KR102551576B1 - Back light uint and display device having the same - Google Patents

Abstract

Disclosed is a backlight unit capable of improving corner darkness and a display device having the same.
To this end, in the backlight unit and the display device having the same according to the present invention, reflective sheets are selectively attached only to oblique surfaces of four corner portions of a reflector having a square frame structure.
As a result, the backlight unit and the display device having the same according to the present invention improved the darkness of the four corners by improving the luminance due to the increase in the reflectance at the corners where the luminance is lower than the central portion of the display panel.

Description

Backlight unit and display device having the same {BACK LIGHT UINT AND DISPLAY DEVICE HAVING THE SAME}

The present invention relates to a backlight unit capable of improving corner darkness and a display device having the same.

The liquid crystal display device has a display panel including an array substrate, a color filter substrate, and a liquid crystal layer interposed between the array substrate and the color filter substrate as essential components, and changes the arrangement direction of liquid crystal molecules with an electric field in the display panel to change transmittance. implement

Since such a display panel does not have a self-light emitting element, a separate light source is required to display the transmittance difference as an image, and for this, a backlight unit serving as a light source is mounted on the rear surface of the display panel.

Such a backlight unit may be divided into an edge type installed on the side of the display panel and a direct type providing light directly from a lower portion of the display panel.

The edge type backlight unit is installed on the side of the display panel to supply light to the display panel through a reflector and a light guide plate. Since such an edge-type backlight unit has a structure that is advantageous for light weight and thinning, it is mainly used in notebook computers and the like.

However, the edge-type backlight unit is difficult to apply to a large-area display panel because a light source emitting light is located on the side of the display panel, and it is difficult to obtain high luminance because light is supplied through a light guide plate.

On the other hand, since light emitted from a light source is directly supplied to the display panel, the direct backlight unit can be applied to a large-area display panel and has high brightness.

As a light source of the direct type backlight unit, a light source emitting light itself, such as a light emitting device (LED) package, is being used instead of a fluorescent lamp. Since such an LED package emits R, G, and B monochromatic light, when applied to a backlight unit, it has a good color gamut and can save driving power.

The direct backlight unit has the advantage of being applicable to a large-area display panel as well as providing high brightness because the light emitted from the LED package is directly supplied to the display panel, but a sufficient amount of light is supplied to the four corners of the display panel. Therefore, the luminance of the corner portion is lowered compared to the luminance of the central portion, resulting in a problem that the corner portion looks dark.

Recently, in order to improve the darkness of the corners, attempts have been made to reduce the distance between the outermost LED package and the end of the reflector, but due to the limitations of the backlight unit structure, even if the minimum distance is applied, the darkness There is a limit to improvement.

In particular, in the case of a multi-vision display device in which a plurality of display panels are fixed using brackets, the corner portion is darker between the display panels.

An object of the present invention is to provide a backlight unit capable of improving corner darkness and a display device having the same.

To this end, in the backlight unit and the display device having the same according to the present invention, reflective sheets are selectively attached only to oblique surfaces of four corner portions of a reflector having a square frame structure.

As a result, the backlight unit and the display device having the same according to the present invention improved the darkness of the four corners by improving the luminance due to the increase in the reflectance at the corners where the luminance is lower than the central portion of the display panel.

A backlight unit and a display device having the same according to the present invention include reflective sheets attached to oblique surfaces of four corner portions of a reflector having a square frame structure.

In this case, the reflective sheet may have a triangular shape having a mutually symmetrical structure based on boundary lines where oblique planes meet each other at four corner portions of the reflective plate.

Such a reflective sheet has a first side disposed along a boundary line of the reflective plate, a second side disposed along a seating surface of the reflective plate, and a third side connecting the first side and the second side.

In this case, the first side of the reflective sheet has a length of 30 to 100 mm, the second side of the reflective sheet has a length of 25 to 88 mm, and the third side of the reflective sheet has a length of 17 to 80 mm.

As a result, the backlight unit and the display device having the same according to the present invention improved the darkness of the four corners by improving the luminance due to the increase in the reflectance at the corners where the luminance is lower than the central portion of the display panel.

In the backlight unit and the display device having the same according to the present invention, reflective sheets are selectively attached only to four corner portions of the reflective plate.

As a result, the backlight unit and the display device having the same according to the present invention improved the darkness of the four corners by improving the luminance due to the increase in the reflectance at the corners where the luminance is lower than the central portion of the display panel.

In addition, the backlight unit and the display device having the same according to the present invention are designed by optimizing the lengths of the first to third sides of the reflective sheet, and the second side of the reflective sheet is tilted at 1 to 15° with respect to the seating surface of the reflective plate. placed to have.

Accordingly, the backlight unit and the display device having the same according to the present invention can improve the darkness of the four corner portions by securing an optimal area and applying a slope without the bright line at the end due to light splashing at the corner portion being visually recognized.

In addition, the backlight unit and the display device having the same according to the present invention apply a silver reflective sheet having a reflectance of 93 to 97% as a reflective sheet, thereby reducing the darkness of the four corner portions without viewing bright lines or bright spots at the corners. improved.

1 is a combined cross-sectional view showing a display device according to an embodiment of the present invention.
2 is an enlarged perspective view of a corner portion of a display device according to an embodiment of the present invention;
3 is an enlarged cross-sectional view of part A of FIG. 1;
4 is a schematic diagram for explaining a principle of enhancing luminance at a corner portion of a display device according to an embodiment of the present invention;
5 is a perspective view of the reflective sheet of FIG. 2 in detail;
6 is a cross-sectional view illustrating the reflective sheet of FIG. 5;
7 is a plan view illustrating luminance measurement results of display devices according to Example 1 and Comparative Example 1;
8 is an optical image showing luminance measurement results of display devices according to Example 1 and Comparative Example 1;
9 is a photograph showing luminance measurement results of a multi-vision display device system to which display devices according to Example 1 and Comparative Example 1 are applied.
10 is a photograph showing optical characteristics of display devices according to Example 1 and Comparative Examples 2 to 4;
11 is a photograph showing optical characteristics of display devices according to Example 1 and Comparative Examples 5 to 7;

The above objects, features and advantages will be described later in detail with reference to the accompanying drawings, and accordingly, those skilled in the art to which the present invention belongs will be able to easily implement the technical spirit of the present invention. In describing the present invention, if it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

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

1 is a combined cross-sectional view showing a display device according to an embodiment of the present invention, FIG. 2 is a perspective view showing an enlarged corner of a display device according to an embodiment of the present invention, and FIG. 3 is an enlarged view of part A of FIG. cross section shown.

1 to 3 , a display device 100 according to an embodiment of the present invention includes a display panel 110, a main supporter 120, a cover bottom 130, a backlight unit 140, and a top case 150. ).

The display panel 110 plays a key role in realizing an image. Although not shown in detail in the drawings, the display panel 110 includes first and second substrates (not shown) spaced apart at regular intervals and bonded thereto, and a liquid crystal layer (not shown) interposed in a space between the spaced apart first and second substrates. city), including In this case, thin film transistors, various wires and pixel electrodes are disposed on the first substrate, and a color filter layer and a black matrix (BM) for displaying three primary colors of RGB are disposed on the second substrate.

The main supporter 120 is disposed below the display panel 110 and supports an edge of the display panel 110 .

To this end, the main supporter 120 may have a square frame shape. That is, the main supporter 120 includes a vertical portion 120a extending in a vertical direction to support the display panel 110, and extending in an inward direction overlapping the display panel 110 from the vertical portion 120a, It has a horizontal part 120b supporting the member 144.

The cover bottom 130 is mounted below the main supporter 120 . The cover bottom 130 may have a shape in which both edges of the cover bottom 130 are bent upward to have sides. Accordingly, the side surface of the cover bottom 130 may be installed to come into contact with the side surface of the main supporter 120 .

The backlight unit 140 is mounted on the upper surface of the cover bottom 130 . The backlight unit 140 includes an LED package module 142 , an optical member 144 , a reflector 146 and a reflector sheet 148 .

The LED package module 142 includes a substrate 142a, an LED package 142b and a lens 142c.

The substrate 142a is made of printed circuit board (PCB), flexible printed circuit board (FPCB), alumina, quartz, calcium zirconate, forsterite, silicon carbide (SiC), Graphite, zirconia, plastic, metal, etc. may be used, but are not limited thereto.

The LED package 142b is a light source for directly irradiating light to the display panel 110, and is mounted in plurality on the substrate 142a. The LED package 142b may be a vertical or horizontal light emitting chip package bonded to the substrate 142a via a metal wire. In addition, the LED package 142b may be a flip chip package that is flip-bonded to the substrate 142a via bumps.

At this time, the plurality of LED packages 142b emit light having colors of red (R), green (G), and blue (B) toward the display panel 110 . By simultaneously turning on the plurality of LED packages 142b, white light can be implemented by color combination.

In the case of the direct-type display device 100 shown in FIG. 1 , light emitted from adjacent LED packages 142b overlaps and mixes with each other and then is directly incident on the display panel 110 to provide a surface light source. will do At this time, the direct-type display device 100 sequentially turns on/off the plurality of LED packages 142b to express a more lively image, and light is emitted for each specific area of the display panel 110. It can be implemented in a backlight division driving (local dimming) method that supplies . For this reason, a contrast ratio can be improved by making a bright image brighter or a dark image darker, so that a more lively image can be implemented.

A lens 142c is mounted on the substrate 142a so as to cover the upper side of the LED package 142b. At this time, the lens 142c is installed in the light path of the LED package 142b, and a translucent material such as glass, acrylic, silicone, epoxy, plastic, or polymer may be used.

The lens 142c is a refractive optical system having an incident surface I facing the LED package 142b and an exit surface O disposed opposite to the incident surface I. The entrance surface (I) of the lens 142c may be designed in a concave groove shape to increase light condensing efficiency, and the exit surface (O) may be designed in a dome structure capable of dispersing light as wide as possible.

The lens 142c is inserted into the lens insertion groove 142e and coupled to the substrate 142a. To this end, the lens 142c may include a fastening protrusion 142d disposed on a lower surface of the lens 142c and protruding toward the substrate 142a. Accordingly, the lens 142c is stably fixed to the substrate 142a by fastening the fastening protrusion 142d into the lens insertion groove 142e of the substrate 142a in a fitting manner. Four fastening protrusions 142d and lens insertion grooves 142e of the lens 142c may be designed, respectively, but this is an example and the number may be changed in various forms.

The optical member 144 is seated on the horizontal portion 120b of the main supporter 120 and mounted on the LED package module 142 . The optical member 144 refracts or scatters light incident from the LED package module 142 in order to widen the viewing angle of the display device 100 and increase luminance.

Specifically, the plurality of optical members 144 include a diffuser sheet (144a), a prism sheet (144b), a protection sheet (144c), and a double brightness enhancement film (DBEF, 144d). ) may include at least two or more of them. At this time, FIG. 1 shows an example of a four-layer structure in which a diffusion sheet 144a, a prism sheet 144b, a protection sheet 144c, and a luminance enhancing sheet 144d are sequentially stacked as a plurality of optical members 144 .

The diffusion sheet 144a serves to diffuse the light emitted from the LED package module 142 along the surface so that the color and brightness of the entire screen of the display device 100 are uniform.

The prism sheet 144b serves to increase luminance by refracting or condensing the light diffused by the diffusion sheet 144a.

The protective sheet 144c serves to protect the diffusion sheet 144a and the prism sheet 144b from external impact or inflow of foreign matter. In addition, the protective sheet 144c is mounted for the purpose of preventing scratches on the prism sheet 144b.

The luminance enhancing sheet 144d is mounted for the purpose of enhancing luminance. The luminance enhancing sheet 144d is a type of polarizing film and is referred to as a reflective polarizing film. At this time, the light is divided into vertical polarization (P polarization) and horizontal polarization (S polarization), and the luminance enhancing sheet 144d almost transmits either polarization of vertical polarization or horizontal polarization, but mostly reflects the other polarization. has the characteristic of For example, when it is assumed that the luminance enhancing sheet 144d passes all of the vertical polarized light and reflects most of the horizontal polarized light, the reflected horizontal polarized light is further separated into vertical and horizontal polarized light. At this time, the separated vertical polarized light passes through the luminance enhancing sheet 144d again, the separated horizontal polarized light is reflected again, and the reflected horizontal polarized light is again separated into vertical and horizontal polarized light. In this way, the luminance enhancing sheet 144d increases the luminance of light.

The reflector 146 serves to reflect light emitted from the LED package 142b toward the display panel 110 . Specifically, the reflector 146 includes a bottom surface 146a disposed on the upper surface of the substrate 142a and an oblique surface 146b extending in an oblique shape from four sides of the bottom surface 146a and having a square frame structure. ), and a seating surface 146c bent from the oblique surface 146b and arranged parallel to the bottom surface. At this time, the seating surface 146c of the reflector is disposed on the horizontal portion 120b of the main supporter 120 and mounted below the optical member 144 .

The reflective sheet 148 is attached to the diagonal surfaces 146b of the four corner portions of the reflective plate 146 . The reflective sheet 148 is installed to reduce the darkness of the corners of the display panel 110 due to lack of light.

To this end, the reflective sheet 148 is selectively attached only to the oblique surfaces 146b of the four corner portions of the reflective plate 146 . As such, by selectively attaching the reflective sheet 148 only to the four corner portions of the reflector 146, the reflectance at the corner portions having lower luminance than the central portion of the display panel 110 is increased to reduce the darkness of the four corner portions. be able to improve

The top case 150 is mounted on the display panel 110 and coupled to the main supporter 120 and the display panel 110 . In this case, the top case 150, the main supporter 120, and the cover bottom 130 may be fastened by screws penetrating each side wall, but are not limited thereto.

In the display device according to the embodiment of the present invention described above, by selectively attaching the reflective sheet only to the four corner portions of the reflector, the reflectance is increased at the corner portions having lower luminance than the central portion of the display panel, thereby increasing the reflectance at the four corner portions of the display panel. Darkness can be improved.

This will be described in more detail with reference to the accompanying drawings.

FIG. 4 is a schematic diagram for explaining a principle of improving luminance at a corner portion of a display device according to an embodiment of the present invention, FIG. 5 is a perspective view showing the reflective sheet of FIG. 2 in detail, and FIG. 6 is a reflective sheet of FIG. 5 is a cross-sectional view showing

As shown in FIGS. 4 to 6 , the reflective sheet 148 is selectively attached only to the oblique surfaces 146b of the four corner portions of the reflective plate 146 . In this way, when the reflective sheet 148 is selectively attached only to the oblique surfaces 146b of the four corner portions of the reflective plate 146, the light emitted from the LED package 142b is reflected efficiently by the reflective sheet 148. This increases the amount of light at the corner portions on the four sides, so that the luminance can be improved.

To this end, a silver reflective sheet having a higher reflectance than that of the reflective plate 146 may be used as the reflective sheet 148 . More preferably, the reflective sheet 148 has a reflectance of 93 to 97%. When the reflectance of the reflective sheet 148 is less than 93%, it may be difficult to properly exhibit the luminance enhancement effect of the corner portion due to the low reflectance. Conversely, when the reflectance of the reflective sheet 148 exceeds 97%, it is advantageous in terms of the luminance enhancement effect of the corner portion, but a contrast difference may occur due to the visibility of a bright line or a bright point at the end portion, resulting in poor image quality.

A detailed configuration of the reflective sheet will be described with reference to FIG. 6 .

As shown in FIG. 6 , the reflective sheet 148 includes a base substrate 148a, a silver reflective layer 148b, and beads 148c.

The base substrate 148a is a part constituting the body of the reflective sheet 148, and a transparent material capable of transmitting light may be used. Materials of the base substrate 148a include polycarbonate, polysulfone, polyacrylate, polystyrene, and polyvinyl chloride. At least one selected from the group consisting of polyvinyl alcohol, polynorbornene, and polyester may be used. Specifically, as the base substrate 148a, polyethylene terephthalate, polyethylene naphthalate, or the like may be used. The base substrate 148a preferably has a thickness of 10 to 300 μm, but is not limited thereto.

A silver reflective layer 148b is disposed on the base substrate 148a. The silver reflective layer 148b may be formed by coating or depositing silver (Ag) having excellent reflectance on the base substrate 148a. For example, the silver reflective layer 148b may be formed by any one method selected from a liquid coating method, a vacuum deposition method, an ionization deposition method, a sputtering method, and an ion plating method.

The silver reflective layer 148b preferably has a thickness of 10 to 200 nm. When the thickness of the silver reflective layer 148b is less than 10 nm, it may be difficult to secure sufficient reflectance because the thickness is too thin. Conversely, when the thickness of the silver reflective layer 148b exceeds 200 nm, it is not economical because it may act as a factor that only increases manufacturing cost without further enhancing the reflectance.

The beads 148c may be distributedly disposed inside the silver reflective layer 148b. In addition, the beads 148c may be distributedly disposed on the silver reflective layer 148b. These beads 148c serve to improve luminance by increasing the amount of light traveling straight toward the display panel 110 due to their scattering characteristics. These beads 148c may have a spherical shape, and the material thereof is selected from polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), nylon, and the like. One or more may be used, but is not limited thereto.

Meanwhile, referring again to FIG. 5 , the reflective sheet 148 has a triangular shape having a mutually symmetrical structure based on the boundary lines where the slanted surfaces 146b meet each other at four corner portions of the reflective plate 146 .

Specifically, the reflective sheet 148 includes a first side S1 disposed along the boundary of the reflective plate 146 and a second side S2 disposed along the seating surface 146c of the reflective plate 146, It has a third side (S3) connecting the first side (S1) and the second side (S2).

At this time, although the lengths of the first side S1, the second side S2, and the third side S3 of the reflective sheet 148 may vary depending on the model size of the display device (100 in FIG. 1), For example, the length deviation between 32 inches and 100 inches does not appear significantly. Accordingly, the first side S1 of the reflective sheet 146 has a length of 30 to 100 mm, and the second side S2 of the reflective sheet 146 has a length of 25 to 88 mm. The third side (S3) preferably has a length of 17 ~ 80mm. Accordingly, the angle formed by the first side S1 and the second side S2 of the reflective sheet 146 may be 35 to 60°, and the angle formed by the second side S2 and the third side S3. may be 60 to 80 °, and the angle formed by the first side (S1) and the third side (S3) may be 35 to 70 °, but this is an example, and the angle can be designed in various forms It will be an obvious fact.

In this way, by optimizing and designing the lengths of the first to third sides S1, S2, and S3 of the reflective sheet 146, an optimal area is secured without the bright lines at the ends due to splashing being visually recognized. It becomes possible to improve the darkness of the side corner part.

As described above, the reflective sheet 146 is preferably attached to the diagonal surfaces 146b of the four corners of the reflective plate 146 to have an optimal shape and area. At this time, the reflective sheet 148 is more advantageous as the overlapping area with the reflective plate 146 is wider in order to improve the luminance of the four corner portions of the reflective plate 146, but when designed with an excessive area, the reflective sheet 148 is damaged by light splashing. A bright line at the end of the image may be recognized, resulting in poor image quality.

That is, when the second side S2 of the reflective sheet 148 and the seating surface 146c of the reflective plate 146 are designed to come into contact with each other, the overlapping area between the reflective sheet 148 and the reflective plate 146 is widened to improve luminance. Although it is advantageous from the side, a bright line at the end may be visually recognized due to light splashing at a portion where the reflective sheet 148 and the reflective plate 146 come into contact with each other, causing poor image quality.

In order to prevent this in advance, it is preferable that the second side S2 of the reflective sheet 148 be spaced apart from the seating surface 146c of the reflective plate 146 . Accordingly, it is preferable that the second side S2 of the reflective sheet 148 has an inclination θ of 1 to 15° with respect to the seating surface 146c of the reflective plate 146 . When the slope θ between the second side S2 of the reflective sheet 148 and the seating surface 146c of the reflective plate 146 is less than 1°, the separation distance between the reflective sheet 148 and the reflective plate 146 is narrow. As a result, there is a high risk that the above effects may not be properly exerted. Conversely, when the inclination θ formed between the second side S2 of the reflective sheet 148 and the seating surface 146c of the reflective plate 146 exceeds 15°, the second side S2 of the reflective sheet 148 ) and the seating surface 146c of the reflector 146, the total area of the reflective sheet 148 is reduced due to the increase in the distance between the reflector 146 and the decrease in reflectance at the corner, resulting in a concern that the effect of reducing the darkness of the core may not be properly exhibited. there is.

The backlight unit according to the embodiment of the present invention described above and the display device having the same are selectively attached to the reflective sheet only on the four corner portions of the reflector to increase the reflectance at the corner portion having lower luminance than the central portion of the display panel. It is possible to improve the darkness of the corner portions on the four sides by improving the luminance according to the luminance.

In addition, the backlight unit and the display device having the same according to an embodiment of the present invention are designed by optimizing the lengths of the first to third sides of the reflective sheet and extend the second side of the reflective sheet at a distance of 1 to 15 from the seating surface of the reflective plate. By arranging them to have an inclination of °, it is possible to improve the darkness of the four corners by securing the optimal area and applying the inclination without the bright line at the end due to light splashing at the corner.

In addition, the backlight unit and the display device having the same according to an embodiment of the present invention apply a silver reflective sheet having a reflectance of 93 to 97% as a reflective sheet, so that bright lines or bright spots at the corners are not visually recognized at the four corners. It can improve the darkness of wealth.

Example

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is presented as a preferred example of the present invention and cannot be construed as limiting the present invention by this in any sense.

Contents not described herein can be technically inferred by those skilled in the art, so descriptions thereof will be omitted.

7 is a plan view showing luminance measurement results of display devices according to Example 1 and Comparative Example 1, and FIG. 8 is an optical image showing luminance measurement results of display devices according to Example 1 and Comparative Example 1. At this time, (a) and (b) of FIG. 7 and (a) and (b) of FIG. 8 show Example 1 and Comparative Example 1, respectively, 21 mm in width from the center of the display panel and the four corners of the display panel. and luminance at 21 mm spaced apart corners, respectively.

At this time, in Example 1, triangular reflective sheets having a reflectance of 95% were attached to the oblique surfaces of the four corner portions of the reflective plate, respectively, and in Comparative Example 1, no reflective sheets were attached. In particular, in the case of Example 1, the second side of the reflective sheet was designed to have an inclination of 7° with respect to the seating surface of the reflective plate, and the lengths of the first, second and third sides were 50.89 mm, 45 mm and 40.58 mm. each designed.

As shown in (a) and (b) of FIG. 7 and (a) and (b) of FIG. 8 , the luminance value measured at the center of the display panel in Example 1 and Comparative Example 1 was 503 cd/m 2 . was the same On the other hand, in the case of the luminance values measured at the four corners of the display panel, Comparative Example 1 was only 376 to 401 cd/m2, but Example 1 was measured at 400 to 418 cd/m2, which increased compared to Comparative Example 1. can confirm that

As can be seen from the above results, in the case of Comparative Example 1, the outermost luminance uniformity was measured at 74.8%, whereas in the case of Example 1, the outermost luminance uniformity was 79.5%, which was approximately 6.3% higher. there is. At this time, the outermost luminance uniformity was evaluated by dividing the minimum value between the luminance value measured at the center of the display panel and the luminance value measured at the four corners of the display panel.

Meanwhile, FIG. 9 is a photograph showing a luminance measurement result of a multi-vision display device system to which display devices according to Example 1 and Comparative Example 1 are applied. At this time, (a) of FIG. 9 shows Example 1, and (b) of FIG. 9 shows Comparative Example 1.

As shown in (a) and (b) of FIG. 9, in the case of a multi-vision display device in which a plurality of display panels are fixedly installed with a bracket, it is necessary to improve the darkness at the four corners between adjacent display panels. .

At this time, in the case of Comparative Example 1, it can be seen that the darkness of the corner portions on the four sides clearly appears in two parts due to the non-application of the reflective sheet. On the other hand, in the case of Example 1, it can be confirmed that the darkness of the corner portions on the four sides is reduced to one part by applying the reflective sheet.

10 is a photograph showing optical characteristics of display devices according to Example 1 and Comparative Examples 2 to 4. In Comparative Example 2, square-shaped reflective sheets having a reflectance of 95% were attached to oblique surfaces of four corner portions of the reflective plate, respectively. At this time, in the case of Comparative Example 2, the second side of the reflective sheet was designed to come into contact with the seating surface of the reflective plate, and the lengths of the first, second, third, and fourth sides were 50.89 mm, 122 mm, 51.25 mm, and 27 mm. were designed respectively.

In Comparative Example 3, triangular reflective sheets having a reflectance of 95% were attached to oblique surfaces of four corner portions of the reflective plate, respectively. At this time, in the case of Comparative Example 3, the second side of the reflective sheet was designed to have an inclination of 37° with respect to the seating surface of the reflective plate, and the lengths of the first, second and third sides were 50.89 mm, 63 mm and 30.25 mm, respectively. each designed.

In Comparative Example 4, triangular reflective sheets having a reflectance of 95% were attached to oblique surfaces of four corner portions of the reflective plate, respectively. At this time, in the case of Comparative Example 4, the second side of the reflective sheet was designed to have an inclination of 35° with respect to the seating surface of the reflective plate, and the lengths of the first, second and third sides were 50.89 mm, 29.25 mm and 26.58 mm, respectively. were designed respectively.

As shown in FIG. 10 , in the case of Example 1, it can be confirmed that the darkness of the corner portion is improved due to the luminance improvement of the corner portion without the end bright line visibility.

On the other hand, in the case of Comparative Example 2, although the darkness of the corner was improved, it could be confirmed that the bright spot at the end was recognized.

In addition, in the case of Comparative Example 3, the effect of reducing the darkness of the corner portion was insignificant, and a bright spot was recognized inside the corner portion.

In addition, in the case of Comparative Example 4, it can be confirmed that although the corner bright spot was not visually recognized, the corner darkening effect was insignificant.

Meanwhile, FIG. 11 is a photograph showing optical characteristics of display devices according to Example 1 and Comparative Examples 5 to 7. In this case, Example 1 applies a reflective sheet having a reflectance of 95%, and Comparative Examples 5 to 7 have the same reflection as Example 1 except for applying a reflective sheet having a reflectance of 99%, 90%, and 86%. A sheet was applied.

As shown in FIG. 11 , in the case of Example 1, it can be confirmed that the darkness of the corner portion is improved due to the luminance improvement of the corner portion without the end bright line visibility.

On the other hand, in the case of Comparative Example 5, although the darkness of the corner portion was improved, it could be confirmed that a contrast difference was generated by viewing the bright point at the end portion.

And, in the case of Comparative Examples 6 and 7, the effect of improving the darkening of the corner part was insignificant due to the low reflectance.

Although the above has been described based on the embodiments of the present invention, various changes or modifications may be made at the level of those skilled in the art. Accordingly, it will be understood that such changes and modifications are included within the scope of the present invention as long as they do not depart from the scope of the present invention.

100: display device 110: display panel
120: main supporter 130: cover bottom
140: backlight unit 142: LED package module
142a: substrate 142b: LED package
142c: lens 144: optical member
144a: diffusion sheet 144b: prism sheet
144c: protection sheet 144d: luminance enhancement sheet
146: reflector 146a: bottom surface of the reflector
146b: oblique surface of the reflector 146c: seating surface of the reflector
148: reflective sheet 148a: base substrate
148b: silver reflective layer 148c: bead
150: Top Case

Claims (8)

An LED package module having a substrate and a plurality of LED packages mounted on the substrate;
an optical member mounted on the LED package module;
A bottom surface disposed on the upper surface of the substrate, oblique surfaces each extending in an oblique shape from four sides of the bottom surface and having a square frame structure, and a seat bent from the oblique surfaces and disposed parallel to the bottom surface. a reflector having a surface; and
reflective sheets attached to oblique surfaces of four corner portions of the reflective plate, respectively;
including,
The reflective sheets are symmetrically attached to each other based on a boundary line where the oblique surfaces of the reflective plate meet,
Each reflective sheet
A first side disposed along the boundary of the reflector;
A second side arranged along the seating surface of the reflector;
Has a triangular shape having a third side connecting the first side and the second side,
The second side of the reflective sheet is spaced apart from the seating surface of the reflective plate,
The second side of the reflective sheet is disposed to have an inclination of 1 to 15° with respect to the seating surface of the reflective plate,
the reflective sheet
base material,
A silver reflective layer disposed on the base substrate;
A backlight unit including beads distributed in or on the silver reflective layer.
delete delete According to claim 1,
The first side of the reflective sheet has a length of 30 to 100 mm,
The second side of the reflective sheet has a length of 25 to 88 mm,
The backlight unit of claim 1 , wherein a third side of the reflective sheet has a length of 17 to 80 mm.
delete According to claim 1,
The backlight unit wherein the reflective sheet has a reflectance of 93 to 97%.
display panel;
a main supporter disposed under the display panel to support an edge of the display panel;
a cover bottom mounted under the main supporter;
a backlight unit mounted on an upper surface of the cover bottom; and
A top case mounted on the display panel and coupled to the main supporter and the display panel; includes,
The backlight unit
An LED package module having a substrate and a plurality of LED packages mounted on the substrate;
An optical member mounted on the LED package module;
A bottom surface disposed on the upper surface of the substrate, oblique surfaces each extending in an oblique shape from four sides of the bottom surface and having a square frame structure, and a seat bent from the oblique surfaces and disposed parallel to the bottom surface. A reflector having a surface;
having reflective sheets attached to oblique surfaces of four corner portions of the reflective plate, respectively;
The reflective sheets are symmetrically attached to each other based on a boundary line where the oblique surfaces of the reflective plate meet,
Each reflective sheet
A first side disposed along the boundary of the reflector;
A second side arranged along the seating surface of the reflector;
Has a triangular shape having a third side connecting the first side and the second side,
The second side of the reflective sheet is spaced apart from the seating surface of the reflective plate,
The second side of the reflective sheet is disposed to have an inclination of 1 to 15° with respect to the seating surface of the reflective plate,
the reflective sheet
base material,
A silver reflective layer disposed on the base substrate;
A display device comprising beads distributed in or on the silver reflective layer.
According to claim 7,
The main supporter
a vertical portion supporting the display panel and a horizontal portion extending inwardly from the vertical portion to support the optical member;
The display device of claim 1 , wherein a seating surface of the reflector is disposed on a horizontal portion of the main supporter and is mounted below the optical member.

Images