Patent Description:
The present invention relates to a backlight unit and a display device using the same.

As the information-oriented society is advanced, a demand for the display device is increased in various ways. In line with this trend, various display devices, such as a liquid crystal display device (LCD), a plasma display panel (PDP), an electroluminescent display (ELD), and a vacuum fluorescent display (VFD) are recently researched and used.

In particular, the liquid crystal panel of an LCD includes a liquid crystal layer and a TFT substrate and a color filter substrate disposed to face each other with the liquid crystal layer interposed therebetween. The liquid crystal panel may display an image using light provided by a backlight unit.

<CIT> relates to a light-emitting device for use in a backlight unit capable of applying light with uniform brightness. The backlight unit comprises a plurality of light-emitting portions disposed on a printed circuit board and having a base support, an LED chip and a lens, and a reflective member disposed on a periphery of each light-emitting portion and having a first and second reflecting portion. <CIT> also relates to a backlight module with a reflective layer and a semitransparent surface recessed and tampered from a top of a protrusion at a centre of a lens of an LED. <CIT> and <CIT> are directed to further LED/lens arrangements for backlight units.

The object of the present invention is to provide a backlight unit achieving a uniform luminance. This object is solved by the present invention as defined in independent claims <NUM> and <NUM>.

In an exemplary aspect to better understand the present invention, there is provided a backlight unit, including a substrate, at least one light source on the substrate, a lenses placed over the light source, a reflection sheet in which at least one through hole corresponding to the lens is formed, and a reflection ring comprising an opening portion corresponding to the at least one light source, and placed between the lens and the substrate.

The reflection ring may be configured to further include a sidewall disposed to face the light source in the opening portion.

Reflectance of the top surface may be greater than reflectance of the substrate.

The thickness of the reflection ring may be different from the thickness of the reflection sheet.

The diameter of the reflection ring may be smaller than the diameter of the lens included in the light assembly.

The opening portion may have any one of a circle, a triangle, and a pentagon.

The backlight unit may further include at least one pattern formed in at least one some region of the top surface.

The backlight unit may further include at least one pattern formed in at least one some region of the at least one sidewall of the reflection ring.

The at least one pattern may include a plurality of regions having different locations, shapes, and colors. The plurality of regions may include a first region and a second region which are repeatedly formed.

The sidewall may include at least one of a first sidewall on the opening portion side in which the light source is placed and a second sidewall outside the reflection ring.

The sidewall may include an inclined plane tilted with respect to the light source.

The sidewall may include an inclined plane of at least one some region and a vertical plane of at least the other region.

The inclined plane may be formed at a tilt angle of <NUM> degrees or more <NUM> degrees or less.

The reflection ring may come in contact with the reflection sheet or at least part of the reflection ring may be disposed to overlap with at least part of the reflection sheet.

The distance between the light source and the opening portion may be <NUM> micrometers or more to <NUM> millimeter or less.

A ratio of the height of the sidewall to the height of the light source may be <NUM> or higher to <NUM> or less.

In another exemplary aspect to better understand the present invention, there is provided a display device, including a backlight unit configured to comprise at least one light source, a display panel placed in the front side of the backlight unit, and a back cover placed in the back side of the backlight unit. The backlight unit comprises a substrate, at least one light source on the substrate, a lens placed over the light source, a reflection sheet in which at least one through hole corresponding to the lens is formed, and a reflection ring comprising an opening portion corresponding to the at least one light source, and placed between the lens and the substrate.

The reflection ring may further include a sidewall disposed to face the light source in the opening portion.

The display device may further include at least one pattern formed in at least one some region of the top surface.

The display device may further include at least one pattern formed in at least one some region of the at least one sidewall of the reflection ring.

The accompanying drawings, which are included to provide a further understanding of the invention, illustrate examples and embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings:.

Reference will now be made in detail to examples illustrated in the accompanying drawings. Since the present invention may be modified in various ways and may have various forms, specific embodiments are illustrated in the drawings and are described in detail in the present specification. However, it should be understood that the present invention is not limited to the specific disclosed embodiments.

The terms 'first', 'second', etc. may be used to describe various components, but the components are not limited by such terms. The terms are used only for the purpose of distinguishing one component from other components. For example, a first component may be designated as a second component without departing from the scope of the present invention. In the same manner, the second component may be designated as the first component.

The term "and/or" encompasses both combinations of the plurality of related items disclosed and any item from among the plurality of related items disclosed.

When an arbitrary component is described as "being connected to" or "being linked to" another component, this should be understood to mean that still another component (s) may exist between them, although the arbitrary component may be directly connected to, or linked to, the second component. In contrast, when an arbitrary component is described as "being directly connected to" or "being directly linked to" another component, this should be understood to mean that no component exists between them.

The terms used in the present application are used to describe only specific embodiments or examples, and are not intended to limit the present invention. A singular expression can include a plural expression as long as it does not have an apparently different meaning in context.

In the present application, the terms "include" and "have" should be understood to be intended to designate that illustrated features, numbers, steps, operations, components, parts or combinations thereof exist and not to preclude the existence of one or more different features, numbers, steps, operations, components, parts or combinations thereof, or the possibility of the addition thereof.

Unless otherwise specified, all of the terms which are used herein, including the technical or scientific terms, have the same meanings as those that are generally understood by a person having ordinary knowledge in the art to which the present invention pertains. The terms defined in a generally used dictionary must be understood to have meanings identical to those used in the context of a related art, and are not to be construed to have ideal or excessively formal meanings unless they are obviously specified in the present application.

The following exemplary embodiments of the present invention are provided to those skilled in the art in order to describe the present invention more completely. Accordingly, shapes and sizes of elements shown in the drawings may be exaggerated for clarity.

<FIG> are diagrams showing a configuration of a display device related to an example to better understand the present invention.

Referring to <FIG>, the display device <NUM> may include a front cover <NUM>, a display panel <NUM>, a backlight unit <NUM>, and a back cover <NUM>.

The front cover <NUM> may cover the top and sides of the display panel <NUM>. The front cover <NUM> may be a rectangular frame shape having an empty center. An image of the display panel <NUM> may be displayed to the outside because the center of the front cover <NUM> is empty.

The display panel <NUM> is provided at the front side of the display device <NUM> and may display an image. The display panel <NUM> may divide an image into a plurality of pixels, may control the image so that each of the plurality of pixels emits light according to its color, brightness, and chroma, and may output the image. The display panel <NUM> may be divided into an active region in which an image is displayed and an inactive region in which an image is not displayed. The display panel <NUM> may include a front substrate and a rear substrate which face each other with a liquid crystal layer interposed therebetween.

The front substrate may include a plurality of pixels formed of red (R), green (G) and blue (B) sub-pixels. When light is applied, the front substrate may generate an image corresponding to red, green, or blue.

The rear substrate may include switching elements. The rear substrate may switch a pixel electrode. For example, the pixel electrode may change the arrangement of the molecules of the liquid crystal layer in response to an external voltage.

The liquid crystal layer may include a plurality of liquid crystal molecules. The liquid crystal molecules may change their arrangement in response to a voltage difference between the pixel electrode and a common electrode. The liquid crystal layer may transfer light provided by the backlight unit <NUM> to the front substrate.

The backlight unit <NUM> may be placed at the back side of the display panel <NUM>. The backlight unit <NUM> may provide light from the back side of the display panel <NUM> to the display panel <NUM>. A detailed structure of the backlight unit <NUM> is described later.

The backlight unit <NUM> may be closely attached to the back side of the display panel <NUM>. For example, the backlight unit <NUM> may be attached and fixed to the back side of the display panel <NUM>. In order to attach the backlight unit <NUM> to the display panel <NUM>, an adhesive layer may be formed between the backlight unit <NUM> and the display panel <NUM>.

The thickness of the display device <NUM> can be reduced because the display panel <NUM> and the backlight unit <NUM> are closely attached together. Furthermore, a fabrication process can be simplified because a structure for fixing the backlight unit <NUM> is not necessary. Furthermore, a malfunction of the display device attributable to the insertion of an alien substance into the space between the backlight unit <NUM> and the display panel <NUM> can be prevented because the space is reduced.

The back cover <NUM> may be placed at the back side of the backlight unit <NUM>. The back cover <NUM> may protect the backlight unit <NUM> against the outside.

The back cover <NUM> may be combined with the front cover <NUM>. The display panel <NUM> and the backlight unit <NUM> may be modulated by the back cover <NUM> and the front cover <NUM>.

Referring to <FIG>, an optical sheet <NUM> may be placed over the back cover <NUM>. The optical sheet <NUM> may be combined with the back cover <NUM> at the edge of the back cover <NUM>. The optical sheet <NUM> may be directly seated in the edge of the back cover <NUM>. That is, the optical sheet <NUM> may be supported by the back cover <NUM>. The top surface of the edge of the reflection sheet <NUM> may be surrounded by an upper guide panel <NUM>. Specifically, the optical sheet <NUM> may be placed between the edge of the back cover <NUM> and the upper guide panel <NUM>.

The display panel <NUM> may be placed over the optical sheet <NUM>. The display panel <NUM> may be combined with the upper guide panel <NUM> at edges of the display device <NUM>. The display panel <NUM> may be directly seated in the upper guide panel <NUM>. That is, the display panel <NUM> may be supported by the upper guide panel <NUM>. The sides of the display panel <NUM> may be guided by the upper guide panel <NUM>. The top surface of the edge of the display panel <NUM> may be surrounded by the front cover <NUM>. Specifically, the display panel <NUM> may be placed between the upper guide panel <NUM> and the front cover <NUM>.

The display device in accordance with an embodiment of the present invention may further include a lower guide panel <NUM> between the back cover <NUM> and the optical sheet <NUM>. In this case, the optical sheet <NUM> may be directly seated in the lower guide panel <NUM>. That is, the optical sheet <NUM> may be supported by the lower guide panel <NUM>.

Referring to <FIG> and <FIG>, the backlight unit <NUM> may include a substrate <NUM>, at least one light assembly <NUM>, a reflection sheet <NUM>, a diffusion plate <NUM>, and the optical sheet <NUM>.

The substrate <NUM> may include a plurality of bands configured to extend in a first direction and spaced apart from each other at a specific interval in a second direction orthogonal to the first direction. The substrate <NUM> may be a substrate on which the at least one light assembly <NUM> is mounted. An electrode pattern for connecting an adaptor and the light assembly <NUM> may be formed in the substrate <NUM>. For example, a carbon nanotube electrode pattern for connecting the light assembly <NUM> and the adaptor may be formed in the substrate <NUM>.

The substrate <NUM> may be made of polyethyleneterephthalate (PET), glass, polycarbonate (PC), or silicon. The substrate <NUM> may be a printed circuit board (PCB) substrate on which the at least one light assembly <NUM> is mounted.

The light assembly <NUM> having a specific interval in the first direction may be mounted on the substrate <NUM>. The diameter of the light assembly <NUM> may be greater than the width of the substrate <NUM> in the second direction. The light assembly <NUM> may be any one of a light-emitting diode (LED) chip and an LED package including at least one LED chip.

The light assembly <NUM> may be a colored LED configured to emit at least one of colors, such as red, blue, and green, or may be formed of a white LED. The colored LED may include at least one of a red LED, a blue LED, and a green LED.

The reflection sheet <NUM> may be placed on the substrate <NUM>. The reflection sheet <NUM> may be placed in a region other than a region in which the light assembly <NUM> of the substrate <NUM> has been formed. That is, the reflection sheet <NUM> may have a through hole in the region in which the light assembly <NUM> has been formed.

The reflection sheet <NUM> may reflect light emitted by the light assembly <NUM>. Furthermore, the reflection sheet <NUM> may reflect light totally reflected by the diffusion plate <NUM>. Accordingly, the reflection sheet <NUM> may diffuse light emitted by the light assembly <NUM>.

The reflection sheet <NUM> may include at least one of reflection substances, such as metal and metal oxides. For example, the reflection sheet <NUM> may include metal or metal oxides having a high reflectance, such as one of aluminum (Al), silver (Ag), gold (Au), and titanium dioxide (TiO2).

The reflection sheet <NUM> may be formed by depositing or coating metal or metal oxides on the substrate <NUM>. The reflection sheet <NUM> may be formed by printing metal ink. The reflection sheet <NUM> may be deposited using a vacuum deposition method, such as a thermal deposition method, an evaporation method, or a sputtering method. The reflection sheet <NUM> may be coated or printed using a printing method, a gravure coating method, or a silk screen method.

Air gaps may be placed on the light assembly <NUM> and the reflection sheet <NUM>. The air gap may function as a buffer for widely spreading light emitted by the light assembly <NUM>. Resin may be deposited on the light assembly <NUM> and the reflection sheet <NUM>. In this case, the resin may function to diffuse light emitted by the light assembly <NUM>.

The diffusion plate <NUM> may be placed on the air gaps. The diffusion plate <NUM> may upward diffuse light emitted by the light assembly <NUM>.

The optical sheet <NUM> may be placed on the diffusion plate <NUM>. The optical sheet <NUM> may include at least one sheet. Specifically, the optical sheet <NUM> may include one or more prism sheets and/or one or more diffusion sheets.

The plurality of sheets included in the optical sheet <NUM> are not spaced apart from each other and are provided in the adhesion or closed state, thereby being capable of reducing the thickness of the optical sheet <NUM> or the backlight unit <NUM>.

The lower side of the optical sheet <NUM> may be closely attached to the diffusion plate <NUM>, and the upper side of the optical sheet <NUM> may be closely attached to the lower side of the display panel.

The diffusion sheet of the optical sheet <NUM> may make luminance of light more uniform by preventing light from the diffusion plate from being partially crowded. Furthermore, the prism sheet of the optical sheet <NUM> may focus light from the diffusion sheet so that the light is vertically incident on the display panel.

The optical sheet <NUM> may include a plurality of sheets having different functions. For example, the optical sheet <NUM> may include first to third optical sheets 125a to 125c. The first optical sheet 125a may have the function of the diffusion sheet, and the second and the third optical sheets 125b and 125c may have the function of the prism sheet.

In some embodiments, the optical sheet <NUM> may include the first and the second optical sheets 125a and 125b. The first optical sheet 125a may have the function of the diffusion sheet, and the second optical sheet 125b may have the function of the prism sheet.

The backlight unit <NUM> may be driven using a total driving method or a partial driving method, such as a local dimming or impulsive method, but is not limited thereto. A method of driving the backlight unit <NUM> may be changed in various ways depending on the circuit design. Accordingly, the display device can sharply represent a dark portion and a bright portion in a screen, thereby being capable of improving picture quality.

Referring to <FIG>, the substrate <NUM> including a plurality of bands configured to extend in the first direction and spaced apart from each other at a specific interval in the second direction orthogonal to the first direction may be provided on the back cover. The ends of a plurality of the substrates <NUM> on one side thereof may be connected to a wiring electrode <NUM>.

The wiring electrode <NUM> may extend in the second direction. The wiring electrode <NUM> may be connected to the end of the first layer <NUM> on one side thereof at a specific interval in the second direction. The wiring electrode <NUM> may electrically connect the substrate <NUM> and the adaptor.

The light assembly <NUM> may be mounted on the substrate <NUM> at a specific interval in the first direction. The diameter of the light assembly <NUM> may be greater than the width of the substrate <NUM> in the second direction. Accordingly, the outside region of the light assembly <NUM> may infringe a region in which the substrate <NUM> is not provided.

<FIG>, <FIG>, <FIG> and <FIG> are detailed diagrams for illustrating the display device in accordance with examples to better understand the present invention and details of a backlight unit in accordance with embodiments of the present invention.

Referring to <FIG>, a light source package <NUM> may be placed on the substrate <NUM>. The light source package <NUM> may be placed at the center of the light assembly <NUM>, but is not limited thereto. In some embodiments, the light source package <NUM> may be placed in a portion other than the center of the light assembly <NUM>.

The light source package <NUM> may include a light source <NUM>, a lead frame <NUM>, a package body <NUM>, and reflection plates <NUM>.

The package body <NUM> may be placed on the substrate <NUM>. The lead frame <NUM> may surround the package body <NUM>. The lead frame <NUM> may connect the light source <NUM> and the substrate <NUM> through a wire. Accordingly, a specific voltage from the substrate <NUM> may be transferred to the light source <NUM> through the wire.

The light source <NUM> may be placed on the lead frame <NUM>. Specifically, the light source <NUM> may be mounted on the lead frame <NUM>.

The reflection plates <NUM> may be placed on the lead frame <NUM>. The reflection plates <NUM> may surround the sides of the light source <NUM>. The reflection plates <NUM> may reflect light emitted from the sides of the light source <NUM>, thereby being capable of improving light-emitting efficiency of the light source <NUM>. The reflection plates <NUM> may control a tilt angle by taking into consideration the characteristic of light from the light source <NUM>.

The light assembly <NUM> may be a package on board (POB) type light assembly <NUM>. Specifically, the light assembly <NUM> may be the light assembly <NUM> in which a package on which a chip has been mounted is mounted on a substrate.

Referring to <FIG>, the POB type light assembly <NUM> may include one or more wires <NUM> on both sides of the light source <NUM> on the light source <NUM>. The at least one wire <NUM> may electrically connect the light source <NUM> and the lead frame <NUM>.

The light source <NUM> may be formed of a combination of a P type semiconductor that provides holes to the light source for substantially generating light and an N type semiconductor that provides electrons to the light source.

A fluorescent layer <NUM> may be placed on the light source <NUM> between the reflection plates <NUM>. The fluorescent layer <NUM> may cover the light source. Furthermore, the fluorescent layer <NUM> may be surrounded by the reflection plates <NUM>. The fluorescent layer <NUM> may include a fluorescent substance for converting light of a spectrum, generated by the light source <NUM>, into white light. The fluorescent layer <NUM> may have the same thickness on the light source <NUM>. Furthermore, the fluorescent layer <NUM> may have the same height as the top of the reflection plates <NUM>. The fluorescent layer <NUM> may have a refractive index of <NUM> to <NUM>.

The light assembly <NUM> can improve reliability of a process. Accordingly, when the light assembly <NUM> is fabricated, additional investment may not be required. In this case, high-current driving may not be easy because a heat-dissipation characteristic is limited.

Referring to <FIG>, the light assembly <NUM> may include the light source <NUM>, a lens <NUM>, and a reflection ring <NUM>.

The light source <NUM> may be placed on the substrate <NUM>. The light source <NUM> may be placed in the central part of the light assembly <NUM>, but is not limited thereto. For instance, the light source <NUM> may be placed in a portion other than the central part of the light assembly <NUM>.

The light source <NUM> may emit light in response to an electrical signal. For example, the light source <NUM> may emit light in a third direction in response to an electrical signal, but is not limited thereto. In some embodiments, the light source <NUM> may emit light in a direction, tilted at a specific angle from the third direction, in response to an electrical signal.

The lens <NUM> may be placed over the light source <NUM>. The lens <NUM> may have a larger diameter than the light source <NUM>. In other words, the lens <NUM> may be configured to surround the light source <NUM>. The lens <NUM> may change the direction in which light emitted by the light source <NUM> travels and send the light to the display panel. A detailed structure of the lens <NUM> is described later.

The upper part of the lens <NUM> may include a protrusion <NUM> having an outside part protruded. In other words, the diameter of the upper part of the lens <NUM> may be greater than that of the lower part of the lens <NUM>.

The lens <NUM> may be surrounded by the reflection sheet <NUM>. The diameter of a region in which the reflection sheet <NUM> is not provided may be greater than the diameter of the bottom of the lens <NUM> and may be smaller than the diameter of the top of the lens <NUM>. That is, the outside region of the top of the lens <NUM> may overlap with one end of the reflection sheet <NUM> in the first and the second directions.

The lens <NUM> may include a substance having a refractive index of <NUM> or more to <NUM> or less. For example, the lens <NUM> may include any one of polymethyl mata acrylate (PMMA), cylic olefin copolymer (COC), or a combination of them.

A top surface of the reflection sheet <NUM> may be higher than the bottom surface of the lens <NUM> and lower than the top surface of the lens <NUM>, but is not limited thereto. The top surface of the reflection sheet <NUM> may be lower than the bottom surface of the lens <NUM>.

The reflection ring <NUM> surrounding the light source <NUM> may be placed. The reflection ring <NUM> may not come in contact with the light source <NUM>. The reflection ring <NUM> may include a first plane configured to face the light source <NUM>, a second plane configured to face the reflection sheet <NUM>, and a third plane configured to face the lens <NUM>.

The reflection ring <NUM> may include the same substance as the reflection sheet <NUM> or may include a substance similar to the substance of the reflection sheet <NUM>. For example, the reflection ring <NUM> may include at least one of metal and metal oxides, that is, reflection substances. The reflection ring <NUM> may have reflectance higher than the substrate <NUM>.

The reflection ring <NUM> may have been separated from the reflection sheet <NUM> at a specific interval. The reflection ring <NUM> may reflect light incident on the inside of the diameter of the lens unlike in the reflection sheet <NUM>. A detailed function and structure of the reflection ring <NUM> are described later.

The light assembly <NUM> may be a chip on board (COB) type light assembly <NUM>. Specifically, the light assembly <NUM> may be the light assembly <NUM> in which a chip is mounted right on a substrate.

In the light assembly <NUM> according to the present embodiment, the light source <NUM> may be placed on the substrate <NUM>. Accordingly, the size and weight of the light assembly <NUM> can be reduced.

Referring to <FIG>, the light source <NUM> of the light assembly <NUM> may have a COB type. The COB type light source <NUM> of the light assembly <NUM> may include at least one of a light-emitting layer <NUM>, first and second electrodes <NUM> and <NUM>, and a fluorescent layer <NUM>.

The light-emitting layer <NUM> may be placed on the substrate <NUM>. The light-emitting layer <NUM> may emit any one color of blue, red, and green. The light-emitting layer <NUM> may include Firpic, (CF3ppy)2Ir (pic), <NUM>, <NUM>-di (<NUM>-naphthyl)anthracene (AND), perylene, distyrybiphenyl, PVK, OXD-<NUM>, UGH-<NUM> (blue), and a combination of them.

The first and the second electrodes <NUM> and <NUM> may be placed on both sides of the bottom surface of the light-emitting layer <NUM>. The first and the second electrodes <NUM> and <NUM> may transfer an external driving signal to the light-emitting layer <NUM>.

The fluorescent layer <NUM> may cover the light-emitting layer <NUM> and the first and the second electrodes <NUM> and <NUM>. The fluorescent layer <NUM> may include a fluorescent substance for converting light of a spectrum, generated by the light-emitting layer <NUM>, into white light. The fluorescent layer <NUM> may have the same thickness on the light-emitting layer <NUM>. The fluorescent layer <NUM> may have a refractive index of <NUM> to <NUM>.

The light assembly <NUM> in accordance with an embodiment of the present invention may have light-emitting efficiency because the light source <NUM> is placed right on the substrate <NUM>. Accordingly, the size of the light assembly <NUM> can be reduced.

Furthermore, the light assembly <NUM> may be driven by a high current because the light source <NUM> is placed right on the substrate <NUM> and heat dissipation is excellent. Accordingly, the number of light assemblies <NUM> for the backlight unit <NUM> can be reduced.

Furthermore, the light assembly <NUM> may not require a wire bonding process because the light source <NUM> is placed right on the substrate <NUM>. Accordingly, a cost can be reduced because the process is simplified.

In such a COB type light assembly <NUM>, light may laterally leak because a reflection plate is not present and the light does not pass through the lens <NUM> unlike in an existing POB type light assembly. The reflection ring <NUM> can prevent light from laterally leaking.

Hereinafter, a construction in which the light source package <NUM> is placed on the substrate <NUM> is omitted, and only a construction in which the light source <NUM> is placed on the substrate <NUM> is illustrated, for convenience of description.

Referring to <FIG>, the lens <NUM> may include the bottom surface <NUM>, a conical groove <NUM>, support parts <NUM>, a conical side part <NUM>, an inverse-conical groove <NUM>, an inverse-conical side part <NUM>, and the top surface <NUM>.

The conical groove <NUM> may be placed in the central part of the bottom surface <NUM>. Specifically, the conical groove <NUM> may be configured to be burrowed from the central part of the bottom surface <NUM> to the upper side of the lens <NUM>. The conical groove <NUM> may have a conical shape in which a vertex surrounding the light source has been cut. The conical groove <NUM> may transfer light, emitted by the light source, to the side or top surface of the lens <NUM>.

The support parts <NUM> may be placed in a region which surrounds the outside in which the conical groove <NUM> is connected to the bottom surface <NUM>. The support parts <NUM> may be placed in the places where the conical groove <NUM> divides the outside connected to the bottom surface <NUM> into three, but is not limited thereto. The support parts <NUM> may be placed in the places where the conical groove <NUM> divides the outside connected to the bottom surface <NUM> into three or more. The support parts <NUM> may have been protruded from the bottom surface <NUM> to the outside of the lens <NUM>. The support parts <NUM> may have a cylinder, a trigonal prism, or a rectangular parallelepiped.

The support parts <NUM> may couple the lens <NUM> and the substrate. The lens <NUM> may have been spaced apart from the substrate at a specific interval by the support parts <NUM>. Accordingly, the light source and the reflection ring may be placed between the lens <NUM> and the substrate.

The conical side part <NUM> may extend from the bottom surface <NUM> to the
<NUM>. The length of the conical side part <NUM> in the third direction may be the same as that of the conical groove <NUM> in the third direction, but is not limited thereto. The length of the conical side part <NUM> in the third direction may be longer than that of the conical groove <NUM> in the third direction. The conical side part <NUM> may refract light which is reflected by the inverse-conical groove <NUM> or is directly incident from the conical groove <NUM>.

The inverse-conical groove <NUM> may be placed in the central part of the top surface <NUM>. Specifically, the inverse-conical groove <NUM> may be configured to be burrowed from the central part of the top surface <NUM> to the bottom surface <NUM>. The inverse-conical groove <NUM> may have a shape opposite a shape in which a vertex has been cut. The center of the inverse-conical groove <NUM> may be matched up with the center of the conical groove <NUM>. The inverse conical groove <NUM> may induce total reflection of incident light and transfer the light to the side or the bottom surface <NUM>.

The inverse-conical side part <NUM> may extend from the top surface <NUM> to the bottom surface <NUM>. The inverse-conical side part <NUM> may have been extended from the conical side part <NUM>. The length of the inverse-conical side part <NUM> in the third direction may be the same as that of the conical groove <NUM> in the third direction, but is not limited thereto. The length of the inverse-conical side part <NUM> in the third direction may be longer than that of the inverse-conical groove <NUM> in the third direction. The inverse-conical side part <NUM> may refract light which is totally reflected by the inverse-conical groove <NUM>.

Referring to <FIG>, when the reflection ring <NUM> is not present, light emitted from the light source <NUM> to the upper side may be totally reflected by the inverse-conical groove (<NUM> of <FIG>). The light totally reflected by the inverse-conical groove (<NUM> of <FIG>) may be totally reflected from the inverse-conical side part (<NUM> of <FIG>) to the bottom surface (<NUM> of <FIG>). The light totally reflected by the bottom surface (<NUM> of <FIG>) may be refracted and directed toward the substrate <NUM>.

At least part of the light refracted by the substrate <NUM> may be absorbed by the substrate <NUM>. Accordingly, the amount of light transferred to the upper side of the lens <NUM> may be small. As a result, luminance uniformity of the backlight unit may be reduced.

In contrast, when the reflection ring <NUM> is present, light refracted toward the substrate <NUM> may be reflected toward the reflection ring <NUM> and refracted by the bottom surface (<NUM> of <FIG>). The light refracted by the bottom surface (<NUM> of <FIG>) may be refracted by the inverse-conical groove (<NUM> of <FIG>) again and directed toward the top surface (<NUM> of <FIG>) of the lens. Accordingly, the amount of light transferred to the upper side of the lens <NUM> may be much. As a result, luminance uniformity of the backlight unit may be increased.

Referring to <FIG>, the diameter LD of the lens <NUM> may be greater than the diameter RD of the reflection ring <NUM>. For example, if the diameter LD of the lens may be <NUM> or more to <NUM> or less, the diameter RD of the reflection ring <NUM> may be <NUM>.

The thickness of the reflection ring <NUM> may be different from the height of the reflection sheet <NUM>. Specifically, the thickness of the reflection ring <NUM> may be smaller than that of the reflection sheet <NUM> because the reflection sheet <NUM> reflects light incident from the lens <NUM> and the reflection ring <NUM> reflects light incident from the light source <NUM> lower than the lens <NUM>.

The diameter RD of the reflection ring <NUM> may not be greater than the diameter LD of the lens <NUM> because the reflection ring <NUM> functions to reflect light incident on the power side of the lens <NUM>.

The reflection sheet <NUM> may be configured to surround the lens <NUM>. Accordingly the reflection sheet <NUM> may be placed outside the lens <NUM>. Since the reflection sheet <NUM> needs to surround the lens <NUM>, the height of the top surface of the reflection sheet <NUM> may be higher than that of the bottom surface <NUM> of the lens <NUM>.

Referring to <FIG>, one or more holes <NUM> may be formed in the reflection ring <NUM> so that the support parts <NUM> of the lens <NUM> are coupled to the substrate <NUM>. If a hole is not formed in the reflection ring <NUM>, the lens <NUM> may not be fixed to the substrate <NUM>. Accordingly, the lens <NUM> may be easily separated from the reflection ring <NUM> or may be easily damaged. Furthermore, light emitted by the light source <NUM> may not be uniform.

The one or more holes <NUM> may be placed in portions corresponding to the support parts <NUM> of the lens <NUM>. Accordingly, the support parts <NUM> of the lens <NUM> may be inserted into the one or more holes <NUM> and coupled to the substrate <NUM>. The diameter of the hole <NUM> may be equal to or greater than the diameter of the support part <NUM> so that the support part <NUM> is inserted into the hole <NUM>. In embodiments to be described later, the one or more holes <NUM> and the support parts <NUM> are not illustrated for convenience of description. However, this can be applied to other embodiments.

Referring to <FIG>, the reflection ring <NUM> may have a circle, a triangle, or a pentagon which surrounds the light source <NUM>. Both the outside 207b and inside 207a of the reflection ring <NUM> may have a circle, a triangle, or a pentagon. If the reflection ring <NUM> has a circle, a triangle, or a pentagon which surrounds the light source <NUM>, the peripheral part of the lens may be brighter than the central part of the lens in the backlight unit.

The reflection ring <NUM> may include an opening portion <NUM>. The opening portion <NUM> may be spaced apart from the light source at a specific interval.

The width L1 of the reflection ring <NUM> in the second direction may be greater than the width L2 of the substrate <NUM> in the second direction. The diameter of the lens may be greater than the width of the substrate <NUM> in the second direction. The width L1 of the reflection ring <NUM> in the second direction may be almost similar to the diameter of the lens because a portion on which light is incident needs to be placed under the lens. Accordingly, the width L1 of the reflection ring <NUM> in the second direction may be greater than the width L2 of the substrate <NUM> in the second direction.

In the backlight unit in accordance with an embodiment of the present invention, at least some of light in all the directions which is incident on the lower side of the lens <NUM> can be reflect toward the upper side of the lens <NUM> because the reflection ring <NUM> is configured to surround the light source <NUM>. Accordingly, luminance uniformity of the backlight unit can be improved.

Referring to <FIG>, the reflection ring <NUM> may be configured to surround the light source <NUM>. Specifically, the inside 207a of the reflection ring <NUM> may have at least three protrusions. Accordingly, the distance between the inside 207a and outside 207b of the reflection ring <NUM> may be changed gradually alternately from a first distance OL1 to a second distance OL2. If the reflection ring <NUM> is configured to surround the light source <NUM> and the distance between the inside 207a and the outside 207b is changed gradually alternately, the central part of the lens may be brighter than the peripheral part of the lens in the backlight unit.

Referring to <FIG>, at least one groove <NUM> may be placed in the inside 207a of the reflection ring <NUM>. The at least one groove <NUM> may be protruded from the direction of the inside 207a to the direction of the outside 207b. The at least one groove <NUM> may have a hemispherical shape, but is not limited thereto. The at least one groove <NUM> may have a triangle, a circle, or a rectangular shape.

The at least one groove <NUM> may be matched up with at least one protrusion placed in the substrate <NUM>. Accordingly, when the reflection ring <NUM> is mounted on the substrate <NUM>, it can be mounted on the substrate <NUM> more easily.

The backlight unit in accordance with an embodiment of the present invention may include the at least one groove <NUM> in the inside 207a of the reflection ring <NUM>. Accordingly, when the reflection ring <NUM> is mounted on the substrate <NUM>, the location in which the reflection ring <NUM> is mounted can be matched up by the at least one groove <NUM>.

Referring to <FIG>, at least one pattern <NUM> may be provided on the top surface of the reflection ring <NUM>. The at least one pattern <NUM> may have a circle, but is not limited thereto. The at least one pattern <NUM> may have a triangle, a rectangular shape, or a star shape.

The at least one pattern <NUM> may include a plurality of regions whose at least one of the location, shape, and color is different. One region and the other region may be repeatedly formed in the plurality of regions.

The at least one pattern <NUM> may be placed in the position spaced apart from the inside 207a of the reflection ring <NUM> at a third distance F1. Furthermore, the at least one pattern <NUM> may be placed in the position spaced apart from the inside 207a of the reflection ring <NUM> at a fourth distance F2.

Only one pattern <NUM> may be placed in a line which connects the inside 207a and outside 207b of the reflection ring <NUM>. In other words, the at least one pattern <NUM> may be placed on the reflection ring <NUM> in zigzags.

The at least one pattern <NUM> may have been engraved in the reflection ring <NUM> in zigzags. Accordingly, the backlight unit can maintain uniform luminance by controlling the amount of light reflected toward the upper side of the lens.

Referring to <FIG>, the at least one pattern <NUM> may be placed only in the position spaced apart from the inside 207a of the reflection ring <NUM> at a specific interval. The at least one pattern <NUM> may be placed in the middle between the inside 207a and outside 207b of the reflection ring <NUM>.

The reflection ring <NUM> can simplify the process and reduce a cost because the patterns are not placed in zigzags, but are placed in a single line.

Referring to <FIG>, the one or more patterns <NUM> placed in zigzags may be connected to one. The connected pattern <NUM> may surround the light source <NUM>. The connected pattern <NUM> may have a shape in which the protrusion is repeated.

In the reflection ring <NUM> of <FIG>, since the one or more patterns <NUM> are connected to one, the amount of light in the front direction can be controlled compared to the case where the one or more patterns <NUM> are separately placed. Accordingly, the backlight unit can maintain uniform luminance.

Referring to <FIG>, the at least one pattern <NUM> may be placed in the location spaced apart from the inside 207a of the reflection ring <NUM> at the third distance F1 and the fourth distance F2. In the reflection ring <NUM>, the number of patterns <NUM> placed in the fourth distance F2 may be greater than the number of patterns <NUM> placed in the third distance F1. For example, the number of patterns <NUM> spaced apart from the inside 207a at the third distance F1 may be twice or more than the number of patterns <NUM> spaced apart from the inside 207a at the fourth distance F2.

In the reflection ring <NUM> of <FIG>, since the number of patterns <NUM> placed in the fourth distance F2 is greater than the number of patterns <NUM> placed in the third distance F1, less light can be reflected toward the outskirt part of the reflection ring <NUM> to which more light is directed. Accordingly, the backlight unit can maintain uniform luminance.

Referring to <FIG>, the inside 207a of the reflection ring <NUM> may have at least three protrusion. The distance between the inside 207a and outside 207b of the reflection ring <NUM> may be changed gradually alternately from a first distance OL1 to a second distance OL2.

The at least one pattern <NUM> may be placed in the location space apart from a portion in which the inside 207a of the reflection ring <NUM> has been depressed at the third distance F1 and the fourth distance F2. The at least one pattern <NUM> may be placed on the reflection ring <NUM> in zigzags.

If the reflection ring <NUM> is configured to surround the light source <NUM> and the distance between the inside 207a and the outside 207b is configured to change gradually alternately, the central part of the lens may be brighter than the peripheral part of the lens in the backlight unit.

Furthermore, in the reflection ring <NUM> of <FIG>, the at least one pattern <NUM> may have been engraved in the reflection ring <NUM> in zigzags. Accordingly, the backlight unit can maintain uniform luminance by controlling the amount of light reflected toward the upper side of the lens.

Referring to <FIG>, the inside 207a of the reflection ring <NUM> may have at least three protrusions, and the distance between the inside 207a and outside 207b of the reflection ring <NUM> may change gradually alternately from the first distance OL1 to the second distance OL2.

In the reflection ring <NUM> in accordance with an embodiment of the present invention, the one or more patterns <NUM> placed in zigzags may be connected to one. The connected pattern <NUM> may surround the light source <NUM>. The connected pattern <NUM> may have a shape in which the protrusion is repeated.

If the reflection ring <NUM> in accordance with an embodiment of the present invention is configured to surround the light source <NUM> and the distance between the inside 207a and the outside 207b is configured to change gradually alternately, the central part of the lens may be brighter than the peripheral part of the lens in the backlight unit.

Furthermore, in the reflection ring <NUM> in accordance with an embodiment of the present invention, the one or more patterns <NUM> are connected to one in the reflection ring <NUM>. Accordingly, the amount of light in the front direction can be controlled compared to the case where the one or more patterns <NUM> are separately placed. Accordingly, the backlight unit can maintain uniform luminance.

Referring to <FIG>, the at least one pattern <NUM> may be placed in a first plane <NUM> of the reflection ring <NUM>, which faces the light source <NUM>. The at least one pattern <NUM> may be placed on the first plane <NUM> in zigzags.

The first plane <NUM> of the reflection ring <NUM> may be tilted. If the first plane <NUM> of the reflection ring <NUM> is tilted, light efficiency can be improved because the amount of light incident on the side is increased compared to the case where the first plane <NUM> of the reflection ring <NUM> is vertical.

The at least one pattern <NUM> may be engraved in zigzags in the first plane <NUM> of the reflection ring <NUM>. Accordingly, the backlight unit can maintain uniform luminance by controlling the amount of light reflected toward the upper side of the lens.

Referring to <FIG>, the at least one pattern <NUM> may be placed on the first plane <NUM> of the reflection ring <NUM>. The at least one pattern <NUM> may be placed on the first plane <NUM> of the reflection ring <NUM> in zigzags.

The first plane <NUM> of the reflection ring <NUM> may be tilted. If the first plane <NUM> of the reflection ring <NUM> is tilted, light efficiency can be increased because the amount of light incident on the side is increased compared to the case where the first plane <NUM> of the reflection ring <NUM> is vertical.

As the first plane <NUM> of the reflection ring <NUM> becomes far from the ground, the number of patterns <NUM> may be increased. In other words, as the height of the first plane <NUM> of the reflection ring <NUM> is increased, the number of patterns <NUM> may be increased.

In the reflection ring <NUM> of <FIG>, light may be less reflected toward the top of the first plane <NUM> on which more light is incident because the number of patterns <NUM> is increased as the first plane <NUM> of the reflection ring <NUM> becomes far from the ground. Accordingly, the backlight unit can maintain uniform luminance.

Referring to <FIG>, when light is incident on two media having different refractive indices, the light may be refracted while passing through the boundary of the two media. A refractive index may be different depending on the wavelength of light. Accordingly, when light is refracted, it may be refracted at a different angle depending on each wavelength. For example, when light is incident from one medium to the other medium, an angle at which yellow light is refracted may be greater than an angle at which blue light is refracted.

In the case of a white LED, a difference between the wavelengths of yellow light and blue light is great. Accordingly, when light is incident on the lens, color may be separated into yellow and blue. If color is separated into yellow and blue, uniformity of color may be deteriorated. In other words, color coordinates may be low around a lens, and color coordinates may be high between lenses.

Referring to <FIG>, in the case of a common backlight unit, when light from the light source <NUM> is incident on the lens <NUM>, color may be separated into blue B and yellow Y due to a difference between refractive indices according to their wavelengths. Accordingly, light of yellow Y may be reflected toward the outside of the reflection ring <NUM> compared to light of blue B.

Light reflected by the reflection ring <NUM> may be refracted by the lens <NUM>, so blue B may more appear in the central part of the lens compared to yellow Y.

In the backlight unit in accordance with an embodiment of the present invention, the at least one pattern <NUM> of the reflection ring <NUM> may be yellow. Accordingly, when blue light is reflected in addition to reflected yellow light, light close to yellow may be reflected due to the at least one pattern <NUM>. Accordingly, a phenomenon in which the color of incident light is separated can be reduced.

Referring to <FIG>, only a pattern <NUM> at the location spaced apart from the inside 207a of the reflection ring <NUM> at the third distance F1 may include yellow. In other words, the pattern <NUM> at the location spaced apart from the inside 207a of the reflection ring <NUM> at the third distance F1 may include yellow, and the pattern <NUM> at the location spaced apart from the outside 207b at the fourth distance F2 may include black.

The black pattern <NUM> and the yellow pattern <NUM> may be placed in zigzags.

In the reflection ring <NUM> in accordance with an embodiment of the present invention, blue light incident on the inside may become close to yellow light because the pattern <NUM> at the location spaced apart from the inside 207a at the third distance F1 includes yellow. Accordingly, a phenomenon in which the color of incident light is separated can be reduced.

Furthermore, the backlight unit can have uniform luminance because the pattern <NUM> at the location spaced apart from the inside 207a at the fourth distance F2 reduces the amount of reflected light.

Referring to <FIG>, protrusions <NUM> may be placed at the third distance F1 and the fourth distance F2 from the inside 207a of the reflection ring <NUM>. Only a single protrusion <NUM> may be placed in a line which connects the inside 207a and outside 207b of the reflection ring <NUM>. In other words, at least one protrusion <NUM> may be placed on the reflection ring <NUM> in zigzags.

The reflection ring <NUM> in accordance with an embodiment of the present invention can make uniform luminance of the backlight unit by controlling an angle of light reflected toward the reflection ring <NUM> because the protrusions <NUM> are placed on the reflection ring <NUM> in zigzags.

<FIG> are diagrams showing another configuration of an exemplary display device.

Referring to <FIG>, a package on board type light assembly, such as that shown in <FIG>, may have less light that laterally leaks because the reflection plate (<NUM> of <FIG>) is placed.

In contrast, in a chip on board (COB) type light assembly, such as that shown in <FIG>, the reflection plate may not be placed. In this case, light may leak out to the side of the light source <NUM>. When light leaks out to the side of the light source <NUM>, a bright point defect may be generated over the lens <NUM>. Accordingly, there may be a problem in that picture quality over the lens <NUM> is not uniform or not smooth.

Light incident from the side of an existing light source <NUM> not including the reflection ring <NUM> may be refracted toward the bottom surface <NUM> of the lens <NUM>. The refracted light may be totally reflected by the inverse-conical side part <NUM> of the lens <NUM>. The totally reflected light may be refracted toward an inverse-conical groove <NUM> and incident on the top of the lens <NUM>.

The light incident from the side of the light source <NUM> may be directed toward the top of the lens <NUM>. Pieces of the light directed toward the top of the lens <NUM> may gather and form a bright point defect. Accordingly, the backlight unit may not maintain luminance uniformity.

In the backlight unit, the reflection ring <NUM> may be placed while surrounding the light source <NUM>. The reflection ring <NUM> may include the opening portion <NUM> spaced apart from the light source <NUM> at a specific interval and a sidewall <NUM> configured to reflect light emitted by the light source <NUM>. Light incident from the side of the light source <NUM> may be reflected toward the sidewall <NUM> of the reflection ring <NUM>. The reflected light may be refracted by the bottom surface <NUM> or conical groove <NUM> of the lens <NUM>. The refracted light may be refracted by the inverse-conical side part <NUM> or may be reflected toward the inverse-conical groove <NUM> and refracted by the inverse-conical side part <NUM>.

The light refracted by the inverse-conical side part <NUM> may be dispersed to several places unlike in the case where the reflection ring <NUM> is not present.

In the backlight unit, side light from the light source <NUM> may not be concentrated on one place, but may be dispersed in all directions by the reflection ring <NUM>. Accordingly, luminance uniformity of the backlight unit can be maintained.

Referring to <FIG>, the height H2 of the reflection ring <NUM> may be smaller than the height H1 of the light source <NUM>. The reflection ring <NUM> may function to block light which leaks from the side of the light source <NUM>. Furthermore, light incident on another part of the light source <NUM> other than the side of the light source <NUM> may be dispersed by the reflection of the inside of the lens <NUM>. Accordingly, the height H2 of the reflection ring <NUM> may be smaller than the height H1 of the light source <NUM> in order to prevent light which leaks from the side of the light source <NUM>.

The height H2 of the reflection ring <NUM> may be greater than <NUM>% of the height H1 of the light source <NUM>. The reflection ring <NUM> may function to prevent light which leaks from the side of the light source <NUM> and reflect the light. If the height H2 of the reflection ring <NUM> is smaller than <NUM>% of the height H1 of the light source <NUM>, the reflection ring <NUM> may not function to prevent light which leaks from the side of the light source <NUM>. Accordingly, the height H2 of the reflection ring <NUM> may be greater than <NUM>% of the height H1 of the light source <NUM>.

Referring to <FIG>, the outside 207b of the reflection ring <NUM> may have a circle. The shape of the inside 207a of the reflection ring <NUM> may be the same as or similar to that of the light source <NUM>. The shape of the inside 207a of the reflection ring <NUM> may be the same as or similar to that of the light source <NUM> in order to maintain a specific interval in the light source <NUM> and all the locations.

The inside 207a of the reflection ring <NUM> may be spaced apart from the light source <NUM> at a specific interval D1. For example, the inside 207a of the reflection ring <NUM> may be spaced apart from the light source <NUM> at an interval of <NUM> micrometers or more to <NUM> millimeter or less. If the distance between the inside 207a of the reflection ring <NUM> and the light source <NUM> is <NUM> micrometers or more to <NUM> millimeter or less, the reflection ring <NUM> may function to prevent light which leaks from the side of the light source <NUM>. If the distance between the inside 207a of the reflection ring <NUM> and the light source <NUM> is less than <NUM> micrometers, the reflection ability of the reflection ring <NUM> may be reduced. If the distance between the inside 207a of the reflection ring <NUM> and the light source <NUM> is more than <NUM> millimeters, the reflection ability of the reflection ring <NUM> is unable to prevent leaking light.

Referring to <FIG>, the reflection ring <NUM> and the reflection sheet <NUM> may come in contact with each other. One side of the reflection ring <NUM> may be protruded to the outside of the lens <NUM> because the reflection ring <NUM> needs to come in contact with the reflection sheet <NUM>.

In the reflection ring <NUM>, the space between the reflection ring <NUM> and the reflection sheet <NUM> can be removed because the reflection ring <NUM> and the reflection sheet <NUM> need to come in contact with each other. Accordingly, light can be prevented from being incident on the space between the reflection ring <NUM> and the reflection sheet <NUM> and from being absorbed by the substrate <NUM>. Accordingly, light efficiency of the backlight unit can be further improved.

Referring to <FIG>, the reflection ring <NUM> and the reflection sheet <NUM> may overlap with each other. One side of the reflection sheet <NUM> may be extended on top of the reflection ring <NUM>. Accordingly, one side of the reflection sheet <NUM> may burrow under the lens <NUM>. Since one side of the reflection sheet <NUM> is extended on top of the reflection ring <NUM>, height including the reflection ring <NUM> and the reflection sheet <NUM> may be higher than the height of the light source <NUM>.

In the reflection ring <NUM>, light may not leak between the reflection ring <NUM> and the reflection sheet <NUM> because the reflection ring <NUM> and the reflection sheet <NUM> overlap with each other. Accordingly, light efficiency can be improved because light absorbed by the substrate <NUM> is reduced.

Referring to <FIG> and <FIG>, the face <NUM> of the reflection sheet <NUM> which faces the light source <NUM> may be tilted. Specifically, the angle A1 of the face <NUM> of the reflection ring <NUM> which faces the light source <NUM> may be <NUM> degrees or more <NUM> degrees or less from the ground. If the angle A1 of the face <NUM> of the reflection ring <NUM> which faces the light source <NUM> is less than <NUM> degrees, light leaking from the side of the light source <NUM> may not be reflected toward the lens <NUM>, but may laterally leak.

The amount of light incident from the side of the light source <NUM> may be greater than the amount of light incident from the lower side of the light source <NUM> toward the top. Accordingly, if the first plane <NUM> of the reflection ring <NUM> is tilted as described above, light incident from the upper side of the light source <NUM> may be reflected toward the upper side of the first plane <NUM> of the reflection ring <NUM>. The reflected light may be totally reflected toward the inverse-conical groove <NUM> of the lens and then laterally dispersed.

Light incident from the lower side of the light source <NUM> may be reflected toward the lower side of the face <NUM> of the reflection sheet <NUM> which faces the light source <NUM>. The reflected light may be totally reflected toward the inverse-conical groove <NUM> of the lens and then laterally dispersed. Light incident from the lower side of the light source <NUM> can be dispersed to a closer portion compared to light incident from the upper side of the light source <NUM>.

In the reflection ring <NUM>, since the face <NUM> of the reflection ring <NUM> which faces the light source <NUM> is tilted, light which is incident on the upper side of the light source <NUM> and is great in the amount of light can be dispersed far away. Light which is incident from the lower side of the light source <NUM> and is small in the amount of light can be dispersed relatively closely.

Referring to <FIG>, the lower side of the first plane <NUM> of the reflection ring <NUM> may not be tilted, but only the upper side of the first plane <NUM> of the reflection ring <NUM> may be tilted. In other words, the first plane <NUM> of the reflection ring <NUM> may include an inclined plane of at least one some region and a vertical plane of at least the other region. The reflection ring <NUM> may have a trapezoid shape. The angle A2 of the upper side of the first plane <NUM> of the reflection ring <NUM> may be <NUM> degrees or more from the ground. If the angle A2 of the upper side of the first plane <NUM> of the reflection ring <NUM> is less than <NUM> degrees, light leaking from the side of the light source <NUM> may laterally leak without being reflected toward the lens <NUM>.

In the reflection ring <NUM>, the lower side of the first plane <NUM> of the reflection ring <NUM> may not be tilted, but only the upper side of the first plane <NUM> of the reflection ring <NUM> may be tilted. Accordingly, light incident from the upper side of the light source <NUM> can be dispersed far away, and light incident from the lower side of the light source <NUM> can be dispersed relatively closely.

Furthermore, since the lower side of the first plane <NUM> of the reflection ring <NUM> is not tilted, dispersion according to the amount of light can become more uniform compared to the case where the first plane <NUM> of the reflection ring <NUM> is fully tilted.

Referring to <FIG>, the first plane <NUM> of the reflection ring <NUM> may be convexly tilted. The angle of the first plane <NUM> of the reflection ring <NUM> may be <NUM> degrees or more <NUM> degrees or less from the ground in all the contact points. If the angle of the first plane <NUM> of the reflection ring <NUM> is less than <NUM> degrees, light leaking from the side of the light source <NUM> may laterally leak without being reflected toward the lens <NUM>.

In the reflection ring <NUM>, since the face <NUM> of the reflection ring <NUM> which faces the light source <NUM> is convexly tilted, light can be better dispersed compared to the case where the face <NUM> of the reflection ring <NUM> is tilted at a specific angle.

Referring to <FIG> and <FIG>, the second plane <NUM> of the reflection ring <NUM> which faces the reflection sheet <NUM> may be tilted. Specifically, the angle of the second plane <NUM> of the reflection ring <NUM> may be <NUM> degrees or more90 degrees or less from the ground. If the angle of the second plane <NUM> of the reflection ring <NUM> is less than <NUM> degrees, light reflected by the lens <NUM> may be absorbed by the substrate <NUM> without being reflected toward the reflection ring <NUM>.

Light incident on the top of the light source <NUM> may be curved in the conical groove <NUM>. The curved light may be totally reflected by the inverse-conical groove <NUM>. The light totally reflected by the inverse-conical groove <NUM> may be reflected by the inverse-conical side part <NUM>. At least some of the reflected light may be incident on the second plane <NUM> of the reflection ring <NUM>.

If the second plane <NUM> of the reflection ring <NUM> is not tilted, light incident on the second plane <NUM> of the reflection ring <NUM> may be absorbed by the substrate <NUM> without being reflected toward the lens <NUM>.

If the second plane <NUM> of the reflection ring <NUM> is tilted, light incident on the second plane <NUM> of the reflection ring <NUM> may be reflected toward the lens <NUM> and may travel toward the top of the lens <NUM>.

In the reflection ring <NUM>, the second plane <NUM> of the reflection ring <NUM> can reflect more light toward the lens <NUM> because the second plane <NUM> is tilted. Accordingly, light efficiency of the backlight unit can be improved.

Referring to <FIG>, the second plane <NUM> of the reflection ring <NUM> may be convexly tilted. The angle of the second plane <NUM> of the reflection ring <NUM> may be <NUM> degrees or more <NUM> degrees or less from the ground in all the contact points. If the angle of the second plane <NUM> of the reflection ring <NUM> is less than <NUM> degrees, light incident on the second plane <NUM> of the reflection ring <NUM> may be absorbed by the substrate <NUM> without being reflected toward the lens <NUM>.

In the reflection ring <NUM>, since the second plane <NUM> of the reflection ring <NUM> is convexly tilted, light can be better dispersed compared to the case where the second plane <NUM> of the reflection ring <NUM> is tilted at a specific angle.

Referring to <FIG>, the reflection ring <NUM> may include a plurality of protrusions in the first plane <NUM>. In other words, the first plane <NUM> of the reflection ring <NUM> may have at least one convex protrusion.

In the reflection ring <NUM>, since the first plane <NUM> of the reflection ring <NUM> includes at least one convex protrusion, light incident on the side of the light source <NUM> can be irregularly dispersed in various directions. Accordingly, the backlight unit can have uniform luminance.

Claim 1:
A backlight unit comprising:
a substrate (<NUM>);
a light source (<NUM>) mounted on the substrate (<NUM>);
a reflecting layer (<NUM>, <NUM>) on the substrate (<NUM>) around the light source (<NUM>);
a lens (<NUM>) disposed over the light source (<NUM>) and including a top surface and a bottom surface opposite to the top surface, and a side part (<NUM>) of the lens (<NUM>) connecting the top surface with the bottom surface; and characterized in that the backlight unit further comprises,
a plurality of elements <NUM>) forming a pattern on the reflecting layer (<NUM>, <NUM>) between the light source (<NUM>) and the side part (<NUM>) of the lens (<NUM>), wherein the plurality of elements (<NUM>) is configured to control an amount of light reflected toward an upper side of the lens,
wherein each of the plurality of elements (<NUM>) is shaped to be elongated and in zigzags and positioned such that ends of each element (<NUM>) are further away from the light source (<NUM>) than a portion of the element (<NUM>) between the terminating ends.