illustrating a direct type backlight module.

2 is a view illustrating a diffusion sheet having grooves used in a direct type backlight module.

3 is a view illustrating a diffusion sheet having a wavy arc surface used in a direct type backlight module.

4 is a view illustrating a diffusion sheet having a plurality of cylindrical lenses used in a direct type backlight module.

5 is a view showing a first embodiment of a direct type backlight module according to the present invention.

6 is a view showing a light-transmitting fabric structure used in the first embodiment of the direct type backlight module according to the present invention.

7 is a view showing a second embodiment of a direct type backlight module according to the present invention.

8 is a view showing the structure of a light-transmitting fabric used in a second embodiment of a direct type backlight module according to the present invention.

9 is a view showing a third embodiment of a direct type backlight module according to the present invention.

10 is a diagram showing the structure of a light-transmitting fabric used in the third embodiment of a direct type backlight module according to the present invention.

11 is a view showing a fourth embodiment of a direct type backlight module according to the present invention.

12 is a view showing the structure of a light-transmitting fabric used in the fourth embodiment of a direct type backlight module according to the present invention.

***** Explanation of symbols for main parts of drawing *****

  10: direct type backlight module 102: frame

 104: reflective sheet 106: light generator

 108: light guide plate 110: lower diffusion sheet

 112: prism lens 114: upper diffusion sheet

 116: liquid crystal panel 20: direct type backlight module

 202: transparent sheet 204: lamp

 206: Reflective Sheet 208: Groove

  30: direct type backlight module 302: reflective sheet

 304: light source 306: diffusion sheet

  40: direct type backlight module 402: light source

 404: transmission sheet 406: cylindrical lens

  50: direct type backlight module 502: cold cathode tube

 504: reflective sheet 506: transparent fabric

 508: diffusion sheet 510: prism lens

  70: direct type backlight module 702: light emitting diode

 704: reflective sheet 706: transparent fabric

 708: diffusion sheet 710: anti-reflective sheet

  90: direct type backlight module 902: external electrode fluorescent lamp

 904: Reflective sheet 906: Translucent fabric

 908: Diffusion Sheet 910: Planar Transparent Sheet

 110: direct type backlight module 1102: external electrode fluorescent lamp

1104: reflective sheet 1106: transparent fabric

1108: diffusion sheet 1110: planar sheet

Claims (17)

A light transmitting substrate for uniformly diffusing light rays; A diffusion sheet comprising an at least one translucent fabric attached to the lower portion of the translucent substrate to reduce the transmission of light. The method of claim 1, The light transmitting substrate is polycarbonate (PC), polymethylmethacrylate (PMMA), polystyrene (PS), acrylonitrile butadiene styrene copolymer (Acrylonitrile Butadiene Styrene, ABS), polyethylene terephthalate glycol (Polyethylene Terephthalate, PET), glycol modified polyethylene terephthalate glycol (Polyethylene Terephthalate Glycol, PETG), diffusion sheet, characterized in that formed of MS resin or glass. The method of claim 1, The light transmitting substrate is a diffusion sheet comprising a light diffusion particle. The method of claim 3, wherein The light diffusing particles include polymethyl methacrylate (PMMA), MS resin, acrylonitrile butadiene styrene copolymer (ABS), polystyrene (PS), silicon dioxide powder (SiO ₂ ), A diffusion sheet comprising barium hydrate powder (BaSO ₄ ), aluminum oxide powder (Al ₂ O _{3 )} , titanium oxide powder (TiO ₂ ) or a mixture of the above elements. The method of claim 1, The transparent fabric is a diffusion sheet, characterized in that formed of polyamide fiber (Polyamide Fiber), polyester fiber (Polyester Fiber), polyethylene fiber (Polyethylene Fiber) or metal wire. The method of claim 1, Wherein the light-transmitting fabric is manufactured by knitting single yarn or plywood, the light-transmitting hole is characterized in that the triangular, rectangular, circular or oval formed. At least one photogenerator for generating light rays; A reflection sheet positioned below the light generator to reflect light rays; A diffusion sheet including a light transmitting substrate for uniformly diffusing light rays and at least one light transmitting fabric positioned below the light transmitting substrate to reduce transmission of light rays, the diffusion sheet being positioned above the light generator to diffuse light rays; And Located directly above the diffusion sheet and a direct type backlight module including at least one exit sheet for controlling the direction of the light emitted from the light generator. The method of claim 7, wherein The light generator is a direct type backlight module, characterized in that consisting of a cold cathode tube. The method of claim 7, wherein The light generator is a direct type backlight module, characterized in that consisting of a light emitting diode. The method of claim 7, wherein The light generator is a direct type backlight module, characterized in that consisting of an external electrode fluorescent lamp. The method of claim 7, wherein The light transmitting substrate is polycarbonate (PC), polymethylmethacrylate (PMMA), polystyrene (PS), acrylonitrile butadiene styrene copolymer (Acrylonitrile Butadiene Styrene, ABS), polyethylene terephthalate glycol (Polyethylene Terephthalate, PET), glycol modified polyethylene terephthalate glycol (PETG), direct type backlight module, characterized in that formed of MS resin or glass. The method of claim 7, wherein The transparent substrate is a direct type backlight module, characterized in that it comprises light diffusing particles. The method of claim 12, The light diffusing particles include polymethyl methacrylate (PMMA), MS resin, acrylonitrile butadiene styrene copolymer (ABS), polystyrene (PS), silicon dioxide powder (SiO ₂ ), A direct backlight module comprising barium hydrate powder (BaSO ₄ ), aluminum oxide powder (Al ₂ O _{3 )} , titanium oxide powder (TiO ₂ ) or a mixture of the above elements. The method of claim 7, wherein The transparent fabric is a direct type backlight module, characterized in that formed of polyamide fibers (Polyamide Fiber), polyester fibers (Polyester Fiber), polyethylene fibers (Polyethylene Fiber) or metal wire. The method of claim 7, wherein Wherein the light-transmitting fabric is manufactured by knitting single yarn or plywood, the light-emitting hole is a direct type backlight module, characterized in that formed in a triangular, square, round or oval. The method of claim 7, wherein The emission sheet is a direct type backlight module, characterized in that consisting of a prism lens, an anti-reflective transparent sheet or a planar transparent sheet. The method of claim 7, wherein The exit sheet is polycarbonate (PC), polymethylmethacrylate (PMMA), polystyrene (PS), acrylonitrile butadiene styrene copolymer (Acrylonitrile Butadiene Styrene, ABS), polyethylene terephthalate glycol (Polyethylene Terephthalate, PET), glycol modified polyethylene terephthalate glycol (PETG), direct type backlight module, characterized in that formed of MS resin or glass.

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