KR101231714B1 - Direct type backlight unit having improved lamp mura - Google Patents

Abstract

The present invention relates to a direct type backlight unit having improved lamp mura, and more particularly, a plurality of linear light sources arranged in parallel at regular intervals, a light transmitting structure surrounding the light sources, and the lamp and the light transmitting structure. It relates to a direct type backlight unit including a lower case for receiving.

According to the present invention, an additional light-transmitting structure may be installed in a light source so that light emitted from a lamp may be dispersed and emitted in a wider area, thereby reducing a difference in luminance to improve a lamp mura, thereby realizing a uniform screen.

Light source, brightness, lamp mura, backlight unit, light transmissive, structure

Description

Direct type backlight unit with improved lamp mura {DIRECT TYPE BACKLIGHT UNIT HAVING IMPROVED LAMP MURA}

The present invention relates to a direct type backlight unit having improved lamp mura, and more particularly, to a direct type backlight unit designed to improve lamp mura by disposing a light-transmitting structure in a lamp of the direct type backlight unit.

Since the liquid crystal display panel of the liquid crystal display device does not emit light by itself, a liquid crystal display panel has a backlight unit for providing light under the liquid crystal display panel. The backlight unit includes an edge type backlight unit and a direct backlight unit according to the position of the light source. Separated by. Among these, the direct type backlight unit has been widely used in large liquid crystal displays because of its high light utilization, easy handling, and no limitation on the size of the display surface. The direct type backlight unit is composed of various optical films such as a light source, a reflective film, a light collecting film, and a diffusion film.

The light source applied to the direct backlight unit is appropriately selected and used according to the size and purpose of the liquid crystal display device. The light source applied to the direct type backlight unit is divided into types of point light sources such as incandescent bulbs and white halogen lamps, fluorescent lamps (hot cathodes, cold cathodes and external electrodes). And a planar light source by EL (Electroluminescent), a matrix-shaped light emitting diode (LED), and the like. Cold Cathode Fluorescent Lamp (CCFL) or External Electrode Fluorescent Lamp (EEFL) can be used. In case of using external electrode fluorescent lamp, multi-drive is possible and inverter can be reduced to one. There is an advantage to reduce the weight of the.

Recently, one of the main concerns of the LCD backlight unit (BLU) configuration is to slim down the configuration of the backlight unit. In particular, efforts have been made to reduce the number of lamps that enter the configuration of the backlight unit, as well as simply reducing the thickness of the backlight unit in the direct-type LCD backlight unit. Here, the reduction in the number of lamps not only reduces the cost of the backlight unit makers, but also reduces the effect that the shape or characteristics of the diffusion plate, the diffusion sheet, or the light collecting sheet disposed on the upper part of the lamp are deformed by the heat generated from the lamp. It is meaningful in that it can.

 However, as the number of lamps decreases and the distance between the lamps and the diffuser plate is thus close, it becomes difficult to conceal the lamp with a conventional diffuser plate, resulting in a difference in luminance between and without the lamp. Mura) occurs. Therefore, many efforts are currently underway to solve this problem.

Slimming in the direct-type backlight unit can generally be expressed as the ratio of P / G indicating how much the gap G between the diffuser plate and the lamp is minimized relative to the gap P between the lamp and the lamp. .

The P / G value of the conventional backlight unit structure without slimming is about 1.7, and it should have a value of at least 2.4 to be considered slimming. This makes the distance between the lamps wider and the distance between the lamps and the diffuser closer, which makes the area with the lamp brighter and the space without the lamp darker. It makes it more difficult to conceal the change in brightness of the lamp. Lamp mura in the direct backlight unit is a problem because it can cause uneven luminance distribution in the image finally seen on the LCD panel.

Currently, the main methods improved for this are the formation of a dot pattern on at least one side of the diffuser plate and the sheet facing the lamp to disperse lamp mura by dispersing light at the center of the lamp and concentrating light between the lamps. As a method of obtaining an effect, a method using an additional pattern applied to an existing diffusion plate or increasing the number of diffusion sheets on the diffusion plate is used depending on a situation.

However, this conventional method tends to use a special sheet or is not suitable for slimming including an additional optical sheet, so that not only the existing general diffusion plate can be applied but also the effect of reducing the number of optical sheets is simultaneously applied. There is a need for a method of improving lamp mura that can be obtained.

One aspect of the present invention is to improve the concealment of the lamp by applying an additional structure to the lamp unlike the conventional method to solve the problem of the lamp line concealment according to the slimming of the direct type backlight unit.

According to one aspect of the present invention, in order to achieve the above object, by providing a light-transmitting structure in the light source, the light emitted from the lamp is refracted to be dispersed in a wider area by emitting a backlight to improve the concealment of the lamp line The unit is provided.

According to the present invention, it is possible to reduce the difference in luminance at the light source while using the conventional diffuser plate without applying an additional diffusion sheet or applying a special pattern for reducing the luminance difference. That is, by forming a light-transmissive polygonal structure surrounding the light source and refracting the light emitted from the light source to distribute the light evenly over a wider area, it is possible to improve the mura of the lamp, thus applying the conventional diffuser plate optical sheet Has the effect of reducing the number of.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

As the backlight unit becomes slimmer, efforts are being made to reduce not only the thickness of the backlight but also the number of lamps.As such, the number of lamps decreases and the location of the lamps increases as the distance between the lamps and the diffuser disposed above the lamps becomes closer. The difference in luminance occurs at and where there is no so-called lamp mura.

Figure 1 (a) is a cross-sectional view of a backlight unit including a conventional light source, according to the present invention by forming a light transmitting structure surrounding the light source as shown in Figure 1 (b) through the refraction of light We propose a method of deriving a uniform distribution.

According to the present invention, there is provided a direct type backlight unit including a plurality of line light sources arranged in parallel at regular intervals, a light transmissive structure surrounding the line light sources, and a lower case for storing the light sources and the light transmissive structures. do.

According to the present invention, unlike the existing light source of FIG. 2 (a), there is provided a backlight unit further including a cylindrical light transmitting structure surrounding the line light sources arranged in parallel at regular intervals (FIG. 2 (b)). .

The light transmissive structure is formed in addition to the light source in order to refract the light emitted from the light source to uniformly diffuse the light in a wider range, the quadrilateral, hexagonal or 8 including a rhombus extending in a direction parallel to the line light source It consists of a polygonal polygonal cylinder structure. For the description of the polygonal structure of the light transmissive structure, as shown in FIG. 3, each vertex sequentially sequential in the clockwise direction with respect to any one vertex is A, B, C, D, E, F, G and H, respectively. It will be referred to as.

The angles θ _A , θ _B , θ _C , θ _D , θ _E , θ _F , θ _G, and θ _H of the vertices of the polygon are the angles of the angle _A of the angle θ _A and the obtuse angle (<90 °). > 90 °), it is preferable to have the following range.

≤θ_A=θ_E≤50°, 내각 θ_B, θ_D, θ_F 및 θ_H는 155°≤θ_B=θ_D=θ_F=θ_H≤

, 그리고 내각 θ_C 및 θ_G는

≤θ_C=θ_G≤180°의 범위인 것이 바람직하다. 여기서, 상기 R₁은 선광원 램프의 중 심으로부터 다각형을 구성하는 변 중 임의로 선택된 하나의 변 또는 이의 연장선까지의 최단 거리를 나타내며, 상기 P는 램프의 중심에서 인접한 다른 램프의 중심까지의 거리(pitch)를 의미하며, G₀는 선광원 램프의 중심으로부터 확산판의 밑면까지의 거리를 나타낸다.First, when the angle of A is an acute angle, the angles θ _A and θ _E are

≤θ _A = θ _E ≤50 °, Cabinet θ _B , θ _D , θ _F and θ _H are 155 ° ≤θ _B = θ _D = θ _F = θ _H ≤

, And the cabinets θ _C and θ _G are

It is preferable that it is the range of ≤ θ _C = θ _G ≤ 180 °. Here, R ₁ represents the shortest distance from the center of the line light source lamp to one of the sides constituting the polygon or an extension line thereof, and P is the distance from the center of the lamp to the center of another lamp ( pitch), and G ₀ represents the distance from the center of the line light source lamp to the bottom of the diffuser plate.

보다 작으면 인접한 램프의 다각형 구조물과 서로 겹쳐지게 되는 문제가 있고, 50°를 초과하면 램프무라 개선 효과가 미미하다. 그리고, B의 내각이 155°보다 작으면 램프무라 개선 효과가 미미하거나 내구성에 취약한 구조를 갖게 되는 문제가 있고 B의 내각은 기하학적으로

보다 클 수 없다. 또한, C의 내각이

미만인 경우는 다각형 구조물의 높이가 선광원 램프와 확산판 사이 거리(G₀)보다 크기 때문에 사용할 수 없고, C의 내각이 180°를 초과하는 경우는 다각형 구조물에서 C 또는 G 지점에서의 두께가 최박부의 두께(GAP 2)보다 작아져서 내구성에 문제를 일으킬 수 있다.Cabinet of A

If smaller, there is a problem of overlapping with the polygonal structures of adjacent lamps, and if it exceeds 50 °, the lampmura improvement effect is insignificant. In addition, if the angle of B is smaller than 155 °, there is a problem in that the lamp mura improvement effect is insignificant or the structure is vulnerable to durability, and the angle of B is geometrically

Cannot be greater than Also, the Cabinet of C

If the height of the polygonal structure is less than the distance (G ₀ ) between the line light source lamp and the diffuser plate, it cannot be used. If the angle of C exceeds 180 °, the thickness at the point C or G of the polygonal structure is the maximum. It may become smaller than the thickness of the thin part (GAP 2), which may cause durability problems.

≤θ_C=θ_G ≤80°의 범위인 것이 바람직하다. A의 내각이 100°미만이면, 램프무라 개선 효과가 미미하며, 180°를 초과하면 다각형 구조물에서 A 또는 E 지점에서의 두께가 최박부의 두께(GAP 2)보다 작아져서 내구성에 문제를 일으킬 수 있다. 그리고, B의 내각이 140°미만이면 램프무라 개선 효과가 미미하거나 내구성에 취약한 구조를 갖게 되는 문제가 있으며, 180°를 초과하는 경우에도 램프무라 개선 효과가 미미하다. 또한, C의 내각이

미만인 경우는 다각형 구조물의 높이가 선광원 램프와 확산판 사이 거리(G₀)보다 크기 때문에 사용할 수 없으며, 80°를 초과할 경우는 램프무라 개선 효과가 미미하다. Next, when the angle of A is an obtuse angle, the angles θ _A and θ _E are 100 ° ≤θ _A = θ _E ≤180 °, and the angles θ _B , θ _D , θ _F and θ _H are 140 ° ≤θ _B = θ _D = θ _F = θ _H ≤ 180 °, and the angles θ _C and θ _G

It is preferable that it is the range of ≤ θ _C = θ _G ≤ 80 °. If the angle of A is less than 100 °, the lampmura improvement effect is insignificant. If it exceeds 180 °, the thickness at the point A or E in the polygonal structure becomes smaller than the thickness of the thinnest part (GAP 2), which may cause durability problems. have. In addition, when the angle of B is less than 140 °, there is a problem that the lamp mura improvement effect is insignificant or has a structure vulnerable to durability, and even when it exceeds 180 °, the lamp mura improvement effect is insignificant. Also, the Cabinet of C

If it is less than the height of the polygonal structure can not be used because it is larger than the distance (G ₀ ) between the line light source lamp and the diffuser plate, if it exceeds 80 ° lampmura improvement effect is insignificant.

In this case, the cabinet of E is the same as the cabinet of A, the cabinets of D, F, and H are the same as the cabinet of B, and the cabinet of G is the same as the cabinet of C for uniform distribution of light. desirable.

In the light-transmitting structure according to the present invention, when the internal angle of A is an acute angle, the smaller the angle of A, the smaller the internal angle of C when the internal angle of A is obtuse, the lower the luminance difference tends to be. A forms an acute angle. This is because when the light transmissive structure is long in shape, the difference in luminance may be lowered because the structure itself spreads light widely. In the case of the light transmissive structure having a long shape, the structure is formed from the light source of the backlight unit on which the structure is placed. In the recycling process in which the light emitted through the upper diffusion plate and the reflective film at the bottom is reflected many times, the light-transmitting structure encounters the light-transmissive structure. At this time, the longitudinally long shape of the light-transmissive structure broadly distributes the light. This is due to having a more favorable trend.

As described above, the light transmissive structure according to the present invention may be formed in the shape of a lozenge, a hexagon, or an octagon, and the lamp is present by inducing a uniform distribution of light by diffusing the light through each side of the polygon formed as described above. It is possible to reduce the difference in luminance between the part of the light emitting device and the part where no lamp exists.

이하인 것이 바람직하다. 여기서, R_L은 램프의 반지름에 해당한다. 최박부의 두께가 0.3mm 미만인 경우 내구성이 떨어지는 문제가 있으며,

초과인 경우, 램프무라의 개선 효과가 미미해지는 문제가 있다. On the other hand, the thickness of the thinnest portion of the structure (GAP 2) is 0.3 or more

Or less. Where R _L corresponds to the radius of the lamp. If the thickness of the thinnest part is less than 0.3mm, there is a problem that durability is poor,

When it exceeds, there exists a problem that the improvement effect of lamp mura becomes insignificant.

이하의 이격거리(GAP 1)를 갖도록 배치되는 것이 바람직하다. 구조물이 광원으로부터 0.1mm 미만의 간격을 갖는 경우 선광원 램프를 구조물 내로 삽입 시 어려움이 있음과 동시에 광원과 구조물 사이에 열적 수축과 팽창에 의한 마찰을 발생시킬 수 있는 문제가 있으며,

를 초과하는 경우 램프 무라 개선 효과가 떨어지는 문제가 있다. In addition, the gap (Gap 1) of the structure and the lamp is 0.1 or more from the line light source as shown in FIG.

It is preferable to be arranged to have the following separation distance (GAP 1). If the structure has a spacing of less than 0.1 mm from the light source, there is a difficulty in inserting the line light source lamp into the structure, and at the same time, there is a problem that may generate friction due to thermal contraction and expansion between the light source and the structure.

If it exceeds, there is a problem that the lamp mura improvement effect falls.

On the other hand, the light-transmitting structure is glass, polymethylmethacrylate (PMMA), polycarbonate (PC), polystyrene (PS), polyethylene terephthalate (polyethylene terephtal-ate, PET), poly It can be selected from the group consisting of carbonate (polycarbonate, PC) and copolymers of PMMA and PS, and polycarbonate (PC), polystyrene (PS), or polyethylene terephtalate (PET) It is more preferable to use.

In addition, the material constituting the light-transmitting structure is preferably 50% or more transparency. If the transparency is less than 50% because the light emitted from the light source is difficult to pass through the structure, there is a problem that light is lost.

Further, the material constituting the light-transmitting structure is preferably a refractive index of 1.3 to 2.0. If the refractive index is less than 1.3, the confinement effect of spreading the light emitted from the light source through the structure is inferior, and if the refractive index is greater than 2.0, the light transmittance and the workability of the material are inferior.

The light transmissive structure according to the present invention is arranged to surround the line light source in a cylindrical shape, and such a structure may be fixed to the backlight unit by further manufacturing a structure holder, for example, in the vicinity of the line light source lamp holder.

The light transmissive structures are disposed to individually surround each of the linear light sources, but each structure may be connected to each other to surround the adjacent linear light sources to form a single plate-like structure. The integrated plate-shaped structure is a structure in which the individual polygonal structures of lamps are connected to each other, as shown in FIG. 2 (c), and has a continuous structure in which the same pattern of polygonal shape exists on the top and bottom surfaces of the line light source. .

)라고 지칭하여 설명한다. More specifically, the unitary plate-like structure, as shown in Figure 3 (b) is based on any one valley of the upper surface of the plate-like structure, each of the sequential clockwise around the ramp A ', B, C, D, E ', E ", F, G, H and A", and the thickness of the bone portion that forms the minimum thickness of the plate is Gap3 (

It will be referred to as).

이며, 꼭지점 C 및 D의 내각은

≤θ_C=θ_G ≤180°의 범위인 것이 바람직하다. 여기서, θ_min과 θ_max 는 하기 식 (1) 및 식 (2)에 의해서 정의된다:The minimum thickness of the plate-shaped polygon, that is, the distance between the valleys A and A 'or E and E', is 0.5 mm ≦ Gap3 ≦ 2 × R _L , and the angles of the vertices B, D, F and H around the lamp are 180 °- θ _max ≤θ _B = θ _D = θ _F = θ _H ≤

The cabinets at vertices C and D are

It is preferable that it is the range of ≤ θ _C = θ _G ≤ 180 °. Where θ _min and θ _max is defined by the following equations (1) and (2):

식 (1)

Formula (1)

식 (2)

Equation (2)

이하인 것이 바람직하며, R_L은 램프의 반지름에 해당한다. 또한, 상기 구조물과 램프의 이격거리(Gap 1)는 상술한 바와 같이 선광원으로부터 0.1 이상

이하의 이격거리(GAP 1)를 갖도록 배치되는 것이 바람직하다. On the other hand, the thickness (GAP 2) of the thinnest portion of the structure is 0.3 or more as described above

It is preferable that it is below, and _RL corresponds to the radius of a lamp | ramp. In addition, the gap (Gap 1) of the structure and the lamp is 0.1 or more from the line light source as described above

It is preferable to be arranged to have the following separation distance (GAP 1).

미만인 경우는 다각형 구조물의 높이가 선광원 램프와 확산판 사이 거리(G₀)보다 크기 때문에 사용할 수 없으며, 180°를 초과하면 다각형 구조물에서 C(또는 G) 지점에서의 두께가 최박부의 두께(GAP 2)보다 작아져서 내구성에 문제를 일으킬 수 있다. 이 때, D, F 및 H의 내각은 상기 B의 내각과 동일하고, G의 내각은 상기 C의 내각과 동일한 것이 빛의 균일한 분 포를 위해 바람직하다.If the minimum thickness (Gap3) of the plate is smaller than 0.5mm, the plate has a problem in that the structure is vulnerable to durability, and when larger than the diameter of the lamp (2 × R _L ), the lamp mura improvement effect is insignificant. If the angle of B is less than 180 ° -θ _max , the plate cannot be formed, If larger, there is a problem in having a structure vulnerable to durability. Also, the Cabinet of C

If the height of the polygonal structure is less than the distance between the line light source lamp and the diffuser plate (G ₀ ), it cannot be used.If the angle is higher than 180 °, the thickness at the point C (or G) of the polygonal structure is the thickness of the thinnest part ( It is smaller than GAP 2) and may cause durability problems. At this time, it is preferable that the cabinets of D, F and H are the same as the cabinets of B, and the cabinets of G are the same as the cabinets of C for the uniform distribution of light.

The individual light-transmissive structure or the plate-shaped light-transmissive structure according to the present invention may be manufactured by an injection process in which, for example, an injection mold of an intaglio shape is produced, a resin melt is injected into the mold, and then cooled to obtain a structure from the mold. However, the present invention is not limited thereto, and may be manufactured by any method in the art, including a method of manufacturing a resin block of any shape through a machining and cutting process into a desired shape through machining. .

As described above, when the light transmissive structure is formed around the light source, the emission angle and the luminance distribution of the light emitted from the light source can be adjusted by the light transmissive structure, so that the luminance of the portion directly above the light source is reduced and the lamp does not exist. The lamp mura can be improved by increasing the luminance of the portion to reduce the luminance difference.

The lamp and the light transmissive structure are included in a lower case which houses them to form a backlight unit. The line light source according to the present invention formed as described above and the light transmissive structure surrounding the same may be used in any direct type backlight unit, for example, a reflecting plate reflecting light passing through the lamp and the structure may be disposed below. The upper portion may include a diffusion member configured to diffuse light passing through the lamp and the structure, and the upper portion of the diffusion member may include a luminance distribution according to a plurality of condensing films or viewing angles that perform a luminance correction function and a condensing function as necessary. It may comprise a plurality of diffusion films and the like for softening.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the following examples are merely examples for describing the present invention, and the present invention is not limited thereto.

Example: Lampmura of a light source surrounded by a light transmissive structure

1. Fabrication of a direct backlight unit comprising a light transmissive structure

The light-transmissive structure surrounding the CCFL light source was formed according to an injection process in which an ingot-shaped injection mold of the structure was manufactured, a resin melt was injected into the mold, and then cooled to obtain a structure from the mold.

At this time, the diameter and spacing (P) of the lamp was 3.4 mm and 26 mm, respectively, and P / G was 4.9. The material of the light-transmitting structure surrounding the light source in the shape of a polyhedral cylinder was polycarbonate having a refractive index of 1.58. The thinnest thickness Gap2 of the structure was 0.5 mm, and the structure was disposed with a gap Gap1 of 0.3 mm from the light source.

2. Lamp mura of light source surrounded by light-transmitting structure

In this case, the luminance distribution seen after the light emitted from the light source is incident on the diffuser plate disposed above the light source is measured using a Ray-tracing Program (Lambda Research Co. TracePro). The luminance distribution with the light source surrounded by the light transmissive structure of was observed. The results are shown in FIG.

(1) When individual light transmissive structures are applied to the light source

As shown in (a) of FIG. 3, the internal angle of the polygonal structure is represented by θ _A to θ _H in the clockwise direction with respect to the left vertex.

1) Maximum brightness difference of 1589 when the inner angles of a polygonal structure are θ _A = θ _E = 30 °, θ _B = θ _D = θ _F = θ _H = 170 °, and θ _C = θ _G = 170 °, respectively. luminance difference), and the result is shown in 4 (a).

2) The maximum luminance difference of 1858 (Max) when the internal angle of the polygonal structure is θ _A = θ _E = 40 °, θ _B = θ _D = θ _F = θ _H = 220 °, and θ _C = θ _G = 120 °, respectively. luminance difference), and the result is shown in 4 (b).

3) Maximum luminance difference of 2288 when the internal angle of a polygonal structure is θ _A = θ _E = 140 °, θ _B = θ _D = θ _F = θ _H = 170 °, θ _C = θ _G = 60 °, respectively luminance difference), and the result is shown in 4 (c).

4) The maximum luminance difference of 2230 when the inner angle of the polygonal structure is θ _A = θ _E = 180 °, θ _B = θ _D = θ _F = θ _H = 150 °, θ _C = θ _G = 60 °, respectively. luminance difference), and the result is shown in 4 (d).

(2) When an integral plate-shaped transparent structure is applied to the light source

As shown in Figure 3 (b) the minimum thickness of the valley of the plate-shaped polygonal structure is represented by Gap3, the internal angle of the upper and lower polygons of the plate-like structure, in the case of the upper polygon, the clock based on the left vertex Directions θ _B to θ _D, respectively _{, and the} lower polygons are θ _F to θ _H in the clockwise direction with respect to the right vertex, respectively.

1) The maximum luminance difference of 1701 when the minimum thickness and the inner angle of the plate-shaped structure are Gap3 = 0.54mm, θ _B = θ _D = θ _F = θ _H = 180 °, θ _C = θ _G = 160 °, respectively. difference), and the results are shown in 4 (e).

2) The maximum luminance difference of 1858 when the minimum thickness and the inner angle of the plate-shaped structure are Gap3 = 2.03mm, θ _B = θ _D = θ _F = θ _H = 180 °, and θ _C = θ _G = 166.8 °, respectively. difference), and the results are shown in 4 (f).

Comparative Example 1: Lampmura of a general light source without a light transmitting structure

Except that the light source is not surrounded by the light transmissive structure, the luminance distribution of the light source shown after being incident on the diffuser plate under the same conditions as in the above embodiment is determined by a Ray-tracing Program (Lambda Research Co., Ltd.). ), And the results are shown in FIG. 5.

1) When the distance P of the general light source without the transparent structure is 26 mm and P / G = 1.7, the maximum luminance difference is 1950 as shown in FIG. 5 (a).

2) When the distance P of the general light source without the transparent structure is 26mm and P / G = 4.9 As shown in FIG. 5 (b), the maximum luminance difference is shown in FIG. 2542 is shown.

Comparative Example 2: Lampmura of the light source according to the cabinet forming the light transmissive structure

1. When individual light transmissive structures are applied to the light source

(1) The maximum luminance difference of 2934 when the inner angles of a polygonal structure are θ _A = θ _E = 70 °, θ _B = θ _D = θ _F = θ _H = 150 °, and θ _C = θ _G = 170 °, respectively. Max. Luminance difference) is shown, and the result is shown in 5 (c).

(2) The maximum luminance difference of 2416 when the interior angles of a polygonal structure are θ _A = θ _E = 94 °, θ _B = θ _D = θ _F = θ _H = 135 °, and θ _C = θ _G = 176 °, respectively. Max. Luminance difference) is shown, and the result is shown in 5 (d).

2. In case the light-transmitting structure of integral plate is applied to the light source

The minimum thickness of the plate-like structure (Gap3) is 3.94 mm, the inner angle is θ _B = θ _D = θ _F = θ _H = 180 °, θ _C = θ _G = 160 °, respectively, with Gap1 0.3mm and Gap2 2.2mm In this case, the maximum luminance difference (Max. Luminance difference) of 2357 was shown, and the result is shown in 5 (e).

As can be seen in Examples and Comparative Example 1, when the P / G values are the same, the maximum luminance difference value in the light source surrounded by the light-transmissive structure according to the present invention was found to be reduced, particularly in Comparative Example 2 As can be seen when the cabinet of the light-transmitting structure is outside the scope of the present invention it was confirmed that the lamp difference improvement effect is reduced by increasing the luminance difference value.

Therefore, in the case of the backlight unit using the light source surrounded by the light transmitting structure of the present invention can be expected to reduce the lamp mura.

1 is a cross-sectional view of a conventional direct type backlight unit (a) and a backlight unit (b) according to the present invention, schematically showing the optical path from a light source.

2 shows a perspective view of a conventional direct type backlight unit (a), a backlight unit (b) having a separate structure according to the present invention, and a backlight unit (c) having a plate structure according to the present invention.

FIG. 3 exemplarily shows a cross section of the case where the light-transmitting structure according to the present invention surrounding the lamp is installed separately in the lamp (a) and in a plate-like structure integrally connected (b).

Figure 4 shows the contrast pattern observed using a light source installed with a light transmitting structure according to the present invention.

Figure 5 shows the contrast pattern observed using a light source that is not provided with a light-transmissive structure according to the present invention, or using a light source provided with a light-transmissive structure formed in an cabinet outside the scope of the present invention.

Claims (10)

delete delete A plurality of linear light sources arranged in parallel at regular intervals, A light transmissive structure surrounding the line light source, A lower case accommodating the linear light source and the light transmissive structure, and It is a direct type backlight unit including a light source and a diffusion plate disposed on the light transmitting structure, Here, the light-transmitting structure is characterized in that the polygonal cylinder structure of a quadrilateral, hexagon or octagon extending in parallel with the line light source, The angles of the sequential vertices of each of the vertices of the polygon are θ _A , θ _B , θ _C , θ _D , θ _E , θ _F , θ _G, and θ _H , respectively, and the angle θ _A is an acute angle. If is The angles θ _A and θ _E are

≤θ _A = θ _E ≤50 °, The internal angles θ _B , θ _D , θ _F and θ _H are 155 ° ≦ θ _B = θ _D = θ _F = θ _H ≤

Wherein the angles θ _C and θ _G are

≤θ _C = θ _G ≤ 180 °, Here, R ₁ represents the shortest distance from the center of the line light source to one side of the polygon or the extension line of one side of the polygon, P means the distance between the center of the line light source and the adjacent line light source, R _L is the radius of the lamp G ₀ represents the distance from the center of the line light source to the bottom of the diffuser plate, Thickness of the light transmitting structure thin portion (GAP 2) is 0.3 to

Wherein the light transmissive structure is from 0.1 to 0.1 from a linear light source

The direct type backlight unit, characterized in that arranged to be spaced apart (GAP 1). A plurality of linear light sources arranged in parallel at regular intervals, A light transmissive structure surrounding the line light source, A lower case accommodating the linear light source and the light transmissive structure, and It is a direct type backlight unit including a light source and a diffusion plate disposed on the light transmitting structure, Here, the light-transmitting structure is characterized in that the polygonal cylinder structure of a quadrilateral, hexagon or octagon extending in parallel with the line light source, The angles of the sequential vertices of the sequential vertices relative to any one vertex of the polygon are θ _A , θ _B , θ _C , θ _D , θ _E , θ _F , θ _G and θ _H , respectively, and the angle θ _A is an obtuse angle If is The internal angles θ _A and θ _E are 100 ° ≦ θ _A = θ _E ≦ 180 °, The internal angles θ _B , θ _D , θ _F and θ _H are 140 ° ≦ θ _B = θ _D = θ _F = θ _H ≤180 °, The angles θ _C and θ _G are

≤θ _C = θ _G ≤80 °, Here, R ₁ represents the shortest distance from the center of the line light source to an extension line of one side of the polygon or one side of the polygon, P is the distance between the center of the line light source and the adjacent line light source, R _L is the radius of the lamp G ₀ represents the distance from the center of the line light source to the bottom of the diffuser plate, Thickness of the light transmitting structure thin portion (GAP 2) is 0.3 to

Wherein the light transmissive structure is from 0.1 to 0.1 from a linear light source

The direct type backlight unit, characterized in that arranged to be spaced apart (GAP 1). delete delete delete A plurality of linear light sources arranged in parallel at regular intervals, A light transmissive structure surrounding the line light source, A lower case accommodating the linear light source and the light transmissive structure, and It is a direct type backlight unit including a light source and a diffusion plate disposed on the light transmitting structure, Here, the light transmissive structure is connected to each other with the adjacent light transmissive structure to form a plate-shaped light transmissive structure, The minimum thickness Gap3 of the plate-shaped light transmissive structure is 0.5mm ≦ Gap3 ≦ 2 × R _L , The vertices of the polygons constituting the upper part of the plate-shaped light transmissive structure are sequentially referred to as B, C, and D, respectively, based on any one valley, and the vertices of the polygons constituting the lower part corresponding to the B, C, and D are sequentially defined. In the reverse direction, respectively, F, G, and H, and the inner corners of the vertices are θ _B , θ _C , θ _D , θ _F , θ _G and θ _H , respectively. The angles θ _B , θ _D , θ _F and θ _H are 180 ° -θ _max ≦ θ _B = θ _D = θ _F = θ _H ≤

Is, The angles θ _C and θ _G are

≤θ _C = θ _G ≤180 °, Here, R ₁ represents the shortest distance from the center of the line light source to the extension line of one side of the polygon or one side of the polygon, P means the distance between the center of the line light source and the adjacent line light source, R _L is the radius of the lamp G ₀ represents the distance from the center of the line light source to the bottom of the diffuser plate, Where θ _min and θ _max is the following formula (1) and formula (2),

Formula (1)

Equation (2) Direct backlight unit, characterized in that defined by. The method according to any one of claims 3, 4 and 8, The light-transmitting structure has a transparency of 50% or more, the direct type backlight unit, characterized in that made of a material having a refractive index of 1.3 to 2.0. The method according to any one of claims 3, 4 and 8, The material of the light transmissive structure is glass, polymethylmethacrylate (PMMA), polycarbonate (PC), polystyrene (PS), polyethylene terephthalate (polyethylene terephtal-ate, PET), polycarbonate ( polycarbonate, PC) and a copolymer of polymethyl methacrylate and polystyrene.

Images