KR20060117058A - Diffusion member and backlight unit and liquid crystal display comprising the same - Google Patents

Abstract

A diffusion member, a backlight unit comprising the diffusion member, and an LCD comprising the backlight unit are provided to improve the uniformity of an exiting light, thereby reducing the thickness of an optical sheet, by improving the structure of the diffusion member. A diffusion member(110) comprises a plurality of flat portions(112) and prism pattern portions(111) between the flat portions. The flat portions refract an incident light to output the refracted light. Each of the prism pattern portions has at least one V-shaped groove. The V-shaped groove of the prism pattern portion refracts a light, which has a larger incident angle than the light incident on the flat portions, in a vertical direction, thereby reducing the reduction rate of brightness.

Description

Diffusion member and backlight unit and liquid crystal display comprising the same

1 is a perspective view of a diffusion member according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view illustrating a light propagation path of a backlight unit including the diffusion member of FIG. 1 as part of a cross-sectional view taken along line AA ′ of FIG. 1.

3 is a perspective view of a diffusion member according to a second embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view illustrating a light propagation path of a backlight unit including the diffusion member of FIG. 3 as part of a cross-sectional view taken along line BB ′ of FIG. 3.

5 is a cross-sectional view illustrating a backlight unit and a liquid crystal display panel including the diffusion member of FIG. 1.

6 is a cross-sectional view illustrating a backlight unit and a liquid crystal display panel including the diffusion member of FIG. 3.

FIG. 7 is an exploded perspective view illustrating the liquid crystal display device including the backlight unit of FIGS. 5 to 6.

<Description of the symbols for the main parts of the drawings>

100: backlight unit 110: diffusion member

111: prism pattern portion 112: flat portion

120: lower storage container 130: mold frame

160: light source 170: reflector

180: optical sheet layer 200: liquid crystal display panel

210: TFT substrate 220: color filter substrate

230: gate TCP 250: data TCP

260: PCB 300: upper storage container

400: liquid crystal display

The present invention relates to a diffusion member, a backlight unit including the same, and a liquid crystal display, and more particularly, to a diffusion member having an increased uniformity of emitted light, a backlight unit including the same, and a liquid crystal display.

Liquid crystal display (LCD) is one of the most widely used flat panel display devices, and is composed of two display panels on which field generating electrodes such as pixel electrodes and common electrodes are formed and a liquid crystal layer interposed therebetween. An electric field is generated by applying a voltage to the field generating electrode, thereby determining an orientation of liquid crystal molecules of the liquid crystal layer and controlling polarization of incident light to display an image.

In general, a liquid crystal display device is a device that displays an image by injecting a liquid crystal between two glass plates and applying power to the upper and lower liquid crystal electrodes to change the liquid crystal molecular array in each pixel, and is composed of a panel, a driving unit, and a backlight unit. .

Unlike a cathode ray tube (CRT), a plasma display panel (PDP), and the like, a display by a liquid crystal display is not light-emitting because it is non-luminous in itself. In order to compensate for these disadvantages and to enable use in a dark place, a backlight unit that is uniformly irradiated on the information display surface is mounted.

In particular, the backlight unit of the liquid crystal display uses a direct type backlight unit that can directly emit light by arranging light sources downward as the liquid crystal display becomes larger.

In the direct type backlight unit, the light source is positioned below the liquid crystal display panel, and the diffusion member and the optical sheet layer are disposed in front of the light source to diffuse the light emitted from the lamp to illuminate the liquid crystal display panel. Since the direct type backlight unit uses light efficiently by using the diffusion member and the optical sheet layer, high brightness can be obtained, and therefore, it is suitable for a backlight unit requiring high brightness.

However, since the backlight unit according to the related art emits light directly from a light source, the bright line and the dark part according to the related art are clearly distinguished. Since the presence of the bright line and the dark portion adversely affects the visibility of the liquid crystal display device, it is required that the bright line and the dark portion are not clearly exposed and emit light uniformly. As a solution for this, a plurality of optical sheets are disposed on the top of the backlight unit, or a thick optical sheet layer is used. However, an increase in the number of optical sheets or the thickness of the optical sheet layer results in a decrease in overall brightness, an increase in cost, and an increase in the thickness of the entire liquid crystal display device. Accordingly, there is a need for the development of a backlight unit in which light is emitted uniformly without causing a decrease in brightness and an increase in thickness.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a diffusion member having an increased uniformity of emitted light.

Another object of the present invention is to provide a backlight unit including the diffusion member as described above.

Another object of the present invention is to provide a liquid crystal display device including the backlight unit as described above.

Technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

Diffusion member according to an embodiment of the present invention for achieving the above technical problem, is generated between a plurality of flat portions, and the flat portion to be refracted by the incident light, and is more than the light incident on the plurality of flat portions It includes a prism pattern portion composed of at least one V-shaped groove for refracting the light incident at a large incident angle toward the vertical direction of the flat portion and relatively small decrease in the luminance relative to the flat portion.

A backlight unit according to an embodiment of the present invention for achieving the above another technical problem, is disposed between the light source, a plurality of flat parts disposed on the light source, and refracted incident light is emitted, and between the flat parts, It includes a prism pattern portion consisting of at least one V-shaped groove for refracting the light incident at a larger angle of incidence than the light incident on the plurality of flat portions toward the vertical direction of the flat portion and relatively small reduction in luminance relative to the flat portion A diffusion member, an optical sheet layer disposed on the diffusion member, and a storage container for storing the light source, the diffusion member, and the optical sheet layer.

According to another aspect of the present invention, there is provided a liquid crystal display device, which is disposed between a light source and a plurality of flat parts disposed on the light source and refracting incident light to emit light. And a prism pattern portion composed of at least one V-shaped groove that refracts light incident at an angle of incidence greater than light incident on the plurality of flat portions toward the vertical direction of the flat portion, and relatively decreases a decrease in luminance relative to the flat portion. A liquid crystal panel comprising a diffusing member comprising; an optical sheet layer disposed on the diffusing member; a liquid crystal panel disposed on the optical sheet layer; a liquid crystal panel configured to receive an electrical signal and determine whether light is transmitted; , An optical sheet layer, and a storage container for containing the liquid crystal panel.

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms, and only the embodiments are to make the disclosure of the present invention complete, and the general knowledge in the technical field to which the present invention belongs. It is provided to fully convey the scope of the invention to those skilled in the art, and the invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, a liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view of a diffusion member according to a first embodiment of the present invention.

The diffusion member 110 serves to uniformly transmit the light emitted from the light source 160 to the upper side, and is spaced apart from the light source 160 by a predetermined interval on the light source 160. Diffusion member 110 according to the first embodiment of the present invention, a prism composed of one V-shaped groove on the upper plate of the dark portion that is generated due to the space between the light source 160 and the light source arranged at regular intervals The pattern portion 111 is included. In addition, the diffusion member 110 according to the first embodiment of the present invention includes a flat portion 112 on the upper plate between the adjacent prism pattern portion 111.

The V-shaped groove constituting the prism pattern portion 111 of the diffusion member 110 serves as a prism and thus transmits more light, and because the thickness of the diffusion member is thinner than the flat portion 112 at the curved portion, the bright line More light is transmitted than the site. Therefore, since the luminance reduction rate of the light passing through the prism pattern portion 111 is relatively smaller than the luminance reduction rate of the light passing through the flat portion 112, the uniformity of the emitted light is higher than that of the diffusion member including only the conventional flat portion 112. Becomes high. An advancing path of light in the backlight unit including the diffusion member according to the present exemplary embodiment will be described with reference to FIG. 2. In FIG. 2, the light propagation path is indicated by an arrow.

Light is emitted from the light source 160 and transmitted upward through the diffusion member 110. Therefore, a portion where the light source 160 is located is relatively bright, and a portion corresponding to the space 101 where the light source 160 is not located is relatively dark, resulting in uneven brightness.

In order to eliminate such unevenness in brightness and to transmit uniform light to the upper optical sheet layer 180, the diffusion member 110 is provided in the space 101 between the light source 160 and the light source as shown in FIG. 2. The prism pattern portion 111 may be disposed in the opposing area. The position of the V-shaped grooves and the open angles of the V-shaped grooves constituting the prism pattern portion 111 may be determined by the arrangement interval of the light source, the distance between the light source and the diffusing member, the refractive index and thickness of the diffusing member, or the difference between the luminance of the bright line and the dark portion. Can be adaptively determined accordingly.

When light emitted obliquely from the light source 160 toward the prism pattern portion 111 of the diffusion member 110 reaches the lower surface 105 of the prism pattern portion 111, the light source 160 to the diffusion member 110 may be used. Is refracted by the difference between the refractive index of the medium (eg, air) and the diffusion member 110. When the refracted light reaches the inclined surfaces 102 and 103 of the prism pattern portion 111 of the diffusion member 110, the refractive index of the diffusion member 110 is different from that of the medium in the cavity 104. Refraction in the upward direction again. Therefore, as shown in FIG. 2, light may be focused onto the diffusion member 110 facing the space 101 between the light source 160 and the light source, and the light may travel generally perpendicular to the diffusion member 110. . In addition, the amount of light emitted to the upper side of the diffusing member 110 opposite the space 101 between the light sources 160 increases, and the amount of light emitted to the upper side of the diffusing member 160 facing the light source 160 increases. The difference is reduced. Therefore, the uniformity of the emitted light reaching the optical sheet layer 180 as a whole may be improved.

In general, as the thickness of the optical sheet layer 180 increases, the uniformity of the emitted light increases. As the uniformity of light is already increased by the diffusing member 110, the optical sheet layer installed on the upper part of the diffusing member 110 ( The thickness of 180 may be reduced, and the thickness of the backlight unit 100 may be reduced.

3 is a perspective view of a diffusion member according to a second embodiment of the present invention.

Diffusion member 110 according to the second embodiment of the present invention, a prism having two or more v-shaped grooves in the upper plate of the dark portion that is generated due to the space between the light source 160 and the light source arranged at regular intervals The pattern portion 111 is included. In addition, the diffusion member 110 according to the second embodiment of the present invention includes a flat portion 112 on the upper plate between the adjacent prism pattern portion 111.

Since the prism pattern portion 111 of the diffusion member 110 serves as a prism, more light is transmitted upward to uniform the light uniformity of the bright line portion and the dark portion. An advancing path of light in the backlight unit including the diffusion member according to the present exemplary embodiment will be described with reference to FIG. 4. In FIG. 4, the light propagation path is indicated by an arrow.

As illustrated in FIG. 4, the diffusion member 110 may include a prism pattern 111 in a region facing the light source 160 and the space 101 of the light source. The position of the prism pattern portion 111, the number of V-shaped grooves constituting the prism pattern portion 111, and the open angle of the V-shaped grooves may include the arrangement interval of the light source, the distance between the light source and the diffusion member, the refractive index and thickness of the diffusion member, Alternatively, it may be adaptively determined in consideration of the difference in luminance of the bright line and the dark portion.

Since the light emitted from the light source 160 in the direction of the prism pattern portion 111 of the diffusion member 110 is refracted in the upward direction of the diffusion member 110 is the same as described above with reference to FIG. Shall be. As shown in FIG. 4, light may be focused onto the diffusion member 110 that faces the arm 101 of the light source 160, and the light may travel generally perpendicular to the diffusion member 110. In addition, the amount of light emitted to the upper side of the diffusing member 110 opposite the space 101 between the light sources 160 increases, and the amount of light emitted to the upper side of the diffusing member 160 facing the light source 160 increases. The difference is reduced. Therefore, the uniformity of the emitted light reaching the optical sheet layer 180 as a whole may be improved. In particular, since the prism pattern portion 111 of the diffusion member 110 according to the present embodiment has two or more v-shaped grooves, the prism pattern portions 111 have more inclined surfaces 102 and 103. Therefore, the uniformity of the emitted light can be further increased by refracting more light upward than the diffusion member shown in FIG. 1 having one V-shaped groove.

Although the diffusion member 110 illustrated in FIGS. 1 to 4 has been described based on an integrated body formed of the same material, the upper plate including the prism pattern portion 111 and the flat portion 112 may be coupled to the lower portion of the upper plate and the lower plate as necessary. It may be formed separately from the substrate. In this case, the top plate and the substrate may be formed of a material having the same refractive index, but may be formed of a material having a different refractive index.

The diffusion member 110 as described above with reference to FIGS. 1 to 4 may use a material having a higher refractive index than air and having a high light transmittance. For example, polymethyl methacrylate (PMMA), polycarbonate (PC) or polyethylene terephthalate (PET) may be used, but is not limited thereto.

5 is a cross-sectional view illustrating a backlight unit and a liquid crystal display panel including the diffusion member of FIG. 1.

The backlight unit 100 according to the present exemplary embodiment includes a liquid crystal display panel 200 having a thin film transistor (TFT) substrate 210 and a color filter substrate 220, a diffusion member 110, a lower storage container 120, The mold frame 130, the light source 160, the reflector plate 170, the optical sheet layer 180, and the like may be included.

The diffusion member 110 of the backlight unit according to the present exemplary embodiment is formed on the upper plate of the dark portion, and includes a prism pattern portion formed of one V-shaped groove that increases the amount of emitted light by refracting the light of the light source incident on the dark portion ( 111, and a flat portion 112 created between the prism pattern portion and the adjacent prism pattern portion.

Functions and operations of other components will be described later with reference to FIG. 7.

6 is a cross-sectional view illustrating a backlight unit and a liquid crystal display panel including the diffusion member of FIG. 3.

The backlight unit 100 according to the present exemplary embodiment includes a liquid crystal display panel 200 having a thin film transistor (TFT) substrate 210 and a color filter substrate 220, a diffusion member 110, a lower storage container 120, The mold frame 130, the light source 160, the reflector plate 170, the optical sheet layer 180, and the like may be included.

The diffusion member 110 of the backlight unit according to the present exemplary embodiment includes a prism pattern portion 111 formed of two or more V-shaped grooves formed on the upper plate of the arm portion, and a flat portion 112 formed on the upper plate of the curved portion adjacent to the arm portion. .

Functions and operations of other components will be described with reference to FIG. 7.

FIG. 7 is an exploded perspective view illustrating a liquid crystal display including the backlight unit of FIG. 6.

The liquid crystal display device 400 according to the exemplary embodiment of the present invention generally includes a liquid crystal display panel 200, a backlight unit 100, an upper storage container 300, and the like.

The liquid crystal display panel 200 includes a thin film transistor substrate 210, a color filter substrate 220, a liquid crystal (not shown), a gate tape carrier package (TCP), a data TCP 250, and a printed circuit board. (PCB: printed circuit board, 260) and so on.

The thin film transistor substrate 210 may include a gate line and a data line, a thin film transistor, a pixel electrode, and the like, and the color filter substrate 220 disposed above and facing the thin film transistor substrate 210 may include a color filter, Black matrix, common electrode and the like, but are not shown.

In this case, the gate TCP 230 is connected to each gate line formed on the thin film transistor substrate 210, and the data TCP 240 is connected to each data line formed on the thin film transistor substrate 210.

On the other hand, the PCB 260 is equipped with various circuit components capable of processing both the gate driving signal and the data driving signal so that the gate driving signal can be input to the gate TCP 230 and the data driving signal can be input to the data TCP 250. do.

The backlight unit 100 includes a diffusion member 110, a lower storage container 120, a mold frame 130, a light source 160, a reflector plate 170, an optical sheet 180, and the like. The support part 150 may be further included to support the diffusion member 110 and to fix the arrangement of the light source 160.

The light source 160 is used to provide light to the liquid crystal display, which is a non-light emitting device. For example, the light source 160 receives a constant voltage from the outside to emit electrons from the cathode and irradiates phosphors to generate visible light. The light source 160 includes a flat fluorescence lamp (FFL) or a linear light source. The line light source may be a cold cathode light source (CCFL) or a hot cathode light source (HCFL). The surface light source is a light source that emits light in a wide area, and unlike a line light source, only one lamp is used. The backlight unit according to the present exemplary embodiment may include an embodiment using an embossed surface light source having convex portions and concave portions as well as a linear light source as the light source 160.

The reflector plate 170 is installed under the light source 160 to reflect light emitted to the lower portion of the light source 160 toward the diffusion member 110 disposed above the reflector plate 170.

The support 150 is attached to the reflector plate 170 to support the diffusion member 110 and the optical sheet layer 180. When the diffusion member 110 and the optical sheet layer 180 absorb moisture, a bending phenomenon may occur, and the support 150 may support the diffusion member 110 and the optical sheet layer 180 to prevent the bending. Can be.

The light irradiated from the light source 160 and the light reflected by the reflecting plate 170 are diffused by the diffusion member 110 to have the same brightness, and then focused by the optical sheet layer 180.

The optical sheet layer 180 is positioned above the diffusion member 110 to uniformly distribute the light emitted from the light source 160. As the optical sheet layer 300, for example, a diffusion sheet, a prism sheet, or a protective sheet may be selectively stacked or arranged at a predetermined interval, and may be formed of a transparent resin such as an acrylic resin, a polyurethane resin, or a silicone resin. Can be molded. The optical sheet layer 180 may include a plurality of optical sheets to improve the uniformity of the emitted light. If the thickness of the entire optical sheet layer 180 is increased too much, the thickness of the backlight may be increased as a whole and the luminance may be reduced. Can be. Therefore, in view of the uniformity of the light emitted from the diffusion member 110, it is necessary to appropriately adjust the number of optical sheets and the thickness of the optical sheet layer 180.

In the internal space partitioned by the combination of the mold frame 130 and the lower storage container 120, the components of the backlight unit 100 described above are accommodated, and the lower storage container 120 is again the upper storage container 300. ) To form a frame of the liquid crystal display.

The coupling of the mold frame 130 and the lower storage container 120, the upper storage container 300 and the lower storage container 120 may be applicable to all known corresponding coupling methods such as hook coupling and screw coupling.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

As described above, according to the liquid crystal display device according to the present invention, by providing a backlight unit in which the uniformity of the emitted light is increased, the thickness of the optical sheet layer can be reduced and the luminance can be improved. In addition, as the thickness of the optical sheet layer is reduced, the manufacturing cost of the backlight unit may be reduced and the thickness of the backlight unit and the liquid crystal display device may be reduced.

Claims (7)

A plurality of flat parts which refracting incident light and exiting the light; And At least one light generated between the flat portions and refracting light incident at an angle of incidence greater than light incident on the plurality of flat portions toward a vertical direction of the flat portion and relatively decreasing a decrease in luminance relative to the flat portion; A diffusion member comprising a prism pattern portion composed of the above V-shaped grooves. Light source; A plurality of flat parts disposed on the light source and refracting incident light, and a plurality of flat parts generated between the flat parts and light incident at a larger incident angle than light incident on the plurality of flat parts. A diffusing member comprising a prism pattern portion composed of at least one v-shaped groove which is refracted toward the vertical direction of the portion and which has a relatively low rate of decrease in brightness relative to the flat portion; An optical sheet layer disposed on the diffusion member; And And a storage container accommodating the light source, the diffusion member, and the optical sheet layer. The method of claim 2, The light source is Backlight unit that is one or more light sources. The method of claim 3, wherein And a flat portion of the diffusion member corresponds to an area where the line light source is located, and a prism pattern portion of the diffusion member is formed to correspond to an area where the line light source is not located. The method of claim 2, The light source is A backlight unit that is an embossed surface light source including convex portions and concave portions on a surface thereof. The method of claim 5, And the flat portion of the diffusion member corresponds to the convex portion of the surface light source, and the prism pattern portion of the diffusion member is formed to correspond to the concave portion of the surface light source. Light source; A plurality of flat parts disposed on the light source and refracting incident light; A diffusing member comprising a prism pattern portion composed of at least one v-shaped groove which is refracted toward the vertical direction of the portion and which has a relatively low rate of decrease in brightness relative to the flat portion; An optical sheet layer disposed on the diffusion member; A liquid crystal panel disposed on the optical sheet layer, the liquid crystal panel including a liquid crystal configured to receive an electrical signal and determine whether light is transmitted; And And a storage container accommodating the light source, the diffusion member, the optical sheet layer, and the liquid crystal panel.

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