KR101307715B1 - Member for controlling luminous flux, light emitting device and display device - Google Patents

Abstract

A light emitting device and a display device including the same are disclosed. The light emitting device includes a light source; And a luminous flux control member through which light is incident from the light source, wherein the luminous flux control member includes a reflection surface reflecting light from the light source; A first refracting surface refracting first light reflected by the reflecting surface; And a second refracting surface that refracts second light reflected by the reflecting surface.

Description

Luminous flux control member, light emitting device and display device {MEMBER FOR CONTROLLING LUMINOUS FLUX, LIGHT EMITTING DEVICE AND DISPLAY DEVICE}

Embodiments relate to a light beam control member, a light emitting device, and a display device including the same.

In general, liquid crystal displays (LCDs) have tended to be gradually widened due to their light weight, thinness, and low power consumption. According to this trend, liquid crystal display devices are used in office automation equipment, audio / video equipment, and the like. The liquid crystal display device displays a desired image on the screen by controlling the amount of transmitted light according to a video signal applied to a plurality of control switches arranged in a matrix form.

Since the liquid crystal display device is not a self-luminous display device, a backlight unit for providing light to the back of a liquid crystal display panel on which an image is displayed is provided.

A liquid crystal panel including a color filter substrate and an array substrate interposed between the color filter substrate and the array substrate, and a backlight unit for emitting light to the liquid crystal panel .

The backlight unit used in such a liquid crystal display may be generally divided into an edge type backlight unit or a direct type backlight unit.

The edge type backlight unit includes a light guide plate and light emitting diodes. The light emitting diodes are disposed on the side surface of the light guide plate, and the light guide plate guides the light emitted from the light emitting diode through total reflection or the like and emits toward the liquid crystal panel.

The direct type backlight unit does not use a light guide plate, and the light emitting diodes are disposed on the rear surface of the light guide plate. Accordingly, the light emitting diodes emit light toward the rear surface of the liquid crystal panel.

Such a backlight unit should emit light uniformly toward the liquid crystal panel. That is, efforts are being made to improve the luminance uniformity of the liquid crystal display device.

Embodiments provide a light flux control member, a light emitting device, and a display device having improved luminance uniformity.

In one embodiment, a light emitting device includes: a light source; And a luminous flux control member through which light is incident from the light source, wherein the luminous flux control member includes a reflection surface reflecting light from the light source; A first refracting surface refracting first light reflected by the reflecting surface; And a second refracting surface that refracts the second light reflected by the reflective surface, and satisfies Equations 1 and 2 below.

Equation 1

-1.2 <θ2 / θ1 <1

Here, θ1 is the angle between the first light reflected by the reflective surface and the horizontal plane orthogonal to the optical axis of the light source, θ2 is the angle between the first light and the horizontal plane refracted by the first refractive surface, When θ1 has a positive angle when the first light reflected by the reflecting surface is in the same direction as the optical axis of the light emitting diode with respect to the horizontal plane, θ1 is negative when the light is different from the optical axis of the light emitting diode. Θ2 has a positive angle and is in a direction different from the optical axis of the light emitting diode when the first light refracted by the first refracting surface is in the same direction as the optical axis of the light emitting diode with respect to the horizontal plane. In this case, θ2 has a negative angle.

Equation 2

-1.2 <θ4 / θ3 <1

Here, θ3 is the angle between the second light reflected by the reflective surface and the horizontal plane orthogonal to the optical axis of the light source, θ4 is the angle between the second light and the horizontal plane refracted by the second refractive surface, When θ3 has a positive angle when the second light reflected by the reflective surface is in the same direction as the optical axis of the light emitting diode with respect to the horizontal plane, θ3 is negative when it is in a direction different from the optical axis of the light emitting diode. Θ4 has a positive angle and is different from the optical axis of the light emitting diode when the second light refracted by the second refracting surface is in the same direction as the optical axis of the light emitting diode with respect to the horizontal plane. In this case, θ4 has a negative angle.

The luminous flux control member according to the embodiment includes an incident surface on which light is incident; A concave portion that is recessed toward the incident surface; A first refracting surface that is bent or curved to extend from the inner surface of the depression; And a second refracting surface that is bent or curved to extend from the first refracting surface, wherein an optical axis passing through the center of the incident surface and the center of the inner surface of the depression is defined, and is orthogonal to the optical axis, And a horizontal plane passing between the second refracting surfaces, wherein the first refracting surface extends in a direction away from the optical axis, and the further away from the optical axis, the distance between the first refracting surface and the horizontal plane becomes smaller and smaller, The second refracting surface extends in a direction closer to the optical axis, and the closer to the optical axis, the greater the distance between the second refracting surface and the horizontal plane.

A display device according to an embodiment includes a light source; A light flux control member through which light from the light source is incident; And a display panel to which light from the light beam control member is incident, wherein the light beam control member includes a reflection surface reflecting light from the light source; A first refracting surface refracting first light reflected by the reflecting surface; And a second refracting surface that refracts the second light reflected by the reflective surface, and satisfies Equation 1 and Equation 2 above.

The light emitting device and the display device according to the embodiment include a light beam control member including the reflective surface, the first refractive surface, and the second refractive index. Accordingly, the luminous flux control member can reflect most of the light emitted from the light source by the reflective surface and emit the light through the first and second refractive surfaces.

In this case, the light beam control member may refract the light closer to the horizontal direction through the first refractive surface and the second refractive surface. In particular, the luminous flux control member may appropriately form the first refractive surface and the second refractive surface according to the reflection angle of the light reflected through the reflective surface, thereby having improved luminance uniformity.

1 is an exploded perspective view illustrating a light emitting device according to an embodiment.
2 is a cross-sectional view showing one end surface of the light emitting device according to the embodiment.
3 to 6 are cross-sectional views showing modifications of the light beam control member.
7 is an exploded perspective view showing a liquid crystal display device according to an embodiment.
FIG. 8 is a cross-sectional view showing a section cut along AA 'in FIG. 7; FIG.
9 is a cross-sectional view showing a light flux control member according to an experimental example.
10 is a diagram illustrating luminance distribution in an experimental example.

In the description of the embodiments, it is described that each panel, sheet, member, guide, unit or the like is formed "on" or "under" of each panel, sheet, member, In this case, "on" and "under " all include being formed either directly or indirectly through another element. In addition, the upper or lower reference of each component is described with reference to the drawings. The size of each component in the drawings may be exaggerated for the sake of explanation and does not mean the size actually applied.

1 is an exploded perspective view illustrating a light emitting device according to an embodiment. 2 is a cross-sectional view showing one end surface of the light emitting device according to the embodiment. 3 to 6 are cross-sectional views showing modifications of the light beam control member.

1 to 6, the light emitting device according to the embodiment includes a light beam control member 10, a light source, for example, a light emitting diode 20 and a driving substrate 30.

The luminous flux control member 10 is disposed on the driving substrate 30. The light flux control member 10 covers the light emitting diode 20. The luminous flux control member 10 may accommodate some or all of the light emitting diodes 20.

Light emitted from the light emitting diodes 20 is incident on the light beam control member 10. A filler 21 may be disposed between the light flux control member 10 and the light emitting diode 20. The light emitted from the light emitting diode 20 may be incident on the light flux control member 10 through the filling part 21. [

The light flux controlling member 10 includes a concave portion 100 and a concave portion 200.

The depression 100 is formed on the light beam control member 10. The depression (100) corresponds to the light emitting diode (20). In addition, the depression 100 is recessed toward the light emitting diode 20. In more detail, the depression 100 is recessed toward the light emitting diode 20. The depression 100 is formed at the central portion of the luminous flux control member 10.

The center 101 of the inner surface of the depression 100 is disposed on the optical axis OA of the light emitting diode 20. That is, the optical axis OA of the light emitting diode 20 passes through the center 101 of the inner surface of the depression 100. In addition, the depression 100 may have a line-symmetric structure about the optical axis OA of the light emitting diode 20.

The center 201 of the inner surface of the concave portion 200 may be disposed on the optical axis OA of the light emitting diode 20. The optical axis OA of the light emitting diode 20 can pass through the center 101 of the inner surface 110 of the depression 100 and the center 201 of the inner surface of the recess 200.

The concave portion 200 corresponds to the light emitting diode 20. Also, the recess 200 is opposed to the depression 100. The recess 200 is formed below the luminous flux control member 10. That is, the recess 200 is formed below the luminous flux control member 10.

The light emitting diode 20 is disposed in the concave portion 200. In more detail, some or all of the light emitting diodes 20 are disposed in the recess 200. That is, some or all of the light emitting diodes 20 are disposed in the luminous flux control member 10.

At this time, light emitted from the light emitting diode 20 may be incident through the inner surface of the recess 200. Accordingly, the inner surface of the concave portion 200 is an incident surface on which light is incident. That is, most light can be incident on the light flux control member 10 through the inner surface of the recess 200.

Unlike this, the concave portion 200 may not be formed in the luminous flux control member 10. In this case, the light emitting diodes 20 may be disposed on a flat rear surface of the luminous flux control member 10. At this time, the rear surface may be an incident surface as a whole.

In addition, the luminous flux control member 10 includes a reflective surface 110, a first refractive surface 210, a second refractive surface 220, and a rear surface 230.

The reflective surface 110 may be an inner surface of the depression 100. The reflective surface 110 may reflect the light from the light emitting diodes 20 laterally, laterally, or laterally. In more detail, the reflective surface 110 may reflect light from the light emitting diodes 20 through total reflection.

The reflective surface 110 extends from the optical axis OA of the light emitting diode 20. In more detail, the reflective surface 110 extends in a direction away from the optical axis OA of the light emitting diode 20. In this case, the direction away from the optical axis OA of the light emitting diode 20 may mean an outer direction perpendicular to or inclined with the optical axis OA of the light emitting diode 20. In more detail, the reflective surface 110 extends laterally from the optical axis OA of the light emitting diode 20. The reflective surface 110 extends outward from the optical axis OA of the light emitting diode 20. Here, the "optical axis" refers to the traveling direction of light from the center of a three-dimensional luminous flux from the point light source.

The distance between the reflective surface 110 and the optical axis OA of the light emitting diode 20 may increase as the distance from the light emitting diode 20 increases. In more detail, the distance between the reflective surface 110 and the optical axis OA of the light emitting diode 20 may increase in proportion to the distance from the light emitting diode 20.

An angle θ5 between the reflective surface 110 and the optical axis OA of the light emitting diode 20 may be about 10 ° to about 65 °.

The reflective surface 110 may surround the optical axis OA of the light emitting diode 20. The reflective surface 110 may have a conical shape. In this case, a vertex of the reflective surface 110 may face the light emitting diode 20.

The reflective surface 110 may reflect light emitted from the light emitting diodes 20. In more detail, the reflective surface 110 may totally reflect the light emitted from the light emitting diodes 20. Accordingly, the reflective surface 110 can prevent the occurrence of a hot spot formed by excessively concentrated light in the central portion of the luminous flux control member 10.

In addition, the reflective surface 110 may reflect light from the light emitting diodes 20 to the first refractive surface 210 or the second refractive surface 220.

The first refractive surface 210 is bent or curved from the reflective surface 110 to extend. The first refractive surface 210 may extend laterally from the reflective surface 110. That is, the first refractive surface 210 may extend from the reflective surface 110 to approach the driving substrate 30. In more detail, the first refractive surface 210 may extend from the reflective surface 110 in a direction away from the optical axis OA of the light emitting diode 20.

Here, bending means a shape that bends rapidly. For example, when two surfaces are curved while forming a curved surface with a radius of curvature of about 0.1 mm or less, the two surfaces may be bent. Here, the curve means a shape that is gently bent. For example, if two faces are curved while forming a curved surface with a radius of curvature larger than about 0.1 mm, the two faces may be curved. Here, the curvature means that the curvature of curvature changes and the curvature changes. For example, when the convex curved surface is bent and changed into a concave curved surface, it can be said that the convex curved surface and the concave curved surface are curved.

The first refracting surface 210 extends laterally from the outside of the recess 100. In this case, a reference horizontal plane 232 passing through a region between the first refractive surface 210 and the second refractive surface 220 may be defined. In this case, the reference horizontal plane 232 is orthogonal to the optical axis OA of the light emitting diode 20. Here, the distance between the first refractive surface 210 and the reference horizontal surface 232 may become smaller as the distance from the optical axis OA of the light emitting diode 20.

The first refracting surface 210 may be spherical or aspherical. The first refractive surface 210 may refract the light reflected by the reflective surface 110. In more detail, the first refraction surface 210 may refract the light reflected by the reflection surface 110 laterally, laterally, or laterally.

 The first refracting surface 210 may surround the optical axis OA of the light emitting diode 20. In addition, the first refractive surface 210 may surround the reflective surface 110.

The second refracting surface 220 extends from the first refracting surface 210. The second refracting surface 220 is bent or curved to extend from the first refracting surface 210. The second refracting surface 220 extends laterally from the first refracting surface 210. In this case, the second refractive surface 220 extends toward the optical axis OA of the light emitting diode 20. That is, the second refractive surface 220 may extend in a direction closer to the optical axis OA of the light emitting diode 20.

The second refracting surface 220 extends laterally downward from the first refracting surface 210 in a direction closer to the optical axis OA of the light emitting diode 20. In this case, the distance between the second refractive surface 220 and the reference horizontal surface 232 may become larger as the distance from the optical axis OA of the light emitting diode 20 becomes closer.

In addition, the second refractive surface 220 extends to the rear surface 230. That is, the second refractive surface 220 may meet the rear surface 230. That is, the second refractive surface 220 extends from the rear surface 230 to the first refractive surface 210. The back surface 230 faces the driving substrate 30. The rear surface 230 extends in a direction away from the optical axis OA of the light emitting diode 20 from the inner surface of the concave portion 200.

The second refracting surface 220 may be spherical or aspherical. The second refractive surface 220 may emit light from the light emitting diodes 20. In addition, the second refractive surface 220 may refract the light reflected by the reflective surface 110.

The first refracting surface 210 and the second refracting surface 220 are formed on the side of the luminous flux control member 10.

The luminous flux control member 10 is transparent. The light flux control member 10 may have a refractive index of about 1.4 to about 1.5. The light flux controlling member 10 may be formed of plastic or glass. In addition, the ratio of the radius D and the thickness T of the luminous flux control member 10 may be about 0.8: 1 to about 1: 0.8.

The light flux control member 10 may be adhered to the driving substrate 30 by a bonding portion 300. In addition, the filling part 21 may be filled in the recess 200. The filling portion 21 may be in close contact with the inner surface of the concave portion 200. The filling part 21 may be integrally formed with the bonding part 300.

As shown in FIG. 3, the luminous flux control member 10 may include a transparent member 11 and a reflective member 12.

The transparent member 11 is transparent and includes a recessed part 100 and a recessed part 200. In addition, the transparent member 11 includes a first refractive surface 210 and a second refractive surface 220.

The reflective member 12 is disposed in the depression 100. The reflective member 12 may be disposed on the entire inner surface of the recess 100. The reflective member 12 may be in close contact with an inner surface of the recessed part 100. The reflective member 12 may be metal or white ink having a high reflectance.

Accordingly, the reflective surface 110 may be formed at an interface between the transparent member 11 and the reflective member 12. In addition, the reflective surface 110 may effectively reflect light from the light emitting diodes 20 even if the total reflection condition is not satisfied.

As shown in FIG. 4, the reflective member 12 may be disposed on a portion of an inner surface of the recess 100. In this case, the reflective member 12 may cover only a part of the inner surface of the recessed part 100.

Accordingly, the first reflective surface 111 is formed at the interface between the reflective member 12 and the transparent member 11, and the second reflective surface 112 is formed only on the inner surface of the recessed part 100. do. That is, the first reflecting surface 111 is closer to the optical axis OA of the light emitting diode 20 than the second reflecting surface 112.

In addition, the second reflecting surface 112 extends outward from the first reflecting surface 111. The second reflective surface 112 is formed only on the transparent member 11.

The first reflective surface 111 may reflect light from the light emitting diodes 20 regardless of total reflection conditions. The second reflecting surface 112 may reflect light emitted from the light emitting diodes 20 by total reflection.

The position of the second reflective surface 112 may satisfy Equation 7 as follows.

Equation 7

90 °-θ5> i

Here, θ5 is an angle between the straight line extending from the light emitting diode 20 to the area P1 between the first reflecting surface 111 and the second reflecting surface 112 and the second reflecting surface 112. And i is the critical angle of the transparent member 11.

As such, when Equation 7 is satisfied, the light from the light emitting diodes 20 may be incident on the second reflective surface 112 at an angle greater than a critical angle and totally reflected.

As such, as the area in which the reflective member 12 is disposed decreases, the overall light efficiency may be improved.

Referring to FIG. 5, the reflective surface 110 may be upwardly convex. In addition, the reflective surface 110 may be an aspherical surface or a spherical surface. The reflective surface 110 may have an inflection point. That is, the reflective surface 110 may have an upwardly convex portion and a downwardly convex portion.

Referring to FIG. 6, the luminous flux control member 10 may have an asymmetrical structure with respect to the optical axis OA of the light emitting diode 20. That is, the reflective surface 110 may be biased to one side, and the first refractive surface 210 and the second refractive surface 220 may be biased to the other side. In addition, the reflective surface 110 may be flat.

 The light emitting diodes 20 generate light. The light emitting diode 20 may be a point light source. The light emitting diodes 20 are electrically connected to the driving substrate 30. The light emitting diode 20 may be mounted on the driving substrate 30. Accordingly, the light emitting diode 20 receives an electrical signal from the driving substrate 30. That is, the light emitting diodes 20 are driven by the driving substrate 30, thereby generating light.

The driving substrate 30 supports the light emitting diodes 20 and the luminous flux control member 10. In addition, the driving substrate 30 is electrically connected to the light emitting diodes 20. The driving substrate 30 may be a driving substrate 30. In addition, the driving substrate 30 may be rigid or flexible.

In this embodiment, it is described that one light emitting diode 20 and one light flux control member 10 are disposed on one drive substrate 30, but the present invention is not limited thereto. For example, a plurality of light emitting diodes 20 may be disposed on one drive substrate 30. [ In addition, a plurality of light flux control members 10 may be disposed corresponding to the respective light emitting diodes 20.

Referring to FIG. 2, a part of light emitted from the light emitting diode 20 (hereinafter, the first light L1) is reflected by the reflecting surface 110 and is refracted through the first refractive surface 210. , Is emitted.

In this case, the path of the first light L1 may satisfy Equation 1 below.

Equation 1

-1.2 <θ2 / θ1 <1.2

Here, θ1 is an angle between the first light L1 reflected by the reflective surface 110 and the horizontal plane 231 orthogonal to the optical axis OA of the light source, and θ2 is the first refractive surface 210. An angle between the first light L1 refracted by the horizontal surface 231 and the first light L1 reflected by the reflective surface 110 based on the horizontal surface 231. Θ1 has a positive angle in the same direction as the traveling direction of the light in the optical axis OA of 20), and θ1 in a different direction from the traveling direction of the light in the optical axis OA of the light emitting diode 20 Has a negative angle, and the first light L1 refracted by the first refracting surface 210 is in the direction of travel of the light in the optical axis OA of the light emitting diode 20 with respect to the horizontal plane 231. In the same direction, θ2 has a positive angle and the light travels in the optical axis OA of the light emitting diode 20. If the direction and the other direction, the angle θ2 has a negative.

That is, when the first light L1 travels laterally upward from the reflective surface 110, θ1 has a positive angle, and when traveled downwardly, θ1 has a negative angle. Further, θ2 has a positive angle when the first light L1 travels laterally from the first refraction surface 210, and θ2 has a negative angle when it travels laterally downward.

In more detail, the path of the first light L1 may satisfy Equation 2 below.

Equation 2

-1.2 <θ2 / θ1 <0

That is, θ1 and θ2 may have different signs. That is, when θ1 is a positive angle, θ2 may be a negative angle.

In addition, the path of the first light L1 may satisfy Equation 3 below.

Equation 3

-1 <θ2 / θ1 <1

That is, the first light L1 reflected by the reflective surface 110 may be refracted closer to the second horizontal surface 231 on the first refractive surface 210. That is, the absolute value of θ2 may be smaller than the absolute value of θ1. In particular, about 60% or more of the light reflected by the reflective surface 110 and incident on the first refractive surface 210 may satisfy Equation 3.

Referring to FIG. 2, another part of the light emitted from the light emitting diode 20 (hereinafter, the second light L2) is reflected by the reflective surface 110 and refracted through the second refractive surface 220. And exit.

In this case, the path of the second light L2 may satisfy Equation 4 below.

Equation 4

-1.2 <θ4 / θ3 <1.2

Here, θ3 is an angle between the second light L2 reflected by the reflecting surface 110 and the second horizontal plane 231 orthogonal to the optical axis OA of the light source, and θ4 is the second refracting surface ( An angle between the second light L2 refracted by 220 and the horizontal plane 231, and the second light L2 reflected by the reflective plane 110 emits light based on the horizontal plane 231. When θ3 has a positive angle and is in a direction different from the traveling direction of light on the optical axis OA of the light emitting diode 20 when the direction is the same as the traveling direction of the light on the optical axis OA of the diode 20 , θ3 has a negative angle, and the second light L2 refracted by the second refracting surface 220 is in the same direction as the optical axis OA of the light emitting diode 20 with respect to the horizontal plane 231. In this case, θ4 has a positive angle, and when θ4 is in a direction different from the optical axis OA of the light emitting diode 20, θ4 is a negative angle. .

In addition, the path of the second light L2 may satisfy Equation 5 below.

Equation 5

-1.2 <θ4 / θ3 <0

That is, θ3 and θ4 may have different signs. That is, when θ4 is a positive angle, θ3 may be a negative angle.

In addition, the path of the second light L2 may satisfy Equation 6 below.

Equation 6

-1 <θ4 / θ3 <1

That is, the second light L2 reflected by the reflective surface 110 may be refracted closer to the horizontal surface 231 on the second refractive surface 220. That is, the absolute value of θ4 may be smaller than the absolute value of θ3. In particular, about 60% or more of the light reflected by the reflective surface 110 and incident on the second refractive surface 220 may satisfy Equation 6.

As such, the light reflected by the reflective surface 110 may be selectively refracted by the first refractive surface 210 or the second refractive surface 220. In particular, the luminous flux control member 10 may be refracted at a desired angle based on an angle of reflection on the reflective surface 110, in particular, an angle with the horizontal surface 231.

Accordingly, the light flux control member 10 can efficiently diffuse the light emitted from the light emitting diode 20 laterally.

Therefore, the light emitting device according to the embodiment can have improved luminance uniformity and can be suitable for forming a planar light source.

7 is an exploded perspective view showing a liquid crystal display device according to an embodiment. 8 is a cross-sectional view showing a section taken along line A-A in Fig. In this embodiment, the above-described light emitting device is referred to. That is, the description of the light emitting device of the foregoing embodiment can be essentially combined with the description of this embodiment.

Referring to FIGS. 7 and 8, the liquid crystal display according to the embodiment includes a liquid crystal display panel 50 and a backlight unit 40. The liquid crystal display panel 50 displays an image. Although not shown in detail, the liquid crystal display panel 50 includes a thin film transistor (TFT) substrate and a color filter substrate bonded together so as to face each other and maintain a uniform cell gap, Layer. The thin film transistor substrate includes a plurality of gate lines, a plurality of data lines intersecting the plurality of gate lines, and a thin film transistor (TFT) formed at an intersection of the gate lines and the data lines.

A gate driving PCB 51 for supplying a scan signal to the gate line is formed at an edge of the liquid crystal display panel 50 and a data driving PCB circuit board 52 is provided.

The gate and data driving PCBs 51 and 52 are electrically connected to the liquid crystal display panel 50 by a chip on film (COF). Here, the COF may be changed to a TCP (Tape Carrier Package).

The liquid crystal display according to the embodiment includes a panel guide 54 for supporting the liquid crystal display panel 50 and a top case 54 for covering the edge of the liquid crystal display panel 50 and being coupled to the panel guide 54 53).

The backlight unit 40 is configured to be a direct-down type provided in a large liquid crystal display device of 20 inches or more. The backlight unit 40 includes a bottom cover 41, a driving substrate 30, a plurality of light emitting diodes 20, a plurality of light flux control members 10 and optical sheets 42.

The bottom cover 41 has a box shape having an open top, and accommodates the driving substrate 30. In addition, the bottom cover 41 supports the optical sheets 42 and the liquid crystal display panel 50.

The bottom cover 41 may be made of metal or the like. For example, the bottom cover 41 may be formed by bending or bending a metal plate or the like. That is, the drive substrate 30 is accommodated in a space formed by bending or curving.

The driving substrate 30 is disposed inside the bottom cover 41. The driving substrate 30 may be a driving substrate 30. The driving substrate 30 is electrically connected to the light emitting diodes 20. That is, the light emitting diodes 20 may be mounted on the driving substrate 30.

The driving substrate 30 has a plate shape. The driving substrate 30 is electrically connected to the light emitting diodes 20 and supplies a driving signal to the light emitting diodes 20.

A reflective layer for improving the performance of the backlight unit 40 may be coated on the upper surface of the driving substrate 30. That is, the reflective layer may reflect the light emitted from the light emitting diodes 20 upward.

The light emitting diodes 20 generate light by using an electric signal received through the driving substrate 30. [ That is, the light emitting diodes 20 are light sources for generating light. More specifically, each light emitting diode 20 is a point light source, and each of the light emitting diodes 20 is gathered to form a surface light source. Here, the light emitting diodes 20 are a light emitting diode 20 package including a light emitting diode 20 chip.

The light emitting diodes 20 are mounted on the driving substrate 30. The light emitting diodes 20 may be disposed on the driving substrate 30 at regular intervals.

The light emitting diodes 20 emit white light. Alternatively, the light emitting diodes 20 may emit blue light, green light, and red light evenly.

The light flux control members 10 cover the light emitting diodes 20, respectively. Light from the light emitting diode 20 is incident on the light flux control member 10, respectively. The incident light has an improved luminance uniformity by the light flux control member 10 and is emitted upward. The configuration and characteristics of the light flux control members 10 may be substantially the same as those of the light flux control member 10 of the previous embodiment.

The optical sheets 42 improve the characteristics of light passing therethrough. The optical sheets 42 may be, for example, a polarizing sheet, a prism sheet, or a diffusion sheet.

As described in the foregoing embodiment, the light flux control member 10 can effectively assure the light emitted from the light emitting diodes 20. Accordingly, the backlight unit 40 according to the embodiment emits light having improved luminance uniformity to the liquid crystal panel.

Therefore, the liquid crystal display device according to the embodiment has improved luminance uniformity and can realize an improved image quality.

In addition, the features, structures, effects and the like described in the embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Experimental Example

As shown in Fig. 9, a light flux control member 10 is provided. At this time, the radius D of the luminous flux control member 10 was about 4.5 mm, the thickness T was about 8.5 mm, and the angle θ5 between the reflective surface and the optical axis of the light emitting diode was about 25 degrees. In addition, the radius of the depression 100 was about 1.5 mm, the width W1 of the first refractive surface was about 6 mm, and the width W2 of the first refractive surface was about 4.5 mm. Thereafter, the light emitting diodes 20 are disposed in the concave portion 200, and the luminance distribution of the light emitted from the luminous flux control member 10 was measured as shown in FIG. 10. In FIG. 10, the thick line shows the intensity in the X-axis direction, and the thin line shows the intensity in the Y-axis direction. As shown in FIG. 10, it can be seen that the light from the light emitting diode 20 is effectively diffused by the luminous flux control member.

Claims (21)

Light source; And
A light beam control member through which light is incident from the light source,
The light flux control member
A reflection surface reflecting light from the light source,
A first refracting surface that refracts first light reflected by the reflecting surface, and
A transparent member including a second refracting surface that refracts second light reflected by the reflective surface; And
A reflection member in close contact with the reflection surface and reflecting light incident from the light source on the contact surface;
The reflective surface
A first reflective surface formed at an interface between the transparent member and the reflective member; And
And a second reflecting surface extending from the first reflecting surface and formed only in the transparent member. The method of claim 1, wherein the luminous flux control member includes a depression recessed toward the light source,
The inner surface of the recessed portion includes the reflective surface. The method of claim 1, wherein the reflective surface extends from the optical axis of the light source,
The first refracting surface is bent or curved to extend from the reflective surface,
And the second refracting surface extends bent or curved from the first refracting surface. delete delete delete The light emitting device of claim 1, wherein the following Equation 7 is satisfied.
Equation 7
90 °-θ5> i
Here, θ5 is an angle between the straight line extending from the light source to the area between the first reflecting surface and the second reflecting surface and the second reflecting surface, and i is a critical angle of the transparent member. The method of claim 1, wherein the transparent member comprises a depression recessed toward the light source,
The reflective member is disposed in the depression. The method of claim 1,
A light emitting device that satisfies Equations 1, 3, 4, and 6 below.
Equation 1
-1.2 <θ2 / θ1 <1.2
Here, θ1 is the angle between the first light reflected by the reflective surface and the horizontal plane orthogonal to the optical axis of the light source, θ2 is the angle between the first light and the horizontal plane refracted by the first refractive surface, When θ1 has a positive angle when the first light reflected by the reflecting surface is in the same direction as the optical axis of the light source with respect to the horizontal plane, θ1 has a negative angle when the light is different from the optical axis of the light source. When the first light refracted by the first refracting surface is in the same direction as the optical axis of the light source with respect to the horizontal plane, θ2 has a positive angle, when θ2 is different from the optical axis of the light source, It has a negative angle.
Equation 4
-1.2 <θ4 / θ3 <1
Here, θ3 is the angle between the second light reflected by the reflective surface and the horizontal plane orthogonal to the optical axis of the light source, θ4 is the angle between the second light and the horizontal plane refracted by the second refractive surface, When θ3 has a positive angle when the second light reflected by the reflective surface is in the same direction as the optical axis of the light source with respect to the horizontal plane, θ3 has a negative angle when the second light is in a direction different from the optical axis of the light source. Θ4 has a positive angle when the second light refracted by the second refracting surface is in the same direction as the optical axis of the light source with respect to the horizontal plane, and when θ4 has a different angle from the optical axis of the light source, It has a negative angle.
Equation 3
-1 <θ2 / θ1 <1
Equation 6
-1 <θ4 / θ3 <1 The light emitting device of claim 1, wherein the reflective surface is planar. An incident surface on which light is incident;
A reflection surface disposed in the depression recessed toward the entrance surface to reflect the incident light,
A first refracting surface that is bent or curved to extend from the reflective surface; and
A transparent member including a second refracting surface that is bent or curved from the first refracting surface; And
A reflection member in close contact with the reflection surface and reflecting light incident from the transparent member on the contact surface;
The reflective surface
A first reflective surface formed at an interface between the transparent member and the reflective member; And
A second reflecting surface extending from the first reflecting surface and formed only in the transparent member;
An optical axis passing through the center of the incident surface and the center of the reflective surface is defined,
A horizontal plane perpendicular to the optical axis and passing between the first and second refractive surfaces is defined,
The first refracting surface extends in a direction away from the optical axis,
The further away from the optical axis, the distance between the first refracting surface and the horizontal plane becomes smaller and smaller,
The second refracting surface extends in a direction closer to the optical axis,
The closer to the optical axis, the greater the distance between the second refracting surface and the horizontal plane becomes. The light beam control member according to claim 11, wherein a part of the light incident from the incident surface is reflected laterally by the reflective surface, and is refracted laterally by the first refractive surface. 13. The light beam control member according to claim 12, wherein another part of the light from the incident surface is reflected laterally by the reflecting surface and is refracted laterally by the second refractive surface. The luminous flux control member according to claim 13, which satisfies Equations 2 and 5 below.
Equation 2
-1.2 <θ2 / θ1 <0
Here, θ1 is an angle between the light reflected laterally by the reflective surface and the horizontal plane, θ2 is an angle between the light refracted by the first refracting surface and the horizontal plane, θ1 has a negative angle, θ2 has a positive angle.
Equation 5
-1.2 <θ4 / θ3 <0
Here, θ3 is an angle between the light reflected laterally downward by the reflective surface and the horizontal plane, θ4 is an angle between the light refracted by the second refracting surface and the horizontal plane, θ3 has a negative angle, θ4 has a positive angle. The method of claim 11, wherein the transparent member further comprises a rear surface extending in a direction away from the optical axis from the incident surface,
And the second refracting surface extends from the first refracting surface to the rear surface. The method of claim 11,
The reflective surface surrounds the periphery of the optical axis,
And the first refracting surface surrounds the periphery of the reflecting surface. Light source;
A light flux control member through which light from the light source is incident; And
A display panel to which light from the luminous flux control member is incident;
The light flux control member
A reflection surface reflecting light from the light source,
A first refracting surface that refracts first light reflected by the reflecting surface, and
A second refracting surface that refracts second light reflected by the reflective surface,
A transparent member covering the light source; And
A reflection member in close contact with the reflection surface and reflecting light incident from the light source on the contact surface;
The reflective surface
A first reflective surface formed at an interface between the transparent member and the reflective member; And
A second reflective surface extending from the first reflective surface and formed only in the transparent member;
A display device that satisfies Equations 1 and 4 below.
Equation 1
-1.2 <θ2 / θ1 <1.2
Here, θ1 is the angle between the first light reflected by the reflective surface and the horizontal plane orthogonal to the optical axis of the light source, θ2 is the angle between the first light and the horizontal plane refracted by the first refractive surface, When θ1 has a positive angle when the first light reflected by the reflecting surface is in the same direction as the optical axis of the light source with respect to the horizontal plane, θ1 has a negative angle when the light is different from the optical axis of the light source. When the first light refracted by the first refracting surface is in the same direction as the optical axis of the light source with respect to the horizontal plane, θ2 has a positive angle, when θ2 is different from the optical axis of the light source, It has a negative angle.
Equation 4
-1.2 <θ4 / θ3 <1.2
Here, θ3 is the angle between the second light reflected by the reflective surface and the horizontal plane orthogonal to the optical axis of the light source, θ4 is the angle between the second light and the horizontal plane refracted by the second refractive surface, When θ3 has a positive angle when the second light reflected by the reflective surface is in the same direction as the optical axis of the light source with respect to the horizontal plane, θ3 has a negative angle when the second light is in a direction different from the optical axis of the light source. Θ4 has a positive angle when the second light refracted by the second refracting surface is in the same direction as the optical axis of the light source with respect to the horizontal plane, and when θ4 has a different angle from the optical axis of the light source, It has a negative angle. The display device of claim 17, wherein the luminous flux control member has an asymmetrical structure about an optical axis of the light source. The display device of claim 17, wherein the reflective surface has a conical shape, and a vertex of the reflective surface faces the light source. The display device of claim 17, wherein Equation 3 and Equation 6 below are satisfied.
Equation 3
-1 <θ2 / θ1 <1
Equation 6
-1 <θ4 / θ3 <1 The method of claim 1,
A light emitting device that satisfies Equations 1 and 4 below.
Equation 1
-1.2 <θ2 / θ1 <1.2
Here, θ1 is the angle between the first light reflected by the reflective surface and the horizontal plane orthogonal to the optical axis of the light source, θ2 is the angle between the first light and the horizontal plane refracted by the first refractive surface, When θ1 has a positive angle when the first light reflected by the reflecting surface is in the same direction as the optical axis of the light source with respect to the horizontal plane, θ1 has a negative angle when the light is different from the optical axis of the light source. When the first light refracted by the first refracting surface is in the same direction as the optical axis of the light source with respect to the horizontal plane, θ2 has a positive angle, when θ2 is different from the optical axis of the light source, It has a negative angle.
Equation 4
-1.2 <θ4 / θ3 <1
Here, θ3 is the angle between the second light reflected by the reflective surface and the horizontal plane orthogonal to the optical axis of the light source, θ4 is the angle between the second light and the horizontal plane refracted by the second refractive surface, When θ3 has a positive angle when the second light reflected by the reflective surface is in the same direction as the optical axis of the light source with respect to the horizontal plane, θ3 has a negative angle when the second light is in a direction different from the optical axis of the light source. Θ4 has a positive angle when the second light refracted by the second refracting surface is in the same direction as the optical axis of the light source with respect to the horizontal plane, and when θ4 has a different angle from the optical axis of the light source, It has a negative angle.

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