KR20170049803A - Backlight Unit with Partition Wall Member and Display Device having the same - Google Patents

Abstract

The present invention relates to a backlight unit and a display device, wherein the backlight unit includes a lattice type partition member for separating each light source between individual light sources in a direct type backlight unit and one or more light transmission patterns are formed on the upper side of a partition of the partition member, thereby securing sufficient brightness in a corresponding region in a partial display mode in which only the part of the light sources are driven, and minimizing the occurrence of a shadow or Mura due to the partition in the entire display mode.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit including a barrier member,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit and a display device including the backlight unit, more specifically, a backlight unit having a partition member separating a light source, and a display device including the same.

2. Description of the Related Art [0002] As an information-oriented society develops, there have been various demands for display devices for displaying images. Recently, liquid crystal displays (LCDs), plasma display panels (PDPs) Various display devices such as an OLED (Organic Light Emitting Diode Display Device) have been utilized.

Among these display devices, a liquid crystal display (LCD) has an array substrate including a thin film transistor, which is a switching element for controlling on / off each pixel region, and an array substrate including a color filter and / or a black matrix A display panel including a top substrate, a liquid crystal material layer formed therebetween, a driving unit for controlling the thin film transistor, a backlight unit (BLU) for providing light to the display panel, and the like , A pixel (PXL) electrode provided in a pixel region, and a common voltage (Vcom) electrode, and the transmittance of light is adjusted accordingly, thereby displaying an image.

In the case of such a liquid crystal display device, a backlight unit for providing light from the outside must be provided, and a direct type backlight unit in which a light source is disposed directly under the display panel among the backlight units, The direct-type backlight unit includes a light source module disposed on an upper portion of a cover bottom, which is a lower support structure of a display device, a diffuser plate (DP) disposed on the upper portion of the light source module, One or more optical sheets disposed on the upper side, and the like.

The light source module of such a direct-type backlight unit includes a light source package such as an LED package, a light diffusing lens disposed above the light source package for diffusing evenly throughout the light source display, and a diffusion plate or diffusion plate disposed on the optical acid lens do.

On the other hand, in the case of a display device using a direct-type backlight unit, there is a case that the display device is driven in a local dimming mode in which only a certain light source is selectively turned on in a mode different from a mode in which the entire light source disposed in the entire backlight unit is turned on.

Such a local dimming mode may be expressed by a high dynamic range (HDR) function, which is to display only a part of the display device by turning on only a part of the light sources of the backlight unit.

On the other hand, since only a part of the light source is turned on in the HDR or the local dimming mode, the luminance of the corresponding region is lowered and the color sensitivity is also sensitive to the mode in which the entire light source is turned on.

Therefore, there is a requirement that the luminance of the light source to be turned on in the HDR or the local dimming mode should be about two times higher than the luminance of the corresponding light source in the mode in which the whole is turned on.

In addition, a secondary lens is disposed above each light source of the conventional direct-type backlight unit to diffuse the light from the light source to about 140 degrees or more, and further, a peak And an angle (peak angle) of about 70 degrees or more.

As described above, since the maximum optical lobe is formed at a certain angle from the light source by the existing secondary lens, it is difficult to secure sufficient luminance around the light source which is turned on in the HDR or local dimming mode.

In view of the foregoing, it is an object of the present invention to provide a backlight unit capable of ensuring brightness in a partial display mode in which only a part of a light source is driven by including a lattice type partition member for separating each light source between individual light sources in a direct- And a display unit including the unit.

Another object of the present invention is to provide a direct-type backlight unit which includes a lattice type partition member between respective light sources, and at least one light transmission pattern is formed in a region above the partition of the partition member, A backlight unit capable of ensuring sufficient brightness in the corresponding area and minimizing the occurrence of shadows or mura due to the partition in the entire display mode, and a display device including the backlight unit.

It is another object of the present invention to provide a liquid crystal display device in which at least one light transmission pattern is formed in a sidewall upper region of a lattice type partition member for partitioning between light sources and by optimizing the formation position, density and size of the light transmission pattern, And a display device including the backlight unit, which can secure sufficient brightness in a corresponding region in a display mode in which only a part of the light source is driven while minimizing the occurrence of shading or mura due to the light source.

According to this configuration, the driving current of the corresponding light source necessary for realizing the same performance in the display mode in which only a part of the light source is driven is minimized, thereby reducing power consumption.

In order to achieve the above-mentioned object, an embodiment of the present invention is a light-emitting device including a light source PCB, a plurality of light source units disposed on the light source PCB, the plurality of light source units being arranged on the light source PCB, And a diffusion plate disposed on the partition member. The backlight unit includes a plurality of light emitting diodes.

According to another embodiment of the present invention, there is provided a liquid crystal display device including a light source PCB, a plurality of light source portions disposed on the light source PCB, and a plurality of grid-like barrier rib members A backlight unit including a diffusion plate disposed on the partition member; A display panel disposed on the diffusion plate; And a support member for supporting at least one of the display panel and the backlight unit.

According to the embodiment of the present invention to be described below, by including the lattice type partition member for separating each light source between the individual light sources in the direct-type backlight unit, There is an effect that the driving current necessary for luminance implementation can be minimized.

Particularly, in the direct-type backlight unit, at least one light transmission pattern is formed in the upper part of the partition of the lattice type partition member for separating the respective light sources, and by optimizing the formation position, density and size of the light transmission pattern, There is an effect that sufficient luminance can be secured in the corresponding region in the display mode in which only a part of the light source is driven while minimizing the occurrence of shading or mura due to the partition member.

As a result, by using the partition member on which the light transmission pattern is formed, the power consumption in the partial display mode can be reduced while the partition is not visible in the entire display mode.

Fig. 1 is a sectional view of two types of backlight units. Fig. 1 (a) is an edge-type backlight unit. Fig. 1 (b) do.
2 shows a structure of an individual light source package used in a direct-type backlight unit and a light diffusion lens disposed thereon. FIG. 2A is an LED package including a mold frame, ) Is a flip chip LED package.
Fig. 3 shows the characteristics of a light source including a conventional secondary lens for light diffusion.
Fig. 4 shows a partial configuration of a backlight unit including a partition member according to an embodiment of the present invention.
Fig. 5 is a view for showing the light distribution in the full display mode and the partial display mode in the case where the partition wall member of Fig. 4 is provided with and without the partition wall member.
6 illustrates a structure including a height H1 of barrier ribs of a barrier rib member and a light transmission pattern formed in an upper region of barrier ribs according to an embodiment of the present invention.
Fig. 7 shows the configuration for the height H2 of the starting point Q 'of the light transmission pattern formed on the partition wall.
Fig. 8 shows an arrangement of the light transmission patterns formed on the partition walls of the partition member, and illustrates a configuration in which the ratio of the arrangement area of the light transmission patterns per unit area of the partition is determined as a function of the distance to the light source.
Fig. 9 shows a configuration in which the transmission area ratio, which is the ratio of the total area of the light transmission pattern to the total area of the partition walls of the partition member, is determined.
Fig. 10 shows the light distribution according to the magnitude of the transmission area ratio in Fig.
Fig. 11 exemplifies various forms of the light transmission pattern formed on the partition wall of the partition member.
12 shows a cross section of a backlight unit including a partition member according to an embodiment of the present invention and an entire display including the backlight unit.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In the drawings, like reference numerals are used to denote like elements throughout the drawings, even if they are shown on different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the components from other components, and the terms do not limit the nature, order, order, or number of the components. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; intervening "or that each component may be" connected, "" coupled, "or " connected" through other components.

Fig. 1 is a sectional view of two types of backlight units. Fig. 1 (a) is an edge-type backlight unit. Fig. 1 (b) do.

1, a display device to which an embodiment of the present invention can be applied includes a display panel 140 such as a liquid crystal display panel and backlight units 120 and 160 disposed below the display panel 140 to irradiate light to the display panel, A cover bottom 110 of metal or plastic that supports the backlight unit and extends over the entire rear surface of the display device, and the like.

The liquid crystal display device further includes a guide panel 130 for supporting the light source housing 127 constituting the backlight unit at the side while supporting the display panel 140 at an upper portion thereof, A case top 150 which is enclosed and extends to a part of the front surface of the display panel, and the like.

In such a liquid crystal display device, a backlight unit for providing light to the display panel is included, and the backlight unit is classified into an edge-type or a direct-type according to the arrangement of light sources and the transmission mode of light .

1, the edge type backlight unit 120 includes a light source module 127 including a light source 128 such as an LED, a holder or a housing for fixing the light source, and a light source driving circuit, A light guide plate (LGP) 124 for diffusing light to the entire panel area, a reflection plate 122 for reflecting light in the direction of the display panel, And one or more optical sheets 126 arranged for use such as improvement, diffusion and protection of light, and the like.

In this edge type backlight unit, light from the light source is incident on the light guide plate entrance portion, and is totally reflected by the light guide plate and spreads toward the display panel in the direction of the display panel.

1 (b), the direct-type backlight unit to which the present invention can be applied includes a light source PCB 161, a diffusion disposed at a predetermined distance above the light source PCB and diffusing light from the light source, Plate 164 and one or more optical sheets 166 disposed on top of the diffuser plate and a plurality of diffuser plate supports 164 (DPS) for preventing deflection of the diffuser plate Respectively.

The light source PCB 161 is disposed over the entire surface of the display device. An LED chip 162, which is a light source, is provided on the light source PCB, and a light diffusion lens 163 for diffusing light from each light source.

Generally, since the edge type backlight unit needs only a space corresponding to the thickness of the light guide plate, it can be slim down to 10 mm or less. However, since light is provided only on the side, it is difficult to realize a high luminance, and manufacturing cost is high due to parts such as a light guide plate , It is difficult to realize a local dimming function of irradiating light only in a local region of the display device.

On the other hand, the direct-type backlight unit has the advantage of high luminance, low manufacturing cost, and easy local dimming because it directs light from a plurality of light sources disposed on the front surface of the display device directly to the display panel. However, The optical gap (OG), which is a gap between the light source and the diffusion plate, must be set to a certain value or more in order to sufficiently diffuse the light from the LED as the display panel.

In particular, in a direct-type backlight unit, a light-emitting device composed of an LED package or the like serves as a kind of point light source, so that a light diffusion lens is used to diffuse the light uniformly. Such a light diffusion lens has a certain size, It is necessary to provide an installation space.

Also, as will be further described below in conjunction with FIG. 3 below, in some display modes, such as local dimming, the brightness reduction in the display area is limited by the fact that the maximum optical peak is at a constant angle from the vertical direction of the light source There was a problem that occurred.

2 shows a structure of an individual light source package used in a direct-type backlight unit and a light diffusion lens disposed thereon. FIG. 2A is an LED package including a mold frame, ) Is an LED package having a flip chip structure to which the present invention can be applied.

The LED package according to FIG. 2A includes a printed circuit board 210 and an LED chip 240 mounted on the printed circuit board 210. The printed circuit board 210 includes a printed circuit board base 211, an insulating layer 213, and a power wiring layer 215.

On the printed circuit board 210 on which the LED chip 240 is mounted, the LED chip 240 protrudes from the printed circuit board 210 to block light generated laterally from the LED chip 240, A sidewall 220 covering the edge of the LED chip 100 may be included and a light conversion layer 250 or a diffusion layer may be disposed in the opening region above the sidewall.

The LED chip 240 in the LED package according to FIG. 2 (a) may be a blue LED that is disposed between two electrodes to emit blue light, and the emitted blue light is reflected by the barrier rib 220 And converted into light of R, G, Y or the like in the rear photoconversion layer 250 to finally emit white light.

The light emitted from the LED package 200 of FIG. 2 (a) typically has a directivity angle or a diffusion angle of about 120 degrees. As described above, the optical gap, which is a gap between the light source and the diffusion plate, OG) is small, it is difficult to distribute the light to the front surface of the display device at a radiation angle of about 120 degrees.

Therefore, a light diffusion lens 300 for spreading the light from the LED package more widely should be used on the LED package 200. When such a light diffusion lens 300 is used, the radiation angle or the directivity angle of light can be increased to 160 to 170 degrees.

2 (b) shows an LED package in which an LED chip is directly formed on a substrate by a surface mount technology (SMT) without a mold frame or a lead frame as shown in FIG. 2 (a).

2B is a light source package represented by a so-called chip-on-board (COB) or chip scale package (CSP), in which an LED package 200 ' A light emitting portion 260 composed of two electrode layers and a light emitting layer disposed therebetween is formed on the growth substrate layer 270 having light transmittance and the phosphor sealing layer 280 is formed around the light emitting portion 260 .

2B is a so-called flip-chip, in which the blue light generated in the light emitting layer is converted into white light while passing through the growth substrate layer 270 and the phosphor sealing layer 280, And the light is also emitted in the lateral direction of the LED chip.

In the light source package of the flip chip structure as shown in FIG. 2 (b), the main emitted light is directed to the top of the package, and therefore, in order to increase the radiation angle or the directing angle of light, It is general to arrange a light diffusion lens on the upper side.

The light diffusing lens 300 may be formed of a material selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate, polymethylmethacrylate (PMMA), polycarbonate, polystyrene, polyolefin ), Cellulose acetate, polyvinyl chloride, and the like, and the top surface is formed to have a curved shape for light diffusion.

Fig. 3 shows the characteristics of a light source including a conventional secondary lens for light diffusion.

As shown in FIG. 3, the secondary lens for light diffusion functions to diffuse the light from the light source. As a result, the peak light lobe 340, which exhibits the strongest luminance among the light from the light source, .

At this time, the directing angle of light emitted from the secondary lens 330 is about 140 to 170 degrees, and thus the angle? Formed by the peak optical lobe 340 with the vertical direction of the light source is about 70 to 85 degrees.

That is, as shown in FIG. 3 (b), strong light is output in a region that is at an angle of about 70 to 80 degrees with respect to the vertical direction of the light source (0 degree).

In a backlight unit in which a plurality of light sources are disposed, the individual light sources each have a light distribution as shown in FIG. 3 (b), thereby providing a uniform overall brightness have.

However, in the partial display mode (HDR mode) such as the local dimming or the HRD mode in which only a part of the plurality of light sources is driven, the intensity of the light directed toward the upper portion of the driven light source is weakened, do.

That is, as shown in the upper graph of FIG. 3 (c), in the entire display mode, the uniform brightness is shown in the entire area of the backlight unit, but in the partial display mode in which only one light source is turned on as shown in the lower graph of FIG. The maximum luminance of the upper portion (x = 0) of the corresponding light source is reduced to about 66% or less of the luminance of the entire display mode.

Particularly, in the partial display mode, there is a requirement that the luminance of about twice (200%) as compared with the entire display mode of the region to be emitted in the partial display mode is guaranteed do.

Accordingly, in the partial display mode in which only one light source block is turned ON, in order to satisfy the luminance brightness reduction tendency in the case of using the conventional light diffusion secondary lens and satisfy the luminance guarantee requirement twice in the light source block, It is necessary to increase the current to about 5 times as much as the entire display mode or to control the other light sources around the light source blocks to be turned on with a constant driving current.

Therefore, the conventional backlight unit using the light-diffusing secondary lens has disadvantages such as increased power consumption in some display modes or additional control.

In order to solve this problem, in the embodiment of the present invention, the problem of brightness reduction in some display modes is solved by arranging the grid-shaped partition members for distinguishing each individual light source, and the partition member between the light sources is uneven Or a Mura pattern, in order to solve the problem of visible light.

4 shows a schematic perspective view of a backlight unit according to an embodiment of the present invention.

The backlight unit according to the embodiment of FIG. 4 includes a light source PCB 410, a plurality of light source units 420 disposed on the light source PCB, and barrier ribs disposed on the light source PCB, A grid-shaped partition member 440, and a diffusion plate 450 disposed on the partition member.

The light source PCB 410 is a plate-shaped printed circuit board disposed over the entire bottom surface of the display device or the backlight unit, and may be composed of a printed circuit board base, an insulating layer, a power wiring layer, or the like.

The light source unit 420 may be mounted on the light source PCB 410. The light source unit may include a light source chip such as an LED chip and a light diffusing lens disposed on the light source chip. 2, a light source package including a light source chip and a structure for supporting the light source chip may be used.

The light source chips constituting the light source unit 420 are arranged on the light source PCB 410 at regular intervals and are mounted on the light source PCB without the mold frame or the lead frame by the surface mount technology (SMT) (COB) or a chip scale package (CSP) type chip, which is a so-called chip-on-chip

Alternatively, the light source chip may be formed of a light emitting layer disposed between the electrodes, and may be a chip called a flip-chip, but is not limited thereto.

The light source chip used in the present embodiment may be a white LED that emits white light, but is not limited thereto. The light source chip may be a blue LED that emits blue light having a wavelength of about 430 to 450 nm, And may further include a light conversion member that converts light into light.

The light source chip used in this embodiment may be a separate chip such as a blue LED chip, but may be a light source package composed of an LED chip, a mold structure, and a lead frame.

Each of the light sources 420 according to the present embodiment emits light so as to have a predetermined directivity angle, and light having the highest brightness or intensity among the emitted light can be expressed as a peak light, and the peak light Lp can be expressed by the light source PCB And may have a constant angle? With respect to the vertical direction.

The lattice-shaped barrier rib member 440 is a lattice-like member including a plurality of barrier ribs disposed between the respective light source portions, and each light source portion is surrounded by the barrier ribs of the barrier rib member 440, do.

In this specification, for convenience, a region surrounded by the four-sided barrier ribs of one barrier rib member is represented by a block, and one of the four barrier ribs constituting one block is represented by one barrier rib.

The partition member 440 may be made of an opaque material that does not allow light to pass, and is a member in which partition walls having a constant thickness are arranged in a lattice pattern.

As the material of the partition member 440, a white resin, a white polycarbonate (PC) or the like having light reflection characteristics may be used, but the metal material such as aluminum may be used.

The partition wall member 440 may be manufactured by injecting a material such as white resin. The smaller the thickness of the partition walls of the partition wall member, the better the thickness may be, taking into account the reasons for the injection process or the self- .

As shown in FIG. 4 (b), the light from each light source part is not propagated to other block areas but emitted only to the upper area of the corresponding block by the partition member 440, The problem that the brightness of the light source turned on in the mode (HDR mode) is reduced can be improved. The effect caused by the partition member 440 will be described in more detail with reference to FIG.

The diffuser plate 450 is a plate-shaped optical member disposed in parallel with the light source PCB 410 at the upper portion of the partition member 440, and functions to diffuse the light from the light source portion evenly over the entire display panel.

The diffusion plate 450 may be formed of a material such as polymethyl methacrylate (PMMA), methyl styrene (MS) resin, polystyrene (PS), polypropylene (PP), polyethylene terephthalate And is formed of at least one light-transmitting material selected from polycarbonate (PC).

Further, in order to improve the light diffusion characteristics of the diffusion plate 450, a plurality of diffusion patterns may be formed on a part of the surface of the diffusion plate 450. Such a diffusion pattern may be formed only in a partial area corresponding to the light source, Or may be formed throughout.

In addition, a plurality of scattering particles may be included in the diffusion plate 450 to widely diffuse the incident light. Such scattering particles may be in the form of a bead, and the shape, size and distribution of the scattering particles may be regular or irregular.

Fig. 5 is a view for showing the light distribution in the full display mode and the partial display mode in the case where the partition wall member of Fig. 4 is provided with and without the partition wall member.

5A shows the light emitting state of the backlight unit in the full display mode (left drawing) and the partial display mode (right drawing) when the partition member according to the present embodiment is not used, and FIG. b show the light emitting state of the backlight unit in the full display mode (left drawing) and the partial display mode (right drawing) when the partition member according to the present embodiment is used.

5, it is assumed that only one light source section is turned on in the partial display mode.

As shown in Fig. 5, in a partial display mode in which only one light source unit is ON, the light source unit has a uniform light distribution throughout the backlight unit in the entire display mode when the partition member is not used, A phenomenon that the light spreads widely in the upper region of the light source portion which is turned on due to the directivity angle is generated (the right drawing of Fig. 5 (a)

Therefore, the brightness around the light source portion, which is turned on in the partial display mode, is much reduced as compared with the entire display mode, and the driving current is increased in order to compensate for the luminance.

In the partial display mode, only a desired specific area is required to emit light. As shown in the right side of FIG. 5 (a), since the light emitting area spreads widely, the performance of the partial display mode emitting only a specific area is deteriorated.

On the other hand, when the partition member according to the present embodiment is used, as shown in the right drawing of FIG. 5 (b), the light from the light source portion emitted in the partial display mode is blocked by the partition walls of the partition member, It is possible to emit only the block of the light source unit which is turned on.

In particular, since the light is concentrated and emitted only to the upper portion of the block by the barrier ribs, the luminance drop of the light emitting region can be minimized.

On the other hand, when the partition wall of the partition member 440 extends to the bottom surface of the diffusion plate 450, there is a possibility that the partition wall is visible with one spot or mura as shown in the left side of FIG. 5 (b).

FIG. 5C is a graph showing the light distribution in the full display mode and the partial display mode in a case where a grid-shaped partition member having a total of 25 blocks (5 * 5) is used and a case where it is not used.

As shown in Fig. 5 (c), in the entire display mode of the backlight unit in which the partition member is not used, a uniform light distribution is shown throughout the backlight unit (dotted line) And the light emitting region spreads widely around the driving light source portion (see the broken line + the triangle line)

On the other hand, when the partition member according to the present embodiment is used, as shown by the dotted line, only the blocks of the light source unit driven in the partial display mode emit light, so that the performance of the partial display mode can be improved, Mode is maintained at about 90% or more of the luminance of the mode, so that the reduction of the luminance can be minimized.

However, when the barrier rib member according to the present embodiment is used as indicated by the one-dot chain line, the brightness in the barrier rib portion is lowered in the entire display mode, and grid-like shading or mura may be generated as a whole.

Accordingly, in another embodiment of the present invention, in order to solve the problem of generation of mura due to the barrier ribs 440, the height of barrier ribs may be limited to a certain range, .

FIG. 6 illustrates a structure including a light transmission pattern formed in a region above a barrier rib of a partition member according to an embodiment of the present invention. FIG. 7 is a cross- (H2). ≪ / RTI >

As shown in FIG. 6, at least one light transmission pattern 620 may be disposed in a region above the partition 610 of the partition member 600.

The light transmission pattern 620 is formed as an opening that punctures a certain portion of the partition 610 so that the light from the light source passes through the partition wall and proceeds to another block.

The height H1 of the partition wall 610 constituting the partition member 600 is determined by the height of the optical gap O / G, which is the distance between the upper surface of the light source PCB 410 or the bottom surface of the diffusion plate 450, It is preferable that the ratio is determined to be 80% or more.

That is, the partition 610 of the partition member 600 may extend all the way between the light source PCB and the diffusion plate, but may extend only to about 80% or more of the optical gap, which is the distance between the light source and the diffusion plate.

6, the structure in which the height H1 of the partition 610 is limited to 80% or more of the optical gap, or the structure in which the light transmission pattern 620 is formed in the upper partial area of the partition wall, Is caused to progress to some other region, it is possible to improve the mura phenomenon caused by the barrier rib in the entire display mode.

As the height H1 of the barrier rib approaches the optical gap O / G, the brightness of the driving block increases, but there is a possibility of a mura due to the barrier in the entire display mode.

On the other hand, as the height H1 of the barrier rib decreases, the possibility of generating a mura in the entire display mode is lowered due to the blocking effect of the barrier ribs, but the brightness of the driving block is reduced in the partial display mode.

6C shows the light distribution in the corresponding block according to the height H1 of the partition. When the height H1 of the partition is 80% or more of the optical gap O / G, The separation function can be guaranteed.

Even if the height H1 of the barrier ribs is made equal to the optical gap, as described later, the light transmission pattern 620 formed in the upper region of the barrier ribs reduces the light blocking effect of the barrier ribs to some extent, It is possible to transmit a part of the data to another block, and as a result, the mura phenomenon due to the partition in the entire display mode can be suppressed.

The detailed structure of the light transmission pattern 620 will be described in detail below.

7, the height H2 of the starting point Q 'of the light transmission pattern is formed in the upper part of the partition wall 610 by the light source part 420, Is preferably equal to or greater than the height of the peak light spot (Q) at which the peak light (Lp)

If the height H2 of the starting point Q 'of the light transmission pattern is smaller than the height of the peak light point Q at which the peak light Lp of the light source unit meets the partition wall, the peak light advances to another adjacent block Therefore, there is a possibility that the light blocking effect by the barrier ribs is greatly reduced.

Therefore, by setting the height H2 of the start point Q 'of the light transmission pattern to be equal to or greater than the height of the peak light point Q at which the peak light Lp of the light source unit meets the partition wall, There is an effect that some light travels to another block through the light transmission pattern to reduce the mura phenomenon due to the partition wall.

Fig. 8 shows an arrangement of the light transmission patterns formed on the partition walls of the partition member, and illustrates a configuration in which the ratio of the arrangement area of the light transmission patterns per unit area of the partition is determined as a function of the distance to the light source.

Since the light from the light source 420 proceeds in a circular shape, the intensity of light reaching the partition wall is proportional to the square of the distance between the light source and the corresponding point on the partition wall.

Accordingly, the light transmission pattern 620 is not distributed at the same density over the entire length of the barrier rib, but can be variably formed as a function of the distance to a specific point of the barrier rib and the light source portion.

In this specification, the point of the partition closest to the center of the light source 420 is represented by the center of the partition, the distance between the center point of the partition and the light source is represented by d1, and the point moved from the center of the partition toward the corner of the block Expressed as an edge.

At this time, the arrangement area of the light transmission pattern per unit area of the partition 610 can be increased in proportion to the square of the distance from the center of the light source.

That is, as shown in FIG. 8A, the density or the arrangement area of the light transmission pattern becomes larger as the distance from the central portion of the partition increases toward the edge. More specifically, the density or the arrangement area of the light transmission pattern becomes Is proportional to the square of the distance (d1, d2) between the point and the light source part.

In the first method for implementing such a configuration, as shown in FIG. 8B, the light transmitting pattern includes a plurality of discrete light transmitting patterns 622 of the same size, Can be arranged more densely.

As shown in FIG. 8C, in the second mode, the light transmission patterns include individual light transmission patterns 624, 624 ', and 624' 'of different sizes, and the sizes of the individual light transmission patterns are It can be configured to become larger from the center to the edge.

That is, in the first method, the individual light transmitting patterns of the same size are used, but the number of the light transmitting patterns is increased as they approach the edge. In the second method, the distance between the light transmitting patterns or the light transmitting pattern per unit area But the larger the light transmission pattern is used to the edge.

When the arrangement area of the light transmission pattern per unit area of the barrier rib 610 is formed to increase in proportion to the square of the distance from the center of the light source part, the transmitted light at the central point of the partition wall where relatively strong light arrives is made small At the edge of the partition where relatively weak light arrives, much light is transmitted and the same amount of light is transmitted throughout the block.

Therefore, since the same amount of light is transmitted to the adjacent blocks over the whole of the partition walls surrounding the light source portion, the generation of mura due to the partition walls in the entire display mode can be uniformly reduced.

Fig. 9 shows a configuration in which the transmission area ratio, which is the ratio of the total area of the light transmission pattern to the total area of the partition walls of the partition member, is determined.

On the other hand, the ratio of the total area of the light transmission pattern to the total area of the partitions constituting one of the four faces of the block can be defined as a transmission area ratio.

As shown in Fig. 9A, the distance between adjacent barrier ribs parallel to the barrier rib, that is, the width of one barrier rib is denoted by b, the thickness of the barrier rib is denoted by a, and the height of the barrier rib is denoted by H1.

In this case, when the total area of one partition is b * H1 and the total sum of the areas of the light transmission patterns formed on the partition is A, the transmission area ratio R is expressed as A / (b * H1) .

In this embodiment, such a transmission area ratio R can be determined as a function of the distance between the adjacent partition walls parallel to the partition wall or the width b of the one partition wall and the thickness a of the partition wall, and more specifically, (R) can satisfy the following expression (1).

[Equation 1]

(Where b is a distance between adjacent barrier ribs parallel to the barrier rib, a (a), a (b) Is the thickness of the partition wall, and H1 is the height of the partition wall)

That is, the transmittance area ratio R, which is the ratio of the total area of the light transmission pattern to the total area of the partition walls of the partition member, is smaller than the value of [1 - (b * H1) / (2a + 2a + b) * H1] It is preferable to form a light transmission pattern.

For example, assuming that b = 80 mm, a = 1 mm and H1 = 10 mm, it is preferable to form the light transmission pattern such that the transmission area ratio R is less than about 4.76% (1-800 / 840) * 100 Do.

Fig. 10 shows the light distribution according to the magnitude of the transmission area ratio in Fig.

10 (a), when the transmissive area ratio R is small, the light transmitting performance of the light transmitting pattern is hardly ensured, so that the brightness reduction area A in the part of the partition wall is generated, Mura can be generated.

On the other hand, as shown in FIG. 10 (b), when the transmissive area ratio R is large enough not to satisfy the expression (1), a large amount of light travels to adjacent blocks, A light increasing region B where two blocks of transmitted light are added is generated.

The light intensity of the partition wall portion becomes stronger than the portion adjacent to the partition wall due to the light increase region B, and as a result, a diverging Mura region B 'in which the partition wall is brighter in the entire display mode can be generated have.

On the other hand, in the case where the transmission area ratio R, which is the ratio of the total area of the light transmission pattern to the total area of the barrier ribs, is determined optimally as described above, The size of the light increase region C 'due to the transmitted light from the adjacent block becomes equal to the size of the light increase region C' lost due to the adjacent block. As a result, It is possible to solve this problem.

Fig. 11 exemplifies various forms of the light transmission pattern formed on the partition wall of the partition member.

However, the present invention is not limited to this. The triangle light transmitting pattern 1620 having an opened upper part as shown in FIG. 11 (a) or another polygon, Circular, elliptical, or the like.

In addition, the light transmission pattern need not necessarily have an open top shape, but may be a closed aperture transmission pattern 1620 'as shown in FIG. 10 (b).

Of course, in all cases, the density or the formation area of the light transmission pattern should be increased toward the edge of the partition, and the light transmission pattern 1620 " in the form of a small circular hole as shown in FIG. 10 (c) It may be a structure that forms more.

12 shows a cross section of a backlight unit including a partition member according to an embodiment of the present invention and an entire display including the backlight unit.

The display device according to the present embodiment includes a backlight unit 1300 including a partition member 1600, a display panel 1240 disposed above the backlight unit, a support member for supporting at least one of the display panel and the backlight unit, And the like.

The backlight unit 1300 further includes a light source PCB 1310, a plurality of light source units 1320 disposed on the light source PCB 1310 so as to be spaced apart from each other, and a light transmission pattern 1620 disposed in the upper region, A lattice type partition wall member 1600 including the partition walls, and a diffusion plate 1350 disposed on the partition wall member.

The light source PCB 1310 may further include a reflection plate 1330 that reflects light from the light source to the display panel side. The reflection plate 1330 may have an opening hole for the light source, May be exposed to the outside of the reflector.

Since the detailed configuration of the partition member 1600, which is a main constituent of the present invention, is the same as that described above, a detailed description thereof will be omitted to avoid duplication.

A plurality of optical sheets 1360 may be disposed on the diffusion plate 1350 to condense the light passing through the diffusion plate and allow a more uniform surface light source to be incident on the display panel 1240.

The optical sheet 1360 includes a condensing sheet or a prism sheet PS having a condensing function, a diffusing sheet DS for diffusing light, a reflective polarizing plate (DBEF) Film, and the like.

In the case of a liquid crystal display panel, the display panel 1240 receiving light by the backlight unit 1300 according to the present embodiment includes a plurality of gate lines, a data line and a pixel defined in the intersection area, An array substrate including a thin film transistor serving as a switching element for adjusting light transmittance in a pixel, an upper substrate provided with a color filter and / or a black matrix, and a liquid crystal material layer formed therebetween have.

Meanwhile, the display panel to which the present invention can be applied is not limited to such a liquid crystal display panel, but may include other types of display devices requiring a backlight unit.

Further, the supporting member for supporting the backlight unit or the display panel includes a cover bottom (Cover Bottom) 1210 which is a metal or plastic back cover covering a part of the rear surface and the side surface of the display device, A guide panel 1230, a case top 1250 covering an outermost side of the display device and a top edge of the display panel, and the like.

As described above, in the display device of a general structure, in the partial display mode in which only one light source block is turned ON, the brightness decreases in the case of using the conventional light diffusion secondary lens, and in the light source block, The driving current of the light source must be increased by about 5 times as compared with the entire display mode.

On the other hand, in the case of using the backlight unit including the partition member according to the present embodiment, even in the partial display mode in which only one light source unit (block) is turned ON, luminance of about 90% or more of the luminance in the entire display mode can be realized. The driving current of the light source may be increased by about 2 to 3 times as compared with the entire display mode. Therefore, the power consumption in the partial display mode can be reduced by about 50% or more as compared with the conventional structure.

As described above, according to this embodiment, by including the lattice type partition member for separating each light source between the individual light sources in the direct-type backlight unit, it is possible to realize a constant luminance of the display region in the partial display mode It is possible to minimize the driving current required for the driving circuit.

Further, at least one light transmission pattern is formed in a region above the partition of the grid-shaped partition member for separating each individual light source in the direct-type backlight unit, and by optimizing the formation position, density and size of the light transmission pattern, There is an effect that sufficient luminance can be ensured in the corresponding region in the display mode in which only a part of the light source is driven while minimizing the occurrence of shadow or mura due to the barrier in the mode.

As a result, by using the partition member provided with the light transmission pattern, the power consumption in the partial display mode can be reduced while the partition in the entire display mode is not visually recognized.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. , Separation, substitution, and alteration of the invention will be apparent to those skilled in the art. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

440, 600, 1600: partition wall member 610: partition wall
620, 1620: light transmission pattern 410, 1310: light source PCB
420, 1320: Light source part 450, 1350: Diffusion plate
1210: Cover bottom 1230: Guide panel
1240: Display panel

Claims (17)

Light source PCB;
A plurality of light sources disposed on the light source PCB and spaced apart from each other;
A lattice type partition wall member disposed on the light source PCB and including partition walls for separating the light source portions;
A diffusion plate disposed on the partition member;
And a backlight unit for a display device. The method according to claim 1,
And at least one light transmission pattern is disposed in a region above the partition of the partition member. 3. The method of claim 2,
Wherein a height H1 of the barrier ribs is 80% or more of an optical gap (O / G), which is a distance between the upper surface of the light source PCB or the bottom surface of the diffusion plate. The method of claim 3,
Wherein a height H2 of a start point Q 'of the light transmission pattern is greater than or equal to a height of a peak light point Q of the light source unit where the peak light Lp meets the partition wall. 3. The method of claim 2,
Wherein the arrangement area of the light transmission pattern per unit area of the partition wall increases in proportion to the square of the distance from the center of the light source part. 6. The method of claim 5,
Wherein the light transmitting pattern includes a plurality of identical individual light transmitting patterns, and the individual light transmitting patterns are densely arranged from the center to the edge of the partition wall portion. 6. The method of claim 5,
Wherein the light transmitting pattern includes individual light transmitting patterns of different sizes and the size of the individual light transmitting pattern is increased from the center to the edge of the partition wall. 3. The method of claim 2,
Wherein a ratio of a transmissive area, which is a ratio of an entire area of the light transmission pattern area to a total area of the barrier ribs, is determined as a function of a distance b between adjacent barrier ribs parallel to the barrier ribs and a thickness a of the barrier ribs. Backlight unit. 9. The method of claim 8,
Wherein the transmissive area ratio (R) is determined by the following equation.
R (transmission area ratio)% 1 - (b * H1) / (2a + 2a + b) * H1 * 100 (%)
(Where b is the distance between adjacent partition walls parallel to the partition, a is the thickness of the partition, and H1 is the height of the partition) A lattice type partition wall member including a light source PCB, a plurality of light source portions disposed on the light source PCB, and a partition having a light transmission pattern disposed in an upper region of the light source portion, A backlight unit including a diffuser plate;
A display panel disposed on the diffusion plate;
A support member for supporting at least one of the display panel and the backlight unit;
. 11. The method of claim 10,
Wherein the height H1 of the partition wall is 80% or more of an optical gap (O / G) which is a distance between the light source PCB and the bottom surface of the light source unit. 12. The method of claim 11,
The height H2 of the starting point Q 'of the light transmission pattern is greater than or equal to the height of the peak light point Q at which the peak light Lp of the light source unit meets the partition wall. 11. The method of claim 10,
Wherein an arrangement area of the light transmission pattern per unit area of the partition wall increases in proportion to a square of a distance from the center of the light source part. 14. The method of claim 13,
Wherein the light transmission pattern includes a plurality of identical individual light transmission patterns, and the individual light transmission patterns are densely arranged from a center to an edge of the partition wall portion. 14. The method of claim 13,
Wherein the light transmission pattern includes individual light transmission patterns of different sizes, and the size of the individual light transmission pattern increases from the center to the edge of the partition wall. 11. The method of claim 10,
Wherein a ratio of a transmissive area, which is a ratio of an entire area of the light transmission pattern area to a total area of the barrier ribs, is determined as a function of a distance b between adjacent barrier ribs parallel to the barrier ribs and a thickness a of the barrier ribs. . 17. The method of claim 16,
Wherein the transmissive area ratio (R) is determined by the following equation.
R (transmission area ratio)% 1 - (b * H1) / (2a + 2a + b) * H1 * 100 (%)
(Where b is the distance between adjacent partition walls parallel to the partition, a is the thickness of the partition, and H1 is the height of the partition)

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