KR20100091613A - Optical sheet improved uniformity and lcd having the same - Google Patents

Abstract

PURPOSE: An optical sheet and a LCD device thereof are provided to reduce the number of an optical film. CONSTITUTION: A plurality of lens parts(5) consecutively arranges unit lens(3) on the first side of a transparent base(2). A pattern unit(6) forms a semisphere shape or poly pyramid in the light source facing position of the second surface of the transparent base. A lower end(3b) of the unit lens is the cross section shape of a cone or polypyramid. The unit lens constitutes the central part(3a) of the lens in a flat, an ellipse or a cupola form.

Description

OPTICAL SHEET IMPROVED UNIFORMITY AND LCD HAVING THE SAME

The present invention relates to an optical sheet having improved lamp hiding property and a liquid crystal display device including the same, and more particularly, a plurality of lens units in which unit lenses are continuously adjacent to each other and arranged on a first surface of a transparent substrate; And a pattern portion having an intaglio polygonal pyramid or hemispherical shape formed at a position facing the light source on the second surface of the transparent substrate. It is about.

BACKGROUND ART Liquid crystal displays (hereinafter referred to as "LCDs") are low power consumption, low heat generation, and high definition image output devices that can be manufactured in an ultra-thin type, and have recently been spotlighted as image display devices in various industrial fields.

However, unlike other flat panel display systems, such liquid crystal displays require a light source because the liquid crystal itself is a non-light-emitting material, and various types of optical sheets are used to uniformly diffuse the light emitted from the light source and increase the efficiency of the light. Such an entire apparatus is referred to as a backlight unit (hereinafter referred to as a BLU).

The BLU includes a side light method and a back light method, and the side light method is mainly used for a small notebook or a monitor, and a light source lamp is accommodated at the side of the screen so that the light guide plate may be used to guide the light to the front. Used. A plurality of optical sheets are used on the light guide plate to diffuse uniformity and focus the induced light again.

On the other hand, the back light method is mainly used for a TV with a wide screen, and a plurality of lamps are stored on the back of the screen for high brightness. Unlike the side light method using the light guide plate, the back light method uses a diffuser plate that serves to uniformly diffuse light immediately instead of the light guide plate because the lamp is located on the rear side. After that, in the conventional configuration of the optical sheet 100 to be laminated, a diffusion sheet, a prism sheet, and a protective film are sequentially stacked on the light guide plate or the diffusion plate.

To describe the back light type BLU in more detail, conventionally, the light emitted from the CCFL lamp, which is a linear light source, diffuses the light of the light source, which is a linear light source, through a diffuser plate to cover and uniformize the lamp. The secondary diffusion was made more uniform, and the light was focused on the effective incident angle of the prism on the upper side to assist the prism's role. The prism sheet condenses the light of the effective incident angle passing through the diffusion film into the vertical light, and the invalid light condenses the light again vertically through the retroreflection.

Conventional The light diffusing plate is a plate having a predetermined thickness (mainly 1 to 2 mm) by extrusion, and is produced by dispersing a diffusing agent having a different refractive index from the resin over the entire thickness, and thus, due to physical phenomena such as refractive, interfacial reflection and scattering, This function converts the line light source from the light source lamp into a surface light source. Therefore, the light diffusion plate serves as a cover for covering the bright lines of the lamp while achieving the uniformity of brightness of the light, while the light diffusion plate serves as a support for various optical films.

The light diffusion sheet positioned on the light diffusion plate performs a function of evenly spreading light, and generally includes a light diffusion layer formed by coating a composition consisting of light diffusion particles and a resin on at least one surface of the base sheet, and a blocking prevention layer on the rear surface of the light diffusion sheet. Formed structure. At this time, the emission angle of the light in the diffusion sheet has been attempted to optimize the particle shape on the surface of the light diffusion layer to achieve a high brightness by the incident angle having a proper effective angle to the prism sheet.

In addition, the prism sheet is formed in a linear prism lens structure having a triangular cross-sectional shape on the base sheet, so that the light condensing efficiency for increasing the second luminance is maximized.

Recently, BLU uses LEDs instead of CCFL lamps to increase contrast and color gamut.

However, the existing optical sheet alone is not enough to change the LED which is a high brightness point light source into a uniform surface light source.

Accordingly, the present inventors have tried to solve the problem of the conventional backlight unit (BLU) using a high-brightness point light source LED, and after the light emitted from the light source passes through the diffuser plate, the light distribution is analyzed to the lower portion of the optical sheet By introducing a pattern that can increase the diffusivity and reflectivity, the lens unit having an optical structure that can improve the light collection efficiency is eliminated by eliminating the difference between the dark portion and the light caused by the light source, and the high brightness and high concealment can be satisfied. The present invention was completed by providing an optical sheet.

It is an object of the present invention to provide an optical sheet devised to improve high brightness and lamp hiding.

Another object of the present invention is to provide a liquid crystal display including the backlight assembly and the backlight assembly having an optical sheet and implementing a high brightness, high concealability and slimming of the liquid crystal display module.

In order to achieve the above object, the present invention includes a plurality of lens units arranged on the first surface of the transparent substrate (2) are continuously adjacent to each other; And a pattern portion 6 having an intaglio polygonal pyramid or a hemispherical shape formed at a position facing the light source on the second surface of the transparent substrate.

The unit lens 3 formed on the first surface of the optical sheet 1 of the present invention has a lower end portion 3b of a polygonal or conical cut face, and the center portion 3a of the lens except for the lower end portion of the lens is flat, elliptical or The optical structure has a hemispherical shape.

The lower end portion 3b of the unit lens 3 has a polygonal or conical cut face shape, and in the unit lens, the center portion 3a of the lens except for the lower end portion 3b has a flat, elliptical or hemispherical structure, which is effective. Not only incident light incident at an angle, but also incident light incident at an invalid angle can be focused. At this time, the width (w, 3a) of the unit lens 3 on the first surface is 50 to 250 µm, and the height (hight, h, 3b) of the unit lens 3 is about the width length of the lens. , 25 to 200% is preferred.

In addition, the pattern portion 6 formed on the second surface of the optical sheet 1 of the present invention has a plurality of polygonal pyramids or hemispherical shapes intaglio, and reflects or diffuses light when light is incident thereon. At this time, the width ( w , 4b) of the unit lens portion of the pattern portion formed on the second surface is preferably 5 to 50% of the width length 3a of the unit lens portion on the first surface, and the height of the unit lens portion on the second surface. (height, h , 4a) is preferably 25 to 200% with respect to the width length 4b of the lens portion.

According to the present invention, the optical sheet 1 provides a backlight assembly that realizes high brightness, high concealability, and a slimmer LCD module, and provides a liquid crystal display including the backlight assembly.

The present invention provides an optical sheet having a lens unit made of an optical structure that can increase the light collecting efficiency on the first surface of the transparent substrate and a pattern portion that can improve lamp concealment on the second surface of the transparent substrate. In addition, it is possible to realize high brightness and improve lamp hiding, which is the biggest problem in a backlight unit (BLU) using an LED light source.

Thus, by providing a backlight assembly with an optical sheet of the present invention and a liquid crystal display device including the same, high brightness, high concealability and the number of optical films mounted on the backlight unit can be reduced, thereby making the liquid crystal display module slim and By simplifying the manufacturing process, the manufacturing cost can be lowered.

Hereinafter, the present invention will be described in more detail.

According to an embodiment of the present invention, a plurality of lens units 5 in which unit lenses 3 are continuously adjacent to each other are arranged on a first surface of a transparent substrate 2; And a pattern part 6 having an intaglio polygonal pyramid or a hemispherical shape formed at a position facing the light source on the second surface of the transparent base material 2, wherein the unit lenses 3 are arranged on the first surface. The lower end portion 3b of) has a polygonal or conical cutting surface shape, and the central portion 3a of the lens except for the lower end portion 3b of the unit lens 3 has a flat, oval or hemispherical shape. [ FIG. 1 and FIG. 2 ].

As shown in FIG . 3 , the light irradiated from the light sources LED 10 is primarily diffused through the diffusion plate 20, and the light is again reflected on the second surface of the optical sheet 1 of the present invention. The light incident on the pattern portion 6 formed in the reflective portion 6 is reflected and / or diffused, and passes through the second surface, and the plurality of lens portions 5 in which the unit lenses 3 on the first surface are successively arranged adjacent to each other. Condensed at an angle effective for luminance. In this process, the optical sheet 1 of the present invention can expect the brightness increase effect while maximizing the lamp concealment of the backlight unit (BLU) composed of the LED light source 10.

When the structure of the optical sheet 1 of the present invention is described in detail, the width ( w ) of the unit lens 3 formed on the first surface of the transparent substrate 2 is preferably 50 to 250 µm, more preferably. Preferably it is 50-200 micrometers, More preferably, it is 150 micrometers or less. At this time, when it exceeds 250 micrometers, moire phenomenon tends to generate | occur | produce and it becomes unpreferable because a pattern is seen in an image.

In addition, the height (hight) h of the unit lens 3 formed on the first surface of the transparent base material 2 is preferably 25 to 200% with respect to the width length w of the unit lens portion. At this time, if it is less than 25%, the light condensing property is lowered, and if it exceeds 200%, the luminance is rather decreased due to the increase in total reflection amount of light, which is not preferable.

The optical sheet 1 of the present invention is composed of a plurality of lens portions 5 in which the unit lenses 3 are successively arranged adjacent to each other on the first surface of the transparent base material 2, and the lower end portion 3b of the unit lens is provided. ) Has a polygonal or conical cutting surface shape, and the central portion 3a of the lens except for the lower portion 3b of the unit lens 3 is formed in a planar, elliptical or hemispherical structure, so that not only incident light incident at an effective angle In addition, it is designed to collect incident light incident from an invalid angle, and the absorption of light by the medium is suppressed as much as possible, thereby realizing luminance improvement.

Therefore, the conventional prism sheet having a triangular cross-sectional shape is difficult to adjust the viewing angle, and in the case of light incident from an invalid direction among the incident light, side lobe is generated, thereby reducing the light collection efficiency. have.

At this time, the lower end of the unit lens formed on the first surface of the optical sheet of the present invention is 20 to 80% of the height h of the unit lens 3 of the optical sheet 1, more preferably 50 to 80% of the time. At this time, if the lower end portion 3b of the lens is less than 20% of the height h of the unit lens 3, the efficiency due to the shape of the polygonal pyramid or the cone is inferior, so that the conventional lenticular lens is incident at an invalid angle. The problem that the incident light shows low light collection efficiency is still not solved.

Further, in the optical sheet 1 of the present invention, an intaglio polygonal pyramidal or hemispherical pattern portion 6 is formed on a second surface of the transparent substrate 2 opposite the light source 10. .

An intaglio polygonal pyramid or hemispherical pattern formed in the pattern portion 6 provides light to the dark portion through reflection and / or diffusion of light in a vertical direction from the light source 10 to the optical sheet. Diffusion reduces the difference between rosters and shadows.

At this time, the distribution of the pattern on the second surface depends on the light distribution coming out through the diffusion plate. Preferably, at least three or more patterns are preferably positioned per one light source lamp (LED), more preferably 5 to 15. At this time, if the number of the patterns is less than three, the optical path optimization effect is not satisfactory, and if the number is more than 15, the optimization efficiency of the optical path is improved, but the production process is difficult and the cost and productivity are lowered.

In the pattern portion 6 of the optical sheet 1 of the present invention, the width ( w, 4b) of the unit lens portion is preferably 5 to 50% of the width length of the unit lens portion 3 formed on the first surface. . In addition, the height (hight, h , 4a) of the unit lens portion in the pattern portion 6 is preferably 25 to 200% with respect to the width length of the unit lens portion 3 formed on the first surface.

The feature of the optical sheet 1 of the present invention is that the pattern portion 6 on the second surface of the transparent substrate 2 is formed to face the light source 10, so that light diffused from the diffusion plate is pattern-shaped. By providing light in the dark portion by reflection and / or diffusion by the dark portion, a point light source is provided as a uniform surface light source.

Subsequently, the optical sheet 1 is formed on the first surface of the transparent substrate 2 at a relatively high density, and is moved to a plurality of lens units 5 having a specific structure. The light is condensed to the front part by the optical refraction, so that the brightness is improved.

That is, the optical sheet 1 of the present invention reflects and / or diffuses the light passing through the diffusion plate 20 by the intaglio polygonal pyramid or hemispherical pattern 6 formed on the second surface of the transparent substrate 2. The point light source of the LED lamp is formed as a uniform surface light source, and the light passing through the second surface is again arranged with the unit lenses 3 on the first surface continuously formed on the transparent substrate 2 continuously adjacent to each other. Increasing the condensing efficiency in a plurality of lenses. Therefore, the optical sheet 1 of the present invention can reduce the number of optical sheets to be mounted on the backlight unit, and can improve the luminance at the same or higher level than that of the conventional optical sheet.

In addition, since the optical sheet 1 of the present invention can reduce the number of optical films mounted on the backlight unit while implementing high concealment, the manufacturing cost can be reduced by slimming the liquid crystal display module and simplifying the manufacturing process. have.

Thus, since the optical sheet having the optical structure implements high brightness and high concealment, the present invention provides a backlight assembly having high brightness, high concealment, and slimming of the LCD module.

Furthermore, the present invention provides a liquid crystal display device including the backlight assembly.

Hereinafter, the present invention will be described in detail with reference to examples.

The following examples are merely illustrative of the present invention, but the scope of the present invention is not limited to the following examples.

≪ Example 1 >

After designing a double-sided pattern on one side of a highly transparent polyester film (Toray Industries, Inc. XG533-100 μm) as shown in Table 1 below , an optical sheet 1 was produced by an ultraviolet curing molding method.

At this time, the lower end of the unit lens arranged on the first surface has a conical cross section, the lens center portion is an elliptical shape, the pattern portion formed on the second surface is a negative hemispherical pattern is formed. At this time, the length of the unit lens and the reflection pattern is as described in Table 1 [Fig. 1].

<Example 2>

Instead of the double-sided pattern of the first embodiment, except that the lower end of the unit lens arranged on the first surface has a conical cross section, the center of the lens is an elliptical shape, the pattern portion formed on the second surface is a negative triangle pattern In the same manner as in the optical sheet manufacturing process of Example 1 [ FIG. 2 ].

Experimental Example 1 Measurement of Optical Properties

1. Measurement of luminance

In order to measure the brightness of the optical sheet (1) prepared above was performed as follows.

Luminance was measured using a 47 "LED direct backlight unit, and the optical sheet (1) was cut to measure a measurement angle of 5 degrees using a Topcon BM-7 measuring instrument, and a distance between the BM-7 and the backlight unit. It was set to 25 cm, the horizontal and vertical equal intervals were divided into 4, and the brightness | luminance of nine points which are the intersection points was measured 9 times, and the brightness was represented by the average value of brightness | luminance.

For comparison, the same light diffusing plate, diffusion sheet, prism, and protective sheet were sequentially stacked in the standard configuration of an optical sheet currently used as a reference, and luminance was measured in the same manner.

As a result, the optical sheet manufactured by the design of Example 1 was compared with the reference, and the results are shown in Table 2 below.

2. Lamp Uniformity Measurement

In order to measure the lamp hiding property of the optical sheet (1) prepared above was performed as follows.

After stacking the diffuser plate and the optical sheet on the 47 "LED direct type backlight unit using Topcon's BM-7 measuring device, the brightness of 11 points was measured in the vertical direction, and the lamp concealment value was determined by Equation 1 below. In this case, the lower the lamp hiding value, the higher the lamp hiding property.

3. Sensory evaluation

The sensory evaluation results of visually evaluating the lamp hiding property of the optical sheet 1 prepared above are shown in Table 2 below. At this time, the evaluation 1 is a lamp is completely visible, the evaluation 5 defined a case where the lamp is completely concealed.

From the results in Table 2 above, the optical sheet 1 of the present invention showed comparable luminance performance when the luminance of the reference made of the standard configuration of the optical sheet was 100% using the currently used optical sheet.

Moreover, the lamp concealment and sensory evaluation results showed that the lamp concealment performance was significantly improved than the reference.

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an optical sheet having a lens portion made of an optical structure on the first surface of a transparent substrate and a pattern portion on the second surface of which is capable of improving lamp concealment. The light passing through the plate is reflected and / or diffused in the pattern portion, thereby providing light to the dark portion or diffusing the light to reduce the difference between the light and dark portions, thereby realizing a high hiding rate of the lamp. Thereafter, the light passing through the pattern part may increase the light condensing efficiency by the optical structure of the lens part, thereby improving brightness.

Thus, the optical sheet 1 of the present invention can improve the lamp concealment which is the biggest problem in the backlight unit (BLU) using the LED light source at the same time, and can realize high brightness.

In addition, the present invention provides a backlight assembly having the optical sheet and a liquid crystal display device including the same, thereby reducing the brightness, high concealment, and the number of optical films mounted on the backlight unit, thereby making the liquid crystal display module slim. And by simplifying the manufacturing process, it is possible to lower the manufacturing cost.

Although the present invention has been described in detail only with respect to the embodiments described, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications belong to the appended claims.

1 is a cross-sectional view of an optical sheet for a first embodiment for a preferred embodiment of the present invention,

2 is a cross-sectional view of an optical sheet for a second embodiment for a preferred implementation of the invention,

3 is a schematic diagram of an optical path of the optical sheet of the present invention.

Claims (10)

A plurality of lens units 5 in which unit lenses 3 are continuously arranged adjacent to each other on a first surface of the transparent substrate 2; And An optical sheet consisting of a pattern portion 6 having an intaglio polygonal pyramid or a hemispherical shape formed at a position facing the light source on a second surface of the transparent substrate 2, wherein the unit lens is arranged on the first surface An optical sheet in which the lower end portion (3b) of (3) has a cross-sectional shape of a polygonal pyramid or a cone, and the central portion (3a) of the lens except for the lower end portion (3b) in the unit lens (3) has a flat, oval or hemispherical shape. The optical sheet according to claim 1, wherein the width (w) of the unit lens (3) arranged on the first surface of the transparent substrate (2) is 50 to 250 mu m. The optical sheet according to claim 1, wherein the height h of the unit lens (3) arranged on the first surface of the transparent substrate (2) is 25 to 200% of the width of the unit lens. The light collecting sheet with a diffuser plate according to claim 1, wherein the lower end portion (3b) of the unit lens is formed at 20 to 80% with respect to the height h of the unit lens. The optical sheet according to claim 1, wherein the pattern formed on the second surface of the transparent substrate (2) is in the form of a lens of an intaglio polygonal pyramid or a semispherical pattern. 6. The optical sheet according to claim 5, wherein the unit width (4b) of the pattern is 5 to 50% with respect to the width (w) of the unit lenses (3) arranged on the first surface. The optical sheet according to claim 5, wherein the unit height (4a) of the pattern is 25 to 200% with respect to the unit width (4b) of the pattern. The optical sheet according to claim 1, wherein three or more patterns formed on the second surface of the transparent substrate (2) are included per one light source. Light Source, Diffuser plate and The backlight assembly according to claim 1, wherein the optical sheet (1) of claim 1 is sequentially formed, with the pattern portion (6) of the optical sheet (1) facing the light source portion (10). A liquid crystal display device comprising a backlight assembly having the optical sheet of claim 1.

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