KR20090059876A - One-body multi functional optical sheet and liquid crystal display device using the same - Google Patents

Abstract

An integrated type multi functional optical sheet and a liquid crystal display device using the same are provided to remove a lamp mura phenomenon. An integrated type multi functional optical sheet(120) includes a base substrate(121), a diffusion layer(123), a condensing layer(127), a reflecting layer(122), a bonding layer, and a slit part. A light from a light source(130) is irradiated on the base substrate. The diffusion layer is formed on a rear surface of the base substrate. The condensing layer is arranged on a top surface of the base substrate in a row. A convex shape and a concave shape are repetitively formed on the condensing layer. The reflecting layer is formed between the base substrate and the condensing layer. The reflecting layer is formed by a reflecting pattern(122a) and an insulation material(122b). The bonding layer bonds the base substrate and the reflecting layer. The slit part is formed in at least one surface of a top surface, a bottom surface, and both surfaces of the base substrate. The slit part is arranged in order to correspond to the light source.

Description

One-body multi functional optical sheet and liquid crystal display device using the same}

The present invention relates to an integrated multi-function optical sheet and a liquid crystal display device using the same.

The present invention relates to a liquid crystal display device capable of realizing a wide viewing angle and high brightness, and more particularly, to an integrated multifunctional optical sheet capable of improving the efficiency of a work process in a modular process of a liquid crystal display device.

In line with the recent information age, the display field has also been rapidly developed, and a liquid crystal display device (FPD) is a flat panel display device (FPD) having advantages of thinning, light weight, and low power consumption. LCD, plasma display panel device (PDP), electroluminescence display device (ELD), field emission display device (FED), etc. : It is rapidly replacing CRT.

Among them, the liquid crystal display device is most actively used in the field of notebooks, monitors, TVs, etc. due to its excellent contrast ratio and high contrast ratio. The liquid crystal display device is a device that does not have a light emitting element. It requires a light source.

As a result, a backlight unit having a fluorescent lamp is provided on the rear surface to irradiate light toward the front of the liquid crystal panel, thereby realizing an image of identifiable luminance. In this case, the backlight unit includes a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), and a light emitting diode (LED) as a light source for generating light. This is used.

Meanwhile, a general backlight unit is classified into an edge type and a direct type according to the arrangement of fluorescent lamps. The edge type has a structure in which one or a pair of lamps is disposed at one side of the light guide plate. Alternatively, two or two pairs of lamps may be disposed on both sides of the light guide plate, and the direct type may have a structure in which several lamps are disposed below the optical sheet.

1 is a cross-sectional view of a liquid crystal display using a general direct type backlight unit.

As shown, a general liquid crystal display module includes a liquid crystal panel 10 and a backlight unit 50 including upper and lower substrates 13 and 15, a support main 60, a cover bottom 80, and a top cover 70. It consists of

The liquid crystal panel 10 includes a printed circuit board (not shown) at one side thereof, and a backlight unit 50 at the rear thereof. The liquid crystal panel 10 is surrounded by a support frame 60 having a rectangular frame shape. The top cover 70 covering the front edge of the panel 10 and the cover bottom 80 covering the back surface of the backlight unit 50 are respectively coupled in front and rear to be integrated through the support main 60.

The backlight unit 50 includes a reflective sheet 40, and a plurality of fluorescent lamps 30 are arranged side by side on an upper surface thereof, and a diffuser plate 22 and a plurality of optics are disposed on the fluorescent lamps 30. The sheet 20 is interposed.

In this case, the plurality of optical sheets 20 includes a diffusion film (not shown) and at least one light collecting film (not shown), which will be described in more detail with reference to FIG. 2.

FIG. 2 is a view schematically illustrating the configuration of the diffusion plate and the plurality of optical sheets of FIG. 1.

As illustrated, a plurality of optical sheets 20, that is, the diffusion film 24 and the light collecting film 26 are sequentially stacked on the diffusion plate 22.

The diffusion plate is configured to have various haze characteristics according to the light uniformity, so that light emitted from a plurality of fluorescent lamps (30 in FIG. 1) is directed toward the liquid crystal panel (10 in FIG. 1), and has a wide range. It serves to diffuse light to be incident on the liquid crystal panel (10 in FIG. 1) at an angle.

In addition, by diffusing the light incident through the diffuser plate 22 and the diffuser film 24 stacked on the diffuser plate 22 to prevent staining due to partial concentration of light, the light condensing film 26 It controls the direction of light so that the light proceeds toward).

In addition, the light collecting film 26 is formed of a base film made of PET resin and a prism acid 28 on the upper surface of the base film in a predetermined arrangement, and is largely reflected and collected by the prism acid 28. It shows optical properties.

That is, as shown in FIG. 3, light incident on the condensing film 26 is incident on the condensing area A on the premise that light incident at an angle of 5 ° with the line perpendicular to the lower surface of the condensing film 26 is incident. The collected light is concentrated in the direction of the liquid crystal panel (10 in FIG. 1) through refraction by the prism acid 28 to substantially improve luminance, and the light incident on the total reflection region B is formed on the surface of the prism mountain 28. It is reflected downward again by the refraction at.

The light reflected downward is reflected by the reflective sheet 40 of FIG. 1 or the like and re-supplied to the condensing film 26, thereby minimizing light loss through the circulation of the light.

However, the light condensing film 26 is accompanied with light loss due to side lobes in addition to the desired light condensing and reflection, which causes a problem of decreasing light efficiency and deteriorating viewing angle characteristics.

That is, the portion indicated by reference numeral C is a region where such side lobes are generated (hereinafter referred to as a side lobe region), which is refracted in an unnecessary direction on the surface of the prism acid 28 of the light collecting film 26 to be moved forward. It is lost without entering the liquid crystal panel (10 in FIG. 1), and light leakage occurs in this region.

3 and 4 are graphs showing luminance distribution and light distribution according to a viewing angle of the backlight unit (50 of FIG. 1) using the light collecting film 26 described above according to an azimuth angle. Referring to these, the central portion of the light collecting film 26 is referred to. It can be seen that bright areas appear on both sides with reference to the side lobe area (C).

The present invention is to solve the above problems, to reduce or remove the side lobe of the backlight unit to improve the light efficiency and viewing angle characteristics, and to achieve the display screen of the liquid crystal display device using the same high quality of uniform brightness do.

An integrated multi-function optical sheet according to an embodiment of the present invention for achieving the above object is arranged in a line on the base substrate, the diffusion layer is formed on the back surface of the base substrate, and the upper surface of the base substrate, the light is incident from the light source And a condensing layer in which peaks and valleys repeatedly appear, an adhesive layer for adhering the base substrate and the condensing layer, and a slit portion formed on at least one of an upper surface, a lower surface, and both sides of the base substrate, and disposed to correspond to the light source. do.

The slit portion may be formed in the diffusion layer, which is one surface of the base substrate, or may be formed in the adhesive layer, which is one surface of the base substrate, or both the diffusion layer and the adhesive layer.

The light source is a plurality of fluorescent lamps.

The length of the slit portion is formed to have a length twice the pitch of the fluorescent lamp.

The distance between the fluorescent lamps is arranged to be five times the pitch of the fluorescent lamps.

According to an exemplary embodiment of the present invention, a liquid crystal display device includes a liquid crystal panel, an integrated multifunction optical sheet provided on a rear surface of the liquid crystal panel, a light source arranged on a rear surface of the integrated multifunction optical sheet, and a rear surface of the integrated multifunction optical sheet. Comprising a light source that is made, the integrated multi-functional optical sheet using any one of the integrated multi-function optical sheet of any one of claims 1 to 7.

According to the present invention, by forming a multifunctional optical sheet including a diffusion layer, a reflection layer, and a light collecting layer, the side lobe is prevented from occurring, thereby improving the viewing angle characteristic and realizing uniform brightness, thereby improving the image quality of the display screen.

In addition, the present invention by disposing the slit portion in the multi-function optical sheet corresponding to the region in which the fluorescent lamp is disposed, by diffracting the light concentrated in the region in which the fluorescent lamp is disposed and the region in which the fluorescent lamp is disposed and the region in which the fluorescent lamp is not disposed; Since the difference in the amount of light is reduced, there is an effect of eliminating the lamp mura phenomenon, which is a phenomenon in which light is concentrated only in the region where the fluorescent lamp is disposed.

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

5 is an exploded perspective view schematically illustrating a liquid crystal display module according to an exemplary embodiment of the present invention.

As shown, the liquid crystal display module is a liquid crystal panel 110 and the backlight unit 150, the liquid crystal panel 110 is a part that plays a key role of the image expression is bonded to face the liquid crystal layer in between It consists of the first and second substrates 113 and 115.

In this case, the gate printed circuit board 117b and the data printed circuit board 117a are connected to each other along the two adjacent edges of the liquid crystal panel 110 via the flexible printed circuit board 116, thereby covering the covertum during the modularization process. Folded to the side or the back of the 180, they are delivered to each of the plurality of gate lines (not shown), the on / off signal of the thin film transistor (not shown) and the image signal for each frame to a plurality of data lines (not shown) do.

In addition, a backlight unit 150 is provided below the liquid crystal panel 110, and a top cover 170 covering the front edge of the liquid crystal panel 110 with the edges of the support main 160 having a rectangular frame shape thereon. The cover bottoms 180 covering the back of the backlight unit 150 are respectively coupled in front and rear to be integrated through the support main 160.

The backlight unit 150 includes a reflective sheet 140, and arranges a plurality of fluorescent lamps 130 on an upper surface thereof, and forms a multifunctional optical sheet 120 on the fluorescent lamps 130. The plurality of fluorescent lamps 130 are fixed by a pair of side supports 132 fastened to the cover bottom 180.

In addition, although not shown, the gap between the fluorescent lamp 130 and the multi-functional optical sheet 120, which is composed of a plurality of parts, is prevented from sagging, and the fluorescent lamp 130 may be impacted. It further includes a plurality of lamp guides (not shown) to prevent the shaking and the possibility of damage.

When the light is emitted from the fluorescent lamp 130 in the above-described configuration, the light is processed into a more uniform surface light source through the multi-function optical sheet 120 is incident on the liquid crystal panel 110, thereby the liquid crystal panel 110 ) Displays an image to the outside.

Next, a multifunctional optical sheet will be described with reference to FIG. 6, which is a cross-sectional view schematically illustrating a structure of a multifunctional optical sheet according to the present invention.

As shown in FIG. 6, the multifunctional optical sheet 120 is positioned on the lower portion of the base substrate 121 to diffuse light emitted from the fluorescent lamp 130 based on the transparent base substrate 121. In order to focus the diffusion layer 123 and the light diffused by the diffusion layer 123 to the liquid crystal panel 110 (see FIG. 5), the light condensing layer 127 disposed on the base substrate 121 and partial light. An adhesive layer disposed between the upper surface of the base substrate 121 and the lower surface of the reflective layer 122 to bond the reflective layer 122 for recycling the base layer 121 to the base substrate 121 and the reflective layer 122. 126.

The diffusion layer 123 forms a diffusion layer 123 on the lower surface of the planar base substrate 121 made of a transparent material, and the diffusion layer 123 has various haze characteristics according to the degree of light uniformity. Use it.

In this case, the haze characteristic is a phenomenon in which light is diffused according to the intrinsic properties of the material in addition to reflection or absorption depending on the kind of material when light passes through the transparent material. Through adjustment, the desired brightness and viewing angle can be realized. When the haze value is 30% or less, the light diffusion rate is low, and the viewing angle is narrowed.

The haze value of the diffusion layer 123 may include a light diffusing agent such as a bead or a fine pattern (not shown) on the lower surface of the diffusion layer 123. In this case, the bead is included in the acrylic resin, the bead is characterized in that the light can be partially prevented by dispersing the light incident to the diffusion layer 123.

In addition, the diffusion layer 123 that does not include the bead has a feature that can adjust the light scattering angle according to the shape of the fine pattern (not shown), the fine pattern (not shown) is an elliptical pattern (elliptical pattern), Polygon patterns, etc. can be configured in various ways, and by using a hologram pattern, the light incident by the interference pattern is refracted in an asymmetrical direction so that the collected light can be diffused at a more inclined angle. can do.

As a result, the light is dispersed to prevent the light from being partially concentrated.

The light collecting layer 127 has a plurality of dome-shaped lenticular lenses 127a for condensing light arranged in a row to protrude, and the plurality of lenticular lenses 127a are arranged adjacent to each other in a band shape to repeat a mountain and a valley. .

In this case, a reflective layer 122 is formed between the base substrate 121 and the lenticular lens 127a, and the reflective layer 122 is a valley portion to which the lenticular lens 127a of the upper surface of the base substrate 121 is connected. The reflective pattern 122a formed of any one material of titanium oxide (TiO 2) or magnesium oxide (MgO) in the band shape, and the space between the reflective pattern 122a and the spaced apart space of the reflective pattern 122a are made of a transparent insulating material 122b. .

Therefore, the light incident on the multi-functional optical sheet 120 is refracted at an angle of about 5 ° with a line perpendicular to the bottom surface of the light collecting layer 127, respectively, depending on the optical characteristics according to the path of light. It may be divided into a light collecting area, a total reflection area, and a separate blocking reflection area.

That is, the light passing through the diffusion layer 123 is focused in the range of 60 to 90 ° with respect to the lower surface of the light collecting layer 127 during the process of entering the light collecting region and passing through the lenticular lens. Indicates. The light incident on the total reflection region is reflected in the incident direction through the refraction on the surface of the lenticular lens 127a, and as a result, the circulating action of the light reflected back by the reflective sheet (140 in FIG. 5) of the liquid crystal display device. To minimize light loss. Finally, the light incident to the blocking reflection region is reflected in the incident direction without passing through the reflective layer 122, and like the total reflection region, the light is again reflected by the reflective sheet (140 in FIG. 5) or the like of the liquid crystal display (FIG. 5). It causes a recycling of the light reflected in the direction of 110) of the to minimize the light loss.

Therefore, the multi-functional optical sheet 120 according to the present invention converts the existing side lobe area into the blocking reflection area, and is refracted in the existing unnecessary direction so as to be lost without being incident on the front liquid crystal panel (110 of FIG. 5). Light is also reflected back by the reflective sheet (140 of FIG. 5), thereby preventing the occurrence of side lobes in advance.

The adhesive layer 125 bonds an upper surface of the base substrate 121 and a lower surface of the reflective layer 122.

On the other hand, the multi-function optical sheet 120 of the present invention is provided so as to correspond to each of the fluorescent lamps 130 is provided with a slit 128 for diffracting the light emitted from the fluorescent lamp. The slit part 128 is disposed to correspond to each fluorescent lamp one by one, and the length P2 of the slit part 128 is formed to have a length twice the pitch P1 of the fluorescent lamp.

In other words, the light emitted from the fluorescent lamp has a similar distribution of the amount of light in a region corresponding to twice the length of the fluorescent lamp pitch (hereinafter referred to as the region in which the fluorescent lamp is arranged). Since a region other than twice the length (hereinafter referred to as 'the region where no fluorescent lamp is arranged') has a distribution of light amount smaller than the region corresponding to twice the length of the fluorescent lamp pitch, The slit portion is disposed correspondingly to the region where the lamp is arranged to diffract the light emitted from the fluorescent lamp so as to lower the light amount distribution in the region where the fluorescent lamp is arranged.

In addition, the slit portion 128 may be disposed on the diffusion plate 123 as shown in FIG. 7, or may be disposed on the adhesive layer 125, as shown in FIG. 8. As described above, the diffusion plate 123 and the adhesive layer 125 may be disposed.

As such, the slit portion 128 is disposed to correspond to the region where the fluorescent lamp is disposed, thereby diffracting the light concentrated in the region where the fluorescent lamp is disposed, so that the region where the fluorescent lamp is disposed and the region where the fluorescent lamp is not arranged. By reducing the difference in the distribution of the amount of light, it is possible to eliminate the phenomenon that the light is concentrated only in the region where the fluorescent lamp is disposed. In addition, the light concentration phenomenon does not appear in the light collecting layer 127 of the area P3 corresponding to 5 times the pitch P1 of the fluorescent lamp, and the distance between adjacent fluorescent lamps is 5 times the pitch of the fluorescent lamp. When arranged to correspond to the corresponding area (P3), it is possible to prevent the optical cumulative phenomenon by the fluorescent lamp radiation angle. Therefore, it is possible to prevent the phenomenon in which light is concentrated only in the region in which the fluorescent lamp is disposed, and the lamp mura phenomenon, which is the optical coincidence phenomenon caused by the fluorescent lamp emission angle.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

1 is a cross-sectional view of a liquid crystal display using a general direct type backlight unit.

FIG. 2 is a cross-sectional view schematically illustrating a configuration of the diffusion plate and the plurality of optical sheets of FIG. 1.

3 and 4 are views according to the viewing angle of the backlight unit using a conventional light collecting film

Graph showing luminance distribution and light distribution according to azimuth

5 is an exploded perspective view schematically illustrating a liquid crystal display module according to an exemplary embodiment of the present invention.

6 is a cross-sectional view schematically showing the structure of an integrated multifunction optical sheet according to the present invention.

7, 8, and 9 are cross-sectional views schematically showing the structure of the integrated multi-function optical sheet according to the embodiment of the present invention.

Claims (8)

A base substrate on which light is incident from a light source, A diffusion layer formed on a rear surface of the base substrate, Condensing layer arranged in a row on the upper surface of the base substrate and the mountain and the valley appear repeatedly, A reflective layer formed between the base substrate and the light collecting layer and formed of a reflective pattern corresponding to the valley portion and an insulating material formed between the reflective patterns; An adhesive layer for adhering the base substrate and the reflective layer; And a slit portion formed on at least one of an upper surface, a lower surface, and both surfaces of the base substrate and disposed to correspond to the light source. The method of claim 1, wherein the slit portion The integrated multi-functional optical sheet for a liquid crystal display device, characterized in that formed on the diffusion layer which is one surface of the base substrate. The method of claim 1, wherein the slit portion The integrated multi-function optical sheet for a liquid crystal display device, characterized in that formed on the adhesive layer that is one surface of the base substrate. The method of claim 1, wherein the slit portion Integrated multifunctional optical sheet for a liquid crystal display device, characterized in that formed on both the diffusion layer and the adhesive layer. The method of claim 1, wherein the light source An integrated multifunctional optical sheet for a liquid crystal display device, characterized in that a plurality of fluorescent lamps. According to claim 1 or 5, wherein the length of the slit portion Integrated multi-function optical sheet for a liquid crystal display device, characterized in that formed to have a length twice the pitch of the fluorescent lamp. The method of claim 5, wherein the interval between the fluorescent lamps The integrated multi-function optical sheet for a liquid crystal display device, characterized in that arranged to be five times the pitch of the fluorescent lamp. A liquid crystal panel; Integrated multifunctional optical sheet provided on the rear of the liquid crystal panel, A light source arranged at the back of the integrated multifunction optical sheet; And a light source arranged on a rear surface of the integrated multi-function optical sheet, wherein the integrated multi-function optical sheet uses any one of the integrated multi-function optical sheets of claim 1.

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