TW201730643A - Lens for edge light type display device and display device having the same - Google Patents

Abstract

The present invention relates to lens for edge light type display device and display device having the same, wherein the lens composed of a spherical surface and an aspheric surface can reduce the angle of direction so as to improve light segregation of a light incident part. The lens for edge light type display device is provided in a light divergence direction of a light source to adjust the angle of direction of the light emitted from the light source. The light source is provided on the side surface of the display device, wherein the lens comprises: a first refraction surface provided in opposition to the light source, and protruding toward the light source side; a partition wall surface continuing from the first refraction surface and extending toward the light source side; a reflection surface formed in the outer contour of the lens and reflecting the light incident into the interior; a refraction-reflection surface extending from the reflection surface and refracting and reflecting the light incident into the interior; and a second refraction surface (137) extending from the refraction-reflection surface and protruding toward the contrary side of the light source.

Description

Lens for edge-light display device and display device including the same

The present invention relates to a lens for an edge-light type display device and a display device including the same, and more particularly to a side light that reduces a pointing angle by a lens composed of a spherical surface and an aspherical surface, thereby improving light segregation in the light incident portion. A lens for a display device and a display device including the lens.

Flat panel display (FPD) devices are widely used in TVs, mobile phones, notebook computers, tablet computers, etc., including plasma display panels (PDPs), liquid crystal displays (LCDs), and organic liquid crystal displays (LCD). An OLED (Organic Light-Emitting Display) device, an electrophoretic display device, or the like.

Such a flat panel display device includes a display panel that displays an image, and the liquid crystal display panel or the like does not generate light by itself, and therefore includes a backlight unit that supplies light to the panel.

The backlight unit can be classified into an edge light type and a direct light type depending on the position of the light source, and an LED (Light Emitting Diode) is often used as a light source.

For the edge-lit backlight unit, since light is received from a light source disposed at the side, a light guide plate that converts light from the side to the direction of the display panel has been used. Recently, a technique of transmitting light through a reflection sheet to a direction of a display panel without using a light guide plate is being developed.

11a is a cross-sectional schematic view of a conventional side light type display device with a light guide plate removed, FIG. 11b is a graph showing a pointing angle of the LED, and FIG. 11c is a view showing a light plane distribution of the display panel of FIG. 11a .

Referring to FIG. 11a, a conventional edge type display device 100P includes a display panel 10, an optical sheet group 20, a reflection sheet 30, and a light source 40. These constituent elements are built in the upper cover 61 and the lower cover 62, and the display panel 10 and the optical sheet group 20 are separated by the molding frame 63.

For example, the display panel 10 may be a liquid crystal display panel, and a diffusion sheet, a prism sheet, or the like may be stacked to form the optical sheet group 20. The reflection sheet 30 is disposed on the back surface of the optical sheet group 20 to form an internal space S whose inner side is reflected toward the incident light.

As the light source 40, an LED can be used. In the edge type display device 100P, the light source 40 is disposed on the side surface of the display panel 10, and illuminates the central portion. The light irradiated from the light source 40 is directed toward the display panel 10 by the reflection sheet 30. Thereby, even if there is no light guide plate, the light from the light source 40 can be made to be far away from the light source, and reflected by the reflection sheet 30 and supplied to the display panel 10.

Referring to Fig. 11b, the pointing angle of the LED used as the light source 40 is about 120o. Due to the directional angle characteristic of such an LED, as shown in Fig. 11c, a phenomenon of photosegregation occurs in the vicinity of the light source 40. That is, a problem of light segregation occurs, that is, light from the light source 40 cannot be transmitted far to the vicinity of the center of the display panel 10, and is emitted to the outside in the vicinity of the light source 40.

In order to eliminate such a phenomenon of light segregation, a method of increasing the interval between the reflection sheet 30 and the optical sheet group 20 has appeared, but it has been difficult to achieve thinning of the display device itself, and thus it is difficult to adopt such a method. Further, if the interval between the conventional reflection sheet 30 and the optical sheet group 20 is maintained, the enlargement of the light source 40 is insufficient to increase the size of the display device.

Related patent documents: Korean Patent Application No. 10-2012-0026165

Technical problem to be solved

The present invention has been made to solve the above problems, and the technical problem to be solved by the present invention is to provide a light source lens for an edge-lit backlight device with a light guide plate removed, and a display device including the same, including a spherical surface and an aspheric surface. The lens, the reflection sheet, and the optical sheet reduce the pointing angle, thereby improving the phenomenon of light segregation in the light incident portion.

The technical problem of the present invention is not limited to the above-mentioned technical problems, and those skilled in the art will be able to clearly know other technical problems not mentioned by the following description.

Solution to technical problems

In order to solve the above problems, a lens for an edge-light type display device according to an embodiment of the present invention is disposed in a light-diffusion direction of a light source for adjusting a directivity angle of light diverging from a light source, and the light source is disposed on the display device. a side surface, wherein the lens comprises: a first refractive surface opposite to the light source and protruding toward the light source side; a partition wall surface continuing from the first refractive surface and extending toward the light source side; the reflective surface forming an outline of the lens, and Reflecting light incident on the interior; refracting the reflective surface, continuing from the reflective surface for refracting and reflecting light incident on the interior; and second refractive surface 137 continuing from the refractive reflective surface and facing the opposite side of the light source The angle between the partition wall surface and the level axis B1 is greater than or equal to 75 degrees and less than or equal to 90 degrees with respect to the optical axis of the light diverging from the light source and the horizontal axis perpendicular to the optical axis.

According to another embodiment of the present invention, the angle between the first refractive surface and the horizontal axis B2 may be greater than 0 degrees and less than 20 degrees, and the angle between the tangent at the end of the second refractive surface and the horizontal axis B3 may be greater than 30 degrees and less than 70 degrees.

According to still another embodiment of the present invention, the angle between the refractive reflecting surface and the horizontal axis B3 may be greater than 0 degrees and less than 25 degrees.

According to still another embodiment of the present invention, the reflecting surface may reflect light that is diverged from the light source and whose angle between the light source and the optical axis A is greater than or equal to 30 degrees.

According to still another embodiment of the present invention, the first refractive surface, the partition wall surface, the reflecting surface, the refractive reflecting surface, and the second refractive surface may be configured as a spherical surface or an aspheric surface, respectively.

In order to solve the above problems, a display device according to an embodiment of the present invention includes: a display panel; an optical sheet group disposed on a back surface of the display panel; and a reflection sheet disposed apart from the back surface of the optical sheet group, and the optical sheet group Forming an internal space together and scattering light to illuminate the optical sheet set; the light source is disposed at a side of the display panel to illuminate the central portion of the display panel; the lens is disposed on the upper surface of the light source; and the bottom cover And surrounding the formed internal space together with the optical sheet set.

According to another embodiment of the present invention, the optical sheet may include a diffusion sheet having a surface roughness of 0 to 2 μm.

According to still another embodiment of the present invention, the reflective sheet may include a bead, and the reflective sheet may have a surface roughness of 0 to 10 micrometers (μm).

According to still another embodiment of the present invention, the glossiness of the reflective sheet may be 20 to 30.

According to still another embodiment of the present invention, the microbeads may include at least one of polyethylene, acryl, nylon, and a mixture of these materials.

According to still another embodiment of the present invention, the bottom cover may be composed of a level portion and an inclined portion.

According to still another embodiment of the present invention, the level portion may have an L value based on the relationship 1, and the angle between the inclined portion and the level portion may be θ based on the relationship 2,

[Relationship 1]

[Relationship 2]

Where D is the thickness of the display device, T is the overall length of the display device in the direction of divergence of the light source, and the pointing angle is the pointing angle of the light source passing through the lens.

According to still another embodiment of the present invention, the length of the level portion may be 80% to 120% of the L value calculated according to the relational expression 1.

According to still another embodiment of the present invention, the plurality of light sources may be arranged in a row spaced apart from each other on one side of the display panel, and the distance between the light source disposed in the central region and the peripheral region and the adjacent light source, that is, the pitch may not be Similarly, in the central region, a row of light sources is disposed on one side of the display panel, and a light source is disposed in the peripheral region with reference to a peripheral portion of one side of the display panel.

According to a further embodiment of the invention, the spacing of the light sources in the peripheral region may be from 70% to 99% of the spacing of the light sources in the central region.

According to still another feature of the present invention, in the central region to the peripheral region, the plurality of light sources are divided into four or more regions from a central portion to a peripheral portion of one side of the display panel, and among the plurality of regions, the light source in the central region The average spacing can be the largest, and the average spacing of the light sources in the area adjacent to the surrounding area can be minimized.

According to still another embodiment of the present invention, the distance between the plurality of light sources from the central region to the peripheral region may vary, although the pitch tends to become smaller from the central region to the peripheral region, and at least one interval may become larger. Inflection point.

According to still another embodiment of the present invention, in one side central portion and peripheral portion of the display panel, the inflection point may be disposed close to the peripheral portion.

According to still another embodiment of the present invention, a highly reflective sheet may be disposed that is disposed on the internal space and has a light reflectance higher than a light reflectance of the reflective sheet for reflecting light from the light source to a position away from the light source. To increase the brightness of the display panel.

According to still another embodiment of the present invention, when the display panel is equally divided along one axis and divided into three equal divisions to form nine regions, the high reflection sheet may be disposed in three regions adjacent to the light source. The two areas of the display panel are adjacent to each other.

According to still another embodiment of the present invention, when the display panel is divided into three equal divisions along one axis and three regions are equally divided along the other axis, the high reflection sheet can be disposed in the three regions farthest from the light source. The side of the display panel of the two adjacent areas of the periphery of the display panel.

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

Effect of the invention

The lens for the edge-light type display device of the present invention and the display device including the lens remove the light guide plate from the backlight unit, and the number of light sources can be reduced by the lens, thereby saving material cost of the product and reducing the weight of the product. .

Further, the display device of the present invention can achieve a thinning of the product and an additional design element by a wedge-shaped structure in which the width of the light source tends to be gradually reduced away from the light source.

The effects of the present invention are not limited to the above exemplified contents, and more diverse effects are included in the present specification.

The advantages and features of the present invention, as well as the means for achieving the same, will become apparent from the detailed description of the embodiments described herein. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and the present embodiments are provided only to complete the disclosure of the present invention, and to those skilled in the art to which the present invention pertains. The scope of the present invention is conveyed, and the present invention is defined only by the scope of the patent application.

The shapes, sizes, proportions, angles, numbers, and the like disclosed in the drawings for explaining the embodiments of the present invention are illustrative, and the present invention is not limited to the illustrated matter. Further, the detailed description of the present invention will be omitted if the detailed description of the related art is not made clear. When "include", "has", "constructed" and the like mentioned in the specification are used, other portions may be added unless 'only' is used. When the constituent elements are expressed in the singular form, the case includes a plurality of cases unless there is a particularly clear description.

When interpreting the constituent elements, even if there is no additional explicit description, it is interpreted as including the error range.

When the positional relationship is described, for example, the positional relationship between the two parts is described as "on", "on", "under", "on", etc., unless "just" is used. Or "direct", otherwise there may be more than one other part between the two parts.

When an element or layer is referred to as being "on" or "on", it is meant to be in the <RTIgt;

Although the first, second, etc. are used to describe various constituent elements, these constituent elements are not limited by these terms. These terms are only used to distinguish one component from another. Therefore, within the technical idea of the present invention, the first constituent element mentioned below may be the second constituent element.

Throughout the specification, the same reference numerals denote the same constituent elements.

The sizes and thicknesses of the various structures shown in the drawings are shown for convenience of explanation, and the present invention is not necessarily limited to the size and thickness of the illustrated structure.

For each feature of various embodiments of the present invention, a part or the whole can be combined or combined with each other, and various linkages and driving can be performed technically, so that those skilled in the art can understand that for each embodiment, it can be independent. The implementation of the land can also be implemented in accordance with the relevant relationship.

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

1 is a cross-sectional schematic view for explaining a display device according to an embodiment of the present invention.

A display device 100 according to an embodiment of the invention includes a display panel 110, a light source 120, a lens 130, a reflective sheet 140, a bottom cover 150, and an optical sheet set 200.

The display panel 110 is disposed on the front side of the display device 100. In the present embodiment, the display panel 110 may be an LCD (Liquid Crystal Display) that requires a light supply portion that illuminates light on the back surface of the display panel 110.

The optical sheet set 200 is disposed on the back surface of the display panel 110. The optical sheet group 200 is constituted by stacking a plurality of optical sheets 210, 220, and 230. Regarding the optical sheet set 200, the diffusion sheet 210 may be disposed at a position where it contacts the internal space S, and the cylindrical lenses 220, 230 may be disposed in the upper layer portion thereof. For the diffusion sheet 210, a detailed description will be made with reference to FIG.

The reflection sheet 140 is disposed apart from the back surface of the optical sheet group 200, forms an internal space S together with the optical sheet group 200, and scatters light to illuminate the optical sheet group 200. Referring specifically to FIG. 1, the reflective sheet 140 is disposed on the bottom cover 150. The reflection sheet 140 can also maintain a certain degree of rigidity capable of maintaining its own shape. Alternatively, the reflection sheet 140 may be disposed on the bottom cover 150, and may be placed on the upper portion of the bottom cover 150 according to the shape of the bottom cover 150. Regarding the reflection sheet 140, a detailed description will be made with reference to FIG.

The light source 120 is disposed on a side of the display panel 110 and illuminates light toward a central portion of the display panel 110. Specifically, the light source 120 may be located at a lower portion of the display panel 110 and illuminate light toward the other side of the display device 100 on the inner side of the display device 100. Since it is a type that is disposed on the side of the display device 100 and diverge light toward the other side of the display device 100, it is the edge-light display device 100. Light source 120 can be an LED or LED package.

The lens 130 is disposed above the light source 120. The function of the lens 130 is to adjust the directivity angle of the light from the light source 120. Specifically, the directivity angle of light from the light source 120 may be approximately 120 degrees with respect to the LED. However, the angle of the light passing through the lens 130 is approximately 6 degrees. Accordingly, the lens 130 reduces the pointing angle of the light source 120 while passing the light of the light source 120 to the reflective sheet 140 or the display panel 110 remote from the light source 120. The shape of the lens 130 will be described in detail with reference to FIGS. 2 and 3.

The bottom cover 150 is formed to surround the formed internal space S together with the optical sheet group 200. The outer side of the bottom cover 150 protects the display device 100 from the outside, and the reflection sheet 140 is disposed inside thereof. The bottom cover 150 may also form the exterior of the display device 100, but a housing surrounding at least a portion of the bottom cover 150 and forming the exterior of the display device 100 may be further disposed outside the bottom cover 150. Regarding the bottom cover 150, a detailed description will be made with reference to FIG.

Fig. 2 is a cross-sectional view for explaining the lens of Fig. 1. Fig. 3 is a conceptual diagram for explaining a shape formed by each surface of the lens of Fig. 2.

As described above, the lens 130 according to an embodiment of the present invention is a lens 130 for an edge-light display device that is disposed in a light-diffusion direction of the light source 120 to adjust a directivity angle of light diverged from the light source 120. The light source is disposed on the side of the display device. Among them, the lens 130 may be formed of one of a plastic having a refractive index of 1.45 to 1.60, glass, and a mixture of these materials.

2 and 3, the lens 130 includes a partition wall surface 131, a support surface 132, a reflecting surface 133, a first refractive surface 135, a second refractive surface 137, and a refractive reflecting surface 139. On the other hand, each surface of the lens 130 may form a prescribed angle with respect to the optical axis A of the light diverging from the light source 120 and the three horizontal axes B1, B2, B3 perpendicular to the optical axis and parallel to each other. Among them, since the three level axes B1, B2, and B3 are axes parallel to each other, they are hereinafter referred to as a level axis.

The first refractive surface 135 is opposed to the light source 120 and protrudes toward the light source 120 side. Most of the light diverging from the light source 120 can be incident on the inside of the lens 130 through the first refractive surface 135. Preferably, the angle formed by the line connecting the center of the divergent surface of the light source 120 and the end portion 135a of the first refractive surface 135 to the optical axis A is less than 30 (θ2 < 30 degrees). Thereby, the width of the first refractive surface 135 can be determined. This is one of the methods of determining the appropriate amount of light that can be incident on the first refractive surface 135 among the light diverging from the light source 120.

Further, the tangent at the end portion 135a of the first refractive surface 135 and the horizontal axis B2 may form an angle greater than 0 degrees and less than 20 degrees (0 degrees < θ3 < 20 degrees). Thereby, the first refractive surface 135 can refract light so that light incident to the first refractive surface 135 is incident on the lens 130 and the pointing angle becomes small.

The partition wall surface 131 continues from the first refractive surface 135 and extends toward the light source 120 side. The partition wall surface 131 is a side surface adjacent to the light source 120, and light emitted from the light source 120 can enter the inside of the lens 130 through the partition wall surface 131. The partition wall 131 separates the light source 120 and the first refractive surface 135 from each other. The partition wall surface 131 forms an angle of 75 degrees or more and 90 degrees or less with the level axis B1 (75 degrees ≤ θ1 ≤ 90 degrees). Thereby, the light diverged from the light source 120 can be incident on the inside of the lens 130 through the partition wall surface 131, and the incident light can be easily reflected by the reflecting surface 133.

The reflecting surface 133 constitutes the outer contour of the lens 130 and reflects light incident on the inside. The reflecting surface 133 forms the outer side of the lens 130. Through the reflecting surface 133, the lens 130 can adjust the pointing angle of the light diverged from the light source 120. On the other hand, the reflecting surface 133 may be formed to reflect light that is diverged from the light source 120 and whose angle between the light source and the optical axis A is 30 degrees or more. As described above, light having an angle of less than 30 degrees from the light axis A among the light diverged from the light source 120 can be incident through the first refractive surface 135. Among the light diverged from the light source 120, light having an angle of more than 30 degrees with respect to the optical axis A enters the inside of the lens 130 through the partition wall surface 131, and the incident light passes through the reflecting surface 133 toward the refractive reflecting surface 139 or the second. The refractive surface 137 is reflected.

The refractive reflecting surface 139 continues from the reflecting surface 133, which refracts and reflects the light incident to the inside, thereby being radiated to the outside of the lens 130. The refractive reflecting surface 139 is disposed at a portion where light incident into the inside of the lens 130 is diverged. Between the refractive reflecting surface 139 and the second refractive surface 137, the angle between the end portion 139a of the refractive reflecting surface 139 and the horizontal axis B3 may be greater than 0 degrees and less than 25 degrees (0 degrees < θ5 < 25 degrees). The directivity angle of the light diverging by the refractive reflecting surface 139 can be reduced in accordance with an increase in the angle of the refractive reflecting surface 139.

The second refractive surface 137 continues from the refractive reflective surface 139 and protrudes toward the opposite side of the light source 120. The tangent at the end 137a of the second refractive surface 137 and the horizontal axis B3 may form an angle greater than 30 degrees and less than 70 degrees (30 degrees < θ4 < 70 degrees). Thereby, the degree of protrusion of the second refractive surface 137 can be set. According to the degree of protrusion of the second refractive surface 137, the pointing angle of the light that is diverged after passing through the lens 130 can be adjusted.

The support surface 132 is a surface that connects between the partition wall surface 131 and the reflection surface 133. The support surface 132 may be configured to be supported by the same surface as the surface on which the light source 120 is disposed, and to expose the lens 130 to the light source 120. On the other hand, unlike the case shown in FIGS. 2 and 3, the support surface 132 may be disposed behind the surface on which the light source 120 is disposed, or may be disposed in front of the surface on which the light source 120 is disposed. This can be adjusted according to the design needs.

The first refractive surface 135, the partition wall surface 131, the reflecting surface 133, the refractive reflecting surface 139, and the second refractive surface 137 may be configured as a spherical surface or an aspheric surface, respectively.

Fig. 4 is an enlarged cross-sectional view for explaining the reflection sheet of Fig. 1.

A reflection sheet 140 according to an embodiment of the present invention includes a microbead 141, a coating layer 143, and a base layer 147.

The microbeads 141 may be disposed on the upper portion of the base layer 147 such that the surface of the reflective sheet 140 forms irregularities and is covered by the coating layer 143. The microbead 141 is preferably a size of 5 μm or less. The reflection sheet 140 which forms the uneven surface by the microbeads 141 can diffusely reflect incident light. On the other hand, the microbeads 141 may include at least one of polyethylene, acryl, nylon, and a mixture of these materials.

The coating layer 143 may be formed to cover the microbeads 141 and the base layer 147. The surface of the coating 143 forms a reflective surface 145 having a defined degree of surface roughness. The reflective surface 145 may have a surface roughness of 0 to 10 μm. Here, Surface Roughness is a value indicating the degree of fine unevenness appearing on the surface of the object and the degree of roughness of the surface. When the roughness is indicated, the surface is cut by a plane perpendicular to the surface, and when the cross section is observed, a curve is formed, and the height from the lowest point to the highest point of the curve is called the highest value roughness, and the average value of the curve is utilized. Can measure the surface roughness.

Light that is not reflected by the coating 143 may be incident on the base layer 147. The material forming the base layer 147 may be a material that absorbs an impact between it and the bottom cover 150 on which the reflection sheet 140 is disposed. The upper portion of the base layer 147 may be covered with beads 141 and a coating 143. Light incident on the base layer 147 may be reflected on the lower surface of the base layer 147 and then diffused to the outside through the coating layer 143.

The glossiness of the reflection sheet 140 may be 20 to 30. Among them, glossiness is an attribute indicating the property of the specular reflected light on the surface of the object. This gloss depends on the constituent materials, roughness, and shape of the surface of the object. The outermost layer of the reflective sheet 140 is the coating 143, so the reflective surface 145 of the coating 143 may have a gloss of 20 to 30.

Fig. 5 is an enlarged cross-sectional view for explaining the diffusion sheet of Fig. 1.

The diffusion sheet 210 according to an embodiment of the present invention may be formed in a shape different from the upper surface and the lower surface.

Specifically, the upper surface of the diffusion sheet 210 may form a diffusion surface 213. The diffusion surface 213 functions to form a non-uniform surface to increase the diffusion of light, thereby ensuring more uniform brightness and illuminance when the light passing through the diffusion sheet 210 is diverged toward the display panel 110.

Then, the lower surface of the diffusion sheet 210 may form a mirror surface 215. The lower surface of the diffusion sheet 210 is a surface on which light is incident into the diffusion sheet 210. The mirror 215 is preferably formed as a flat surface with a high degree of flatness in order to reduce reflection of light and thereby absorb more light. As described above, the surface roughness of the diffusion sheet 210 is preferably 0 to 2 μm in order to absorb more light into the inside of the diffusion sheet 210.

Further, the diffusion sheet 210 may include a dispersing agent 211. The dispersant 211 is irregularly disposed inside the diffusion sheet 210. The light incident on the diffusion sheet 210 is diffused and reflected after hitting the dispersant 211. Therefore, light is diffused and diffused by the dispersing agent 211 inside the diffusion sheet 210 regardless of the position of the incident light.

Fig. 6 is a cross-sectional view for explaining the bottom cover and the reflection sheet of Fig. 1.

The bottom cover 150 according to an embodiment of the present invention may be constituted by the level portion a and the inclined portion b. At this time, the length of the level portion a may be an L value based on the relational expression 1, and the inclined portion b and the level portion may form an angle θ based on the relational expression 2. [Relationship 1] [Relationship 2]

Where L represents the length of the leveling portion a. D represents the thickness of the display device 100. The size of D changes depending on the size of the display device 100. D may be a thickness of about 10 mm (millimeter, mm) to 50 mm. T represents the overall length of the display device in the diverging direction of the light source 120. The size of T varies depending on the size of the display device 100, and may be a length of about 300 mm to 1000 mm. The pointing angle represents the pointing angle of the light source 120 after passing through the lens 130. And, where θ represents θ6 in the drawing.

That is, the bottom cover 150 includes a level portion a formed at a portion close to the light source 120 and an inclined portion b closer to the display panel 110 side from a portion distant from the light source 120 by a predetermined distance or more. In the bottom cover 150, a portion of the bottom cover 150 that is apart from the light source 120 by a predetermined distance or more is bent toward the display device, so that the internal space S at the upper portion of the inclined portion b tends to become smaller as it goes from the level portion a to the inclined portion b.

On the other hand, the length of the level portion may be 80% to 120% of the L value calculated according to the above relational expression 1. The length of the level portion can be determined as a value approximate to the length L value calculated according to the relational expression 1 due to a design error, a productization process, or the like. That is, the length of the level portion may be determined as a design error, a productization process, or the like, having an error range of about 20% based on the value obtained by the relationship 1.

The bottom cover 150 forms the leveling portion a and the inclined portion b based on the above-described relational expression 1 and relational expression 2, so that light that is diverged by the lens 130 can be more efficiently reflected toward the display panel 110.

In addition, since the bottom cover 150 has a wedge-shaped structure that is closer to the display panel 110 as it is away from the light source 120, there is an advantage that the display device 100 can be made thinner and design elements can be added.

In the present embodiment, since the reflection sheet 140 is placed on the bottom cover 150, as the bottom cover 150 is composed of the level portion a and the inclined portion b, the reflection sheet 140 is also constituted by the level portion and the inclined portion. However, when there is an excessive space between the reflection sheet 140 and the bottom cover 150, that is, when the shape of the reflection sheet 140 is different from the shape of the bottom cover 150, the reflection sheet 140 is preferably constituted by the level portion and the inclined portion based on the above relationship. That is, it is important that the reflection sheet 140 form the level portion and the inclined portion. This is because the above relationship makes the light diverged by the lens 130 more efficiently reflected toward the display panel 110.

On the other hand, as described above, the bottom cover 150 may form the outer shape of the display device 100. However, it is also possible to further include an additional housing forming the outer shape of the display device 100 on the outside of the bottom cover 150.

Fig. 7 is a graph showing a conceptual diagram for explaining a cross section of the IIV-IIV ́ portion in Fig. 1. FIG. 8 is a table showing brightness uniformity of a display device corresponding to a pitch of a light source.

First, referring to Fig. 7, which is a conceptual diagram for explaining a cross section of the IIV-IIV ́ portion in Fig. 1. However, the lens shown in Fig. 1 is omitted for convenience of explanation.

Referring to FIG. 7, a plurality of light sources 120 are arranged in a line spaced apart from each other on one side of the display panel. The distance between the light source 120 disposed in the central area 121 and the peripheral area 125 and the adjacent light source 120 is different, that is, the distance is different. The central area 121 is configured with the light source 120 based on a central portion of one side of the display panel. The peripheral region 125 is provided with the light source 120 on the basis of the peripheral portion of one side surface of the display panel. Here, the central region 121 refers to an adjacent region of a region in which the central axis C of the display panel in the width direction is disposed.

Specifically, the plurality of light sources 120 are arranged in a line spaced apart from each other on one side of the display device. In the central region 121 to the peripheral region 125, the plurality of light sources 120 are divided into four or more regions 121, 122, 123, 124, 125 from one central portion of the display panel to the peripheral portion.

The central area 121 is an area including the central axis C of the display panel and having the same length toward both sides. Further, the remaining regions 122, 123, 124, 125 are regions having the same length in the direction of one side with respect to the central axis C of the display panel.

Such individual regions 121, 122, 123, 124, 125 are equidistant from each other. That is, each of the regions 121, 122, 123, 124, and 125 is preferably a region having the same length. Specifically, when the length of one region is L, the length from the central axis C of the display panel to the peripheral portion of the display panel is 4L+1/2L. Also, the overall length of the display panel is 9L. However, the respective regions 121, 122, 123, 124, and 125 may have a slight difference for reasons such as the shape of the display device, the design reason, and the like. At this time, it may be configured such that, among the plurality of regions, the distance between the light sources 120 in the central region 121 is the largest, and the distance between the light sources 120 in the region 124 adjacent to the peripheral region 125 is the smallest.

For example, referring to FIG. 7 , for the light source 120 disposed in the central region 121 and the light source 120 disposed in the peripheral region 125 , the region where the light source 120 is disposed is sequentially divided into the first region to the fifth region 121 , 122 , 123 , 124 , 125. At this time, in order to increase the brightness of the light emitted from the light source 120 on the entire display device, the light source 120 is disposed such that the pitches P1, P2, P3, P4, and P5 in the respective regions are in accordance with the first region 121 and the second region 122. The order of the third area 123, the fifth area 125, and the fourth area 124 is decreased.

The first region 121 is a central region 121 corresponding to the central portion of the display panel, and thus receives light from the light source 120 disposed in the second region 122 and the third region 123 on both sides. Therefore, by the light diverging from the second region 122 and the third region 123, a sufficient amount of light can be secured in the first region 121, so that the density of the light source 120 in the region can be reduced. At this time, the decrease in the density of the light source 120 of the first region 121 means that the pitch P1 of the light source 120 disposed in the first region 121 becomes large.

On the other hand, in a state where the light guide plate is not provided, the light diverging from the light source 120 is refracted by the lens. At this time, the directivity angle of the light refracted by the lens is about 94 degrees. Such a pointing angle causes the area from which the light from the adjacent light source 120 overlaps to become smaller from the center of the display device, thereby reducing the amount of light in the area. That is, the amount of light decreases as it approaches the periphery. Therefore, in order to increase the amount of light reduced in the periphery, it is preferable to increase the density of the light source 120 in the fourth region 124 and the fifth region 125. Thereby, the brightness uniformity of the entire display device can be improved.

The reason why the density of the light source 120 of the fourth region 124 is higher than the density of the light source 120 of the fifth region 125 is explained below.

First, when the density of the light source 120 of the fifth region 125 is excessively increased, the brightness of the entire display device may be lowered. Specifically, the directivity angle of the light source 120 disposed in the fifth region 125 is originally 120 degrees, and the pointing angle after passing through the lens is approximately 94 degrees. A considerable amount of light passing through the lens faces the side wall side of the display device. At this time, light loss may occur through the side of the display device. This is the reason why the efficiency of the backlight unit on the display device is lowered.

Second, as the density of the light source 120 of the fifth region 125 increases, the brightness of the peripheral region 125 increases a lot. However, this means that the brightness of the central area 121 is relatively lowered. Thereby, it is possible to reduce the brightness uniformity of the entire display device. Further, since the brightness of the central area 121 is lowered, the efficiency of the backlight unit may be lowered as a whole.

For the above reasons, it is preferable to make the light source 120 of the fourth region 124 denser. In other words, the light source 120 pitch P4 of the fourth region 124 is smaller than the light source 120 pitch P5 of the fifth region 125.

Reference is then made to Fig. 8, which is a table showing the brightness of each region of the first to fifth regions 121, 122, 123, 124, 125 corresponding to the density of the light source 120 by numerical values. Among them, the higher the density of each region, the smaller the spacing of each region. Further, the brightness shown in the table of Fig. 8 refers to the brightness measured in the A-A ́ portion of Fig. 7.

The "reference" shows a state in which the density of the light sources 120 in the respective regions is the same, that is, a state in which the average pitch of the light sources 120 in the respective regions is the same. At this time, the luminance of the first region 121 is the highest, and the luminance of the fifth region 125 is approximately 59% of the first region 121. This is because, in the first region 121, a large amount of light is superimposed by the light source of the adjacent region, and thus the amount of light is rich. However, in the fifth region 125, light overlapping by the light source of the adjacent region is relatively insufficient, resulting in the fifth. The brightness of the area 125 is lowered.

"Case 1" shows by numerical values the density of the light source 120 disposed in the first region 121 to the fifth region 125 when the density of the light source 120 of the third region 123 is counted as 100%. The density of the light source 120 of the first region 121 is 91%. This means that the spacing of the light sources 120 in the first region 121 is greater than the spacing of the light sources 120 in the third region 123. Further, the density of the light source 120 in the fourth region 124 is 108%. This means that the spacing of the light sources 120 in the fourth region 124 is smaller than the spacing of the light sources 120 in the third region 123, and is configured more closely. As shown in the table, when the pitch is thus changed, the uniformity of the fifth region 125 is increased to approximately 61%.

As the case 2 to the case 4, the difference between the average pitch P3 of the light sources 120 in the third region 123 and the average pitches P1, P5 in the first region 121 and the fifth region 125 is larger. When the pitch in each region or the density of the light source is gradually increased from "Case 2" to "Case 4", since the number of light sources disposed in the fourth region 124 and the fifth region 125 is relatively large (because the density is high), The amount of light in the area will increase. Therefore, if the brightness of the first area 121 is counted as 100%, the brightness of the fifth area 125 is relatively increased. Thus, from "Case 2" to "Case 4", the uniformity of the fifth region 125 is gradually increased.

Specifically, referring to "Case 4", the density of the light source 120 in the first region 121 is 80% of the third region 123. Also, the density of the light source 120 in the fourth region 124 is 124% of the third region 123. If you convert it to a pitch, it is as follows. It is assumed that the pitch P1 between the light sources 120 in the first region 121 is 1. At this time, the pitch P3 between the light sources 120 in the third region 123 is 0.8. Also, the pitch P4 between the light sources 120 in the fourth region 124 having the smallest pitch is about 0.64. Also, the pitch P5 between the light sources 120 in the fifth region 125 is approximately 0.7. In the case of finishing, when the pitch P1 between the light sources 120 in the first region 121 is set to 1, the pitch P4 in the fourth region 124 having the smallest pitch may be 0.64, and the outermost edge region (the fifth region 125) The case where the pitch P5 is 0.7 is a preferable scheme for improving the overall brightness.

FIG. 9 is a graph showing the pitch of the light sources of the respective regions shown in FIG. 7 in a non-linear manner.

As described above, from the central region to the peripheral region, the plurality of light sources are configured to vary in pitch from each other. Fig. 9 is a graph showing the variation of the pitch of the light source from the central region to the peripheral region in a non-linear manner.

Referring to Fig. 9, from the central region to the peripheral region, the interval between the light sources tends to become small, and at least one inflection point P2 where the pitch becomes large exists. Specifically, the pitch of the light sources becomes smaller from the first region to the fourth region. However, the inflection point P2 appears in the fourth region, and the pitch of the light source becomes larger again up to the fifth region. On the other hand, in the central portion (first region) and the peripheral portion (fifth region) of one side of the display panel, such an inflection point P2 is close to the peripheral portion (fifth region).

The reason why the inflection point P2 is not disposed in the fifth region as the peripheral portion but in the fourth region in the vicinity of the fifth region is as described above. Specifically, it is because when the pitch of the light sources in the fifth region is small, it is possible to cause a light leakage phenomenon through the side surface of the display panel. In addition, when the pitch of the light source in the fifth region is small, the brightness near the fifth region is increased according to the degree of light source concentration, and at this time, if the brightness of the fifth region becomes too high, the entire display panel may occur. The effect of reduced brightness.

For reference, there is also another inflection point P1 in the first region, however such another inflection point P1 may or may not exist depending on the design of the display device.

In the case of finishing, from the central region (first region) of the display panel to the peripheral region (fifth region), the distance between the light sources can be nonlinearly reduced, but in the fourth region, the inflection point where the spacing becomes larger again occurs. P1.

10a and 10b are conceptual views for explaining a division on a display panel and a high reflection sheet disposed in an inner region of the division, and a conceptual diagram showing a luminance distribution of the display panel corresponding thereto.

Referring to Figures 10a and 10b, the display device includes a high reflection sheet 160 having a light reflectance higher than that of the reflective sheet.

The high reflection sheet 160 is disposed on the inner space for reflecting light from the light source in a direction away from the light source, thereby improving the brightness of the display panel. Specifically, the high reflection sheet 160 is disposed in a region where the brightness of the display panel is likely to decrease, and the amount of light reflected on the display panel is increased by the high reflection sheet 160, whereby the brightness can be improved.

The display panel can be divided into nine areas. Referring to FIG. 10a, the display panel can be divided into nine regions 1P, 2P, 3P, 4P, 5P, 6P by virtual lines X1, X2, Y1, Y2 which are equally divided along the X axis and the Y axis, respectively. 7P, 8P, 9P. At this time, the average brightness can be measured based on the difference in brightness between the respective regions.

In each of the regions of the conventional display device, the 1P region and the 3P region have the lowest luminance measurement results. Specifically, a high luminance is distributed in the 7P region to the 9P region where the light source is distributed. The most concentrated light is concentrated in the 5P region by the pointing angle of the light source disposed adjacent to the 7P region to the 9P region, and thus the luminance is the highest. Further, the 1P region and the 3P region having the furthest distance from the light source and overlapping by the directivity angle of the light source have the lowest luminance.

At this time, in order to increase the brightness of the 1P area and the 3P area, when the display panel is divided into three regions which are equally divided along one axis and divided into three equal divisions along the other axis, the high reflection sheet 160 is disposed adjacent to the light source. In the two areas adjacent to the perimeter of the display panel. Specifically, the first high reflection sheet 161 may be further disposed on the reflection sheets of the 7P region and the 9P region. Thereby, the light reflectance of the 7P region and the 9P region is increased, and the luminance of the 1P region and the 3P region can be improved. That is, in the light irradiated onto the reflection sheets of the 7P region and the 9P region, the amount of light reflected to the 1P region and the 3P region is increased, thereby increasing the luminance of the 1P region and the 3P region. At this time, the brightness of the 7P area and the 9P area is lowered according to the improvement of the light reflectance of the 7P area and the 9P area. However, the difference between the luminance reduced in the 7P region and the 9P region and the luminance of the 1P region and the 3P region becomes small, thereby having an effect of improving the uniformity of the luminance distribution of the display panel.

Further, when the display panel is divided into three regions which are equally divided into three axes and equally divided along the other axis, the high reflection sheet 160 is disposed in the three regions farthest from the light source and is adjacent to the periphery of the display panel. The sides of the display panel of the two adjacent areas. Specifically, referring to FIG. 10a, in order to increase the brightness of the 1P region and the 3P region, the second high reflection sheet 162 is disposed on the display device cover on the side surface side of the 1P region and the 3P region. By the second high reflection sheet 162, a part of the light that has a light leakage phenomenon passing through the side surface of the display device cover is reflected to the 1P region and the 3P region, whereby the luminance of the 1P region and the 3P region can be improved. For the reason of design or the like, the first high reflection sheet 161 and the second high reflection sheet 162 described above may be used at the same time, or only one type may be used.

Referring to FIG. 10b, it is a conceptual diagram showing a luminance distribution of a 1P region to a 9P region of the display panel when the first high reflection sheet 161 is employed. The brightness of the 1P area is 255, the brightness of the 2P area is 300, the brightness of the 3P area is 255, the brightness of the 4P area is 265, the brightness of the 5P area is 319, the brightness of the 6P area is 265, and the brightness of the 7P area is 255, 8P. The brightness of the area is 300, and the brightness of the 9P area is 255.

It can be seen that in the conventional display device, the brightness of the 7P area to the 9P area is substantially similar. On the contrary, when the first high reflection sheet 161 is used, the brightness is lower than the 8P area according to the improvement of the light reflectance of the 7P area and the 9P area. . Further, it can be seen that the luminances of the 1P region and the 3P region are the same as or similar to those of the 7P region and the 9P region. According to the conceptual diagram, the brightness uniformity of the entire display panel can be increased to approximately 80%. It can be seen that the uniformity of luminance distribution is raised to an extremely high level compared with the uniformity of luminance distribution of the conventional display panel of approximately 65%.

The above values may vary depending on the width of the display device. However, when the density difference of each region shown in "Case 4" is exceeded, the brightness or efficiency of the entire backlight unit may be lowered for the above reasons. The embodiments of the present invention have been described in detail with reference to the accompanying drawings. However, the present invention is not limited thereto, and various modifications can be made without departing from the spirit and scope of the invention. Therefore, the embodiments of the present invention are not intended to limit the technical idea of the present invention, but are intended to be illustrative, and the scope of the technical idea of the present invention is not limited by the embodiments. The scope of the present invention should be construed as the scope of the claims, and all the technical ideas within the scope of the invention are to be construed as being within the scope of the invention.

10‧‧‧ display panel
100, 100P‧‧‧ display device
110‧‧‧ display panel
120‧‧‧Light source
121‧‧‧First area
122‧‧‧Second area
123‧‧‧ Third Area
124‧‧‧fourth area
125‧‧‧ Fifth Area
130‧‧‧ Collimating lens
131‧‧‧ next door
132‧‧‧Support surface
133‧‧‧reflecting surface
135‧‧‧First refractive surface
135a‧‧‧ end
137‧‧‧second refractive surface
137a‧‧‧End
139‧‧‧Reflective reflective surface
139a‧‧‧End
140‧‧‧reflector
141‧‧‧microbeads
143‧‧‧ coating
145‧‧‧Reflective surface
147‧‧‧ basal layer
150‧‧‧ bottom cover
160‧‧‧High reflection sheet
161‧‧‧First high reflection sheet
162‧‧‧Second high reflection film
1P~9P‧‧‧ area
200‧‧‧ optical film set
210‧‧‧Diffuser
211‧‧‧Dispersant
213‧‧‧Diffusion surface
215‧‧ ‧ mirror
220, 230‧‧‧ column lenses
30‧‧‧reflector
40‧‧‧Light source
61‧‧‧Upper cover
62‧‧‧Under the cover
63‧‧‧ Forming frame
a‧‧‧Levels
A‧‧‧ optical axis
B‧‧‧inclined section
B1, B2, B3‧‧‧ level axis
C‧‧‧ center axis
L‧‧‧The length of the level a
P1~P5‧‧‧ spacing
S‧‧‧Internal space
T‧‧‧ length
X1, X2, Y1, Y2‧‧‧ virtual lines

1 is a cross-sectional schematic view for explaining a display device according to an embodiment of the present invention. Fig. 2 is a cross-sectional view for explaining the lens of Fig. 1. Fig. 3 is a conceptual diagram for explaining a shape formed by each surface of the lens of Fig. 2. Fig. 4 is an enlarged cross-sectional view for explaining the reflection sheet of Fig. 1. Fig. 5 is an enlarged cross-sectional view for explaining the diffusion sheet of Fig. 1. Fig. 6 is a cross-sectional view for explaining the bottom cover and the reflection sheet of Fig. 1. Fig. 7 is a graph showing a conceptual diagram for explaining a cross section of the IIV-IIV ́ portion in Fig. 1. Fig. 8 is a table showing numerical uniformity of luminance uniformity of a display device corresponding to the pitch of a light source. FIG. 9 is a graph showing the pitch of the light sources of the respective regions shown in FIG. 7 in a non-linear manner. 10a and 10b are conceptual views for explaining a division on a display panel and a high reflection sheet disposed in an inner region of the division, and a conceptual diagram showing a luminance distribution of the display panel corresponding thereto. 11a is a cross-sectional schematic view of a conventional side light type display device with a light guide plate removed, FIG. 11b is a graph showing a pointing angle of the LED, and FIG. 11c is a view showing a light plane distribution of the display panel of FIG. 11a .

120‧‧‧Light source

130‧‧‧ Collimating lens

131‧‧‧ next door

132‧‧‧Support surface

133‧‧‧reflecting surface

135‧‧‧First refractive surface

137‧‧‧second refractive surface

139‧‧‧Reflective reflective surface

Claims (21)

A lens for an edge-lit display device is disposed in a light-emitting direction of a light source for adjusting a directivity angle of light diverging from the light source, the light source being disposed on a side of a display device, the lens comprising: a first a refractive surface opposed to the light source and protruding toward the light source side; a partition wall surface continuing from the first refractive surface and extending toward the light source side; a reflective surface forming an outline of the lens, and The light incident inside is reflected; a refraction reflecting surface continues from the reflecting surface for refracting and reflecting light incident inside; and a second refractive surface continuing from the refraction reflecting surface and facing the light source The opposite side of the protrusion, relative to the optical axis (A) of the light diverging from the light source and a first level axis, a second level axis and a third level axis (B1, B2, B3) perpendicular to the optical axis And an angle between the partition wall surface and the first horizontal axis is greater than or equal to 75 degrees and less than or equal to 90 degrees, and a line connecting the central axis of the light source and the end of the first refractive surface and the optical axis (A) The angle between them is less than 30 degrees. The lens for an edge-light display device according to claim 1, wherein an angle between the first refractive surface and the second horizontal axis (B2) is greater than 0 degrees and less than 20 degrees, and the end of the second refractive surface The angle between the tangent at the portion and the third level axis (B3) is greater than 30 degrees and less than 70 degrees. The lens for an edge-light type display device according to claim 1, wherein an angle between the refractive reflecting surface and the third horizontal axis (B3) is greater than 0 degrees and less than 25 degrees. A lens for an edge-light type display device according to claim 1, wherein the reflection is reflected by light that is diverged from the light source and whose angle between the light source and the optical axis (A) is 30 degrees or more. The lens for an edge-light type display device according to any one of claims 1 to 4, wherein the first refractive surface, the partition wall surface, the reflecting surface, the refractive reflecting surface, and the second refractive surface are respectively configured as a spherical surface or an aspheric surface . A display device includes: a display panel; an optical sheet group disposed on a back surface of the display panel; a reflective sheet disposed apart from the back surface of the optical sheet group, and forming an internal space together with the optical sheet group, and Light is scattered to illuminate the optical sheet group; a light source is disposed on a side of the display panel to illuminate the central portion of the display panel; and the side light type display device according to claim 1 a lens disposed on the light source; and a bottom cover surrounding the formed internal space together with the optical sheet set. The display device according to claim 6, wherein the optical sheet comprises a diffusion sheet having a surface roughness of 0 to 2 micrometers (um). The display device according to claim 6, wherein the reflective sheet comprises microbeads having a surface roughness of 0 to 10 μm. The display device according to claim 6, wherein the reflection sheet has a gloss of 20 to 30. The display device according to claim 8, wherein the microbeads comprise at least one of polyethylene, acryl, nylon, and a mixture of these materials. The display device according to claim 6, wherein the bottom cover is composed of a level portion and an inclined portion. The display device according to claim 11, wherein the level portion has an L value based on the following relation 1, the angle between the inclined portion and the level portion is θ based on the relation 2, [Relationship 1] [Relationship 2] Where D is the thickness of the display device, T is the overall length of the display device in the direction of divergence of the light source, and the pointing angle is the pointing angle of the light source passing through the lens. The display device according to claim 12, wherein the length of the level portion is 80% to 120% of the L value calculated according to the relational expression 1. The display device according to claim 6, wherein the plurality of light sources are arranged in a row spaced apart from each other on a side of the display panel, and the light sources disposed in the central region and the peripheral region are spaced apart from adjacent light sources. The light source is disposed on the basis of a central portion of one side surface of the display panel, and the light source is disposed on the peripheral portion of one side surface of the display panel. . The display device of claim 14, wherein the distance of the light sources in the peripheral region is 70% to 99% of the pitch of the light sources in the central region. The display device according to claim 14, wherein the light sources are divided into four or more regions from a central portion to a peripheral portion of one side of the display panel from the central region to the peripheral region, in the regions The average spacing of the light sources in the central region is the largest, and the average spacing of the light sources in the region adjacent to the peripheral region is the smallest. The display device according to claim 14, wherein a distance between the light sources is changed from the central region to the peripheral region, and a pitch tends to become smaller from the central region to the peripheral region, and at least one location exists The inflection point where the pitch becomes larger. The display device according to claim 17, wherein the inflection point is disposed close to the peripheral portion in a side central portion and a peripheral portion of the display panel. A display device according to claim 6, comprising a highly reflective sheet disposed in the internal space and having a light reflectance higher than a light reflectance of the reflective sheet for emitting light from the light source Reflected to a position away from the light source to increase the brightness of the display panel. The display device according to claim 19, wherein the high reflection sheet is disposed at three adjacent to the light source when the display panel is equally divided along one axis and divided into three equal divisions to form nine regions. Within two regions of the region that are adjacent to the perimeter of the display panel. The display device according to claim 19, wherein the high reflection sheet is disposed at the farthest from the light source when the display panel is equally divided along one axis and divided into three equal divisions to form nine regions. The side of the display panel of the two regions adjacent to the periphery of the display panel in the area.