KR100738111B1 - High output light guide panel, backlight unit and display employing the lightguide panel - Google Patents

Abstract

A high output light guide panel, and a backlight unit and a display device having the same are provided to form projection unit with concave and prism parts on the light guide panel for increasing amount of light projected upward and vertically. A high output light guide panel includes a first layer(105) having a light incident surface(105a), an opposite surface(105b) thereof, and a top surface(105c) for projecting light, a second layer(110) formed on the first layer and having projection units formed of an indent concave part(112) and a convex prism part(114), and a third layer(120) formed of anisotropic materials on the second layer. Lights of first polarization components passing through the concave parts are fully reflected by the prism and projected upward. The lights of second polarization components are reflected from a top surface of the third layer. Plane surfaces(111) are formed between the projection units. The concave part is formed of a curved surface and a plane surface or at least two plane surfaces.

Description

High output light guide panel, backlight unit and display employing the same {High output light guide panel, backlight unit and display employing the lightguide panel}

1 illustrates a light guide plate in which a prism array is conventionally formed on an adhesive layer.

2A to 2E illustrate the amount of vertical emitted light of the light guide plate measured by varying the prism angle of the prism array of the light guide plate shown in FIG. 1 by 50 degrees, 60 degrees, 70 degrees, 80 degrees, and 90 degrees, respectively.

3 illustrates a conventional light guide plate in which a prism array is formed without an adhesive layer.

4A to 4E illustrate the amount of vertical emitted light of the light guide plate measured by varying the prism angle of the prism array of the light guide plate illustrated in FIG. 3 by 50 degrees, 60 degrees, 70 degrees, 80 degrees, and 90 degrees, respectively.

5 shows a light guide plate according to a first embodiment of the present invention.

FIG. 6 is an enlarged view of an H portion of the light guide plate illustrated in FIG. 5.

FIG. 7 illustrates the amount of upper emitted light of the light guide plate illustrated in FIG. 5.

FIG. 8 illustrates the vertical emitted light amount of the light guide plate shown in FIG. 5.

9A and 9B show a comparison of the emission process of the light from the light emitting unit formed in the light guide plate shown in FIG. 5 with the prism in the comparative example.

10A to 10D show various examples of the light emitting unit of the light guide plate according to the first embodiment of the present invention.

11 shows a light guide plate according to a second embodiment of the present invention.

FIG. 12 is an enlarged view of a portion J of the light guide plate illustrated in FIG. 11.

13A and 13B illustrate various examples of the emitting unit of the light guide plate according to the second embodiment of the present invention.

FIG. 14 is a view for explaining a light emission process of an emission unit formed in the light guide plate according to the second embodiment of the present invention.

15A and 16A illustrate upper emission light amounts measured by changing the center angle of the second recess in the emission unit of the light guide plate shown in FIG. 11.

15B and 16B illustrate a vertical amount of emitted light measured by changing the center angle of the second recess in the emission unit of the light guide plate illustrated in FIG. 11.

17 shows a display employing a light guide plate according to a first embodiment of the present invention.

18 shows a display employing a light guide plate according to a second embodiment of the present invention.

<Description of main part of drawing>

100,200 ... light source, 105,205 ... 1st floor

105a, 205a ... incident plane, 105b, 205b ... highlight plane

105c, 205c ... exit surface, 110, 210 ... 2nd floor

112,212,216 ... concave, 114,214 ... prism

115,218 ... Exit unit, 120,220 ... 3rd floor

140,240 ... light guide plate, 150 ... backlight unit

Diffusion plate, 155,157 prism sheet

170 ... display panel

The present invention relates to a light guide plate having a high output, which has improved both an upper emission light amount and a vertical emission light amount, a backlight unit and a display employing the same.

A liquid crystal display device, which is a kind of light-receiving flat panel display used in notebooks, desktop computers, LCD-TVs, mobile communication terminals, etc., does not have its own light emitting capability, and thus forms an image by selectively transmitting illumination light emitted from the outside. To this end, a backlight unit for illuminating light is provided on the back of the liquid crystal display.

The backlight unit is classified into a direct light type and an edge light type according to the arrangement of the light sources. The direct type is a method in which a lamp installed directly below the liquid crystal panel directly irradiates light directly onto the liquid crystal panel.

The direct type is suitable for large displays of 30 inches or more such as LCD TVs because the light source can be freely and effectively placed in a large area. The metering type is a small and medium-sized digital device that is used in a monitor or a mobile phone because the light source is placed at a limited position on the side of the light guide plate. Suitable for splay

FIG. 1 illustrates a light guide plate employed in a conventional photometric backlight unit, and includes a light source 10, a first layer 15 formed of an isotropic material, and a second layer 18 formed on the first layer 15. ) And a third layer 25 formed of an anisotropic material. The first layer 15 includes a light incident surface 15a through which light is incident from the light source 10, and a light facing surface 15b facing the light incident surface 15a.

The second layer 18 is an adhesive layer having a prism array 20, and the third layer 25 is a birefringent layer having a different refractive index depending on the polarization direction of incident light.

2A to 2E illustrate the amount of light according to the exit light angle of the light guide plate while varying the prism angle θ ₁ of the prism array 20 by 50 degrees, 60 degrees, 70 degrees, 80 degrees, and 90 degrees, respectively. In the graph, A represents the amount of light along the X direction of FIG. 1, and B represents the amount of light along the Y direction of FIG. 1. According to the graph, the largest amount of light emitted in the vertical direction is when the prism angle θ ₁ is 50 degrees. When the amount of light emitted in the vertical direction is large, the light efficiency is increased and has a uniform light distribution.

Table 1 shows the amount of light emitted to the upper side (Z direction) of the light guide plate and the amount of light toward the light facing surface 15b when the incident light amount of the polarized light emitted upward is 100.

 Prism angle (°)     50     60    70     80     90 Upper exit light  50.61100   61.35100   69.33000  71.81500  67.61300 Light intensity  30.91300   22.88000   16.41000  14.15700  14.69100

Referring to Table 1, the upper emitted light is maximum when the prism angle is 80 degrees.

As described above, the light guide plate having the structure shown in FIG. 1 does not optimally satisfy two conditions, namely, upper emission light quantity and vertical emission, and when one of them is optimal, the remaining conditions do not satisfy the optimum.

The light guide plate illustrated in FIG. 3 includes a light source 50, a first layer 55 having a prism array 57, and a second layer 60 formed on the first layer 55. The first layer 55 is formed of an isotropic material, and the second layer 60 is formed of an anisotropic material.

4A to 4E show the amount of light according to the exit light angle of the light guide plate while varying the prism angle θ ₂ of the prism array 57 by 50 degrees, 60 degrees, 70 degrees, 80 degrees, and 90 degrees, respectively. When the angle is 50 degrees, the amount of vertical emitted light is maximum. In the graph, A represents the amount of light along the X direction of FIG. 4, and B represents the amount of light along the Y direction of FIG. 4.

Next, when the incident light amount of the polarized light emitted upward is 100, the light amount emitted to the upper side (Z direction) of the light guide plate and the light amount emitted to the light facing surface 55b are shown.

Prism angle (°)     50     60    70     80     90 Upper exit light  50.61100   61.35100   69.33000  71.81500  67.61300  Light intensity  30.91300   22.88000   16.41000  14.15700  14.69100

     The light guide plate of the structure shown in FIG. 3 does not optimally satisfy two conditions, namely, upper emission light quantity and vertical emission. That is, the prism angle is 80 degrees when the upper emission light is maximum, and 50 degrees when the vertical emission light is maximum. As described above, there is a limit in satisfying the upper output light quantity and the vertical output light quantity simultaneously.

The present invention has been made to solve the above problems, and an object thereof is to provide a light guide plate that emits light at a high output by satisfying both an upper emission light amount and a vertical emission light amount, and a backlight unit and display employing the same.

The light guide plate according to the present invention to achieve the above object,

A first layer having an incident surface on which light from the light source is incident, a light facing surface opposite the incident surface, and an upper surface on which light is emitted;

A second layer formed on the first layer and having a concave portion recessed and recessed and an emission unit composed of convex prisms;

And a third layer formed on the second layer and formed of an anisotropic material. The first polarized light of the light passing through the concave portion is totally reflected by the prism and emitted upward, and the second polarized light is emitted to the third layer. And is reflected at the top of the layer.

A flat part is provided between the emitting unit and the neighboring emitting unit.

The recess may have a curved surface and a flat surface.

The curved surface may have an arc-shaped cross section.

The recess may have at least two planes.

The planar portion is formed to be narrower as it is farther from the light source.

The recess and the prism are formed continuously.

A light guide plate for achieving the above object comprises: a first layer having an incident surface on which light from a light source is incident, a light facing surface opposite to the incident surface, and an upper surface on which light is emitted; A second layer formed on the first layer and having a first concave and concave recess, a convex prism, and a second concave-out unit formed continuously on the prism; A third layer formed on the second layer and formed of an anisotropic material; the first polarized light of the light passing through the first recess is totally reflected by the prism and emitted upward, and the light passes through the second recess. The light of the first polarized light is totally reflected from the inner surface of the second recess, and is emitted upward, and the light of the second polarized light is reflected from the upper surface of the third layer.

In order to achieve the above object, the backlight unit according to the present invention is a backlight unit for irradiating light to a display,

Light source; A light guide plate for guiding light incident from the light source; And a prism sheet positioned above the light guide plate to focus the emitted light.

The light guide plate is formed on the first layer and the first layer having an incident surface on which the light from the light source is incident, an opposing surface facing the incident surface, and an upper surface on which the light is emitted. A first layer of light that has passed through the recess, including a second layer in which a concave portion and an emission unit composed of convex prisms are repeatedly arranged, and a third layer formed on the second layer and formed of an anisotropic material; It is characterized in that the total reflection from the prism is emitted upward, the light of the second polarized light is reflected on the upper surface of the third layer.

The backlight unit for achieving the above object is a backlight unit for irradiating light to the display,

Light source; A light guide plate for guiding light incident from the light source; And a prism sheet positioned above the light guide plate to focus the emitted light.

The light guide plate includes: a first layer having an incident surface on which light from a light source is incident, a light facing surface opposite to the incident surface, and an upper surface on which light is emitted; A second layer formed on the first layer and having a first concave and concave recess, a convex prism, and a second concave-out unit formed continuously on the prism; A third layer formed on the second layer and formed of an anisotropic material; the first polarized light of the light passing through the first recess is totally reflected by the prism and emitted upward, and the light passes through the second recess. The light of the first polarized light is totally reflected from the inner surface of the second recess, and is emitted upward, and the light of the second polarized light is reflected from the upper surface of the third layer.

In order to achieve the above object, a display according to the present invention,

Light source; A light guide plate for guiding light incident from the light source; A diffuser plate positioned above the light guide plate to diffusely transmit incident light;

And a display panel for forming an image using light supplied through the diffusion plate.

The light guide plate is formed on the first layer and the first layer having an incident surface on which the light from the light source is incident, an opposing surface facing the incident surface, and an upper surface on which the light is emitted. A first layer of light that has passed through the recess, including a second layer in which a concave portion and an emission unit composed of convex prisms are repeatedly arranged, and a third layer formed on the second layer and formed of an anisotropic material; It is characterized in that the total reflection from the prism is emitted upward, the light of the second polarized light is reflected on the upper surface of the third layer.

Hereinafter, a light guide plate according to a preferred embodiment of the present invention, a backlight unit and a display employing the same, will be described in detail with reference to the accompanying drawings.

Referring to FIG. 5, the light guide plate according to the first embodiment of the present invention includes a first layer 105 for guiding light emitted from the light source 100 and a second layer 110 formed on the first layer 105. And a third layer 120 formed of an anisotropic material.

The first layer 105 may include an incident surface 105a on which light from the light source 100 is incident, an opposing surface 105b facing the incident surface 105a, and an upper surface 105c on which light is emitted. Include. The lower surface of the first layer 105 is provided with a reflecting plate 103 for reflecting light traveling toward the lower side of the first layer 105.

In the second layer 110, a light emitting unit 115 including a concave recessed recess 112 and a convex prism 114 is repeatedly arranged. The recess 112 and the prism 114 are formed continuously, and the connection portion of the recess 112 and the prism 114 is formed in a plane. The flat part 111 is formed between the emission unit 115 and the neighboring emission unit. The recess 112 may be formed of a curved surface and a plane or at least two planes. The exit unit 115 may be manufactured in various forms and specific shapes will be described later.

The third layer 120 is formed of an anisotropic material and has different refractive characteristics according to the polarization direction of incident light. In other words, it has a birefringence characteristic having a first refractive index for light of the first polarized light and a second refractive index for light of the second polarized light. As an anisotropic material, PET (PolyEthylene Terephthalate), PBT (PolyButylene Terephthalate), PEN (PolyEthyleneNaphthalate) and the like are used. The first layer 105 and the second layer 110 are isotropic materials and are formed of materials having the same refractive index or substantially the same. For example, the first layer 105 may be formed of PMMA (PMMA) having a refractive index of 1.49, and the second layer 110 may be formed of resin having a refractive index of 1.5. Meanwhile, the first layer 105 and the second layer 110 may be integrally formed of the same material. The third layer 120 has a first refractive index that is approximately equal to that of the first layer 105 and the second layer 110 for P-polarized light, and the first layer for S-polarized light. And a second refractive index relatively larger than the refractive index of the second layer 110. As a result, the P-polarized light does not sense a difference in refractive index at the boundary of each layer, and proceeds to the first layer 105, the second layer 110, and the third layer 120. In the most ideal case, the first refractive index of the first layer 105, the second layer 110, and the third layer 120 is the same, and only the second refractive index is relatively large, where P polarization is the first , The second and third layers proceed with one and the same material.

Referring to FIG. 6, the emission unit 115 includes a concave portion 112 and a convex prism 114. The recess 112 may be formed of at least two planes, and FIG. 6 illustrates an example having a prism shape including first and second planes 112a and 112b. The prism 114 is composed of third and fourth planes 114a and 114b, and the second plane 112b and the third plane 114a are continuously formed to form one plane.

Meanwhile, in FIG. 5, the second layer 110 and the third layer 120 have a smaller area than the first layer 105 in consideration of the occurrence of a dark portion at the light incident portion 105a. This is to use the portion except the dark portion generating area as the effective screen without using the portion as the screen. However, when no dark portion is generated, the areas of the first to third layers can be made to be the same.

Referring to the operation of the light guide plate configured as described above is as follows.

Light emitted from the light source 100 is incident on the first layer 105 and radiated in all directions. The light directed downward is reflected by the reflector plate 103 and directed upward, and the light directed upward refracts the second layer 110. Light incident on the second layer 110 passes through the planar part 111 and the first to fourth surfaces 112a, 112b, 114a, and 114b and enters the third layer 120. Since the first layer 105 and the second layer 110 are made of an isotropic material, they are not influenced by the polarization direction of the light, while the light incident on the third layer 120 has different refractive characteristics depending on the polarization direction. Is different. When the first refractive index ne for the light Is of the first polarized light is greater than the refractive index of the second layer 110 and the second refractive index no for the light Ip of the second polarized light, The light Is and the light Ip of the second polarized light proceed separately from the third layer 120. The light of the first polarized light is incident at an angle smaller than the critical angle to transmit the upper surface of the third layer, while the light of the second polarized light is incident and reflected at an angle greater than the critical angle on the upper surface of the third layer 120. That is, most of the light of the first polarized light is incident and transmitted at an angle close to perpendicular to the upper surface of the third layer.

The light of the second polarized light is reflected by the upper surface of the third layer and directed downward. Since the difference in refractive index between the third layer, the second layer, and the first layer is small with respect to the light of the second polarized light, most of the light of the second polarized light is refracted and transmitted to the first layer. In addition, when the light of the second polarized light passes through the first surface 112a and is incident on the second surface 112b and the third surface 114a, the difference in refractive index between the third layer and the second layer is small. The light is refracted and returned to the first layer 105.

On the other hand, the light of the first polarized light is refracted and transmitted through the first surface 112a to be incident on the second surface 112b and the third surface 114a between the third layer 120 and the second layer 110. Since the difference in refractive index is large, most of the light is totally reflected and directed upwards. In addition, since the totally reflected light travels upward, the vertical emission amount is increased.

When the third layer 120 is formed of an anisotropic material to separate light of the first polarization and light of the second polarization, the overall display structure can be simplified when using the liquid crystal panel as a display element. A liquid crystal panel is an element which depends on the polarization characteristic of incident light, and needs a polarizing film for processing the light of a different polarization direction in order to use only the light of a specific polarization direction. However, in the present invention, as described above, the light of the second polarized light in the third layer 120 becomes downwardly unused, and only the light of the first polarized light is emitted upwards to be useful light, so that only light in a specific polarization direction is used. There is an advantage that no separate polarizing film for use is required.

Of the light traveling through the second layer 110, the light incident on the planar portion 111 is transmitted and proceeds to the third layer 120, and is reflected from the upper surface of the third layer 120 to be reflected by the first layer 105. Return to the light facing surface 105b. The planar portion 111 is irradiated from a light source located on one side of the light guide plate so that light incident through the light incident surface 105a is reflected through the planar portion to travel toward the light facing surface 105b. The planar portion 111 adjusts the light uniformly distributed between the light incident surface 105a and the light facing surface 105b. In order to increase the amount of light reaching the upper side of the light facing surface 105b, it is better to narrow the width away from the light source.

On the other hand, the vertical output light amount and the upper output light amount can be adjusted by changing the shape of the emission unit, such as the center angle (θ11 + θ12) of the recess 112 and the center angle (θ21 + θ22) of the prism 114. 7 and 8 illustrate the upper output light amount and the output light angular distribution for the light guide plate according to the present invention. Here, θ11 = 65 degrees, θ12 = θ21 = 25 degrees, θ22 = 20 degrees, H1 = 50 μm, H2 = 50 μm, and pitch = 80 μm. Here, the pitch represents the periodic distance between the neighboring emitting unit and the unit, and represents the distance between the vertex and the vertex of the neighboring prism 114. The amount of emitted light is 70.03400 with respect to the amount of incident light 100 of polarized light that is emitted, and the amount of light emitted from the light-emitting part is 14.90300. FIG. 8 shows the exit light angular distribution, where A is the exit light angular distribution in the X direction and B is the exit light angular distribution in the Y direction. Referring to A, it can be seen that the amount of emitted light in the vertical direction is large. In addition, the output light quantity is 70.03400, and the maximum output light quantity in the structure shown in FIG. 1 is 71.81500, and the maximum output light quantity in the structure shown in FIG. 3 is 71.81500. That is, the vertical emission light quantity and the upper emission light quantity are both satisfied with optimum conditions. In the related art, a problem in which the amount of vertical emission light is relatively small and the amount of upper emission light is small and the amount of vertical emission light is small so that it is difficult to satisfy both conditions in the present invention.

In the present invention, what can satisfy both the upper output light quantity and the vertical output light quantity in the desired range will be described together with the structure having only the prism.

Figure 9a shows the structure of the emission unit according to the present invention, Figure 9b shows a structure consisting of only the prism. In the present invention, since only the useful light of a specific polarized light is emitted from the light guide plate by polarization separation according to the birefringence characteristic of the anisotropic material in the third layer, in FIGS. I will explain only. When the refractive index of the second layer 110 is n1 and the refractive index of the third layer 120 for s polarization is n2, n1 <n2. Among the light traveling to the second layer 110, the first light I ₁ and the second light I ₂ incident through the first surface 112a are refracted to form the second surface 112b and the third surface ( Incident on 114a). The first light I ₁ and the second light I ₂ are incident and totally reflected at an angle greater than a critical angle that satisfies the total reflection condition when the light is incident on an n 2 medium having a relatively high refractive index. .

Meanwhile, some light is transmitted through the upper portion of the third layer 120 and some light is reflected and proceeds downward. The third light (I ₃ ) reflected from the upper portion of the third layer 120 is incident on the second layer 110, partly transmitted and partly reflected to the second surface 112b and the third surface 114a. Incident. When the third light I ₃ incident on the second surface 112b and the third surface 114a is incident at an angle greater than the critical angle, it is totally reflected and directed upward.

As described above, the light incident on the second surface 112b and the third surface 114a through the first surface 112a of the concave portion 112 is emitted to the upper part by total reflection of the light, and is emitted during the total reflection. Each distribution of light has a distribution close to the vertical direction.

Meanwhile, in the structure in which only the prism P is formed without the concave portion as shown in FIG. 9B, a part of the light traveling toward the prism P in the second layer 110 is reflected, and part of the light is transmitted and refracted, and transmitted and refracted The light proceeds upward through the third layer 120, but proceeds upward at an angle closer to the horizontal direction than to the vertical direction. In addition, when the second layer 110 proceeds from the third layer 120, the fifth light I ₅ refracted and transmitted through the interface between the second layer 110 and the third layer 120 without passing through a prism is formed. After entering the prism P, it is reflected and directed upward.

9A and 9B, in the light guide plate according to the present invention, most of the light incident on the prism 114 through the recess 112 is reflected from the second surface 112b and the third surface 114a and upwards. And furthermore, the reflected light is directed to be emitted at an angle close to the vertical. On the contrary, in the structure shown in FIG. 9B, most of the light refracted and transmitted upward through the prism proceeds at an angle closer to the horizontal direction than to the vertical direction.

The recess 112 may be manufactured in various forms. For example, as shown in Figure 6 can be produced in the form of a prism consisting of two planes, as shown in Figure 10a consists of a curved surface and at least one plane, or as shown in Figure 10b It is made of a plane, but may be made of a plane parallel to the inclined plane and the horizontal direction. Alternatively, as illustrated in FIG. 10C, a plurality of planes may be formed as planes inclined at different angles. 10D shows an example in which the curved surface has an arc-shaped cross section.

The recess 112 allows the light transmitted through the recess 112 to be incident on the total reflection condition when the light is incident on the prism 114, and the light reflected from the prism is reflected at an angle close to the vertical direction, thereby providing high power. To achieve the light guide plate.

Meanwhile, in the present invention, as illustrated in FIG. 11, a polarization conversion plate 107 may be further provided between the first layer 105 and the reflection plate 103 to increase light efficiency. The polarization converting plate 107 converts the unused light into useful light by converting the light Ip of the second polarized light into the unused light into the light Is of the first polarized light by changing the polarization direction.

Next, a light guide plate according to a second embodiment of the present invention will be described with reference to FIG. 12. As shown in FIG. 12, the light guide plate according to the present invention includes a first layer 205 for guiding light emitted from the light source 200, a second layer 210 formed over the first layer 205, and an anisotropic material. The third layer 220 is formed.

The first layer 205 may include an incident surface 205a through which light from the light source 200 is incident, a light facing surface 205b opposite to the incident surface 205a, and an upper surface 205c through which light is emitted. Include. The lower surface of the first layer 205 is provided with a reflecting plate 203 for reflecting light traveling toward the lower side of the first layer 205.

In the second layer 210, a concave recessed first recessed part 212, a convex prism 214, and a second concave part 216, the emission unit 218 is repeatedly arranged. The flat part 211 is provided between neighboring emission units.

The third layer 220 is formed of an anisotropic material and has different refractive characteristics according to the polarization direction of the incident light. Branches have birefringence characteristics. The first layer 205 and the second layer 210 are isotropic materials and are formed of a material having the same or substantially the same refractive index. Since the operations of the first and second polarizations on the first layer 205, the second layer 210, and the third layer 220 are substantially the same as those described in the first embodiment, detailed descriptions thereof will be omitted herein. Shall be.

The emission unit 218 will be described in more detail as follows. The first concave portion 212 may include at least two planes as shown in FIG. 13, or at least one plane and a curved surface as shown in FIGS. 14A and 14B. When the first concave portion 212 has a curved surface, the curved surface is located in front of the plane as shown in FIG. 14A. The second concave portion 216 may also consist of at least two planes or at least one plane and a curved surface. When the second concave portion 216 has a curved surface, the curved surface is located behind the plane as shown in FIG. 14B.

Referring to FIG. 13, the first concave portion 212 is formed of the first and second planes 212a and 212b, and the prism 214 is formed of the third and fourth planes 214a and 214b. The second concave portion 216 is composed of the fifth and sixth planes 216a and 216b. The second plane 212b and the third plane 214a are continuously formed to form one plane, and the fourth plane 214b and the fifth plane 216a are continuously formed to form one plane. When the depth of the first recess 212 is h1, the height of the prism 214 is h2, and the depth of the second recess 216 is h3, h1 and h2 have different sizes or It may have the same size, and h1 and h3 may have the same size. In addition, by adjusting the size of the center angle of each of the first recess 212, the prism 214 and the second recess 216, the upper output light and the vertical output light can be increased together. The center angle α11 + α12 of the first recess portion 212 may be larger than the center angle α31 + α32 of the second recess portion 216.

Since the first recess 212 and the prism 214 function substantially the same as the recess 112 and the prism 114 in the first embodiment, a detailed description thereof will be omitted. The second recess 216 is to increase the vertical output light by reducing the light emitted with a large exit angle among the upper output light. Here, the exit angle represents an angle with respect to the normal of the first layer 205, and the vertical exit light represents a light close to zero degrees. Referring to FIG. 8, a portion denoted by C represents light emitted with a relatively large emission angle among upper emission light amounts. The second recess 216 serves to make the light emitted with a relatively large exit angle close to the vertical exit light. In other words, the light of the first polarization of the light passing through the fifth surface 216a of the second recess 216 is totally reflected from the sixth surface 216b of the second recess and is emitted upward. When reflected from the sixth surface of the second recess, the light exits with a near vertical exit angle.

FIG. 15 illustrates an example in which the prism 214 and the second concave portion 216 are formed so that their cross sections have a right triangle shape. That is, the plane where the prism 214 and the concave portion 216 meet is formed to be perpendicular to the first layer 205. Α22 = 0 in the prism 214 and α31 = 0 in the second recess 216. Part of the light I ₇ from the light source 200 is reflected from the prism 214 through the first recess 212 and directed upward, and the partial light I ₈ is totally reflected through the second recess 216. To the top. The light I ₆ reflected from the upper surface of the third layer 220 toward the lower portion of the light traveling through the first layer 205 and the second layer 210 to the third layer 220 is a prism. Total reflection at 214 is directed upwards. 16A and 16B show the top emission light distribution when h1 = 10 μm, h2 = 50 μm, h3 = 10 μm, θ11 = 65 degrees, θ12 = θ21 = 25 degrees, θ22 = θ31 = 0 degrees, θ32 = 25 degrees It is shown. Here, when the space | interval between a neighboring prism and a prism is called pitch, the pitch comprised 60 micrometers. A represents the exit light angular distribution along the X direction in FIG. 12, and B represents the exit light angular distribution along the Y direction. The upper output light amount is 70.50500 with respect to the incident light amount 100, and the large light exit light amount is 15.16300. Referring to A graph of FIG. 16B, it can be seen that the amount of light (part C of FIG. 8) at a large emission angle is greatly reduced when compared with FIG. 8. And the peak value of emitted light increased.

 17A and 17B are h1 = 10 μm, h2 = 50 μm, h3 = 10 μm, θ11 = 65 degrees, θ12 = θ21 = 25 degrees, θ22 = θ31 = 0 degrees, θ32 = 30 degrees, and pitch is 60 degrees. The upper emission light distribution is shown when the micrometer. The upper output light quantity is 71.14000 with respect to the incident light quantity 100, and the large light output portion is 14.75700. Referring to the A graph of FIG. 17B, the amount of light at the large emission angle is greatly reduced as compared with FIG. 8, and the peak value of the emission light is increased. As such, the bandwidth and the light intensity of the vertically emitted light may be increased through the second recess.

FIG. 18 illustrates an example in which the polarization converting plate 207 is further provided between the first layer 205 and the reflecting plate 203 in the structure shown in FIG. 12. The polarization converting plate 207 converts the unused light into useful light by converting the light Ip of the second polarized light into the unpolarized light into the light Is of the first polarized light by changing the polarization direction. This increases the light efficiency.

19 shows a display with a light guide plate according to a first embodiment of the present invention.

The display according to the present invention includes a backlight unit 150 and a display panel 170 for forming an image using light emitted from the backlight unit 150. The backlight unit 150 includes a light source 100 and a light guide plate 140 for guiding light emitted from the light source 100 toward the display panel 170. The light guide plate 140 is configured as described above, and since the light guide plate 140 has the same effect, a detailed description thereof will be omitted.

A diffusion plate 153 for diffusing light, a first prism sheet 155 and a second prism sheet 157 are disposed between the light guide plate 140 and the display panel 170. do. The first prism sheet 155 and the second prism sheet 157 are arranged to be orthogonal to each other, thereby refracting and condensing the light emitted from the diffusion plate 153 to improve the direction of the light, thereby increasing the brightness and reducing the incident angle of the light. Play a role. Sheets and components used between the light guide plate 140 and the display panel 170 may have better performance when they have a function of polarization preservation.

The display panel 170 may be configured of, for example, a liquid crystal panel. The liquid crystal panel uses only light in a specific polarization direction as useful light. In the present invention, the light is separated from the light guide plate according to the polarization direction in the third layer 120 formed of an anisotropic material so that only the light in the specific polarization direction is directed upward. There is an advantage that there is no need to separately provide a film for separation. Meanwhile, a polarization converting plate (107 in FIG. 11) may be further provided between the first layer 105 and the reflecting plate 103.

FIG. 21 illustrates a display employing a light guide plate 240 according to a second embodiment of the present invention. The display for forming an image using the backlight unit 150 and the light emitted from the backlight unit 150 is illustrated. And panel 170. The backlight unit 150 includes a light source 100 and a light guide plate 240 for guiding the light emitted from the light source 100 toward the display panel 170. The light guide plate 240 has a configuration as described with reference to FIG. 12 and has the same effect. In addition, the members using the same reference numerals as in FIG. 12 function substantially the same, and detailed description thereof will be omitted herein. Meanwhile, a polarization conversion plate (207 in FIG. 18) may be further provided between the first layer 205 and the reflective plate 203 to increase light efficiency.

As described above, the light guide plate according to the present invention includes a light emitting unit consisting of a concave portion and a prism, thereby increasing the upper output light amount and also increasing the vertical output light amount to realize high output.

In addition, the backlight unit and the display employing the light guide plate according to the present invention provide a screen of bright and good image quality by using high output light. The display of the present invention includes a layer of an anisotropic material on the light guide plate to separate polarized light from the light guide plate and emit only one direction of polarized light to the top.

In addition, the light guide plate according to the present invention includes a light emitting unit having a concave portion disposed before and after the prism so that the light emitted upwardly with a relatively large light exit angle is vertically emitted to increase the vertical light output in addition to the top light output. Let's do it.

The above embodiments are merely exemplary, and various modifications and equivalent other embodiments are possible to those skilled in the art. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the invention described in the claims below.

Claims (35)

A first layer having an incident surface on which light from the light source is incident, a light facing surface opposite the incident surface, and an upper surface on which light is emitted; A second layer formed on the first layer and having a concave portion recessed and recessed and an emission unit composed of convex prisms; And a third layer formed on the second layer and formed of an anisotropic material. The first polarized light of the light passing through the concave portion is totally reflected by the prism and emitted upward, and the second polarized light is emitted to the third layer. A light guide plate, characterized in that reflected from the upper surface of the layer. The method of claim 1, A light guide plate is provided between the emission unit and a neighboring emission unit. The method according to claim 1 or 2, The recess is a light guide plate, characterized in that consisting of a curved surface and a plane. The method of claim 3, wherein The curved surface has a light guide plate, characterized in that it has an arc-shaped cross section. The method according to claim 1 or 2, The recess is a light guide plate, characterized in that consisting of at least two planes. The method of claim 2, The light guide plate, characterized in that the width becomes smaller as the planar portion away from the light source. The method of claim 1, The concave portion and the prism are formed in a continuous light guide plate. The method according to claim 1 or 2, The concave portion allows the light passing through the concave portion to be incident at an angle greater than a critical angle of the prism. The method according to claim 1 or 2, The light guide plate, characterized in that the first layer and the second layer are formed integrally. A first layer having an incident surface on which light from the light source is incident, a light facing surface opposite the incident surface, and an upper surface on which light is emitted; A second layer formed on the first layer and having a first concave and concave recess, a convex prism, and a second concave-out unit formed continuously on the prism; A third layer formed on the second layer and formed of an anisotropic material; the first polarized light of the light passing through the first recess is totally reflected by the prism and emitted upward, and the light passes through the second recess. The light guide plate, characterized in that the light of the first polarized light is totally reflected from the inner surface of the second recess portion is emitted upward, the light of the second polarized light is reflected from the upper surface of the third layer. The method of claim 10, The first and second concave portions have a light guide plate, characterized in that having a triangular cross section. The method of claim 11, The center angle of the first recessed portion is larger than the center angle of the second recessed portion. The method of claim 11, The surface of which the prism and the second concave portion meet is a plane, and the plane is formed at right angles to the first layer. The method of claim 10, The second recess is a light guide plate, characterized in that consisting of a flat surface. The method of claim 14, The light guide plate, characterized in that the surface formed by the prism and the second concave portion is a plane. The method of claim 15, Wherein the plane is formed at right angles to the first layer. The method of claim 10, The light guide plate further comprises a plane between the neighboring emitting unit. A backlight unit for irradiating light to a display, Light source; A light guide plate for guiding light incident from the light source; And a prism sheet positioned above the light guide plate to focus the emitted light. The light guide plate is formed on the first layer and the first layer having an incident surface on which the light from the light source is incident, an opposing surface facing the incident surface, and an upper surface on which the light is emitted. A first layer of light that has passed through the recess, including a second layer in which a concave portion and an emission unit composed of convex prisms are repeatedly arranged, and a third layer formed on the second layer and formed of an anisotropic material; Totally reflected from the prism and emitted upward, and the second polarized light is reflected from the upper surface of the third layer. The method of claim 18, And a flat part is provided between the emission unit and a neighboring emission unit. The method of claim 18 or 19, The recessed unit is characterized in that the curved surface and planar. The method of claim 20, And the curved surface has an arc shaped cross section. The method of claim 18 or 19, And the recess is formed of at least two planes. The method of claim 19, And a width thereof decreases as the plane portion moves away from the light source. The method of claim 18 or 19, And the recess and the prism are formed continuously. The method of claim 18 or 19, And the concave portion allows light passing through the concave portion to be incident at an angle greater than a critical angle of the prism. A backlight unit for irradiating light to a display, Light source; A light guide plate for guiding light incident from the light source; And a prism sheet positioned above the light guide plate to focus the emitted light. The light guide plate includes: a first layer having an incident surface on which light from a light source is incident, a light facing surface opposite to the incident surface, and an upper surface on which light is emitted; A second layer formed on the first layer and having a first concave and concave recess, a convex prism, and a second concave-out unit formed continuously on the prism; A third layer formed on the second layer and formed of an anisotropic material; the first polarized light of the light passing through the first recess is totally reflected by the prism and emitted upward, and the light passes through the second recess. The light of the first polarized light is totally reflected from the inner surface of the second recess portion is emitted upwards, the light of the second polarized light is reflected on the upper surface of the third layer. The method of claim 26, And the first and second concave portions have a triangular cross section. The method of claim 27, And a center angle of the first recess is greater than a center angle of the second recess. The method of claim 27, And the plane formed by the prism and the second concave portion is a plane, and the plane is formed at a right angle with respect to the first layer. The method of claim 25, And the second concave portion is formed of a flat surface and a curved surface. The method of claim 30, And the plane formed by the prism and the second concave portion is a plane, and the plane is formed at a right angle with respect to the first layer. The method of claim 18 or 26, And a polarization converting plate for converting the polarization direction of incident light on the lower surface of the first layer. A backlight unit according to claim 18 or 19; And a display panel for forming an image by using the light emitted from the backlight unit. A backlight unit according to claim 22; And a display panel for forming an image by using the light emitted from the backlight unit. A backlight unit according to any one of claims 26 to 31; And a display panel for forming an image by using the light emitted from the backlight unit.

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