KR100975536B1 - Optical sheet and back light assembly of luquid crystal display equipped with the prism sheet - Google Patents

Abstract

The present invention relates to an optical sheet for improving optical characteristics of light emitted from a light source, and a backlight assembly provided with the optical sheet.

An optical sheet according to the spirit of the present invention is an optical sheet for moving light moved from a light source toward a liquid crystal display panel, wherein the optical sheet includes a body portion facing the light source, and a plurality of optics formed on the body portion. And each of the optical patterns includes a first protrusion protruding a predetermined thickness from the body portion, and a second protrusion having a shape different from that of the first protrusion, wherein the first protrusion and the second protrusion are the light source. Its size is formed differently based on the vertically upward area of.

Optical sheet

Description

Optical sheet and back light assembly of luquid crystal display equipped with the prism sheet

The present invention relates to an optical sheet for improving optical characteristics of light emitted from a light source, and a backlight assembly provided with the optical sheet.

The liquid crystal display device includes a liquid crystal display panel, which includes a TFT array substrate in which unit pixels are arranged and thin film transistors are arranged as switching elements for each unit pixel, and the TFT array substrate faces and expresses colors. A color filter substrate, and a liquid crystal layer filled between the two substrates.

Since the liquid crystal display panel does not emit light by itself, light must be supplied from the outside in order to express an image.

In addition, the LCD may be classified into an edge type and a direct type according to a structure in which a backlight, which is a light source, is installed. The edge type has a backlight assembly formed on the side of the liquid crystal display panel, and the direct type has a backlight assembly formed under the liquid crystal display panel.

Edge type liquid crystal display devices are used for small liquid crystal display devices, and direct type liquid crystal display devices are mainly used for large liquid crystal display devices.

1 and 2 illustrate a backlight assembly of a conventional direct type liquid crystal display.

In the backlight assembly, as a light source, a plurality of bar lamps 103 are formed under the liquid crystal display panel (not shown) in parallel with each other, and are protected by a lower cover 101 which is a mold frame. The upper surface of the lower cover 101 is provided with a reflecting plate 102 for reflecting the light of the lamp 103 to the liquid crystal panel, a plurality of lamps 103 are arranged on the reflecting plate 102. Further, a diffusion plate 104 for uniformly diffusing the light generated from the lamp 103 into the liquid crystal panel, a diffusion sheet 105 placed on the diffusion plate 104, and the diffusion sheet 105. A prism sheet 106 is further provided for refracting the light diffused by.

In addition, although not shown, in general, a protective sheet (not shown) is further provided on the prism sheet 106, and thus, a cost of the product is increased as a plurality of films or sheets are used in the direct backlight assembly in the related art. Will rise.

The diffusion plate 104 and the diffusion sheet 105 are supported by the edge of the lower cover.

A plurality of lamps 103, which are light sources, are formed on the reflecting plate 102 in parallel with each other, and the lamps 103 are supported by the lamp fixing members 111.

Electrodes for supplying power to the lamp are formed at both ends of the lamp 103, the lamp electrode is supported by the lamp support 112 formed on both sides of the lower substrate (101). In addition, an electrode supply line (not shown) for supplying power to the lamp is connected to both electrodes of the lamp 103.

The power supply lines are connected to each other to form a closed circuit around a single lamp. In the closed circuit, an inverter that converts a DC voltage applied from the outside into an AC voltage and supplies a current to the lamp is installed.

In general, a cold cathode fluorescent lamp (CCFL) is used as the lamp. Looking at the structure of the lamp, the lamp includes a light emitting part coated with a fluorescent material and an external device for applying a voltage to the lamp. It can be divided into electrode parts.

Meanwhile, a problem occurring in the conventional direct type backlight assembly will be described with reference to FIG. 3.

3 and 4 are diagrams showing the movement of light in a conventional backlight assembly.

Referring to FIG. 3, as a lamp is used as a light source, which is generally circular in cross section, the light emitted from the lamp is not evenly incident on all regions of the diffusion plate.

That is, as shown, the reflecting plate portion 3A positioned above the light source has a high density of incident light, but the reflecting plate portion 3B positioned in the region between the light source and the light source has a relatively low density of incident light.

In addition, in the conventional direct backlight assembly, efforts have been made to reduce the number of plates or sheets used, and among them, the diffusion sheet 105 and 3 together with the diffusion plate 104. In some cases, only chapters are used.

However, in this case, too, as the three diffusion sheets are laminated in addition to the diffusion plate 104, the manufacturing cost thereof increases, and there is a limit in improving the optical characteristics.

In addition, the incident angle of the incident light is often greater than the magnitude of the critical angle totally reflected in the portion 3B of the reflecting plate formed at the position of the region between the lamp and the lamp, and is reflected on the surface of the reflecting plate, and the reflected light is moved toward the lamp side. As a result, there is a problem of lowering the optical efficiency of the backlight assembly.

In addition, since the density of light incident on the portion of the reflector located in the area between the lamp and the lamp is low, the luminance of the light emitted through the liquid crystal display becomes uneven and the image is not clearly displayed through the liquid crystal display. There is this.

The present invention is proposed to solve the above problems, and an object of the present invention is to propose an optical sheet and a backlight assembly provided with the optical sheet, which can reduce the generation of the bright line of the light source for generating light.

An optical sheet according to the spirit of the present invention is an optical sheet for moving light moved from a light source toward a liquid crystal display panel, wherein the optical sheet includes a body portion facing the light source, and a plurality of optics formed on the body portion. A pattern, each of the optical patterns includes a first protrusion protruding a predetermined thickness from the body portion, and a second protrusion formed in a shape different from the first protrusion, wherein the plurality of optical patterns are vertically upward of the light source A first optical pattern positioned in an area of the second optical pattern and a second optical pattern positioned in an area vertically upward with respect to a space between the light sources, wherein a size of the second protrusion of the first optical pattern is defined by the second optical pattern It is characterized in that it is formed differently from the size of the second protrusion of the pattern.

In addition, the optical sheet according to the spirit of the present invention is an optical sheet for moving the light from the light source to the liquid crystal display panel side, the optical sheet is a body portion facing the light source, a plurality formed on the body portion Has an optical pattern, and each of the optical patterns includes a first protrusion formed on the body portion and a second protrusion formed of a microlens having a surface contacting the body portion being a circle or an ellipse. .

In addition, the backlight assembly according to the spirit of the present invention includes a light source for generating light; A reflection plate provided below the light source and reflecting light generated from the light source; And an optical sheet disposed above the reflective plate and configured to guide incident light toward a liquid crystal display panel, wherein the optical sheet includes a body portion facing the light source, and a plurality of optical portions formed on the body portion. A pattern, each of the optical patterns includes a first protrusion protruding a predetermined thickness from the body portion, and a second protrusion formed in a shape different from the first protrusion, wherein the plurality of optical patterns are vertically upward of the light source A first optical pattern positioned in an area of the second optical pattern and a second optical pattern positioned in an area vertically upward with respect to a space between the light sources, wherein a size of the second protrusion of the first optical pattern is defined by the second optical pattern It is characterized in that it is formed differently from the size of the second protrusion of the pattern.

According to the embodiment of the present invention as proposed, it is possible to reduce the observation of the bright line of the light source for generating light.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail. However, the spirit of the present invention is not limited to the embodiments in which the present invention is presented, and those skilled in the art who understand the spirit of the present invention easily suggest other embodiments by adding, changing, adding, and deleting elements within the scope of the same idea. Although this may be done, this also falls within the scope of the spirit of the present invention.

In addition, in the following description, the word 'comprising' does not exclude the presence of elements other than those listed.

In addition, while the idea of the present invention is described as related to the 'sheet', it is noted that the 'sheet' is applicable to a plate as well as an optical sheet applicable in the backlight assembly. Here, the optical 'sheet' may be a case where the thickness thereof is in the range of 25 μm to 300 μm, and the 'plate' may be a case where the thickness thereof is in the range of 0.5 mm to 2.0 mm.

5 is a view illustrating a configuration of a backlight assembly of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the backlight assembly of the present invention has a light source 310 for generating light and a lower side of the light source 310 for reflecting the light generated from the light source 310 toward the liquid crystal display panel 320. It includes a reflector 300 provided in the, the optical sheet 200 for improving the optical characteristics of the light is provided on the upper side of the light source 310, and the liquid crystal display panel 320 for displaying an image.

In detail, the optical sheet 200 is formed with a plurality of patterns on the body portion forming the substrate, the density of the pattern is formed differently depending on whether the pattern is located above the light source 310 vertically It features.

The patterns of the optical sheet 200 may include a first optical pattern 210 positioned vertically above the light source 310 and an upper portion perpendicular to an area between the light sources in the backlight assembly. It may be defined as two optical patterns 220.

The first optical pattern 210 and the second optical pattern 220 may be divided into different sizes of subpatterns constituting them.

That is, the optical sheet according to the embodiment of the present invention is composed of a plurality of optical patterns, the optical pattern is composed of a first protrusion having a triangular cross section and a second protrusion having a circular or elliptical cross section.

Both the first optical pattern 210 and the second optical pattern 220 are formed of the first protrusion and the second protrusion, and the size of the first protrusion 211 of the first optical pattern 210 is the second thereof. The protrusion 212 is formed to be larger than the size of the protrusion 212, and the size of the first protrusion 221 of the second optical pattern 220 is smaller than the size of the second protrusion 222.

This may be defined by dividing the patterns of the optical sheet into patterns that are located vertically above the light source and patterns that are not. The first optical pattern 210 may have a region located vertically above the light source 310. The second optical pattern 220 is an area that is not positioned vertically upward with respect to the light source.

For convenience of description, the first optical pattern 210 is defined as a pattern of the optical sheet which is positioned above the light source 310 vertically, and the second optical pattern 220 is perpendicular to the area between the light source and the light source. It defines as the pattern of the optical sheet located above.

In the first optical pattern 210, the size of the first protrusion 211 having a triangular cross-sectional shape is larger than that of the second protrusion 212, where the size between the protrusions is the horizontal length of the cross-section. Or its volume.

In the second optical pattern 220, the size of the second protrusion 222 whose cross-sectional shape is a circle or an ellipse is larger than that of the first protrusion 221.

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And, in the case of the second protrusion having a cross-sectional shape of a circle or ellipse, as opposed to the case of the first protrusion above, the second protrusion has the smallest size vertically upward with respect to the light source, and gradually increases in size, and then gradually As it is positioned vertically upward with respect to the light source, its size becomes smaller.

By considering the position of the light source 310 to have a pattern having a different shape, it is possible to ultimately conceal the bright line of the light source 310.

In the following description, various shapes that the first optical pattern or the second optical pattern may have will be described.

6 to 11 are diagrams for describing an optical pattern according to various embodiments of the present disclosure.

The optical sheet according to the present invention may be formed of optical patterns that are a plurality of unit structures, and the optical patterns may be defined by being classified into first and second optical patterns according to positions of light sources. In the following description, various embodiments that may be formed of the first optical pattern or the second optical pattern will be described.

FIG. 6 shows a first embodiment of an optical pattern (first optical pattern or second optical pattern) according to the spirit of the present invention, wherein the first protrusion 411 has a prism array shape, and a second protrusion 412. ) Has a cylindrical shape.

In detail, the second protrusion 412 is arranged in the longitudinal direction of the first protrusion 411, and the cross section is formed in a shape of a circle or an ellipse.

In the optical pattern 410 according to the first embodiment, the size (width) of the first protrusion 411 is shown by reference numeral 411a, and the size (width length) of the second protrusion 412 is Reference numeral 412a is shown.

In this case, the optical pattern 410 becomes a first optical pattern positioned vertically above the light source of the backlight assembly, and the second optical pattern positioned vertically upward with respect to the area between the light sources. Listen In this case, the size (or lateral length) of the second protrusion in the first optical pattern is formed smaller than the size (or lateral length) of the second protrusion in the second optical pattern.

The reason why the size of the first protrusion and the second protrusion of the optical pattern are formed differently according to the position of the light source is that the effect of concealing the bright line of the lamp is excellent, as shown in FIG.

Next, a second embodiment of the optical pattern according to the spirit of the present invention is shown in FIG.

The optical pattern 500 of the second embodiment includes a first protrusion 511 having a prism array shape having a cross-sectional shape of a triangle, and a second protrusion 512 irregularly arranged with micro lens patterns having a fine size.

Here, the second protrusion 512 of the optical pattern 500 according to the second embodiment is formed to protrude a predetermined thickness on the body portion 530 of the optical pattern, irregularly arranged on the body portion 530 do.

The thickness of the second protrusion 512 is formed to be smaller than the thickness of the first protrusion 511, and the cross section of the second protrusion 512 has a shape of a circle or an ellipse.

Here, the size of the first protrusion 511 and the second protrusion 512 may be differently formed according to the position of the light source (or distance from the light source) of the backlight assembly according to the second embodiment. The first protrusion 511 is formed to be the largest in the vertical direction with respect to the light source.

The second protrusion 512 is formed to increase or decrease the number of micro lenses constituting the second protrusion 512. In addition, the size of the micro lens constituting the second protrusion 512 is formed small or large.

For example, the size of the first protrusion 511 is large for the first optical pattern positioned vertically upward with respect to the light source of the backlight assembly, so that the number of micro lenses constituting the second protrusion 512 is increased. It is reduced or the size of the micro lens is made small.

In contrast, for the second optical pattern positioned vertically upward with respect to the area between the light sources in the backlight assembly, the size of the first protrusion 511 is formed smaller than that in the first optical pattern, and the second protrusion The number of micro lenses of 512 is formed more than in the case of the first optical pattern.

8 illustrates a third embodiment of the optical pattern according to the spirit of the present invention, and the first protrusion 611 constituting the optical pattern 600 includes a plurality of surfaces having an inclination with respect to the body portion 630. Consists of polyhedrons.

That is, the first protrusion 611 is formed of a polyhedron having a plurality of surfaces, and FIG. 8 shows a square pyramid whose bottom surface is rectangular.

In addition, the second protrusion 612 constituting the optical pattern 600 includes a convex portion formed by a circle or an ellipse in contact with the body portion 630, and a cross section of the second protrusion 612 is also a circle or an ellipse. It is made in the shape of.

In addition, the optical pattern 600 according to the third embodiment is also formed in consideration of the position of the light source of the backlight assembly, the size of the first projection 611 made of a polyhedron and the second projection 612 of the micro lens type. ) Is formed differently depending on the distance between the light sources.

That is, an area where the first protrusion 611 and the body 630 touch each other and an area where the second protrusion 612 and the body 630 touch each other are formed according to the position of the light source of the backlight assembly. In the case of the size of the first protrusion 611, the largest area is formed in the unit optical pattern positioned in an area vertically upward with respect to the light source, so that the area that reaches the body portion 630 is largest.

9 illustrates a fourth embodiment of the optical pattern according to the spirit of the present invention. The first protrusion 711 of the optical pattern 700 is formed of a quadrangular pyramid having a rectangular bottom surface as a polyhedron, and a second protrusion 712. ) Is composed of a plurality of micro lenses arranged irregularly as mentioned in the second embodiment.

In the case of the fourth embodiment, it may be understood that the second protrusion of the second embodiment and the first protrusion of the third embodiment are mixed.

FIG. 10 illustrates a fifth embodiment of the optical pattern according to the spirit of the present invention, and the protrusion 811 of the optical pattern 800 has a prism array shape on the body portion 830 and has a triangular cross section.

The concave portion 812 of the optical pattern 800 has an intaglio shape with respect to the body portion 830, and has an intaglio pattern having a circle or ellipse shape with respect to one surface of the body portion 830. Is done.

That is, while the protrusion 811 protrudes from one surface of the body portion 830, the concave portion 812 is formed to have a predetermined depth recessed with respect to one surface of the body portion 830.

The cross-sectional shape of the concave portion 812 is formed in the shape of a circle or an ellipse in the drawings, but is not limited thereto and may be modified in various ways such as a triangular shape or a square shape.

In this case, the horizontal lengths (or sizes) of the protrusions and the recesses are differently formed in consideration of the position of the light source of the backlight assembly, and the horizontal length 811a of the protrusions in the first optical pattern is the protrusion in the second optical pattern. It is formed larger than the horizontal length of, the concave portion is reversed.

Meanwhile, a plurality of micro lenses may be irregularly arranged on one surface of the recess 812, which is illustrated in FIG. 11.

That is, a sixth embodiment of the optical pattern according to the spirit of the present invention is shown in FIG. 11, the protrusion 911 having a predetermined thickness protruding from one surface of the body portion 930 in the optical pattern 900 according to the sixth embodiment. And a concave portion 912 recessed in a predetermined depth with respect to one surface of the body portion 930.

In addition, a plurality of micro lenses 912a protruding from a predetermined thickness are irregularly arranged in the concave portion 912.

The protrusion 911 has a prism array shape, and its cross section has a triangular shape.

The concave portion 912 is formed to be recessed into the body portion 930, and microlenses of minute size are irregularly arranged on one surface thereof.

12 is a view for revealing the extent to which the bright line of the lamp is concealed when using a diffusion plate to which the optical pattern according to the spirit of the present invention is applied and when using a conventional diffusion plate.

The photograph (a) of FIG. 12 shows a case where a conventional diffusion plate (manufactured by Cheil Industries, product name: PS (DRE58)) is used for the backlight assembly, and the photograph (b) shows the first embodiment of the present invention. This shows the case of using a diffusion plate with an optical pattern.

From the observation of such a photograph, it can be seen that the sheet or plate to which the idea of the present invention is applied can obtain an excellent effect in concealing the bright line or the dark line of the lamp (light source).

1 and 2 are views for explaining a backlight assembly of a conventional direct type liquid crystal display device.

3 and 4 show the movement of light in a conventional backlight assembly.

5 is a view illustrating a configuration of a backlight assembly of a liquid crystal display according to an exemplary embodiment of the present invention.

6 to 11 illustrate optical patterns according to various embodiments of the present disclosure.

12 is a view for revealing the extent to which the bright line of the lamp is concealed when using a diffusion plate to which the optical pattern according to the spirit of the present invention is applied and when using a conventional diffusion plate.

Claims (16)

An optical sheet for moving light moved from a light source toward a liquid crystal display panel, The optical sheet has a body portion facing the light source and a plurality of optical patterns formed on the body portion, Each of the optical patterns may include a first protrusion protruding a predetermined thickness from the body portion and a second protrusion having a shape different from that of the first protrusion, The plurality of optical patterns are defined as a first optical pattern located in an area vertically upward of the light source, and a second optical pattern located in an area vertically upward with respect to a space between the light sources. And the size of the second protrusion of the first optical pattern is smaller than the size of the second protrusion of the second optical pattern. The method of claim 1, The first protrusion is formed of a prism array whose cross section is triangular, The second projection has an optical sheet, characterized in that its cross section has a circular or elliptic shape. delete The method of claim 2, And the second protrusion has a cylindrical shape with a predetermined thickness protruding from the body. An optical sheet for moving light moved from a light source toward a liquid crystal display panel, The optical sheet has a body portion facing the light source and a plurality of optical patterns formed on the body portion, Each of the optical patterns includes a first protrusion formed to protrude a predetermined thickness on the body portion, and a second protrusion formed of a micro lens having a surface contacting the body portion to be a circle or an ellipse, The plurality of optical patterns are defined as a first optical pattern located in an area vertically upward of the light source, and a second optical pattern located in an area vertically upward with respect to a space between the light sources. And the size of the second protrusion of the first optical pattern is smaller than the size of the second protrusion of the second optical pattern. The method of claim 5, And the micro lenses constituting the second protrusions are irregularly formed. The method of claim 5, And the number of micro lenses in the first optical pattern is smaller than the number of micro lenses in the second optical pattern. The method of claim 5, The first protruding portion is formed of a plurality of surfaces inclined at a predetermined angle with respect to one surface of the body portion. The method of claim 8, The first protruding portion is an optical sheet, characterized in that made of a square pyramid in contact with the body portion is a square. An optical sheet for moving light moved from a light source toward a liquid crystal display panel, The optical sheet has a body portion facing the light source and a plurality of optical patterns formed on the body portion, Each of the optical patterns may include a protrusion formed to protrude a predetermined thickness on the body portion and a concave portion formed to be recessed into the body portion. The plurality of optical patterns are defined as a first optical pattern located in an area vertically upward of the light source, and a second optical pattern located in an area vertically upward with respect to a space between the light sources. The cross sectional horizontal length of the concave portion of the first optical pattern is smaller than the cross sectional horizontal length of the concave portion of the second optical pattern, The protrusion is formed in a prism array shape, The recess is an optical sheet, characterized in that the cross section is in the shape of a circle or ellipse. delete The method of claim 10, The optical sheet, characterized in that a plurality of micro lenses are irregularly arranged on one surface of the recess. A light source for generating light; A reflection plate provided below the light source and reflecting light generated from the light source; And An optical sheet disposed on an upper side of the reflecting plate and configured to guide incident light toward a liquid crystal display panel; The optical sheet has a body portion facing the light source and a plurality of optical patterns formed on the body portion, Each of the optical patterns may include a first protrusion protruding a predetermined thickness from the body portion and a second protrusion having a shape different from that of the first protrusion, The plurality of optical patterns are defined as a first optical pattern positioned in an area vertically upward of the light source, and a second optical pattern positioned in an area vertically upward with respect to a space between the light sources. And the size of the second protrusion of the first optical pattern is smaller than the size of the second protrusion of the second optical pattern. delete A light source for generating light; A reflection plate provided below the light source and reflecting light generated from the light source; And An optical sheet disposed on an upper side of the reflecting plate and configured to guide incident light toward a liquid crystal display panel; The optical sheet has a body portion facing the light source and a plurality of optical patterns formed on the body portion, Each of the optical patterns includes a first protrusion formed to protrude a predetermined thickness on the body portion, and a second protrusion formed of a micro lens having a surface contacting the body portion to be a circle or an ellipse, The plurality of optical patterns are defined as a first optical pattern positioned in an area vertically upward of the light source, and a second optical pattern positioned in an area vertically upward with respect to a space between the light sources. And the size of the second protrusion of the first optical pattern is smaller than the size of the second protrusion of the second optical pattern. delete

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